1-Minute Consult

Yes. The prevalence of sleep apnea is exceedingly high in patients with atrial fibrillation—50% to 80% compared with 30% to 60% in respective control groups.^1–3 Conversely, atrial fibrillation is more prevalent in those with sleep-disordered breathing than in those without (4.8% vs 0.9%).⁴

Sleep-disordered breathing comprises obstructive sleep apnea and central sleep apnea. Obstructive sleep apnea, characterized by repetitive upper-airway obstruction during sleep, is accompanied by intermittent hypoxia, rises in carbon dioxide, autonomic nervous system fluctuations, and intrathoracic pressure alterations.⁵ Central sleep apnea may be neurally mediated and, in the setting of cardiac disease, is characterized by alterations in chemosensitivity and chemoresponsiveness, leading to a state of high loop gain—ie, a hypersensitive ventilatory control system leading to ventilatory drive oscillations.⁶

Both obstructive and central sleep apnea have been associated with atrial fibrillation. Experimental data implicate obstructive sleep apnea as a trigger of atrial arrhythmogenesis,^7,8 and epidemiologic studies support an association between central sleep apnea, Cheyne-Stokes respiration, and incident atrial fibrillation.⁹

HOW SLEEP APNEA COULD LEAD TO ATRIAL FIBRILLATION

In experiments in animals, intermittent upper-airway obstruction led to forced inspiration, substantial negative intrathoracic pressure, subsequent left atrial distention, and increased susceptibility to atrial fibrillation.¹⁰ The autonomic nervous system may be a mediator of apnea-induced atrial fibrillation, as apnea-induced atrial fibrillation is suppressed with autonomic blockade.¹⁰

Emerging data also support the hypothesis that intermittent hypoxia⁷ and resolution of hypercapnia,⁸ as observed in obstructive sleep apnea, exert atrial electrophysiologic changes that increase vulnerability to atrial arrhythmogenesis.

In a case-crossover study,¹¹ the odds of paroxysmal atrial fibrillation occurring after a respiratory disturbance were 17.9 times higher than after normal breathing (95% confidence interval [CI] 2.2–144.2), though the absolute rate of overall arrhythmia events (including both atrial fibrillation and nonsustained ventricular tachycardia) associated with respiratory disturbances was low (1 excess arrhythmia event per 40,000 respiratory disturbances).

EFFECT OF SLEEP APNEA ON ATRIAL FIBRILLATION MANAGEMENT

Sleep apnea also seems to affect the efficacy of a rhythm-control strategy for atrial fibrillation. For example, patients with obstructive sleep apnea have a higher risk of recurrent atrial fibrillation after cardioversion (82% vs 42% in controls)¹² and up to a 25% greater risk of recurrence after catheter ablation compared with those without obstructive sleep apnea (risk ratio 1.25, 95% CI 1.08–1.45).¹³

Several observational studies showed a higher rate of atrial fibrillation after pulmonary vein isolation in obstructive sleep apnea patients who do not use continuous positive airway pressure (CPAP) than in those who do.^14–17 CPAP therapy appears to exert beneficial effects on cardiac structural remodeling;  cardiac magnetic resonance imaging shows that patients with sleep apnea who received less than 4 hours of CPAP per night had larger left atrial dimensions and increased left ventricular mass compared with those who received more than 4 hours of CPAP at night.¹⁷ However, a need remains for high-quality, large randomized controlled trials to eliminate potential unmeasured biases due to differences that may exist between CPAP users and non-users, such as general adherence to medical therapy and healthcare interventions.

An additional consideration is that the overall utility and value of obtaining a diagnosis of obstructive sleep apnea strictly as it pertains to atrial fibrillation management is affected by whether a rhythm- or rate-control strategy is pursued. In other words, if a patient is deemed to be in permanent atrial fibrillation and a rhythm-control strategy is therefore not pursued, the potential effect of untreated obstructive sleep apnea on atrial fibrillation recurrence could be less important. In this case, however, the other beneficial cardiovascular and systemic effects of diagnosing and treating underlying obstructive sleep apnea would remain.

Epidemiologic and clinic-based studies have supported an association between sleep apnea (mostly central, but also obstructive) and atrial fibrillation.^4,18

Community-based studies such as the Sleep Heart Health Study⁴ and the Outcomes of Sleep Disorders in Older Men Study (MrOS Sleep),¹⁸ involving thousands of participants, have found the strongest cross-sectional associations of both obstructive and central sleep apnea with nocturnal atrial fibrillation. The findings included a 2 to 5 times higher odds of nocturnal atrial fibrillation, particularly in those with a moderate to severe degree of sleep-disordered breathing—even after adjusting for confounding influences (eg, obesity) and self-reported cardiac disease such as heart failure.

In MrOS Sleep, in an older male cohort, both obstructive and central sleep apnea were associated with nocturnal atrial fibrillation, though central sleep apnea and Cheyne-Stokes respirations had a stronger magnitude of association.¹⁸

Further insights can be drawn specifically from patients with heart failure. Sin et al,¹⁹ in a 1999 study, found that in 450 patients with systolic heart failure (85% men), the prevalence of sleep-disordered breathing was 25% to 33% (depending on the apnea-hypopnea index cutoff used) for central sleep apnea, and similarly 27% to 38% for obstructive sleep apnea. The prevalence of atrial fibrillation in this group was 10% in women and 15% in men. Atrial fibrillation was reported as a significant risk factor for central sleep apnea, but not for obstructive sleep apnea (for which only male sex and increasing body mass index were significant risk factors). Directionality was not clearly reported in this retrospective study in terms of timing of sleep studies and other assessments: ie, the report did not clearly state which came first, the atrial fibrillation or the sleep apnea. Therefore, the possibility that central sleep apnea is a predictor of atrial fibrillation cannot be excluded.  

Yumino et al,²⁰ in a study published in 2009, evaluated 218 patients with heart failure (with a left ventricular ejection fraction of ≤ 45%) and reported a prevalence of moderate to severe sleep apnea of 21% for central sleep apnea and 26% for obstructive sleep apnea. In multivariate analysis, atrial fibrillation was independently associated with central sleep apnea but not obstructive sleep apnea.

In recent cohort studies, central sleep apnea was associated with 2 to 3 times higher odds of developing atrial fibrillation, while obstructive sleep apnea was not a predictor of incident atrial fibrillation.^9,21

Although most available studies associate sleep apnea with atrial fibrillation, findings of a case-control study²² did not support a difference in the prevalence of sleep apnea syndrome (defined as apnea index ≥ 5 and apnea-hypopnea index ≥ 15, and the presence of sleep symptoms) in patients with lone atrial fibrillation (no evident cardiovascular disease) compared with controls matched for age, sex, and cardiovascular morbidity.

But observational studies are limited by the potential for residual unmeasured confounding factors and lack of objective cardiac structural data, such as left ventricular ejection fraction and atrial enlargement. Moreover, there can be significant differences in sleep apnea definitions among studies, thus limiting the ability to reach a definitive conclusion about the relationship between sleep apnea and atrial fibrillation.

SCREENING AND DIAGNOSIS

The 2014 joint guidelines of the American Heart Association, American College of Cardiology, and Heart Rhythm Society for the management of atrial fibrillation state that a sleep study may be useful if sleep apnea is suspected.²³ The 2019 focused update of the 2014 guidelines²⁴ state that for overweight and obese patients with atrial fibrillation, weight loss combined with risk-factor modification is recommended (class I recommendation, level of evidence B-R, ie, data derived from 1 or more randomized trials or meta-analysis of such studies). Risk-factor modification in this case includes assessment and treatment of underlying sleep apnea, hypertension, hyperlipidemia, glucose intolerance, and alcohol and tobacco use.

Laboratory polysomnography has long been considered the gold standard for sleep apnea diagnosis. In one study,¹³ obstructive sleep apnea was a greater predictor of atrial fibrillation when diagnosed by polysomnography (risk ratio 1.40, 95% CI 1.16–1.68) compared with identification by screening using the Berlin questionnaire (risk ratio 1.07, 95% CI 0.91–1.27). However, a laboratory sleep study is associated with increased patient burden and limited availability.

Home sleep apnea testing is being increasingly used in the diagnostic evaluation of obstructive sleep apnea and may be a less costly, more available alternative. However, since a home sleep apnea test is less sensitive than polysomnography in detecting obstructive sleep apnea, the American Academy of Sleep Medicine guidelines²⁸ state that if a single home sleep apnea test is negative or inconclusive, polysomnography should be done if there is clinical suspicion of sleep apnea. Moreover, current guidelines from this group recommend that patients with significant cardiorespiratory disease should be tested with polysomnography rather than home sleep apnea testing.²²

Further study is needed to determine the optimal screening method for sleep apnea in patients with atrial fibrillation and to clarify the role of home sleep apnea testing. While keeping in mind the limitations of a screening questionnaire in this population, as a general approach it is reasonable to use a screening questionnaire for sleep apnea. And if the screen is positive, further evaluation with a sleep study is merited, whether by laboratory polysomnography, a home sleep apnea test, or referral to a sleep specialist.

MULTIDISCIPLINARY CARE MAY BE IDEAL

Overall, given the high prevalence of sleep apnea in patients with atrial fibrillation, the deleterious effects of sleep apnea in general, the influence of sleep apnea on atrial fibrillation, and the cardiovascular and other beneficial effects of adequate treatment of sleep apnea, patients with atrial fibrillation should be assessed for sleep apnea.

While the optimal strategy in evaluating for sleep apnea in these patients needs to be further defined, a multidisciplinary approach to care involving a primary care provider, cardiologist, and sleep specialist may be ideal.

Yes. The prevalence of sleep apnea is exceedingly high in patients with atrial fibrillation—50% to 80% compared with 30% to 60% in respective control groups.^1–3 Conversely, atrial fibrillation is more prevalent in those with sleep-disordered breathing than in those without (4.8% vs 0.9%).⁴

Sleep-disordered breathing comprises obstructive sleep apnea and central sleep apnea. Obstructive sleep apnea, characterized by repetitive upper-airway obstruction during sleep, is accompanied by intermittent hypoxia, rises in carbon dioxide, autonomic nervous system fluctuations, and intrathoracic pressure alterations.⁵ Central sleep apnea may be neurally mediated and, in the setting of cardiac disease, is characterized by alterations in chemosensitivity and chemoresponsiveness, leading to a state of high loop gain—ie, a hypersensitive ventilatory control system leading to ventilatory drive oscillations.⁶

Both obstructive and central sleep apnea have been associated with atrial fibrillation. Experimental data implicate obstructive sleep apnea as a trigger of atrial arrhythmogenesis,^7,8 and epidemiologic studies support an association between central sleep apnea, Cheyne-Stokes respiration, and incident atrial fibrillation.⁹

HOW SLEEP APNEA COULD LEAD TO ATRIAL FIBRILLATION

In experiments in animals, intermittent upper-airway obstruction led to forced inspiration, substantial negative intrathoracic pressure, subsequent left atrial distention, and increased susceptibility to atrial fibrillation.¹⁰ The autonomic nervous system may be a mediator of apnea-induced atrial fibrillation, as apnea-induced atrial fibrillation is suppressed with autonomic blockade.¹⁰

Emerging data also support the hypothesis that intermittent hypoxia⁷ and resolution of hypercapnia,⁸ as observed in obstructive sleep apnea, exert atrial electrophysiologic changes that increase vulnerability to atrial arrhythmogenesis.

In a case-crossover study,¹¹ the odds of paroxysmal atrial fibrillation occurring after a respiratory disturbance were 17.9 times higher than after normal breathing (95% confidence interval [CI] 2.2–144.2), though the absolute rate of overall arrhythmia events (including both atrial fibrillation and nonsustained ventricular tachycardia) associated with respiratory disturbances was low (1 excess arrhythmia event per 40,000 respiratory disturbances).

EFFECT OF SLEEP APNEA ON ATRIAL FIBRILLATION MANAGEMENT

Sleep apnea also seems to affect the efficacy of a rhythm-control strategy for atrial fibrillation. For example, patients with obstructive sleep apnea have a higher risk of recurrent atrial fibrillation after cardioversion (82% vs 42% in controls)¹² and up to a 25% greater risk of recurrence after catheter ablation compared with those without obstructive sleep apnea (risk ratio 1.25, 95% CI 1.08–1.45).¹³

Several observational studies showed a higher rate of atrial fibrillation after pulmonary vein isolation in obstructive sleep apnea patients who do not use continuous positive airway pressure (CPAP) than in those who do.^14–17 CPAP therapy appears to exert beneficial effects on cardiac structural remodeling;  cardiac magnetic resonance imaging shows that patients with sleep apnea who received less than 4 hours of CPAP per night had larger left atrial dimensions and increased left ventricular mass compared with those who received more than 4 hours of CPAP at night.¹⁷ However, a need remains for high-quality, large randomized controlled trials to eliminate potential unmeasured biases due to differences that may exist between CPAP users and non-users, such as general adherence to medical therapy and healthcare interventions.

An additional consideration is that the overall utility and value of obtaining a diagnosis of obstructive sleep apnea strictly as it pertains to atrial fibrillation management is affected by whether a rhythm- or rate-control strategy is pursued. In other words, if a patient is deemed to be in permanent atrial fibrillation and a rhythm-control strategy is therefore not pursued, the potential effect of untreated obstructive sleep apnea on atrial fibrillation recurrence could be less important. In this case, however, the other beneficial cardiovascular and systemic effects of diagnosing and treating underlying obstructive sleep apnea would remain.

Epidemiologic and clinic-based studies have supported an association between sleep apnea (mostly central, but also obstructive) and atrial fibrillation.^4,18

Community-based studies such as the Sleep Heart Health Study⁴ and the Outcomes of Sleep Disorders in Older Men Study (MrOS Sleep),¹⁸ involving thousands of participants, have found the strongest cross-sectional associations of both obstructive and central sleep apnea with nocturnal atrial fibrillation. The findings included a 2 to 5 times higher odds of nocturnal atrial fibrillation, particularly in those with a moderate to severe degree of sleep-disordered breathing—even after adjusting for confounding influences (eg, obesity) and self-reported cardiac disease such as heart failure.

In MrOS Sleep, in an older male cohort, both obstructive and central sleep apnea were associated with nocturnal atrial fibrillation, though central sleep apnea and Cheyne-Stokes respirations had a stronger magnitude of association.¹⁸

Further insights can be drawn specifically from patients with heart failure. Sin et al,¹⁹ in a 1999 study, found that in 450 patients with systolic heart failure (85% men), the prevalence of sleep-disordered breathing was 25% to 33% (depending on the apnea-hypopnea index cutoff used) for central sleep apnea, and similarly 27% to 38% for obstructive sleep apnea. The prevalence of atrial fibrillation in this group was 10% in women and 15% in men. Atrial fibrillation was reported as a significant risk factor for central sleep apnea, but not for obstructive sleep apnea (for which only male sex and increasing body mass index were significant risk factors). Directionality was not clearly reported in this retrospective study in terms of timing of sleep studies and other assessments: ie, the report did not clearly state which came first, the atrial fibrillation or the sleep apnea. Therefore, the possibility that central sleep apnea is a predictor of atrial fibrillation cannot be excluded.  

Yumino et al,²⁰ in a study published in 2009, evaluated 218 patients with heart failure (with a left ventricular ejection fraction of ≤ 45%) and reported a prevalence of moderate to severe sleep apnea of 21% for central sleep apnea and 26% for obstructive sleep apnea. In multivariate analysis, atrial fibrillation was independently associated with central sleep apnea but not obstructive sleep apnea.

In recent cohort studies, central sleep apnea was associated with 2 to 3 times higher odds of developing atrial fibrillation, while obstructive sleep apnea was not a predictor of incident atrial fibrillation.^9,21

Although most available studies associate sleep apnea with atrial fibrillation, findings of a case-control study²² did not support a difference in the prevalence of sleep apnea syndrome (defined as apnea index ≥ 5 and apnea-hypopnea index ≥ 15, and the presence of sleep symptoms) in patients with lone atrial fibrillation (no evident cardiovascular disease) compared with controls matched for age, sex, and cardiovascular morbidity.

But observational studies are limited by the potential for residual unmeasured confounding factors and lack of objective cardiac structural data, such as left ventricular ejection fraction and atrial enlargement. Moreover, there can be significant differences in sleep apnea definitions among studies, thus limiting the ability to reach a definitive conclusion about the relationship between sleep apnea and atrial fibrillation.

SCREENING AND DIAGNOSIS

The 2014 joint guidelines of the American Heart Association, American College of Cardiology, and Heart Rhythm Society for the management of atrial fibrillation state that a sleep study may be useful if sleep apnea is suspected.²³ The 2019 focused update of the 2014 guidelines²⁴ state that for overweight and obese patients with atrial fibrillation, weight loss combined with risk-factor modification is recommended (class I recommendation, level of evidence B-R, ie, data derived from 1 or more randomized trials or meta-analysis of such studies). Risk-factor modification in this case includes assessment and treatment of underlying sleep apnea, hypertension, hyperlipidemia, glucose intolerance, and alcohol and tobacco use.

Laboratory polysomnography has long been considered the gold standard for sleep apnea diagnosis. In one study,¹³ obstructive sleep apnea was a greater predictor of atrial fibrillation when diagnosed by polysomnography (risk ratio 1.40, 95% CI 1.16–1.68) compared with identification by screening using the Berlin questionnaire (risk ratio 1.07, 95% CI 0.91–1.27). However, a laboratory sleep study is associated with increased patient burden and limited availability.

Home sleep apnea testing is being increasingly used in the diagnostic evaluation of obstructive sleep apnea and may be a less costly, more available alternative. However, since a home sleep apnea test is less sensitive than polysomnography in detecting obstructive sleep apnea, the American Academy of Sleep Medicine guidelines²⁸ state that if a single home sleep apnea test is negative or inconclusive, polysomnography should be done if there is clinical suspicion of sleep apnea. Moreover, current guidelines from this group recommend that patients with significant cardiorespiratory disease should be tested with polysomnography rather than home sleep apnea testing.²²

Further study is needed to determine the optimal screening method for sleep apnea in patients with atrial fibrillation and to clarify the role of home sleep apnea testing. While keeping in mind the limitations of a screening questionnaire in this population, as a general approach it is reasonable to use a screening questionnaire for sleep apnea. And if the screen is positive, further evaluation with a sleep study is merited, whether by laboratory polysomnography, a home sleep apnea test, or referral to a sleep specialist.

MULTIDISCIPLINARY CARE MAY BE IDEAL

Overall, given the high prevalence of sleep apnea in patients with atrial fibrillation, the deleterious effects of sleep apnea in general, the influence of sleep apnea on atrial fibrillation, and the cardiovascular and other beneficial effects of adequate treatment of sleep apnea, patients with atrial fibrillation should be assessed for sleep apnea.

While the optimal strategy in evaluating for sleep apnea in these patients needs to be further defined, a multidisciplinary approach to care involving a primary care provider, cardiologist, and sleep specialist may be ideal.

Yes. The prevalence of sleep apnea is exceedingly high in patients with atrial fibrillation—50% to 80% compared with 30% to 60% in respective control groups.^1–3 Conversely, atrial fibrillation is more prevalent in those with sleep-disordered breathing than in those without (4.8% vs 0.9%).⁴

Sleep-disordered breathing comprises obstructive sleep apnea and central sleep apnea. Obstructive sleep apnea, characterized by repetitive upper-airway obstruction during sleep, is accompanied by intermittent hypoxia, rises in carbon dioxide, autonomic nervous system fluctuations, and intrathoracic pressure alterations.⁵ Central sleep apnea may be neurally mediated and, in the setting of cardiac disease, is characterized by alterations in chemosensitivity and chemoresponsiveness, leading to a state of high loop gain—ie, a hypersensitive ventilatory control system leading to ventilatory drive oscillations.⁶

Both obstructive and central sleep apnea have been associated with atrial fibrillation. Experimental data implicate obstructive sleep apnea as a trigger of atrial arrhythmogenesis,^7,8 and epidemiologic studies support an association between central sleep apnea, Cheyne-Stokes respiration, and incident atrial fibrillation.⁹

HOW SLEEP APNEA COULD LEAD TO ATRIAL FIBRILLATION

In experiments in animals, intermittent upper-airway obstruction led to forced inspiration, substantial negative intrathoracic pressure, subsequent left atrial distention, and increased susceptibility to atrial fibrillation.¹⁰ The autonomic nervous system may be a mediator of apnea-induced atrial fibrillation, as apnea-induced atrial fibrillation is suppressed with autonomic blockade.¹⁰

Emerging data also support the hypothesis that intermittent hypoxia⁷ and resolution of hypercapnia,⁸ as observed in obstructive sleep apnea, exert atrial electrophysiologic changes that increase vulnerability to atrial arrhythmogenesis.

In a case-crossover study,¹¹ the odds of paroxysmal atrial fibrillation occurring after a respiratory disturbance were 17.9 times higher than after normal breathing (95% confidence interval [CI] 2.2–144.2), though the absolute rate of overall arrhythmia events (including both atrial fibrillation and nonsustained ventricular tachycardia) associated with respiratory disturbances was low (1 excess arrhythmia event per 40,000 respiratory disturbances).

EFFECT OF SLEEP APNEA ON ATRIAL FIBRILLATION MANAGEMENT

Sleep apnea also seems to affect the efficacy of a rhythm-control strategy for atrial fibrillation. For example, patients with obstructive sleep apnea have a higher risk of recurrent atrial fibrillation after cardioversion (82% vs 42% in controls)¹² and up to a 25% greater risk of recurrence after catheter ablation compared with those without obstructive sleep apnea (risk ratio 1.25, 95% CI 1.08–1.45).¹³

Several observational studies showed a higher rate of atrial fibrillation after pulmonary vein isolation in obstructive sleep apnea patients who do not use continuous positive airway pressure (CPAP) than in those who do.^14–17 CPAP therapy appears to exert beneficial effects on cardiac structural remodeling;  cardiac magnetic resonance imaging shows that patients with sleep apnea who received less than 4 hours of CPAP per night had larger left atrial dimensions and increased left ventricular mass compared with those who received more than 4 hours of CPAP at night.¹⁷ However, a need remains for high-quality, large randomized controlled trials to eliminate potential unmeasured biases due to differences that may exist between CPAP users and non-users, such as general adherence to medical therapy and healthcare interventions.

An additional consideration is that the overall utility and value of obtaining a diagnosis of obstructive sleep apnea strictly as it pertains to atrial fibrillation management is affected by whether a rhythm- or rate-control strategy is pursued. In other words, if a patient is deemed to be in permanent atrial fibrillation and a rhythm-control strategy is therefore not pursued, the potential effect of untreated obstructive sleep apnea on atrial fibrillation recurrence could be less important. In this case, however, the other beneficial cardiovascular and systemic effects of diagnosing and treating underlying obstructive sleep apnea would remain.

Epidemiologic and clinic-based studies have supported an association between sleep apnea (mostly central, but also obstructive) and atrial fibrillation.^4,18

Community-based studies such as the Sleep Heart Health Study⁴ and the Outcomes of Sleep Disorders in Older Men Study (MrOS Sleep),¹⁸ involving thousands of participants, have found the strongest cross-sectional associations of both obstructive and central sleep apnea with nocturnal atrial fibrillation. The findings included a 2 to 5 times higher odds of nocturnal atrial fibrillation, particularly in those with a moderate to severe degree of sleep-disordered breathing—even after adjusting for confounding influences (eg, obesity) and self-reported cardiac disease such as heart failure.

In MrOS Sleep, in an older male cohort, both obstructive and central sleep apnea were associated with nocturnal atrial fibrillation, though central sleep apnea and Cheyne-Stokes respirations had a stronger magnitude of association.¹⁸

Further insights can be drawn specifically from patients with heart failure. Sin et al,¹⁹ in a 1999 study, found that in 450 patients with systolic heart failure (85% men), the prevalence of sleep-disordered breathing was 25% to 33% (depending on the apnea-hypopnea index cutoff used) for central sleep apnea, and similarly 27% to 38% for obstructive sleep apnea. The prevalence of atrial fibrillation in this group was 10% in women and 15% in men. Atrial fibrillation was reported as a significant risk factor for central sleep apnea, but not for obstructive sleep apnea (for which only male sex and increasing body mass index were significant risk factors). Directionality was not clearly reported in this retrospective study in terms of timing of sleep studies and other assessments: ie, the report did not clearly state which came first, the atrial fibrillation or the sleep apnea. Therefore, the possibility that central sleep apnea is a predictor of atrial fibrillation cannot be excluded.  

Yumino et al,²⁰ in a study published in 2009, evaluated 218 patients with heart failure (with a left ventricular ejection fraction of ≤ 45%) and reported a prevalence of moderate to severe sleep apnea of 21% for central sleep apnea and 26% for obstructive sleep apnea. In multivariate analysis, atrial fibrillation was independently associated with central sleep apnea but not obstructive sleep apnea.

In recent cohort studies, central sleep apnea was associated with 2 to 3 times higher odds of developing atrial fibrillation, while obstructive sleep apnea was not a predictor of incident atrial fibrillation.^9,21

Although most available studies associate sleep apnea with atrial fibrillation, findings of a case-control study²² did not support a difference in the prevalence of sleep apnea syndrome (defined as apnea index ≥ 5 and apnea-hypopnea index ≥ 15, and the presence of sleep symptoms) in patients with lone atrial fibrillation (no evident cardiovascular disease) compared with controls matched for age, sex, and cardiovascular morbidity.

But observational studies are limited by the potential for residual unmeasured confounding factors and lack of objective cardiac structural data, such as left ventricular ejection fraction and atrial enlargement. Moreover, there can be significant differences in sleep apnea definitions among studies, thus limiting the ability to reach a definitive conclusion about the relationship between sleep apnea and atrial fibrillation.

SCREENING AND DIAGNOSIS

The 2014 joint guidelines of the American Heart Association, American College of Cardiology, and Heart Rhythm Society for the management of atrial fibrillation state that a sleep study may be useful if sleep apnea is suspected.²³ The 2019 focused update of the 2014 guidelines²⁴ state that for overweight and obese patients with atrial fibrillation, weight loss combined with risk-factor modification is recommended (class I recommendation, level of evidence B-R, ie, data derived from 1 or more randomized trials or meta-analysis of such studies). Risk-factor modification in this case includes assessment and treatment of underlying sleep apnea, hypertension, hyperlipidemia, glucose intolerance, and alcohol and tobacco use.

Laboratory polysomnography has long been considered the gold standard for sleep apnea diagnosis. In one study,¹³ obstructive sleep apnea was a greater predictor of atrial fibrillation when diagnosed by polysomnography (risk ratio 1.40, 95% CI 1.16–1.68) compared with identification by screening using the Berlin questionnaire (risk ratio 1.07, 95% CI 0.91–1.27). However, a laboratory sleep study is associated with increased patient burden and limited availability.

Home sleep apnea testing is being increasingly used in the diagnostic evaluation of obstructive sleep apnea and may be a less costly, more available alternative. However, since a home sleep apnea test is less sensitive than polysomnography in detecting obstructive sleep apnea, the American Academy of Sleep Medicine guidelines²⁸ state that if a single home sleep apnea test is negative or inconclusive, polysomnography should be done if there is clinical suspicion of sleep apnea. Moreover, current guidelines from this group recommend that patients with significant cardiorespiratory disease should be tested with polysomnography rather than home sleep apnea testing.²²

Further study is needed to determine the optimal screening method for sleep apnea in patients with atrial fibrillation and to clarify the role of home sleep apnea testing. While keeping in mind the limitations of a screening questionnaire in this population, as a general approach it is reasonable to use a screening questionnaire for sleep apnea. And if the screen is positive, further evaluation with a sleep study is merited, whether by laboratory polysomnography, a home sleep apnea test, or referral to a sleep specialist.

MULTIDISCIPLINARY CARE MAY BE IDEAL

Overall, given the high prevalence of sleep apnea in patients with atrial fibrillation, the deleterious effects of sleep apnea in general, the influence of sleep apnea on atrial fibrillation, and the cardiovascular and other beneficial effects of adequate treatment of sleep apnea, patients with atrial fibrillation should be assessed for sleep apnea.

While the optimal strategy in evaluating for sleep apnea in these patients needs to be further defined, a multidisciplinary approach to care involving a primary care provider, cardiologist, and sleep specialist may be ideal.

Hospital-acquired infections related to construction and renovation activities account for more than 5,000 deaths per year across the United States.¹

Hospital construction, renovation, and demolition projects ultimately serve the interests of patients, but they also can put inpatients at risk of mold infection, Legionnaires disease, sleep deprivation, exacerbation of lung disease, and in rare cases, physical injury.

Hospitals are in a continuous state of transformation to meet the needs of medical and technologic advances and an increasing patient population,¹ and in the last 10 years, more than $200 billion has been spent on construction projects at US healthcare facilities. Therefore, constant attention is needed to reduce the risks to the health of hospitalized patients during these projects.

HOSPITAL-ACQUIRED INFECTIONS

Mold infections

Construction can cause substantial dust contamination and scatter large amounts of fungal spores. An analysis conducted during a period of excavation at a hospital campus showed a significant association between excavation activities and hospital-acquired mold infections (hazard ratio [HR] 2.8, P = .01) but not yeast infections (HR 0.75, P = .78).²

Aspergillus species have been the organisms most commonly involved in hospital-acquired mold infection. In a review of 53 studies including 458 patients,³A fumigatus was identified in 154 patients, and A flavus was identified in 101 patients. A niger, A terreus, A nidulans, Zygomycetes, and other fungi were also identified, but to a much lesser extent. Hematologic malignancies were the predominant underlying morbidity in 299 patients. Half of the sources of healthcare-associated Aspergillus outbreaks were estimated to result from construction and renovation activities within or surrounding the hospital.³

Heavy demolition and transportation of wreckage have been found to cause the greatest concentrations of Aspergillus species,¹ but even small concentrations may be sufficient to cause infection in high-risk hospitalized patients.³ Invasive pulmonary aspergillosis is the mold infection most commonly associated with these activities, particularly in immunocompromised and critically ill patients. It is characterized by invasion of lung tissue by Aspergillus hyphae. Hematogenous dissemination occurs in about 25% of patients, and the death rate often exceeds 50%.⁴

A review of cases of fungal infection during hospital construction, renovation, and demolition projects from 1976 to 2014 identified 372 infected patients, of whom 180 died.⁵ The majority of infections were due to Aspergillus. Other fungi included Rhizopus, Candida, and Fusarium. Infections occurred mainly in patients with hematologic malignancies and patients who had undergone stem cell transplant (76%), followed by patients with other malignancies or transplant (19%). Rarely affected were patients in the intensive care unit or patients with rheumatologic diseases or on hemodialysis.⁵

Legionnaires disease

Legionnaires disease is a form of atypical pneumonia caused by the bacterium Legionella, often associated with differing degrees of gastrointestinal symptoms. Legionella species are the bacteria most often associated with construction in hospitals, as construction and demolition often result in collections of stagnant water.

The primary mode of transmission is inhalation of contaminated mist or aerosols. Legionella species can also colonize newly constructed hospital buildings within weeks of installation of water fixtures.

In a large university-affiliated hospital, 2 cases of nosocomial legionellosis were identified during a period of major construction.⁶ An epidemiologic investigation traced the source to a widespread contamination of potable water within the hospital. One patient’s isolate was similar to that of a water sample from the faucet in his room, and an association between Legionnaires disease and construction was postulated.

Another institution’s newly constructed hematology-oncology unit identified 10 cases of Legionnaires disease over a 12-week period in patients and visitors with exposure to the unit during and within the incubation period.⁷ A clinical and environmental assessment found 3 clinical isolates of Legionella identical to environmental isolates found from the unit, strongly implicating the potable water system as the likely source.⁷

In Ohio, 11 cases of hospital-acquired Legionnaires disease were identified in patients moved to a newly constructed 12-story addition to a hospital, and 1 of those died.⁸

Legionella infections appear to be less common than mold infections when reviewing the available literature on patients exposed to hospital construction, renovation, or demolition activities. Yet unlike mold infections, which occur mostly in immunocompromised patients, Legionella also affects people with normal immunity.¹

Sleep deprivation

Noise in hospitals has been linked to sleep disturbances in inpatients. A study using noise dosimeters in a university hospital found a mean continuous noise level of 63.5 dBA (A-weighting of decibels indicates risk of hearing loss) over a 24-hour period, a level more than 2 times higher than the recommended 30 dBA.⁹ The same study also found a significant correlation between sleep disturbance in inpatients and increasing noise levels, in a dose-response manner.

Common sources of noise during construction may include power generators, welding and cutting equipment, and transport of materials. While construction activities themselves have yet to be directly linked to sleep deprivation in patients, construction is inevitably accompanied by noise.

Noise is the most common factor interfering with sleep reported by hospitalized patients. Other effects of noise on patients include a rise in heart rate and blood pressure, increased cholesterol and triglyceride levels, increased use of sedatives, and longer length of stay.^9,10 Although construction is rarely done at night, patients generally take naps during the day, so the noise is disruptive.

Physical injuries

Hospitalized patients rarely suffer injuries related to hospital construction. However, these incidents may be underreported. Few cases of physical injury in patients exposed to construction or renovation in healthcare facilities can be found through a Web search.^11,12

Exacerbation of lung disease

Inhalation of indoor air pollutants exposed during renovation can directly trigger an inflammatory response and cause exacerbation in patients with chronic lung diseases such as asthma and chronic obstructive pulmonary disease. No study has specifically examined the effect of hospital construction or renovation on exacerbation of chronic lung diseases in hospitalized patients. Nevertheless, dust and indoor air pollutants from building renovation have often been reported as agents associated with work-related asthma.¹³

THE MESSAGE

Although the risks to inpatients during hospital construction projects appear minimal, their effect can at times be detrimental, especially to the immunocompromised. Hospitals should adhere to infection control risk assessment protocols during construction events. The small number of outbreaks of construction-related infections can make the diagnosis of nosocomial origin of these infections challenging; a high index of suspicion is needed.

Currently in the United States, there is no standard regarding acceptable levels of airborne mold concentrations, and data to support routine hospital air sampling or validation of available air samplers are inadequate. This remains an area for future research.^14,15

Certain measures have been shown to significantly decrease the risk of mold infections and other nosocomial infections during construction projects, including¹⁶:

• Effective dust control through containment units and barriers
• Consistent use of high-efficiency particulate air filters in hospital units that care for immunocompromised and critically ill patients
• Routine surveillance.

Noise and vibration can be reduced by temporary walls and careful tool selection and scheduling. Similarly, temporary walls and other barriers help protect healthcare employees and patients from the risk of direct physical injury.

Preconstruction risk assessments that address infection control, safety, noise, and air quality are crucial, and the Joint Commission generally requires such assessments. Further, education of hospital staff and members of the construction team about the potential detrimental effects of hospital construction and renovation is essential to secure a safe environment.        

Hospital-acquired infections related to construction and renovation activities account for more than 5,000 deaths per year across the United States.¹

Hospital construction, renovation, and demolition projects ultimately serve the interests of patients, but they also can put inpatients at risk of mold infection, Legionnaires disease, sleep deprivation, exacerbation of lung disease, and in rare cases, physical injury.

Hospitals are in a continuous state of transformation to meet the needs of medical and technologic advances and an increasing patient population,¹ and in the last 10 years, more than $200 billion has been spent on construction projects at US healthcare facilities. Therefore, constant attention is needed to reduce the risks to the health of hospitalized patients during these projects.

HOSPITAL-ACQUIRED INFECTIONS

Mold infections

Construction can cause substantial dust contamination and scatter large amounts of fungal spores. An analysis conducted during a period of excavation at a hospital campus showed a significant association between excavation activities and hospital-acquired mold infections (hazard ratio [HR] 2.8, P = .01) but not yeast infections (HR 0.75, P = .78).²

Aspergillus species have been the organisms most commonly involved in hospital-acquired mold infection. In a review of 53 studies including 458 patients,³A fumigatus was identified in 154 patients, and A flavus was identified in 101 patients. A niger, A terreus, A nidulans, Zygomycetes, and other fungi were also identified, but to a much lesser extent. Hematologic malignancies were the predominant underlying morbidity in 299 patients. Half of the sources of healthcare-associated Aspergillus outbreaks were estimated to result from construction and renovation activities within or surrounding the hospital.³

Heavy demolition and transportation of wreckage have been found to cause the greatest concentrations of Aspergillus species,¹ but even small concentrations may be sufficient to cause infection in high-risk hospitalized patients.³ Invasive pulmonary aspergillosis is the mold infection most commonly associated with these activities, particularly in immunocompromised and critically ill patients. It is characterized by invasion of lung tissue by Aspergillus hyphae. Hematogenous dissemination occurs in about 25% of patients, and the death rate often exceeds 50%.⁴

A review of cases of fungal infection during hospital construction, renovation, and demolition projects from 1976 to 2014 identified 372 infected patients, of whom 180 died.⁵ The majority of infections were due to Aspergillus. Other fungi included Rhizopus, Candida, and Fusarium. Infections occurred mainly in patients with hematologic malignancies and patients who had undergone stem cell transplant (76%), followed by patients with other malignancies or transplant (19%). Rarely affected were patients in the intensive care unit or patients with rheumatologic diseases or on hemodialysis.⁵

Legionnaires disease

Legionnaires disease is a form of atypical pneumonia caused by the bacterium Legionella, often associated with differing degrees of gastrointestinal symptoms. Legionella species are the bacteria most often associated with construction in hospitals, as construction and demolition often result in collections of stagnant water.

The primary mode of transmission is inhalation of contaminated mist or aerosols. Legionella species can also colonize newly constructed hospital buildings within weeks of installation of water fixtures.

In a large university-affiliated hospital, 2 cases of nosocomial legionellosis were identified during a period of major construction.⁶ An epidemiologic investigation traced the source to a widespread contamination of potable water within the hospital. One patient’s isolate was similar to that of a water sample from the faucet in his room, and an association between Legionnaires disease and construction was postulated.

Another institution’s newly constructed hematology-oncology unit identified 10 cases of Legionnaires disease over a 12-week period in patients and visitors with exposure to the unit during and within the incubation period.⁷ A clinical and environmental assessment found 3 clinical isolates of Legionella identical to environmental isolates found from the unit, strongly implicating the potable water system as the likely source.⁷

In Ohio, 11 cases of hospital-acquired Legionnaires disease were identified in patients moved to a newly constructed 12-story addition to a hospital, and 1 of those died.⁸

Legionella infections appear to be less common than mold infections when reviewing the available literature on patients exposed to hospital construction, renovation, or demolition activities. Yet unlike mold infections, which occur mostly in immunocompromised patients, Legionella also affects people with normal immunity.¹

Sleep deprivation

Noise in hospitals has been linked to sleep disturbances in inpatients. A study using noise dosimeters in a university hospital found a mean continuous noise level of 63.5 dBA (A-weighting of decibels indicates risk of hearing loss) over a 24-hour period, a level more than 2 times higher than the recommended 30 dBA.⁹ The same study also found a significant correlation between sleep disturbance in inpatients and increasing noise levels, in a dose-response manner.

Common sources of noise during construction may include power generators, welding and cutting equipment, and transport of materials. While construction activities themselves have yet to be directly linked to sleep deprivation in patients, construction is inevitably accompanied by noise.

Noise is the most common factor interfering with sleep reported by hospitalized patients. Other effects of noise on patients include a rise in heart rate and blood pressure, increased cholesterol and triglyceride levels, increased use of sedatives, and longer length of stay.^9,10 Although construction is rarely done at night, patients generally take naps during the day, so the noise is disruptive.

Physical injuries

Hospitalized patients rarely suffer injuries related to hospital construction. However, these incidents may be underreported. Few cases of physical injury in patients exposed to construction or renovation in healthcare facilities can be found through a Web search.^11,12

Exacerbation of lung disease

Inhalation of indoor air pollutants exposed during renovation can directly trigger an inflammatory response and cause exacerbation in patients with chronic lung diseases such as asthma and chronic obstructive pulmonary disease. No study has specifically examined the effect of hospital construction or renovation on exacerbation of chronic lung diseases in hospitalized patients. Nevertheless, dust and indoor air pollutants from building renovation have often been reported as agents associated with work-related asthma.¹³

THE MESSAGE

Although the risks to inpatients during hospital construction projects appear minimal, their effect can at times be detrimental, especially to the immunocompromised. Hospitals should adhere to infection control risk assessment protocols during construction events. The small number of outbreaks of construction-related infections can make the diagnosis of nosocomial origin of these infections challenging; a high index of suspicion is needed.

Currently in the United States, there is no standard regarding acceptable levels of airborne mold concentrations, and data to support routine hospital air sampling or validation of available air samplers are inadequate. This remains an area for future research.^14,15

Certain measures have been shown to significantly decrease the risk of mold infections and other nosocomial infections during construction projects, including¹⁶:

• Effective dust control through containment units and barriers
• Consistent use of high-efficiency particulate air filters in hospital units that care for immunocompromised and critically ill patients
• Routine surveillance.

Noise and vibration can be reduced by temporary walls and careful tool selection and scheduling. Similarly, temporary walls and other barriers help protect healthcare employees and patients from the risk of direct physical injury.

Preconstruction risk assessments that address infection control, safety, noise, and air quality are crucial, and the Joint Commission generally requires such assessments. Further, education of hospital staff and members of the construction team about the potential detrimental effects of hospital construction and renovation is essential to secure a safe environment.        

Hospital-acquired infections related to construction and renovation activities account for more than 5,000 deaths per year across the United States.¹

Hospital construction, renovation, and demolition projects ultimately serve the interests of patients, but they also can put inpatients at risk of mold infection, Legionnaires disease, sleep deprivation, exacerbation of lung disease, and in rare cases, physical injury.

Hospitals are in a continuous state of transformation to meet the needs of medical and technologic advances and an increasing patient population,¹ and in the last 10 years, more than $200 billion has been spent on construction projects at US healthcare facilities. Therefore, constant attention is needed to reduce the risks to the health of hospitalized patients during these projects.

HOSPITAL-ACQUIRED INFECTIONS

Mold infections

Construction can cause substantial dust contamination and scatter large amounts of fungal spores. An analysis conducted during a period of excavation at a hospital campus showed a significant association between excavation activities and hospital-acquired mold infections (hazard ratio [HR] 2.8, P = .01) but not yeast infections (HR 0.75, P = .78).²

Aspergillus species have been the organisms most commonly involved in hospital-acquired mold infection. In a review of 53 studies including 458 patients,³A fumigatus was identified in 154 patients, and A flavus was identified in 101 patients. A niger, A terreus, A nidulans, Zygomycetes, and other fungi were also identified, but to a much lesser extent. Hematologic malignancies were the predominant underlying morbidity in 299 patients. Half of the sources of healthcare-associated Aspergillus outbreaks were estimated to result from construction and renovation activities within or surrounding the hospital.³

Heavy demolition and transportation of wreckage have been found to cause the greatest concentrations of Aspergillus species,¹ but even small concentrations may be sufficient to cause infection in high-risk hospitalized patients.³ Invasive pulmonary aspergillosis is the mold infection most commonly associated with these activities, particularly in immunocompromised and critically ill patients. It is characterized by invasion of lung tissue by Aspergillus hyphae. Hematogenous dissemination occurs in about 25% of patients, and the death rate often exceeds 50%.⁴

A review of cases of fungal infection during hospital construction, renovation, and demolition projects from 1976 to 2014 identified 372 infected patients, of whom 180 died.⁵ The majority of infections were due to Aspergillus. Other fungi included Rhizopus, Candida, and Fusarium. Infections occurred mainly in patients with hematologic malignancies and patients who had undergone stem cell transplant (76%), followed by patients with other malignancies or transplant (19%). Rarely affected were patients in the intensive care unit or patients with rheumatologic diseases or on hemodialysis.⁵

Legionnaires disease

Legionnaires disease is a form of atypical pneumonia caused by the bacterium Legionella, often associated with differing degrees of gastrointestinal symptoms. Legionella species are the bacteria most often associated with construction in hospitals, as construction and demolition often result in collections of stagnant water.

The primary mode of transmission is inhalation of contaminated mist or aerosols. Legionella species can also colonize newly constructed hospital buildings within weeks of installation of water fixtures.

In a large university-affiliated hospital, 2 cases of nosocomial legionellosis were identified during a period of major construction.⁶ An epidemiologic investigation traced the source to a widespread contamination of potable water within the hospital. One patient’s isolate was similar to that of a water sample from the faucet in his room, and an association between Legionnaires disease and construction was postulated.

Another institution’s newly constructed hematology-oncology unit identified 10 cases of Legionnaires disease over a 12-week period in patients and visitors with exposure to the unit during and within the incubation period.⁷ A clinical and environmental assessment found 3 clinical isolates of Legionella identical to environmental isolates found from the unit, strongly implicating the potable water system as the likely source.⁷

In Ohio, 11 cases of hospital-acquired Legionnaires disease were identified in patients moved to a newly constructed 12-story addition to a hospital, and 1 of those died.⁸

Legionella infections appear to be less common than mold infections when reviewing the available literature on patients exposed to hospital construction, renovation, or demolition activities. Yet unlike mold infections, which occur mostly in immunocompromised patients, Legionella also affects people with normal immunity.¹

Sleep deprivation

Noise in hospitals has been linked to sleep disturbances in inpatients. A study using noise dosimeters in a university hospital found a mean continuous noise level of 63.5 dBA (A-weighting of decibels indicates risk of hearing loss) over a 24-hour period, a level more than 2 times higher than the recommended 30 dBA.⁹ The same study also found a significant correlation between sleep disturbance in inpatients and increasing noise levels, in a dose-response manner.

Common sources of noise during construction may include power generators, welding and cutting equipment, and transport of materials. While construction activities themselves have yet to be directly linked to sleep deprivation in patients, construction is inevitably accompanied by noise.

Noise is the most common factor interfering with sleep reported by hospitalized patients. Other effects of noise on patients include a rise in heart rate and blood pressure, increased cholesterol and triglyceride levels, increased use of sedatives, and longer length of stay.^9,10 Although construction is rarely done at night, patients generally take naps during the day, so the noise is disruptive.

Physical injuries

Hospitalized patients rarely suffer injuries related to hospital construction. However, these incidents may be underreported. Few cases of physical injury in patients exposed to construction or renovation in healthcare facilities can be found through a Web search.^11,12

Exacerbation of lung disease

Inhalation of indoor air pollutants exposed during renovation can directly trigger an inflammatory response and cause exacerbation in patients with chronic lung diseases such as asthma and chronic obstructive pulmonary disease. No study has specifically examined the effect of hospital construction or renovation on exacerbation of chronic lung diseases in hospitalized patients. Nevertheless, dust and indoor air pollutants from building renovation have often been reported as agents associated with work-related asthma.¹³

THE MESSAGE

Although the risks to inpatients during hospital construction projects appear minimal, their effect can at times be detrimental, especially to the immunocompromised. Hospitals should adhere to infection control risk assessment protocols during construction events. The small number of outbreaks of construction-related infections can make the diagnosis of nosocomial origin of these infections challenging; a high index of suspicion is needed.

Currently in the United States, there is no standard regarding acceptable levels of airborne mold concentrations, and data to support routine hospital air sampling or validation of available air samplers are inadequate. This remains an area for future research.^14,15

Certain measures have been shown to significantly decrease the risk of mold infections and other nosocomial infections during construction projects, including¹⁶:

• Effective dust control through containment units and barriers
• Consistent use of high-efficiency particulate air filters in hospital units that care for immunocompromised and critically ill patients
• Routine surveillance.

Noise and vibration can be reduced by temporary walls and careful tool selection and scheduling. Similarly, temporary walls and other barriers help protect healthcare employees and patients from the risk of direct physical injury.

Preconstruction risk assessments that address infection control, safety, noise, and air quality are crucial, and the Joint Commission generally requires such assessments. Further, education of hospital staff and members of the construction team about the potential detrimental effects of hospital construction and renovation is essential to secure a safe environment.        

My adult nonacutely ill patient, weighing 70 kg with a glomerular filtration rate (GFR) greater than 60 mL/min/1.73 m², is admitted to the general medical service. She is to receive nothing by mouth for at least the next 24 hours for testing. Do I need to provide maintenance fluids intravenously?

The question seems like it should have an easy answer. However, there is no consensus either on the type of fluids or the need for them at all.

Mortiz and Ayus¹ have described the role of maintenance intravenous (IV) fluids in acutely ill patients and made the case for isotonic saline (0.9% NaCl) to minimize the risk of hyponatremia, while acknowledging that it provides 7 to 10 g of sodium per day.

Recommendations for IV fluids for nonacutely ill hospitalized patients range from isotonic solutions such as 0.9% NaCl and lactated Ringer’s, to hypotonic fluids such as 5% dextrose in water (D5W) in 0.45% NaCl and D5W in 0.2% NaCl.^2–5

The 2013 guidelines of the UK National Institute for Health and Care Excellence (NICE) recommend hypotonic fluids to provide 25 to 30 mL/kg/day of water with 1 mmol/kg/day of sodium. For a 70-kg patient (body surface area 1.7 m²), this would be 1,750 to 2,000 mL of water, with a maximum of 70 mEq/L of sodium (35 mEq/L).⁵ An option would be D5W in 0.2% NaCl, which has 34 mEq/L of sodium.

When choosing maintenance IV fluids, we need to consider the following questions:

• What is my patient’s volume status?
• What is the baseline serum sodium and renal function?
• Are there comorbid conditions that may affect antidiuretic hormone (ADH) status such as physiologic stimulation from volume depletion, drugs, pathologic medical conditions, or syndrome of inappropriate ADH stimulation?
• Will my patient be receiving strictly nothing by mouth?
• Are there unusual fluid losses?

SCENARIO 1: ‘USUAL’ MAINTENANCE

If the patient is euvolemic, with a normal serum osmolality, a GFR more than 60 mL/min/1.73 m², no stimuli for ADH secretion, and no unusual fluid losses, “usual” maintenance would be expected. The usual volume for this patient can be estimated by the following formulas:

• Maintenance volume: 2,550 mL (1,500 mL × 1.7 m² body surface area)
• Holliday-Segar method⁶: 2,500 mL (1,500 mL plus 20 mL/kg for every kilogram over 20 kg).

The usual sodium can be also estimated by the following formulas:

• 2 g Na/day = 2,000 mg/day = 87 mEq/day
• Holliday-Segar⁶: 3 mEq Na/100 mL and 2 mEq K/100 mL of maintenance fluid.

Maintenance IV fluids for our nonacutely ill adult patient could be:

• NICE guideline⁵: D5W in 0.2% NaCl with 20 mEq KCl, to run at 75 mL/hour
• Holliday-Segar method⁶: D5W in 0.2% NaCl with 20 mEq KCl, to run at 100 mL/hour.

Twenty-four hours later, assuming no unusual fluid losses or stimulation of ADH secretion, our patient would weigh the same and would have no significant change in serum osmolality.

OTHER OPTIONS

What if I provide 0.9% NaCl instead?

Each 1 L of normal saline provides 154 mEq of sodium, equivalent to 3.5 g of sodium. Thus, for the 24 hours, with administration of 2 to 2.5 L, the patient would receive a sodium load of 7 to 8.75 g. The consequences of this can be debated, but for 24 hours, more than likely, nothing will happen or be noticeable. The kidneys have a wonderful ability to “dump” excess sodium ingested in the diet, as evidenced by the average Western diet with a sodium load in the range of 4 g per day.^7,8

What if I provide 0.45% NaCl instead?

Each liter provides 50% of the sodium load of 0.9% NaCl. With the 24-hour administration of 2 to 2.5 L of D5W in 0.45% NaCl, the sodium load would be 3.5 to 4.8 g, and the kidneys would dump the excess sodium.

What if I provide ‘catch-up’ fluids after 24 hours, not maintenance fluids?

Assuming only usual losses and no unusual ADH stimulation except for the physiologic stimuli from volume depletion for 24 hours, our patient would lose 2 kg (1 L fluid loss = 1 kg weight loss) and 87 mEq of sodium. This is approximately 4.5% dehydration; thus, other than increased thirst, no physical findings of volume depletion would be clinically evident.

However, serum osmolality and sodium would increase. After 24 hours of nothing by mouth with usual fluid losses, there would be a rise in serum osmolality of 13.5 mOsm/L (a rise in sodium of 6 to 7 mEq/L), which would stimulate ADH in an attempt to minimize further urinary losses. There would be an intracellular volume loss of 1.3 L (Table 1). Clinically, just as with the administration of 0.9% sodium, these changes would not likely be of any clinical consequence in the first 24 hours.

SCENARIO 2: IMPAIRED WATER EXCRETION, AND FLUIDS GIVEN

If the patient is euvolemic but has or is at risk for ADH stimulation,^1,9 providing maintenance IV fluids according to the NICE or Holliday-Segar recommendations (a total of 2 L of 0.2% NaCl = 34 mEq Na/L = 68 mOsm/L) would result in an excess of free water, as an increase in ADH secretion impairs free water clearance. A potential scenario with impaired water excretion is shown in Table 2.

After 24 hours, the patient’s serum osmolality would drop by about 7 mOsm/L, and the serum sodium would decrease by 3 or 4 mEq. The consequence of the intracellular fluid shift would be seen by the expansion of the intracellular volume from 28 to 28.7 L.

If this patient were to have received 2 L of 0.9% NaCl (308 mOsm/L × 2 L = 616 Osm) as suggested by Moritz and Ayus,¹ the result would be a serum osmolality of 284 mOsm/L, thus avoiding hyponatremia and intracellular fluid shifts.

THE BOTTOM LINE

Know your patient, answer the clinical questions noted above, and decide.

For a euvolemic patient with normal serum sodium, GFR greater than 60 mL/1.73 m², and no ADH stimulation, for 24 hours it probably doesn’t matter that much, but a daily reassessment of the continued need for and type of intravenous fluids is critical.

For patients not meeting the criteria noted above such as a patient with systolic or diastolic heart failure, advanced or end-stage renal disease puts the patient at risk for early potential complications of either hyponatremia or sodium overload. For these patients, maintenance intravenous fluids need to be chosen wisely. Daily weights, examinations, and laboratory testing will let you know if something is not right and will allow for early detection and treatment.

My adult nonacutely ill patient, weighing 70 kg with a glomerular filtration rate (GFR) greater than 60 mL/min/1.73 m², is admitted to the general medical service. She is to receive nothing by mouth for at least the next 24 hours for testing. Do I need to provide maintenance fluids intravenously?

The question seems like it should have an easy answer. However, there is no consensus either on the type of fluids or the need for them at all.

Mortiz and Ayus¹ have described the role of maintenance intravenous (IV) fluids in acutely ill patients and made the case for isotonic saline (0.9% NaCl) to minimize the risk of hyponatremia, while acknowledging that it provides 7 to 10 g of sodium per day.

Recommendations for IV fluids for nonacutely ill hospitalized patients range from isotonic solutions such as 0.9% NaCl and lactated Ringer’s, to hypotonic fluids such as 5% dextrose in water (D5W) in 0.45% NaCl and D5W in 0.2% NaCl.^2–5

The 2013 guidelines of the UK National Institute for Health and Care Excellence (NICE) recommend hypotonic fluids to provide 25 to 30 mL/kg/day of water with 1 mmol/kg/day of sodium. For a 70-kg patient (body surface area 1.7 m²), this would be 1,750 to 2,000 mL of water, with a maximum of 70 mEq/L of sodium (35 mEq/L).⁵ An option would be D5W in 0.2% NaCl, which has 34 mEq/L of sodium.

When choosing maintenance IV fluids, we need to consider the following questions:

• What is my patient’s volume status?
• What is the baseline serum sodium and renal function?
• Are there comorbid conditions that may affect antidiuretic hormone (ADH) status such as physiologic stimulation from volume depletion, drugs, pathologic medical conditions, or syndrome of inappropriate ADH stimulation?
• Will my patient be receiving strictly nothing by mouth?
• Are there unusual fluid losses?

SCENARIO 1: ‘USUAL’ MAINTENANCE

If the patient is euvolemic, with a normal serum osmolality, a GFR more than 60 mL/min/1.73 m², no stimuli for ADH secretion, and no unusual fluid losses, “usual” maintenance would be expected. The usual volume for this patient can be estimated by the following formulas:

• Maintenance volume: 2,550 mL (1,500 mL × 1.7 m² body surface area)
• Holliday-Segar method⁶: 2,500 mL (1,500 mL plus 20 mL/kg for every kilogram over 20 kg).

The usual sodium can be also estimated by the following formulas:

• 2 g Na/day = 2,000 mg/day = 87 mEq/day
• Holliday-Segar⁶: 3 mEq Na/100 mL and 2 mEq K/100 mL of maintenance fluid.

Maintenance IV fluids for our nonacutely ill adult patient could be:

• NICE guideline⁵: D5W in 0.2% NaCl with 20 mEq KCl, to run at 75 mL/hour
• Holliday-Segar method⁶: D5W in 0.2% NaCl with 20 mEq KCl, to run at 100 mL/hour.

Twenty-four hours later, assuming no unusual fluid losses or stimulation of ADH secretion, our patient would weigh the same and would have no significant change in serum osmolality.

OTHER OPTIONS

What if I provide 0.9% NaCl instead?

Each 1 L of normal saline provides 154 mEq of sodium, equivalent to 3.5 g of sodium. Thus, for the 24 hours, with administration of 2 to 2.5 L, the patient would receive a sodium load of 7 to 8.75 g. The consequences of this can be debated, but for 24 hours, more than likely, nothing will happen or be noticeable. The kidneys have a wonderful ability to “dump” excess sodium ingested in the diet, as evidenced by the average Western diet with a sodium load in the range of 4 g per day.^7,8

What if I provide 0.45% NaCl instead?

Each liter provides 50% of the sodium load of 0.9% NaCl. With the 24-hour administration of 2 to 2.5 L of D5W in 0.45% NaCl, the sodium load would be 3.5 to 4.8 g, and the kidneys would dump the excess sodium.

What if I provide ‘catch-up’ fluids after 24 hours, not maintenance fluids?

Assuming only usual losses and no unusual ADH stimulation except for the physiologic stimuli from volume depletion for 24 hours, our patient would lose 2 kg (1 L fluid loss = 1 kg weight loss) and 87 mEq of sodium. This is approximately 4.5% dehydration; thus, other than increased thirst, no physical findings of volume depletion would be clinically evident.

However, serum osmolality and sodium would increase. After 24 hours of nothing by mouth with usual fluid losses, there would be a rise in serum osmolality of 13.5 mOsm/L (a rise in sodium of 6 to 7 mEq/L), which would stimulate ADH in an attempt to minimize further urinary losses. There would be an intracellular volume loss of 1.3 L (Table 1). Clinically, just as with the administration of 0.9% sodium, these changes would not likely be of any clinical consequence in the first 24 hours.

SCENARIO 2: IMPAIRED WATER EXCRETION, AND FLUIDS GIVEN

If the patient is euvolemic but has or is at risk for ADH stimulation,^1,9 providing maintenance IV fluids according to the NICE or Holliday-Segar recommendations (a total of 2 L of 0.2% NaCl = 34 mEq Na/L = 68 mOsm/L) would result in an excess of free water, as an increase in ADH secretion impairs free water clearance. A potential scenario with impaired water excretion is shown in Table 2.

After 24 hours, the patient’s serum osmolality would drop by about 7 mOsm/L, and the serum sodium would decrease by 3 or 4 mEq. The consequence of the intracellular fluid shift would be seen by the expansion of the intracellular volume from 28 to 28.7 L.

If this patient were to have received 2 L of 0.9% NaCl (308 mOsm/L × 2 L = 616 Osm) as suggested by Moritz and Ayus,¹ the result would be a serum osmolality of 284 mOsm/L, thus avoiding hyponatremia and intracellular fluid shifts.

THE BOTTOM LINE

Know your patient, answer the clinical questions noted above, and decide.

For a euvolemic patient with normal serum sodium, GFR greater than 60 mL/1.73 m², and no ADH stimulation, for 24 hours it probably doesn’t matter that much, but a daily reassessment of the continued need for and type of intravenous fluids is critical.

For patients not meeting the criteria noted above such as a patient with systolic or diastolic heart failure, advanced or end-stage renal disease puts the patient at risk for early potential complications of either hyponatremia or sodium overload. For these patients, maintenance intravenous fluids need to be chosen wisely. Daily weights, examinations, and laboratory testing will let you know if something is not right and will allow for early detection and treatment.

My adult nonacutely ill patient, weighing 70 kg with a glomerular filtration rate (GFR) greater than 60 mL/min/1.73 m², is admitted to the general medical service. She is to receive nothing by mouth for at least the next 24 hours for testing. Do I need to provide maintenance fluids intravenously?

The question seems like it should have an easy answer. However, there is no consensus either on the type of fluids or the need for them at all.

Mortiz and Ayus¹ have described the role of maintenance intravenous (IV) fluids in acutely ill patients and made the case for isotonic saline (0.9% NaCl) to minimize the risk of hyponatremia, while acknowledging that it provides 7 to 10 g of sodium per day.

Recommendations for IV fluids for nonacutely ill hospitalized patients range from isotonic solutions such as 0.9% NaCl and lactated Ringer’s, to hypotonic fluids such as 5% dextrose in water (D5W) in 0.45% NaCl and D5W in 0.2% NaCl.^2–5

The 2013 guidelines of the UK National Institute for Health and Care Excellence (NICE) recommend hypotonic fluids to provide 25 to 30 mL/kg/day of water with 1 mmol/kg/day of sodium. For a 70-kg patient (body surface area 1.7 m²), this would be 1,750 to 2,000 mL of water, with a maximum of 70 mEq/L of sodium (35 mEq/L).⁵ An option would be D5W in 0.2% NaCl, which has 34 mEq/L of sodium.

When choosing maintenance IV fluids, we need to consider the following questions:

• What is my patient’s volume status?
• What is the baseline serum sodium and renal function?
• Are there comorbid conditions that may affect antidiuretic hormone (ADH) status such as physiologic stimulation from volume depletion, drugs, pathologic medical conditions, or syndrome of inappropriate ADH stimulation?
• Will my patient be receiving strictly nothing by mouth?
• Are there unusual fluid losses?

SCENARIO 1: ‘USUAL’ MAINTENANCE

If the patient is euvolemic, with a normal serum osmolality, a GFR more than 60 mL/min/1.73 m², no stimuli for ADH secretion, and no unusual fluid losses, “usual” maintenance would be expected. The usual volume for this patient can be estimated by the following formulas:

• Maintenance volume: 2,550 mL (1,500 mL × 1.7 m² body surface area)
• Holliday-Segar method⁶: 2,500 mL (1,500 mL plus 20 mL/kg for every kilogram over 20 kg).

The usual sodium can be also estimated by the following formulas:

• 2 g Na/day = 2,000 mg/day = 87 mEq/day
• Holliday-Segar⁶: 3 mEq Na/100 mL and 2 mEq K/100 mL of maintenance fluid.

Maintenance IV fluids for our nonacutely ill adult patient could be:

• NICE guideline⁵: D5W in 0.2% NaCl with 20 mEq KCl, to run at 75 mL/hour
• Holliday-Segar method⁶: D5W in 0.2% NaCl with 20 mEq KCl, to run at 100 mL/hour.

Twenty-four hours later, assuming no unusual fluid losses or stimulation of ADH secretion, our patient would weigh the same and would have no significant change in serum osmolality.

OTHER OPTIONS

What if I provide 0.9% NaCl instead?

Each 1 L of normal saline provides 154 mEq of sodium, equivalent to 3.5 g of sodium. Thus, for the 24 hours, with administration of 2 to 2.5 L, the patient would receive a sodium load of 7 to 8.75 g. The consequences of this can be debated, but for 24 hours, more than likely, nothing will happen or be noticeable. The kidneys have a wonderful ability to “dump” excess sodium ingested in the diet, as evidenced by the average Western diet with a sodium load in the range of 4 g per day.^7,8

What if I provide 0.45% NaCl instead?

Each liter provides 50% of the sodium load of 0.9% NaCl. With the 24-hour administration of 2 to 2.5 L of D5W in 0.45% NaCl, the sodium load would be 3.5 to 4.8 g, and the kidneys would dump the excess sodium.

What if I provide ‘catch-up’ fluids after 24 hours, not maintenance fluids?

Assuming only usual losses and no unusual ADH stimulation except for the physiologic stimuli from volume depletion for 24 hours, our patient would lose 2 kg (1 L fluid loss = 1 kg weight loss) and 87 mEq of sodium. This is approximately 4.5% dehydration; thus, other than increased thirst, no physical findings of volume depletion would be clinically evident.

However, serum osmolality and sodium would increase. After 24 hours of nothing by mouth with usual fluid losses, there would be a rise in serum osmolality of 13.5 mOsm/L (a rise in sodium of 6 to 7 mEq/L), which would stimulate ADH in an attempt to minimize further urinary losses. There would be an intracellular volume loss of 1.3 L (Table 1). Clinically, just as with the administration of 0.9% sodium, these changes would not likely be of any clinical consequence in the first 24 hours.

SCENARIO 2: IMPAIRED WATER EXCRETION, AND FLUIDS GIVEN

If the patient is euvolemic but has or is at risk for ADH stimulation,^1,9 providing maintenance IV fluids according to the NICE or Holliday-Segar recommendations (a total of 2 L of 0.2% NaCl = 34 mEq Na/L = 68 mOsm/L) would result in an excess of free water, as an increase in ADH secretion impairs free water clearance. A potential scenario with impaired water excretion is shown in Table 2.

After 24 hours, the patient’s serum osmolality would drop by about 7 mOsm/L, and the serum sodium would decrease by 3 or 4 mEq. The consequence of the intracellular fluid shift would be seen by the expansion of the intracellular volume from 28 to 28.7 L.

If this patient were to have received 2 L of 0.9% NaCl (308 mOsm/L × 2 L = 616 Osm) as suggested by Moritz and Ayus,¹ the result would be a serum osmolality of 284 mOsm/L, thus avoiding hyponatremia and intracellular fluid shifts.

THE BOTTOM LINE

Know your patient, answer the clinical questions noted above, and decide.

For a euvolemic patient with normal serum sodium, GFR greater than 60 mL/1.73 m², and no ADH stimulation, for 24 hours it probably doesn’t matter that much, but a daily reassessment of the continued need for and type of intravenous fluids is critical.

For patients not meeting the criteria noted above such as a patient with systolic or diastolic heart failure, advanced or end-stage renal disease puts the patient at risk for early potential complications of either hyponatremia or sodium overload. For these patients, maintenance intravenous fluids need to be chosen wisely. Daily weights, examinations, and laboratory testing will let you know if something is not right and will allow for early detection and treatment.

No, they are not required or needed, but daily radiography and arterial blood gas testing are common practice: eg, 60% of intensive care unit (ICU) patients get daily radiographs,¹ even though results provide low diagnostic yield and are unlikely to alter patient management compared with testing only when indicated.

The Choosing Wisely campaign,² a collaborative effort of a number of professional societies, advises against ordering these diagnostic tests daily because routine testing increases risks to patients and burdens the healthcare system. Instead, testing is recommended only in response to a specific clinical question, or when the test results will affect the patient’s treatment.

CHEST RADIOGRAPHS: DAILY VS CLINICALLY INDICATED

Chest radiographs enable practitioners to monitor the position of endotracheal tubes and central venous catheters, evaluate fluid status, follow up on abnormal findings, detect complications of procedures (such as a pneumothorax), and identify otherwise undetected conditions.

And daily chest radiographs often detect abnormalities. A 1991 study by Hall et al³ of 538 chest radiographs in 74 patients on mechanical ventilation reported that 30% of daily routine chest radiographs disclosed a new but minor finding (eg, a small change in endotracheal tube position or a small infiltrate). The new findings were major in 13 (17.6%) of the 74 patients (95% confidence interval [CI] 9%–26%). These included findings that required an immediate diagnostic or therapeutic intervention (eg, endotracheal tube below the tracheal carina, malposition of a catheter, pneumothorax, large pleural effusion).

But most studies say daily radiographs are not needed. In a large prospective study published in 2006, Graat et al⁴ evaluated the clinical value of 2,457 routine chest radiographs in 754 patients in a combined surgical and medical ICU. Daily chest radiographs revealed new or unexpected findings in 5.8% of cases, but only 2.2% warranted a change in therapy. No differences were found between the medical and surgical patients. The authors concluded that daily routine radiographs in ICU patients seldom reveal unexpected, clinically relevant abnormalities, and those findings rarely require urgent intervention.

A 2010 meta-analysis of 8 studies (7,078 patients) by Oba and Zaza⁵ compared on-demand and daily routine strategies of performing chest radiographs. They estimated that eliminating daily routine chest radiographs would not affect death rates in the hospital (odds ratio [OR] 1.02, 95% CI 0.89–1.17, P = .78) or the ICU (OR 0.92, 95% CI 0.76–1.11, P = .4). They also found no significant differences in length of stay or duration of mechanical ventilation. This meta-analysis suggests that routine radiographs can be eliminated without adversely affecting outcomes in ICU patients.

A larger meta-analysis (9 trials, 39,358 radiographs, 9,611 patients) published in 2012 by Ganapathy et al⁶ also found no harm associated with restrictive radiography protocols. These investigators compared a daily chest radiography protocol against a protocol based on clinical indications. The primary outcome was the mortality rate in the ICU; secondary outcomes were the mortality rate in the hospital, the length of stay in the ICU, and duration of mechanical ventilation. They found no differences between routine and restrictive strategies in terms of ICU mortality (risk ratio [RR] 1.04, 95% CI 0.84–1.28, P = .72), hospital mortality (RR 0.98, 95% CI 0.68–1.41, P = .91), or other secondary outcomes.

Clinically indicated testing is better

The conclusion from these studies is that routine chest radiographs in patients undergoing mechanical ventilation does not improve patient outcomes, and thus, a clinically indicated protocol is preferred.

Furthermore, routine daily radiographs have adverse effects such as more cumulative radiation exposure to the patient⁷ and greater risk of accidental removal of devices (eg, catheters, tubes).⁸ Another concern is a higher risk of hospital-associated infections from bacterial spread from caregivers’ hands.⁹

Finally, daily radiographs increase the use of healthcare resources and expenditures. In a 2011 study, Gershengorn et al¹ estimated that adopting a clinically indicated radiography strategy could save more than $144 million annually in the United States.

The ACR agrees. Appropriateness criteria published by the American College of Radiology (ACR) in 2015¹⁰ recommend against routine daily chest radiographs in the ICU, in keeping with the findings of the critical care community. The ACR recommends an initial radiograph at admission to the ICU. However, follow-up radiographs should be obtained only for specific clinical indications, including a change in the patient’s clinical condition or to check for proper placement of endotracheal or nasogastric or orogastric tubes, pulmonary arterial catheters, central venous catheters, chest tubes, and other life-support devices.

Ultrasonography as an alternative

Ultrasonography is widely available and provides an alternative to chest radiography for detecting significant abnormalities in patients on mechanical ventilation without exposing them to radiation and using relatively fewer resources.

A 2012 meta-analysis (8 studies, 1,048 patients) found that bedside ultrasonography reliably detects pneumothorax.¹¹ It can also provide a rapid diagnosis of the cause of acute respiratory failure such as pneumonia or pulmonary edema.¹² Ultrasonography, with the appropriate expertise, can also confirm the position of an endotracheal tube¹³ or central venous catheter.¹⁴

Arterial blood gas testing has value for managing patients undergoing mechanical ventilation, and it is one of the most commonly performed diagnostic tests in the ICU. It provides reliable information about the patient’s oxygenation and acid-base status. It is commonly requested when changing ventilator settings.

Downsides. Arterial blood gas measurements account for 10% to 20% of the cost incurred during ICU stay.¹⁵ In addition, they require an arterial puncture—an invasive procedure associated with potentially serious complications such as occlusion of the artery, digital embolization leading to digital ischemia, local infection, pseudoaneurysm, hematoma, bleeding, and skin necrosis.

Is daily testing needed?

Guidelines say no. The 2013 American Association for Respiratory Care¹⁶ guidelines suggest that arterial blood gas testing should be based on the clinical assessment of the patient. They recommend blood gas analysis to evaluate the patient’s ventilatory status (reflected by the partial pressure of arterial carbon dioxide [PaCO₂], acid-base status (reflected by pH), arterial oxygenation (partial pressure of arterial oxygen [PaO₂] and oxyhemoglobin saturation), oxygen-carrying capacity, and whether the patient likely has an intrapulmonary shunt. They state that testing is useful to quantify the response to therapeutic or diagnostic interventions such as cardiopulmonary exercise testing, to monitor severity and progression of documented disease, and to assess the adequacy of circulatory response.

Studies agree

The ACR recommendation to test “as clinically indicated” is supported by studies showing that patient outcomes are not inferior for arterial blood gas testing when clinically indicated instead of daily, and that this practice is associated with fewer complications, less resource use, and reduced overall patient care costs.

A 2015 study compared the efficacy and safety of obtaining arterial blood gases based on clinical assessment vs daily in 300 critically ill patients.¹⁷ Overall, fewer samples were obtained per patient in the clinical assessment group than in the daily group (all patients 3.7 vs 5.5; ventilated patients 2.03 vs 6.12; P < .001 for both). In ventilated patients, there was a 60% decrease in arterial blood gas orders without affecting patient outcomes and safety, including a lower risk of complications and overall cost of care.

In another study, Martinez-Balzano et al¹⁸ evaluated the effect of guidelines they developed to optimize the use of arterial blood gas testing in their ICUs. These guidelines encouraged testing of arterial blood gases after an acute respiratory event or for a rational clinical concern, and discouraged testing for routine surveillance, after planned changes of positive end-expiratory pressure or inspired oxygen fraction on mechanical ventilation, for spontaneous breathing trials, or when a disorder was not suspected.

Compared with data collected before implementation, these guidelines reduced the number of arterial blood gas tests by 821.5 per month (41.5%), or approximately 1 test per patient per mechanical-ventilation day for each month (43.1%; P < .001). Appropriately indicated testing rose to 83.4% from a baseline of 67.5% (P = .002). Additionally, this approach was associated with saving 49 liters of blood, reducing ICU costs by $39,432, and freeing up 1,643 staff work hours for other tasks. There were no significant differences in days on mechanical ventilation, severity of illness, or mortality between the 2 periods.¹⁸

Extubation effects. Routine arterial blood gas testing has not been shown to affect extubation decisions in patients on mechanical ventilation. In a study of 83 patients who completed a spontaneous breathing trial (total of 100 trials), Salam et al¹⁹ found arterial blood gas values obtained during the trial did not change the extubation decision in 93% of the cases.

In a study of 54 extubations in 52 patients,²⁰ 65% of the extubations were performed without obtaining an arterial blood gas test after the patient completed a trial of spontaneous breathing. The extubation success rate was 94% for the entire group, and it was the same regardless of whether testing was done (94.7% vs 94.3%, respectively).

Alternatives to arterial blood gases

There are less-invasive means to obtain the information that comes from an arterial blood gas test.

Pulse oximetry is a rapid noninvasive tool that provides continuous assessment of peripheral arterial oxygen saturation as a surrogate marker for tissue arterial oxygenation. However, it cannot measure PaO₂ or PaCO₂.²¹

Transcutaneous carbon dioxide (PTCO₂) monitoring is another continuous noninvasive alternative. The newer PTCO₂ devices are useful in patients with acute respiratory failure and in critically ill patients on vasopressors or vasodilators. Studies have shown good correlation between PTCO₂ and PaCO₂.^22,23

End-tidal carbon dioxide (PetCO₂) is another alternative to estimate PaCO₂. It can also be used to confirm endotracheal tube placement, during transportation, during procedures in which the patient is under conscious sedation, and to monitor the effectiveness of cardiopulmonary resuscitation and return of circulation after cardiac arrest. PetCO₂ measurements are not as accurate as arterial blood gas testing owing to a difference of approximately 2 to 5 mm Hg between PaCO₂ and PetCO₂ in normal lungs due to alveolar dead space. This difference may be much higher depending on the clinical condition and the degree of alveolar dead space.^21,24,25

Venous blood gases, which can be obtained from a peripheral or central venous catheter, are adequate to assess pH and partial pressure of carbon dioxide (PCO₂) in hemodynamically stable patients. Walkey et al²⁶ found that the accuracy of venous blood gas measurement to predict arterial blood gases was 90%. They recommended adjusting the venous pH up by 0.05 and the PCO₂ down by 5 mm Hg to account for the positive bias of venous blood gases. A limitation of this method is that the values are not reliable in patients who are in shock.

These alternatives can be used as a substitute for daily arterial blood gases. However, in certain clinical scenarios, arterial blood gas measurement remains a necessary and useful clinical tool.

TAKE-HOME MESSAGE

Most scientific evidence suggests that chest radiographs and arterial blood gas measurement in patients undergoing mechanical ventilation—and critically ill, in general—are best done when clinically indicated rather than routinely on a daily basis. This will reduce cost and harm to patients that may result from these unnecessary tests and not adversely affect outcomes.

No, they are not required or needed, but daily radiography and arterial blood gas testing are common practice: eg, 60% of intensive care unit (ICU) patients get daily radiographs,¹ even though results provide low diagnostic yield and are unlikely to alter patient management compared with testing only when indicated.

The Choosing Wisely campaign,² a collaborative effort of a number of professional societies, advises against ordering these diagnostic tests daily because routine testing increases risks to patients and burdens the healthcare system. Instead, testing is recommended only in response to a specific clinical question, or when the test results will affect the patient’s treatment.

CHEST RADIOGRAPHS: DAILY VS CLINICALLY INDICATED

Chest radiographs enable practitioners to monitor the position of endotracheal tubes and central venous catheters, evaluate fluid status, follow up on abnormal findings, detect complications of procedures (such as a pneumothorax), and identify otherwise undetected conditions.

And daily chest radiographs often detect abnormalities. A 1991 study by Hall et al³ of 538 chest radiographs in 74 patients on mechanical ventilation reported that 30% of daily routine chest radiographs disclosed a new but minor finding (eg, a small change in endotracheal tube position or a small infiltrate). The new findings were major in 13 (17.6%) of the 74 patients (95% confidence interval [CI] 9%–26%). These included findings that required an immediate diagnostic or therapeutic intervention (eg, endotracheal tube below the tracheal carina, malposition of a catheter, pneumothorax, large pleural effusion).

But most studies say daily radiographs are not needed. In a large prospective study published in 2006, Graat et al⁴ evaluated the clinical value of 2,457 routine chest radiographs in 754 patients in a combined surgical and medical ICU. Daily chest radiographs revealed new or unexpected findings in 5.8% of cases, but only 2.2% warranted a change in therapy. No differences were found between the medical and surgical patients. The authors concluded that daily routine radiographs in ICU patients seldom reveal unexpected, clinically relevant abnormalities, and those findings rarely require urgent intervention.

A 2010 meta-analysis of 8 studies (7,078 patients) by Oba and Zaza⁵ compared on-demand and daily routine strategies of performing chest radiographs. They estimated that eliminating daily routine chest radiographs would not affect death rates in the hospital (odds ratio [OR] 1.02, 95% CI 0.89–1.17, P = .78) or the ICU (OR 0.92, 95% CI 0.76–1.11, P = .4). They also found no significant differences in length of stay or duration of mechanical ventilation. This meta-analysis suggests that routine radiographs can be eliminated without adversely affecting outcomes in ICU patients.

A larger meta-analysis (9 trials, 39,358 radiographs, 9,611 patients) published in 2012 by Ganapathy et al⁶ also found no harm associated with restrictive radiography protocols. These investigators compared a daily chest radiography protocol against a protocol based on clinical indications. The primary outcome was the mortality rate in the ICU; secondary outcomes were the mortality rate in the hospital, the length of stay in the ICU, and duration of mechanical ventilation. They found no differences between routine and restrictive strategies in terms of ICU mortality (risk ratio [RR] 1.04, 95% CI 0.84–1.28, P = .72), hospital mortality (RR 0.98, 95% CI 0.68–1.41, P = .91), or other secondary outcomes.

Clinically indicated testing is better

The conclusion from these studies is that routine chest radiographs in patients undergoing mechanical ventilation does not improve patient outcomes, and thus, a clinically indicated protocol is preferred.

Furthermore, routine daily radiographs have adverse effects such as more cumulative radiation exposure to the patient⁷ and greater risk of accidental removal of devices (eg, catheters, tubes).⁸ Another concern is a higher risk of hospital-associated infections from bacterial spread from caregivers’ hands.⁹

Finally, daily radiographs increase the use of healthcare resources and expenditures. In a 2011 study, Gershengorn et al¹ estimated that adopting a clinically indicated radiography strategy could save more than $144 million annually in the United States.

The ACR agrees. Appropriateness criteria published by the American College of Radiology (ACR) in 2015¹⁰ recommend against routine daily chest radiographs in the ICU, in keeping with the findings of the critical care community. The ACR recommends an initial radiograph at admission to the ICU. However, follow-up radiographs should be obtained only for specific clinical indications, including a change in the patient’s clinical condition or to check for proper placement of endotracheal or nasogastric or orogastric tubes, pulmonary arterial catheters, central venous catheters, chest tubes, and other life-support devices.

Ultrasonography as an alternative

Ultrasonography is widely available and provides an alternative to chest radiography for detecting significant abnormalities in patients on mechanical ventilation without exposing them to radiation and using relatively fewer resources.

A 2012 meta-analysis (8 studies, 1,048 patients) found that bedside ultrasonography reliably detects pneumothorax.¹¹ It can also provide a rapid diagnosis of the cause of acute respiratory failure such as pneumonia or pulmonary edema.¹² Ultrasonography, with the appropriate expertise, can also confirm the position of an endotracheal tube¹³ or central venous catheter.¹⁴

Arterial blood gas testing has value for managing patients undergoing mechanical ventilation, and it is one of the most commonly performed diagnostic tests in the ICU. It provides reliable information about the patient’s oxygenation and acid-base status. It is commonly requested when changing ventilator settings.

Downsides. Arterial blood gas measurements account for 10% to 20% of the cost incurred during ICU stay.¹⁵ In addition, they require an arterial puncture—an invasive procedure associated with potentially serious complications such as occlusion of the artery, digital embolization leading to digital ischemia, local infection, pseudoaneurysm, hematoma, bleeding, and skin necrosis.

Is daily testing needed?

Guidelines say no. The 2013 American Association for Respiratory Care¹⁶ guidelines suggest that arterial blood gas testing should be based on the clinical assessment of the patient. They recommend blood gas analysis to evaluate the patient’s ventilatory status (reflected by the partial pressure of arterial carbon dioxide [PaCO₂], acid-base status (reflected by pH), arterial oxygenation (partial pressure of arterial oxygen [PaO₂] and oxyhemoglobin saturation), oxygen-carrying capacity, and whether the patient likely has an intrapulmonary shunt. They state that testing is useful to quantify the response to therapeutic or diagnostic interventions such as cardiopulmonary exercise testing, to monitor severity and progression of documented disease, and to assess the adequacy of circulatory response.

Studies agree

The ACR recommendation to test “as clinically indicated” is supported by studies showing that patient outcomes are not inferior for arterial blood gas testing when clinically indicated instead of daily, and that this practice is associated with fewer complications, less resource use, and reduced overall patient care costs.

A 2015 study compared the efficacy and safety of obtaining arterial blood gases based on clinical assessment vs daily in 300 critically ill patients.¹⁷ Overall, fewer samples were obtained per patient in the clinical assessment group than in the daily group (all patients 3.7 vs 5.5; ventilated patients 2.03 vs 6.12; P < .001 for both). In ventilated patients, there was a 60% decrease in arterial blood gas orders without affecting patient outcomes and safety, including a lower risk of complications and overall cost of care.

In another study, Martinez-Balzano et al¹⁸ evaluated the effect of guidelines they developed to optimize the use of arterial blood gas testing in their ICUs. These guidelines encouraged testing of arterial blood gases after an acute respiratory event or for a rational clinical concern, and discouraged testing for routine surveillance, after planned changes of positive end-expiratory pressure or inspired oxygen fraction on mechanical ventilation, for spontaneous breathing trials, or when a disorder was not suspected.

Compared with data collected before implementation, these guidelines reduced the number of arterial blood gas tests by 821.5 per month (41.5%), or approximately 1 test per patient per mechanical-ventilation day for each month (43.1%; P < .001). Appropriately indicated testing rose to 83.4% from a baseline of 67.5% (P = .002). Additionally, this approach was associated with saving 49 liters of blood, reducing ICU costs by $39,432, and freeing up 1,643 staff work hours for other tasks. There were no significant differences in days on mechanical ventilation, severity of illness, or mortality between the 2 periods.¹⁸

Extubation effects. Routine arterial blood gas testing has not been shown to affect extubation decisions in patients on mechanical ventilation. In a study of 83 patients who completed a spontaneous breathing trial (total of 100 trials), Salam et al¹⁹ found arterial blood gas values obtained during the trial did not change the extubation decision in 93% of the cases.

In a study of 54 extubations in 52 patients,²⁰ 65% of the extubations were performed without obtaining an arterial blood gas test after the patient completed a trial of spontaneous breathing. The extubation success rate was 94% for the entire group, and it was the same regardless of whether testing was done (94.7% vs 94.3%, respectively).

Alternatives to arterial blood gases

There are less-invasive means to obtain the information that comes from an arterial blood gas test.

Pulse oximetry is a rapid noninvasive tool that provides continuous assessment of peripheral arterial oxygen saturation as a surrogate marker for tissue arterial oxygenation. However, it cannot measure PaO₂ or PaCO₂.²¹

Transcutaneous carbon dioxide (PTCO₂) monitoring is another continuous noninvasive alternative. The newer PTCO₂ devices are useful in patients with acute respiratory failure and in critically ill patients on vasopressors or vasodilators. Studies have shown good correlation between PTCO₂ and PaCO₂.^22,23

End-tidal carbon dioxide (PetCO₂) is another alternative to estimate PaCO₂. It can also be used to confirm endotracheal tube placement, during transportation, during procedures in which the patient is under conscious sedation, and to monitor the effectiveness of cardiopulmonary resuscitation and return of circulation after cardiac arrest. PetCO₂ measurements are not as accurate as arterial blood gas testing owing to a difference of approximately 2 to 5 mm Hg between PaCO₂ and PetCO₂ in normal lungs due to alveolar dead space. This difference may be much higher depending on the clinical condition and the degree of alveolar dead space.^21,24,25

Venous blood gases, which can be obtained from a peripheral or central venous catheter, are adequate to assess pH and partial pressure of carbon dioxide (PCO₂) in hemodynamically stable patients. Walkey et al²⁶ found that the accuracy of venous blood gas measurement to predict arterial blood gases was 90%. They recommended adjusting the venous pH up by 0.05 and the PCO₂ down by 5 mm Hg to account for the positive bias of venous blood gases. A limitation of this method is that the values are not reliable in patients who are in shock.

These alternatives can be used as a substitute for daily arterial blood gases. However, in certain clinical scenarios, arterial blood gas measurement remains a necessary and useful clinical tool.

TAKE-HOME MESSAGE

Most scientific evidence suggests that chest radiographs and arterial blood gas measurement in patients undergoing mechanical ventilation—and critically ill, in general—are best done when clinically indicated rather than routinely on a daily basis. This will reduce cost and harm to patients that may result from these unnecessary tests and not adversely affect outcomes.

No, they are not required or needed, but daily radiography and arterial blood gas testing are common practice: eg, 60% of intensive care unit (ICU) patients get daily radiographs,¹ even though results provide low diagnostic yield and are unlikely to alter patient management compared with testing only when indicated.

The Choosing Wisely campaign,² a collaborative effort of a number of professional societies, advises against ordering these diagnostic tests daily because routine testing increases risks to patients and burdens the healthcare system. Instead, testing is recommended only in response to a specific clinical question, or when the test results will affect the patient’s treatment.

CHEST RADIOGRAPHS: DAILY VS CLINICALLY INDICATED

Chest radiographs enable practitioners to monitor the position of endotracheal tubes and central venous catheters, evaluate fluid status, follow up on abnormal findings, detect complications of procedures (such as a pneumothorax), and identify otherwise undetected conditions.

And daily chest radiographs often detect abnormalities. A 1991 study by Hall et al³ of 538 chest radiographs in 74 patients on mechanical ventilation reported that 30% of daily routine chest radiographs disclosed a new but minor finding (eg, a small change in endotracheal tube position or a small infiltrate). The new findings were major in 13 (17.6%) of the 74 patients (95% confidence interval [CI] 9%–26%). These included findings that required an immediate diagnostic or therapeutic intervention (eg, endotracheal tube below the tracheal carina, malposition of a catheter, pneumothorax, large pleural effusion).

But most studies say daily radiographs are not needed. In a large prospective study published in 2006, Graat et al⁴ evaluated the clinical value of 2,457 routine chest radiographs in 754 patients in a combined surgical and medical ICU. Daily chest radiographs revealed new or unexpected findings in 5.8% of cases, but only 2.2% warranted a change in therapy. No differences were found between the medical and surgical patients. The authors concluded that daily routine radiographs in ICU patients seldom reveal unexpected, clinically relevant abnormalities, and those findings rarely require urgent intervention.

A 2010 meta-analysis of 8 studies (7,078 patients) by Oba and Zaza⁵ compared on-demand and daily routine strategies of performing chest radiographs. They estimated that eliminating daily routine chest radiographs would not affect death rates in the hospital (odds ratio [OR] 1.02, 95% CI 0.89–1.17, P = .78) or the ICU (OR 0.92, 95% CI 0.76–1.11, P = .4). They also found no significant differences in length of stay or duration of mechanical ventilation. This meta-analysis suggests that routine radiographs can be eliminated without adversely affecting outcomes in ICU patients.

A larger meta-analysis (9 trials, 39,358 radiographs, 9,611 patients) published in 2012 by Ganapathy et al⁶ also found no harm associated with restrictive radiography protocols. These investigators compared a daily chest radiography protocol against a protocol based on clinical indications. The primary outcome was the mortality rate in the ICU; secondary outcomes were the mortality rate in the hospital, the length of stay in the ICU, and duration of mechanical ventilation. They found no differences between routine and restrictive strategies in terms of ICU mortality (risk ratio [RR] 1.04, 95% CI 0.84–1.28, P = .72), hospital mortality (RR 0.98, 95% CI 0.68–1.41, P = .91), or other secondary outcomes.

Clinically indicated testing is better

The conclusion from these studies is that routine chest radiographs in patients undergoing mechanical ventilation does not improve patient outcomes, and thus, a clinically indicated protocol is preferred.

Furthermore, routine daily radiographs have adverse effects such as more cumulative radiation exposure to the patient⁷ and greater risk of accidental removal of devices (eg, catheters, tubes).⁸ Another concern is a higher risk of hospital-associated infections from bacterial spread from caregivers’ hands.⁹

Finally, daily radiographs increase the use of healthcare resources and expenditures. In a 2011 study, Gershengorn et al¹ estimated that adopting a clinically indicated radiography strategy could save more than $144 million annually in the United States.

The ACR agrees. Appropriateness criteria published by the American College of Radiology (ACR) in 2015¹⁰ recommend against routine daily chest radiographs in the ICU, in keeping with the findings of the critical care community. The ACR recommends an initial radiograph at admission to the ICU. However, follow-up radiographs should be obtained only for specific clinical indications, including a change in the patient’s clinical condition or to check for proper placement of endotracheal or nasogastric or orogastric tubes, pulmonary arterial catheters, central venous catheters, chest tubes, and other life-support devices.

Ultrasonography as an alternative

Ultrasonography is widely available and provides an alternative to chest radiography for detecting significant abnormalities in patients on mechanical ventilation without exposing them to radiation and using relatively fewer resources.

A 2012 meta-analysis (8 studies, 1,048 patients) found that bedside ultrasonography reliably detects pneumothorax.¹¹ It can also provide a rapid diagnosis of the cause of acute respiratory failure such as pneumonia or pulmonary edema.¹² Ultrasonography, with the appropriate expertise, can also confirm the position of an endotracheal tube¹³ or central venous catheter.¹⁴

Arterial blood gas testing has value for managing patients undergoing mechanical ventilation, and it is one of the most commonly performed diagnostic tests in the ICU. It provides reliable information about the patient’s oxygenation and acid-base status. It is commonly requested when changing ventilator settings.

Downsides. Arterial blood gas measurements account for 10% to 20% of the cost incurred during ICU stay.¹⁵ In addition, they require an arterial puncture—an invasive procedure associated with potentially serious complications such as occlusion of the artery, digital embolization leading to digital ischemia, local infection, pseudoaneurysm, hematoma, bleeding, and skin necrosis.

Is daily testing needed?

Guidelines say no. The 2013 American Association for Respiratory Care¹⁶ guidelines suggest that arterial blood gas testing should be based on the clinical assessment of the patient. They recommend blood gas analysis to evaluate the patient’s ventilatory status (reflected by the partial pressure of arterial carbon dioxide [PaCO₂], acid-base status (reflected by pH), arterial oxygenation (partial pressure of arterial oxygen [PaO₂] and oxyhemoglobin saturation), oxygen-carrying capacity, and whether the patient likely has an intrapulmonary shunt. They state that testing is useful to quantify the response to therapeutic or diagnostic interventions such as cardiopulmonary exercise testing, to monitor severity and progression of documented disease, and to assess the adequacy of circulatory response.

Studies agree

The ACR recommendation to test “as clinically indicated” is supported by studies showing that patient outcomes are not inferior for arterial blood gas testing when clinically indicated instead of daily, and that this practice is associated with fewer complications, less resource use, and reduced overall patient care costs.

A 2015 study compared the efficacy and safety of obtaining arterial blood gases based on clinical assessment vs daily in 300 critically ill patients.¹⁷ Overall, fewer samples were obtained per patient in the clinical assessment group than in the daily group (all patients 3.7 vs 5.5; ventilated patients 2.03 vs 6.12; P < .001 for both). In ventilated patients, there was a 60% decrease in arterial blood gas orders without affecting patient outcomes and safety, including a lower risk of complications and overall cost of care.

In another study, Martinez-Balzano et al¹⁸ evaluated the effect of guidelines they developed to optimize the use of arterial blood gas testing in their ICUs. These guidelines encouraged testing of arterial blood gases after an acute respiratory event or for a rational clinical concern, and discouraged testing for routine surveillance, after planned changes of positive end-expiratory pressure or inspired oxygen fraction on mechanical ventilation, for spontaneous breathing trials, or when a disorder was not suspected.

Compared with data collected before implementation, these guidelines reduced the number of arterial blood gas tests by 821.5 per month (41.5%), or approximately 1 test per patient per mechanical-ventilation day for each month (43.1%; P < .001). Appropriately indicated testing rose to 83.4% from a baseline of 67.5% (P = .002). Additionally, this approach was associated with saving 49 liters of blood, reducing ICU costs by $39,432, and freeing up 1,643 staff work hours for other tasks. There were no significant differences in days on mechanical ventilation, severity of illness, or mortality between the 2 periods.¹⁸

Extubation effects. Routine arterial blood gas testing has not been shown to affect extubation decisions in patients on mechanical ventilation. In a study of 83 patients who completed a spontaneous breathing trial (total of 100 trials), Salam et al¹⁹ found arterial blood gas values obtained during the trial did not change the extubation decision in 93% of the cases.

In a study of 54 extubations in 52 patients,²⁰ 65% of the extubations were performed without obtaining an arterial blood gas test after the patient completed a trial of spontaneous breathing. The extubation success rate was 94% for the entire group, and it was the same regardless of whether testing was done (94.7% vs 94.3%, respectively).

Alternatives to arterial blood gases

There are less-invasive means to obtain the information that comes from an arterial blood gas test.

Pulse oximetry is a rapid noninvasive tool that provides continuous assessment of peripheral arterial oxygen saturation as a surrogate marker for tissue arterial oxygenation. However, it cannot measure PaO₂ or PaCO₂.²¹

Transcutaneous carbon dioxide (PTCO₂) monitoring is another continuous noninvasive alternative. The newer PTCO₂ devices are useful in patients with acute respiratory failure and in critically ill patients on vasopressors or vasodilators. Studies have shown good correlation between PTCO₂ and PaCO₂.^22,23

End-tidal carbon dioxide (PetCO₂) is another alternative to estimate PaCO₂. It can also be used to confirm endotracheal tube placement, during transportation, during procedures in which the patient is under conscious sedation, and to monitor the effectiveness of cardiopulmonary resuscitation and return of circulation after cardiac arrest. PetCO₂ measurements are not as accurate as arterial blood gas testing owing to a difference of approximately 2 to 5 mm Hg between PaCO₂ and PetCO₂ in normal lungs due to alveolar dead space. This difference may be much higher depending on the clinical condition and the degree of alveolar dead space.^21,24,25

Venous blood gases, which can be obtained from a peripheral or central venous catheter, are adequate to assess pH and partial pressure of carbon dioxide (PCO₂) in hemodynamically stable patients. Walkey et al²⁶ found that the accuracy of venous blood gas measurement to predict arterial blood gases was 90%. They recommended adjusting the venous pH up by 0.05 and the PCO₂ down by 5 mm Hg to account for the positive bias of venous blood gases. A limitation of this method is that the values are not reliable in patients who are in shock.

These alternatives can be used as a substitute for daily arterial blood gases. However, in certain clinical scenarios, arterial blood gas measurement remains a necessary and useful clinical tool.

TAKE-HOME MESSAGE

Most scientific evidence suggests that chest radiographs and arterial blood gas measurement in patients undergoing mechanical ventilation—and critically ill, in general—are best done when clinically indicated rather than routinely on a daily basis. This will reduce cost and harm to patients that may result from these unnecessary tests and not adversely affect outcomes.

In patients with cardiac stents, do not stop aspirin. If the risk of bleeding outweighs the benefit (eg, with intracranial procedures), an informed discussion involving the surgeon, cardiologist, and patient is critical to ascertain risks vs benefits.

See related editorial

In patients using aspirin for secondary prevention, the decision depends on the patient’s cardiac status and an assessment of risk vs benefit. Aspirin has no role in patients undergoing noncardiac surgery who are at low risk of a major adverse cardiac event.^1,2

Aspirin used for secondary prevention reduces rates of death from vascular causes,³ but data on the magnitude of benefit in the perioperative setting are still evolving. In patients with coronary stents, continuing aspirin is beneficial,^4,5 whereas stopping it is associated with an increased risk of acute stent thrombosis, which causes significant morbidity and mortality.⁶

SURGERY AND THROMBOTIC RISK: WHY CONSIDER ASPIRIN?

The Vascular Events in Noncardiac Surgery Patients Cohort Evaluation (VISION) study⁷ prospectively screened 15,133 patients for myocardial injury with troponin T levels daily for the first 3 consecutive postoperative days; 1,263 (8%) of the patients had a troponin elevation of 0.03 ng/mL or higher. The 30-day mortality rate in this group was 9.8%, compared with 1.1% in patients with a troponin T level of less than 0.03 ng/mL (odds ratio 10.07; 95% confidence interval [CI] 7.84–12.94; P < .001).⁸ The higher the peak troponin T concentration, the higher the risk of death within 30 days:

• 0.01 ng/mL or less, risk 1.0%
• 0.02 ng/mL, risk 4.0%
• 0.03 to 0.29 ng/mL, risk 9.3%
• 0.30 ng/mL or greater, risk 16.9%.⁷

Myocardial injury is a common postoperative vascular complication.⁷ Myocardial infarction (MI) or injury perioperatively increases the risk of death: 1 in 10 patients dies within 30 days after surgery.⁸

Surgery creates substantial physiologic stress through factors such as fasting, anesthesia, intubation, surgical trauma, extubation, and pain. It promotes coagulation⁹ and inflammation with activation of platelets,¹⁰ potentially leading to thrombosis.¹¹ Coronary thrombosis secondary to plaque rupture^11,12 can result in perioperative MI. Perioperative hemodynamic variability, anemia, and hypoxia can lead to demand-supply mismatch and also cause cardiac ischemia.

Aspirin is an antiplatelet agent that irreversibly inhibits platelet aggregation by blocking the formation of cyclooxygenase. It has been used for several decades as an antithrombotic agent in primary and secondary prevention. However, its benefit in primary prevention is uncertain, and the magnitude of antithrombotic benefit must be balanced against the risk of bleeding.

The Antithrombotic Trialists’ Collaboration¹³ performed a systematic review of 6 primary prevention trials involving 95,000 patients and found that aspirin therapy was associated with a 12% reduction in serious vascular events, which occurred in 0.51% of patients taking aspirin per year vs 0.57% of controls (P = .0001). However, aspirin also increased the risk of major bleeding, at a rate of 0.10% vs 0.07% per year (P < .0001), with 2 bleeding events for every avoided vascular event.¹³

WILL ASPIRIN PROTECT PATIENTS AT CARDIAC RISK?

The second Perioperative Ischemic Evaluation trial (POISE 2),¹ in patients with atherosclerotic disease or at risk for it, found that giving aspirin in the perioperative period did not reduce the rate of death or nonfatal MI, but increased the risk of a major bleeding event.

The trial included 10,010 patients undergoing noncardiac surgery who were randomly assigned to receive aspirin or placebo. The aspirin arm included 2 groups: patients who were not on aspirin (initiation arm), and patients on aspirin at the time of randomization (continuation arm).

Death or nonfatal MI (the primary outcome) occurred in 7.0% of patients on aspirin vs 7.1% of patients receiving placebo (hazard ratio [HR] 0.99, 95% CI 0.86–1.15, P = .92). The risk of major bleeding was 4.6% in the aspirin group vs 3.8% in the placebo group (HR 1.23, 95% CI 1.01–1.49, ^P = .04).¹

George et al,¹⁴ in a prospective observational study in a single tertiary care center, found that fewer patients with myocardial injury in noncardiac surgery died if they took aspirin or clopidogrel postoperatively. Conversely, lack of antithrombotic therapy was an independent predictor of death (P < .001). The mortality rate in patients with myocardial injury who were on antithrombotic therapy postoperatively was 6.7%, compared with 12.1% in those without postoperative antithrombotic therapy (estimated number needed to treat, 19).¹⁴

Percutaneous coronary intervention (PCI) accounts for 3.6% of all operating-room procedures in the United States,¹⁵ and 20% to 35% of patients who undergo PCI undergo noncardiac surgery within 2 years of stent implantation.^16,17

Antiplatelet therapy is discontinued in about 20% of patients with previous PCI who undergo noncardiac surgery.¹⁸

Observational data have shown that stopping antiplatelet therapy in patients with previous PCI with stent placement who undergo noncardiac surgery is the single most important predictor of stent thrombosis and death.^19–21 The risk increases if the interval between stent implantation and surgery is shorter, especially within 180 days.^16,17 Patients who have stent thrombosis are at significantly higher risk of death.

Graham et al⁴ conducted a subgroup analysis of the POISE 2 trial comparing aspirin and placebo in 470 patients who had undergone PCI (427 had stent placement, and the rest had angioplasty or an unspecified type of PCI); 234 patients received aspirin and 236 placebo. The median time from stent implantation to surgery was 5.3 years.

Of the patients in the aspirin arm, 14 (6%) had the primary outcome of death or nonfatal MI compared with 27 patients (11.5%) in the placebo arm (absolute risk reduction 5.5%, 95% CI 0.4%–10.5%). The result, which differed from that in the primary trial,¹ was due to reduction in MI in the PCI subgroup on aspirin. PCI patients who were on aspirin did not have increased bleeding risk. This subgroup analysis, albeit small and limited, suggests that continuing low-dose aspirin in patients with previous PCI, irrespective of the type of stent or the time from stent implantations, minimizes the risk of perioperative MI.

GUIDELINES AND RECOMMENDATIONS

Routine perioperative use of aspirin increases the risk of bleeding without a reduction in ischemic events.¹ Patients with prior PCI are at increased risk of acute stent thrombosis when antiplatelet medications are discontinued.^20,21 Available data, although limited, support continuing low-dose aspirin without interruption in the perioperative period in PCI patients,⁴ as do the guidelines from the American College of Cardiology.⁵

We propose a management algorithm for patients undergoing noncardiac surgery on antiplatelet therapy that takes into consideration whether the surgery is urgent, elective, or time-sensitive (Figure 1). It is imperative to involve the cardiologist, surgeon, anesthesiologist, and the patient in the decision-making process.

In the perioperative setting for patients undergoing noncardiac surgery:

• Discontinue aspirin in patients without coronary heart disease, as bleeding risk outweighs benefit.
• Consider aspirin in patients at high risk for a major adverse cardiac event if benefits outweigh risk.
• Continue low-dose aspirin without interruption in patients with a coronary stent, irrespective of the type of stent.
• If a patient has had PCI with stent placement but is not currently on aspirin, talk with the patient and the treating cardiologist to find out why, and initiate aspirin if no contraindications exist.

In patients with cardiac stents, do not stop aspirin. If the risk of bleeding outweighs the benefit (eg, with intracranial procedures), an informed discussion involving the surgeon, cardiologist, and patient is critical to ascertain risks vs benefits.

See related editorial

In patients using aspirin for secondary prevention, the decision depends on the patient’s cardiac status and an assessment of risk vs benefit. Aspirin has no role in patients undergoing noncardiac surgery who are at low risk of a major adverse cardiac event.^1,2

Aspirin used for secondary prevention reduces rates of death from vascular causes,³ but data on the magnitude of benefit in the perioperative setting are still evolving. In patients with coronary stents, continuing aspirin is beneficial,^4,5 whereas stopping it is associated with an increased risk of acute stent thrombosis, which causes significant morbidity and mortality.⁶

SURGERY AND THROMBOTIC RISK: WHY CONSIDER ASPIRIN?

The Vascular Events in Noncardiac Surgery Patients Cohort Evaluation (VISION) study⁷ prospectively screened 15,133 patients for myocardial injury with troponin T levels daily for the first 3 consecutive postoperative days; 1,263 (8%) of the patients had a troponin elevation of 0.03 ng/mL or higher. The 30-day mortality rate in this group was 9.8%, compared with 1.1% in patients with a troponin T level of less than 0.03 ng/mL (odds ratio 10.07; 95% confidence interval [CI] 7.84–12.94; P < .001).⁸ The higher the peak troponin T concentration, the higher the risk of death within 30 days:

• 0.01 ng/mL or less, risk 1.0%
• 0.02 ng/mL, risk 4.0%
• 0.03 to 0.29 ng/mL, risk 9.3%
• 0.30 ng/mL or greater, risk 16.9%.⁷

Myocardial injury is a common postoperative vascular complication.⁷ Myocardial infarction (MI) or injury perioperatively increases the risk of death: 1 in 10 patients dies within 30 days after surgery.⁸

Surgery creates substantial physiologic stress through factors such as fasting, anesthesia, intubation, surgical trauma, extubation, and pain. It promotes coagulation⁹ and inflammation with activation of platelets,¹⁰ potentially leading to thrombosis.¹¹ Coronary thrombosis secondary to plaque rupture^11,12 can result in perioperative MI. Perioperative hemodynamic variability, anemia, and hypoxia can lead to demand-supply mismatch and also cause cardiac ischemia.

Aspirin is an antiplatelet agent that irreversibly inhibits platelet aggregation by blocking the formation of cyclooxygenase. It has been used for several decades as an antithrombotic agent in primary and secondary prevention. However, its benefit in primary prevention is uncertain, and the magnitude of antithrombotic benefit must be balanced against the risk of bleeding.

The Antithrombotic Trialists’ Collaboration¹³ performed a systematic review of 6 primary prevention trials involving 95,000 patients and found that aspirin therapy was associated with a 12% reduction in serious vascular events, which occurred in 0.51% of patients taking aspirin per year vs 0.57% of controls (P = .0001). However, aspirin also increased the risk of major bleeding, at a rate of 0.10% vs 0.07% per year (P < .0001), with 2 bleeding events for every avoided vascular event.¹³

WILL ASPIRIN PROTECT PATIENTS AT CARDIAC RISK?

The second Perioperative Ischemic Evaluation trial (POISE 2),¹ in patients with atherosclerotic disease or at risk for it, found that giving aspirin in the perioperative period did not reduce the rate of death or nonfatal MI, but increased the risk of a major bleeding event.

The trial included 10,010 patients undergoing noncardiac surgery who were randomly assigned to receive aspirin or placebo. The aspirin arm included 2 groups: patients who were not on aspirin (initiation arm), and patients on aspirin at the time of randomization (continuation arm).

Death or nonfatal MI (the primary outcome) occurred in 7.0% of patients on aspirin vs 7.1% of patients receiving placebo (hazard ratio [HR] 0.99, 95% CI 0.86–1.15, P = .92). The risk of major bleeding was 4.6% in the aspirin group vs 3.8% in the placebo group (HR 1.23, 95% CI 1.01–1.49, ^P = .04).¹

George et al,¹⁴ in a prospective observational study in a single tertiary care center, found that fewer patients with myocardial injury in noncardiac surgery died if they took aspirin or clopidogrel postoperatively. Conversely, lack of antithrombotic therapy was an independent predictor of death (P < .001). The mortality rate in patients with myocardial injury who were on antithrombotic therapy postoperatively was 6.7%, compared with 12.1% in those without postoperative antithrombotic therapy (estimated number needed to treat, 19).¹⁴

Percutaneous coronary intervention (PCI) accounts for 3.6% of all operating-room procedures in the United States,¹⁵ and 20% to 35% of patients who undergo PCI undergo noncardiac surgery within 2 years of stent implantation.^16,17

Antiplatelet therapy is discontinued in about 20% of patients with previous PCI who undergo noncardiac surgery.¹⁸

Observational data have shown that stopping antiplatelet therapy in patients with previous PCI with stent placement who undergo noncardiac surgery is the single most important predictor of stent thrombosis and death.^19–21 The risk increases if the interval between stent implantation and surgery is shorter, especially within 180 days.^16,17 Patients who have stent thrombosis are at significantly higher risk of death.

Graham et al⁴ conducted a subgroup analysis of the POISE 2 trial comparing aspirin and placebo in 470 patients who had undergone PCI (427 had stent placement, and the rest had angioplasty or an unspecified type of PCI); 234 patients received aspirin and 236 placebo. The median time from stent implantation to surgery was 5.3 years.

Of the patients in the aspirin arm, 14 (6%) had the primary outcome of death or nonfatal MI compared with 27 patients (11.5%) in the placebo arm (absolute risk reduction 5.5%, 95% CI 0.4%–10.5%). The result, which differed from that in the primary trial,¹ was due to reduction in MI in the PCI subgroup on aspirin. PCI patients who were on aspirin did not have increased bleeding risk. This subgroup analysis, albeit small and limited, suggests that continuing low-dose aspirin in patients with previous PCI, irrespective of the type of stent or the time from stent implantations, minimizes the risk of perioperative MI.

GUIDELINES AND RECOMMENDATIONS

Routine perioperative use of aspirin increases the risk of bleeding without a reduction in ischemic events.¹ Patients with prior PCI are at increased risk of acute stent thrombosis when antiplatelet medications are discontinued.^20,21 Available data, although limited, support continuing low-dose aspirin without interruption in the perioperative period in PCI patients,⁴ as do the guidelines from the American College of Cardiology.⁵

We propose a management algorithm for patients undergoing noncardiac surgery on antiplatelet therapy that takes into consideration whether the surgery is urgent, elective, or time-sensitive (Figure 1). It is imperative to involve the cardiologist, surgeon, anesthesiologist, and the patient in the decision-making process.

In the perioperative setting for patients undergoing noncardiac surgery:

• Discontinue aspirin in patients without coronary heart disease, as bleeding risk outweighs benefit.
• Consider aspirin in patients at high risk for a major adverse cardiac event if benefits outweigh risk.
• Continue low-dose aspirin without interruption in patients with a coronary stent, irrespective of the type of stent.
• If a patient has had PCI with stent placement but is not currently on aspirin, talk with the patient and the treating cardiologist to find out why, and initiate aspirin if no contraindications exist.

In patients with cardiac stents, do not stop aspirin. If the risk of bleeding outweighs the benefit (eg, with intracranial procedures), an informed discussion involving the surgeon, cardiologist, and patient is critical to ascertain risks vs benefits.

See related editorial

In patients using aspirin for secondary prevention, the decision depends on the patient’s cardiac status and an assessment of risk vs benefit. Aspirin has no role in patients undergoing noncardiac surgery who are at low risk of a major adverse cardiac event.^1,2

Aspirin used for secondary prevention reduces rates of death from vascular causes,³ but data on the magnitude of benefit in the perioperative setting are still evolving. In patients with coronary stents, continuing aspirin is beneficial,^4,5 whereas stopping it is associated with an increased risk of acute stent thrombosis, which causes significant morbidity and mortality.⁶

SURGERY AND THROMBOTIC RISK: WHY CONSIDER ASPIRIN?

The Vascular Events in Noncardiac Surgery Patients Cohort Evaluation (VISION) study⁷ prospectively screened 15,133 patients for myocardial injury with troponin T levels daily for the first 3 consecutive postoperative days; 1,263 (8%) of the patients had a troponin elevation of 0.03 ng/mL or higher. The 30-day mortality rate in this group was 9.8%, compared with 1.1% in patients with a troponin T level of less than 0.03 ng/mL (odds ratio 10.07; 95% confidence interval [CI] 7.84–12.94; P < .001).⁸ The higher the peak troponin T concentration, the higher the risk of death within 30 days:

• 0.01 ng/mL or less, risk 1.0%
• 0.02 ng/mL, risk 4.0%
• 0.03 to 0.29 ng/mL, risk 9.3%
• 0.30 ng/mL or greater, risk 16.9%.⁷

Myocardial injury is a common postoperative vascular complication.⁷ Myocardial infarction (MI) or injury perioperatively increases the risk of death: 1 in 10 patients dies within 30 days after surgery.⁸

Surgery creates substantial physiologic stress through factors such as fasting, anesthesia, intubation, surgical trauma, extubation, and pain. It promotes coagulation⁹ and inflammation with activation of platelets,¹⁰ potentially leading to thrombosis.¹¹ Coronary thrombosis secondary to plaque rupture^11,12 can result in perioperative MI. Perioperative hemodynamic variability, anemia, and hypoxia can lead to demand-supply mismatch and also cause cardiac ischemia.

Aspirin is an antiplatelet agent that irreversibly inhibits platelet aggregation by blocking the formation of cyclooxygenase. It has been used for several decades as an antithrombotic agent in primary and secondary prevention. However, its benefit in primary prevention is uncertain, and the magnitude of antithrombotic benefit must be balanced against the risk of bleeding.

The Antithrombotic Trialists’ Collaboration¹³ performed a systematic review of 6 primary prevention trials involving 95,000 patients and found that aspirin therapy was associated with a 12% reduction in serious vascular events, which occurred in 0.51% of patients taking aspirin per year vs 0.57% of controls (P = .0001). However, aspirin also increased the risk of major bleeding, at a rate of 0.10% vs 0.07% per year (P < .0001), with 2 bleeding events for every avoided vascular event.¹³

WILL ASPIRIN PROTECT PATIENTS AT CARDIAC RISK?

The second Perioperative Ischemic Evaluation trial (POISE 2),¹ in patients with atherosclerotic disease or at risk for it, found that giving aspirin in the perioperative period did not reduce the rate of death or nonfatal MI, but increased the risk of a major bleeding event.

The trial included 10,010 patients undergoing noncardiac surgery who were randomly assigned to receive aspirin or placebo. The aspirin arm included 2 groups: patients who were not on aspirin (initiation arm), and patients on aspirin at the time of randomization (continuation arm).

Death or nonfatal MI (the primary outcome) occurred in 7.0% of patients on aspirin vs 7.1% of patients receiving placebo (hazard ratio [HR] 0.99, 95% CI 0.86–1.15, P = .92). The risk of major bleeding was 4.6% in the aspirin group vs 3.8% in the placebo group (HR 1.23, 95% CI 1.01–1.49, ^P = .04).¹

George et al,¹⁴ in a prospective observational study in a single tertiary care center, found that fewer patients with myocardial injury in noncardiac surgery died if they took aspirin or clopidogrel postoperatively. Conversely, lack of antithrombotic therapy was an independent predictor of death (P < .001). The mortality rate in patients with myocardial injury who were on antithrombotic therapy postoperatively was 6.7%, compared with 12.1% in those without postoperative antithrombotic therapy (estimated number needed to treat, 19).¹⁴

Percutaneous coronary intervention (PCI) accounts for 3.6% of all operating-room procedures in the United States,¹⁵ and 20% to 35% of patients who undergo PCI undergo noncardiac surgery within 2 years of stent implantation.^16,17

Antiplatelet therapy is discontinued in about 20% of patients with previous PCI who undergo noncardiac surgery.¹⁸

Observational data have shown that stopping antiplatelet therapy in patients with previous PCI with stent placement who undergo noncardiac surgery is the single most important predictor of stent thrombosis and death.^19–21 The risk increases if the interval between stent implantation and surgery is shorter, especially within 180 days.^16,17 Patients who have stent thrombosis are at significantly higher risk of death.

Graham et al⁴ conducted a subgroup analysis of the POISE 2 trial comparing aspirin and placebo in 470 patients who had undergone PCI (427 had stent placement, and the rest had angioplasty or an unspecified type of PCI); 234 patients received aspirin and 236 placebo. The median time from stent implantation to surgery was 5.3 years.

Of the patients in the aspirin arm, 14 (6%) had the primary outcome of death or nonfatal MI compared with 27 patients (11.5%) in the placebo arm (absolute risk reduction 5.5%, 95% CI 0.4%–10.5%). The result, which differed from that in the primary trial,¹ was due to reduction in MI in the PCI subgroup on aspirin. PCI patients who were on aspirin did not have increased bleeding risk. This subgroup analysis, albeit small and limited, suggests that continuing low-dose aspirin in patients with previous PCI, irrespective of the type of stent or the time from stent implantations, minimizes the risk of perioperative MI.

GUIDELINES AND RECOMMENDATIONS

Routine perioperative use of aspirin increases the risk of bleeding without a reduction in ischemic events.¹ Patients with prior PCI are at increased risk of acute stent thrombosis when antiplatelet medications are discontinued.^20,21 Available data, although limited, support continuing low-dose aspirin without interruption in the perioperative period in PCI patients,⁴ as do the guidelines from the American College of Cardiology.⁵

We propose a management algorithm for patients undergoing noncardiac surgery on antiplatelet therapy that takes into consideration whether the surgery is urgent, elective, or time-sensitive (Figure 1). It is imperative to involve the cardiologist, surgeon, anesthesiologist, and the patient in the decision-making process.

In the perioperative setting for patients undergoing noncardiac surgery:

• Discontinue aspirin in patients without coronary heart disease, as bleeding risk outweighs benefit.
• Consider aspirin in patients at high risk for a major adverse cardiac event if benefits outweigh risk.
• Continue low-dose aspirin without interruption in patients with a coronary stent, irrespective of the type of stent.
• If a patient has had PCI with stent placement but is not currently on aspirin, talk with the patient and the treating cardiologist to find out why, and initiate aspirin if no contraindications exist.

Pneumocystis jirovecii (previously carinii) pneumonia (PCP) is rare in patients taking biologic response modifiers for rheumatic disease.^1–10 However, prophylaxis should be considered in patients who have granulomatosis with polyangiitis or underlying pulmonary disease, or who are concomitantly receiving glucocorticoids in high doses. There is some risk of adverse reactions to the prophylactic medicine.^1,11–21 Until clear guidelines are available, the decision to initiate PCP prophylaxis and the choice of agent should be individualized.

THE BURDEN OF PCP

In a meta-analysis²³ of 867 patients who developed PCP and did not have HIV infection, 20.1% had autoimmune or chronic inflammatory disease and the rest were transplant recipients or had malignancies. The mortality rate was 30.6%.

PHARMACOLOGIC RISK FACTORS FOR PCP

Treatment with glucocorticoids

Treatment with glucocorticoids is an important risk factor for PCP, independent of biologic therapy.

Calero-Bernal et al¹¹ reported on 128 patients with non-HIV PCP, of whom 114 (89%) had received a glucocorticoid for more than 4 weeks, and 98 (76%) were currently receiving one. The mean daily dose was equivalent to 27.73 mg of prednisone per day in those on glucocorticoids only, and 21.34 mg in those receiving glucocorticoids in combination with other immunosuppressants.

Park et al,¹² in a retrospective study of Korean patients treated for rheumatic disease with high-dose glucocorticoids (≥ 30 mg/day of prednisone or equivalent for more than 4 weeks), reported an incidence rate of PCP of 2.37 per 100 patient-years in those not on prophylaxis.

Other studies^13,14 have also found a prednisone dose greater than 15 to 20 mg per day for more than 4 weeks or concomitant use of 2 or more disease-modifying antirheumatic drugs to be a significant risk factor.^13,14

Tumor necrosis factor alpha antagonists

A US Food and Drug Administration review¹ of voluntary reports of adverse drug events estimated the incidence of PCP to be 2.3 per 100,000 patient-years with infliximab and 1.6 per 100,000 patient-years with etanercept. In most cases, other immunosuppressants were used concomitantly.¹

Postmarketing surveillance² of 5,000 patients with rheumatoid arthritis showed an incidence of suspected PCP of 0.4% within the first 6 months of starting infliximab therapy.

Komano et al,¹⁵ in a case-control study of patients with rheumatoid arthritis treated with infliximab, reported that all 21 patients with PCP were also on methotrexate (median dosage 8 mg per week) and prednisolone (median dosage 7.5 mg per day).

PCP has also been reported after adalimumab use in combination with prednisone, azathioprine, and methotrexate, as well as with certolizumab, golimumab, tocilizumab, abatacept, and rituximab.^{3–6,24–26}

Rituximab

Calero-Bernal et al¹¹ reported that 23% of patients with non-HIV PCP who were receiving immunosuppressant drugs were on rituximab.

Alexandre et al¹⁶ performed a retrospective review of 11 cases of PCP complicating rituximab therapy for autoimmune disease, in which 10 (91%) of the patients were also on corticosteroids, with a median dosage of 30 mg of prednisone daily. A literature review of an additional 18 cases revealed similar findings.

Pulmonary disease, age, other factors

Komano et al,¹⁵ in their study of patients with rheumatoid arthritis treated with infliximab, found that 10 (48%) of 21 patients with PCP had preexisting pulmonary disease, compared with 11 (10.8%) of 102 patients without PCP (P < .001). Patients with PCP were older (mean age 64 vs 54, P < .001), were on higher median doses of prednisolone per day (7.5 vs 5 mg, P = .001), and had lower median serum immunoglobulin G (IgG) levels (944 vs 1,394 mg/dL, P < .001).¹⁵ 

Tadros et al¹³ performed a case-control study that also showed that patients with autoimmune disease who developed PCP had lower lymphocyte counts than controls on admission. Other risk factors included low CD4 counts and age older than 50.

Li et al¹⁷ found that patients with autoimmune or inflammatory disease with PCP were more likely to have low CD3, CD4, and CD8 cell counts, as well as albumin levels less than 28 g/L. They therefore suggested that lymphocyte subtyping may be a useful tool to guide PCP prophylaxis.

Granulomatosis with polyangiitis

Patients with granulomatosis with polyangiitis have a significantly higher incidence of PCP than patients with other connective tissue diseases.

Ward and Donald¹⁸ reviewed 223 cases of PCP in patients with connective tissue disease. The highest frequency (89 cases per 10,000 hospitalizations per year) was in patients with granulomatosis with polyangiitis, followed by 65 per 10,000 hospitalizations per year for patients with polyarteritis nodosa. The lowest frequency was in rheumatoid arthritis patients, at 2 per 10,000 hospitalizations per year. In decreasing order, diseases with significant associations with PCP were:

• Polyarteritis nodosa (odds ratio [OR] 10.20, 95% confidence interval [CI] 5.69–18.29)
• Granulomatosis with polyangiitis (OR 7.81, 95% CI 4.71–13.05)
• Inflammatory myopathy (OR 4.44, 95% CI 2.67–7.38)
• Systemic lupus erythematosus (OR 2.52, 95% CI 1.66–3.82).

Vallabhaneni and Chiller,²⁶ in a meta-analysis including rheumatoid arthritis patients on biologics, did not find an increased risk of PCP (OR 1.77, 95% CI 0.42–7.47).

Park et al¹² found that the highest incidences of PCP were in patients with granulomatosis with polyangiitis, microscopic polyangiitis, and systemic sclerosis. For systemic sclerosis, the main reason for giving high-dose glucocorticoids was interstitial lung disease.

Other studies^19,20,28 also found an association with coexisting pulmonary disease in patients with rheumatoid arthritis.

CURRENT GUIDELINES

There are guidelines for primary and secondary prophylaxis of PCP in HIV-positive patients with CD4 counts less than 200/mm³ or a history of acquired immunodeficiency syndrome (AIDS)-defining illness.²⁷ Additionally, patients with a CD4 cell percentage less than 14% should be considered for prophylaxis.²⁷

Unfortunately, there are no guidelines for prophylaxis in patients taking immunosuppressants for rheumatic disease.

The recommended regimen for PCP prophylaxis in HIV-infected patients is trimethoprim-sulfamethoxazole, 1 double-strength or 1 single-strength tablet daily. Alternative regimens include 1 double-strength tablet 3 times per week, dapsone, aerosolized pentamidine, and atovaquone.²⁷

There are also guidelines for prophylaxis in kidney transplant recipients, as well as for patients with hematologic malignancies and solid-organ malignancies, particularly those on chemotherapeutic agents and the T-cell-depleting agent alemtuzumab.^29–31

Italian clinical practice guidelines for the use of tumor necrosis factor antagonists in inflammatory bowel disease recommend consideration of PCP prophylaxis in patients who are also on other immunosuppressants, particularly high-dose glucocorticoids.³²

Prophylaxis has been shown to increase life expectancy and quality-adjusted life-years and to reduce cost for patients on immunosuppressive therapy for granulomatosis with polyangiitis.²¹ The European Society of Clinical Microbiology and Infectious Diseases recently produced consensus statements recommending PCP prophylaxis for patients on rituximab with other concomitant immunosuppressants such as the equivalent of prednisone 20 mg daily for more than 4 weeks.³³ Prophylaxis was not recommended for other biologic therapies.^34,35

THE RISKS OF PROPHYLAXIS

The risk of PCP should be weighed against the risk of prophylaxis in patients with rheumatic disease. Adverse reactions to sulfonamide antibiotics including disease flares have been reported in patients with systemic lupus erythematosus.^36,37 Other studies have found no increased risk of flares in patients taking trimethoprim-sulfamethoxazole for PCP prophylaxis.^12,38 A retrospective analysis of patients with vasculitis found no increased risk of combining methotrexate and trimethoprim-sulfamethoxazole.³⁹

KEY POINTS

• PCP is an opportunistic infection with a high risk of death.
• PCP has been reported with biologics used as immunomodulators in rheumatic disease.
• PCP prophylaxis should be considered in patients at high risk of PCP, such as those who have granulomatosis with polyangiitis, underlying pulmonary disease or who are concomitantly taking glucocorticoids.

Pneumocystis jirovecii (previously carinii) pneumonia (PCP) is rare in patients taking biologic response modifiers for rheumatic disease.^1–10 However, prophylaxis should be considered in patients who have granulomatosis with polyangiitis or underlying pulmonary disease, or who are concomitantly receiving glucocorticoids in high doses. There is some risk of adverse reactions to the prophylactic medicine.^1,11–21 Until clear guidelines are available, the decision to initiate PCP prophylaxis and the choice of agent should be individualized.

THE BURDEN OF PCP

In a meta-analysis²³ of 867 patients who developed PCP and did not have HIV infection, 20.1% had autoimmune or chronic inflammatory disease and the rest were transplant recipients or had malignancies. The mortality rate was 30.6%.

PHARMACOLOGIC RISK FACTORS FOR PCP

Treatment with glucocorticoids

Treatment with glucocorticoids is an important risk factor for PCP, independent of biologic therapy.

Calero-Bernal et al¹¹ reported on 128 patients with non-HIV PCP, of whom 114 (89%) had received a glucocorticoid for more than 4 weeks, and 98 (76%) were currently receiving one. The mean daily dose was equivalent to 27.73 mg of prednisone per day in those on glucocorticoids only, and 21.34 mg in those receiving glucocorticoids in combination with other immunosuppressants.

Park et al,¹² in a retrospective study of Korean patients treated for rheumatic disease with high-dose glucocorticoids (≥ 30 mg/day of prednisone or equivalent for more than 4 weeks), reported an incidence rate of PCP of 2.37 per 100 patient-years in those not on prophylaxis.

Other studies^13,14 have also found a prednisone dose greater than 15 to 20 mg per day for more than 4 weeks or concomitant use of 2 or more disease-modifying antirheumatic drugs to be a significant risk factor.^13,14

Tumor necrosis factor alpha antagonists

A US Food and Drug Administration review¹ of voluntary reports of adverse drug events estimated the incidence of PCP to be 2.3 per 100,000 patient-years with infliximab and 1.6 per 100,000 patient-years with etanercept. In most cases, other immunosuppressants were used concomitantly.¹

Postmarketing surveillance² of 5,000 patients with rheumatoid arthritis showed an incidence of suspected PCP of 0.4% within the first 6 months of starting infliximab therapy.

Komano et al,¹⁵ in a case-control study of patients with rheumatoid arthritis treated with infliximab, reported that all 21 patients with PCP were also on methotrexate (median dosage 8 mg per week) and prednisolone (median dosage 7.5 mg per day).

PCP has also been reported after adalimumab use in combination with prednisone, azathioprine, and methotrexate, as well as with certolizumab, golimumab, tocilizumab, abatacept, and rituximab.^{3–6,24–26}

Rituximab

Calero-Bernal et al¹¹ reported that 23% of patients with non-HIV PCP who were receiving immunosuppressant drugs were on rituximab.

Alexandre et al¹⁶ performed a retrospective review of 11 cases of PCP complicating rituximab therapy for autoimmune disease, in which 10 (91%) of the patients were also on corticosteroids, with a median dosage of 30 mg of prednisone daily. A literature review of an additional 18 cases revealed similar findings.

Pulmonary disease, age, other factors

Komano et al,¹⁵ in their study of patients with rheumatoid arthritis treated with infliximab, found that 10 (48%) of 21 patients with PCP had preexisting pulmonary disease, compared with 11 (10.8%) of 102 patients without PCP (P < .001). Patients with PCP were older (mean age 64 vs 54, P < .001), were on higher median doses of prednisolone per day (7.5 vs 5 mg, P = .001), and had lower median serum immunoglobulin G (IgG) levels (944 vs 1,394 mg/dL, P < .001).¹⁵ 

Tadros et al¹³ performed a case-control study that also showed that patients with autoimmune disease who developed PCP had lower lymphocyte counts than controls on admission. Other risk factors included low CD4 counts and age older than 50.

Li et al¹⁷ found that patients with autoimmune or inflammatory disease with PCP were more likely to have low CD3, CD4, and CD8 cell counts, as well as albumin levels less than 28 g/L. They therefore suggested that lymphocyte subtyping may be a useful tool to guide PCP prophylaxis.

Granulomatosis with polyangiitis

Patients with granulomatosis with polyangiitis have a significantly higher incidence of PCP than patients with other connective tissue diseases.

Ward and Donald¹⁸ reviewed 223 cases of PCP in patients with connective tissue disease. The highest frequency (89 cases per 10,000 hospitalizations per year) was in patients with granulomatosis with polyangiitis, followed by 65 per 10,000 hospitalizations per year for patients with polyarteritis nodosa. The lowest frequency was in rheumatoid arthritis patients, at 2 per 10,000 hospitalizations per year. In decreasing order, diseases with significant associations with PCP were:

• Polyarteritis nodosa (odds ratio [OR] 10.20, 95% confidence interval [CI] 5.69–18.29)
• Granulomatosis with polyangiitis (OR 7.81, 95% CI 4.71–13.05)
• Inflammatory myopathy (OR 4.44, 95% CI 2.67–7.38)
• Systemic lupus erythematosus (OR 2.52, 95% CI 1.66–3.82).

Vallabhaneni and Chiller,²⁶ in a meta-analysis including rheumatoid arthritis patients on biologics, did not find an increased risk of PCP (OR 1.77, 95% CI 0.42–7.47).

Park et al¹² found that the highest incidences of PCP were in patients with granulomatosis with polyangiitis, microscopic polyangiitis, and systemic sclerosis. For systemic sclerosis, the main reason for giving high-dose glucocorticoids was interstitial lung disease.

Other studies^19,20,28 also found an association with coexisting pulmonary disease in patients with rheumatoid arthritis.

CURRENT GUIDELINES

There are guidelines for primary and secondary prophylaxis of PCP in HIV-positive patients with CD4 counts less than 200/mm³ or a history of acquired immunodeficiency syndrome (AIDS)-defining illness.²⁷ Additionally, patients with a CD4 cell percentage less than 14% should be considered for prophylaxis.²⁷

Unfortunately, there are no guidelines for prophylaxis in patients taking immunosuppressants for rheumatic disease.

The recommended regimen for PCP prophylaxis in HIV-infected patients is trimethoprim-sulfamethoxazole, 1 double-strength or 1 single-strength tablet daily. Alternative regimens include 1 double-strength tablet 3 times per week, dapsone, aerosolized pentamidine, and atovaquone.²⁷

There are also guidelines for prophylaxis in kidney transplant recipients, as well as for patients with hematologic malignancies and solid-organ malignancies, particularly those on chemotherapeutic agents and the T-cell-depleting agent alemtuzumab.^29–31

Italian clinical practice guidelines for the use of tumor necrosis factor antagonists in inflammatory bowel disease recommend consideration of PCP prophylaxis in patients who are also on other immunosuppressants, particularly high-dose glucocorticoids.³²

Prophylaxis has been shown to increase life expectancy and quality-adjusted life-years and to reduce cost for patients on immunosuppressive therapy for granulomatosis with polyangiitis.²¹ The European Society of Clinical Microbiology and Infectious Diseases recently produced consensus statements recommending PCP prophylaxis for patients on rituximab with other concomitant immunosuppressants such as the equivalent of prednisone 20 mg daily for more than 4 weeks.³³ Prophylaxis was not recommended for other biologic therapies.^34,35

THE RISKS OF PROPHYLAXIS

The risk of PCP should be weighed against the risk of prophylaxis in patients with rheumatic disease. Adverse reactions to sulfonamide antibiotics including disease flares have been reported in patients with systemic lupus erythematosus.^36,37 Other studies have found no increased risk of flares in patients taking trimethoprim-sulfamethoxazole for PCP prophylaxis.^12,38 A retrospective analysis of patients with vasculitis found no increased risk of combining methotrexate and trimethoprim-sulfamethoxazole.³⁹

KEY POINTS

• PCP is an opportunistic infection with a high risk of death.
• PCP has been reported with biologics used as immunomodulators in rheumatic disease.
• PCP prophylaxis should be considered in patients at high risk of PCP, such as those who have granulomatosis with polyangiitis, underlying pulmonary disease or who are concomitantly taking glucocorticoids.

Pneumocystis jirovecii (previously carinii) pneumonia (PCP) is rare in patients taking biologic response modifiers for rheumatic disease.^1–10 However, prophylaxis should be considered in patients who have granulomatosis with polyangiitis or underlying pulmonary disease, or who are concomitantly receiving glucocorticoids in high doses. There is some risk of adverse reactions to the prophylactic medicine.^1,11–21 Until clear guidelines are available, the decision to initiate PCP prophylaxis and the choice of agent should be individualized.

THE BURDEN OF PCP

In a meta-analysis²³ of 867 patients who developed PCP and did not have HIV infection, 20.1% had autoimmune or chronic inflammatory disease and the rest were transplant recipients or had malignancies. The mortality rate was 30.6%.

PHARMACOLOGIC RISK FACTORS FOR PCP

Treatment with glucocorticoids

Treatment with glucocorticoids is an important risk factor for PCP, independent of biologic therapy.

Calero-Bernal et al¹¹ reported on 128 patients with non-HIV PCP, of whom 114 (89%) had received a glucocorticoid for more than 4 weeks, and 98 (76%) were currently receiving one. The mean daily dose was equivalent to 27.73 mg of prednisone per day in those on glucocorticoids only, and 21.34 mg in those receiving glucocorticoids in combination with other immunosuppressants.

Park et al,¹² in a retrospective study of Korean patients treated for rheumatic disease with high-dose glucocorticoids (≥ 30 mg/day of prednisone or equivalent for more than 4 weeks), reported an incidence rate of PCP of 2.37 per 100 patient-years in those not on prophylaxis.

Other studies^13,14 have also found a prednisone dose greater than 15 to 20 mg per day for more than 4 weeks or concomitant use of 2 or more disease-modifying antirheumatic drugs to be a significant risk factor.^13,14

Tumor necrosis factor alpha antagonists

A US Food and Drug Administration review¹ of voluntary reports of adverse drug events estimated the incidence of PCP to be 2.3 per 100,000 patient-years with infliximab and 1.6 per 100,000 patient-years with etanercept. In most cases, other immunosuppressants were used concomitantly.¹

Postmarketing surveillance² of 5,000 patients with rheumatoid arthritis showed an incidence of suspected PCP of 0.4% within the first 6 months of starting infliximab therapy.

Komano et al,¹⁵ in a case-control study of patients with rheumatoid arthritis treated with infliximab, reported that all 21 patients with PCP were also on methotrexate (median dosage 8 mg per week) and prednisolone (median dosage 7.5 mg per day).

PCP has also been reported after adalimumab use in combination with prednisone, azathioprine, and methotrexate, as well as with certolizumab, golimumab, tocilizumab, abatacept, and rituximab.^{3–6,24–26}

Rituximab

Calero-Bernal et al¹¹ reported that 23% of patients with non-HIV PCP who were receiving immunosuppressant drugs were on rituximab.

Alexandre et al¹⁶ performed a retrospective review of 11 cases of PCP complicating rituximab therapy for autoimmune disease, in which 10 (91%) of the patients were also on corticosteroids, with a median dosage of 30 mg of prednisone daily. A literature review of an additional 18 cases revealed similar findings.

Pulmonary disease, age, other factors

Komano et al,¹⁵ in their study of patients with rheumatoid arthritis treated with infliximab, found that 10 (48%) of 21 patients with PCP had preexisting pulmonary disease, compared with 11 (10.8%) of 102 patients without PCP (P < .001). Patients with PCP were older (mean age 64 vs 54, P < .001), were on higher median doses of prednisolone per day (7.5 vs 5 mg, P = .001), and had lower median serum immunoglobulin G (IgG) levels (944 vs 1,394 mg/dL, P < .001).¹⁵ 

Tadros et al¹³ performed a case-control study that also showed that patients with autoimmune disease who developed PCP had lower lymphocyte counts than controls on admission. Other risk factors included low CD4 counts and age older than 50.

Li et al¹⁷ found that patients with autoimmune or inflammatory disease with PCP were more likely to have low CD3, CD4, and CD8 cell counts, as well as albumin levels less than 28 g/L. They therefore suggested that lymphocyte subtyping may be a useful tool to guide PCP prophylaxis.

Granulomatosis with polyangiitis

Patients with granulomatosis with polyangiitis have a significantly higher incidence of PCP than patients with other connective tissue diseases.

Ward and Donald¹⁸ reviewed 223 cases of PCP in patients with connective tissue disease. The highest frequency (89 cases per 10,000 hospitalizations per year) was in patients with granulomatosis with polyangiitis, followed by 65 per 10,000 hospitalizations per year for patients with polyarteritis nodosa. The lowest frequency was in rheumatoid arthritis patients, at 2 per 10,000 hospitalizations per year. In decreasing order, diseases with significant associations with PCP were:

• Polyarteritis nodosa (odds ratio [OR] 10.20, 95% confidence interval [CI] 5.69–18.29)
• Granulomatosis with polyangiitis (OR 7.81, 95% CI 4.71–13.05)
• Inflammatory myopathy (OR 4.44, 95% CI 2.67–7.38)
• Systemic lupus erythematosus (OR 2.52, 95% CI 1.66–3.82).

Vallabhaneni and Chiller,²⁶ in a meta-analysis including rheumatoid arthritis patients on biologics, did not find an increased risk of PCP (OR 1.77, 95% CI 0.42–7.47).

Park et al¹² found that the highest incidences of PCP were in patients with granulomatosis with polyangiitis, microscopic polyangiitis, and systemic sclerosis. For systemic sclerosis, the main reason for giving high-dose glucocorticoids was interstitial lung disease.

Other studies^19,20,28 also found an association with coexisting pulmonary disease in patients with rheumatoid arthritis.

CURRENT GUIDELINES

There are guidelines for primary and secondary prophylaxis of PCP in HIV-positive patients with CD4 counts less than 200/mm³ or a history of acquired immunodeficiency syndrome (AIDS)-defining illness.²⁷ Additionally, patients with a CD4 cell percentage less than 14% should be considered for prophylaxis.²⁷

Unfortunately, there are no guidelines for prophylaxis in patients taking immunosuppressants for rheumatic disease.

The recommended regimen for PCP prophylaxis in HIV-infected patients is trimethoprim-sulfamethoxazole, 1 double-strength or 1 single-strength tablet daily. Alternative regimens include 1 double-strength tablet 3 times per week, dapsone, aerosolized pentamidine, and atovaquone.²⁷

There are also guidelines for prophylaxis in kidney transplant recipients, as well as for patients with hematologic malignancies and solid-organ malignancies, particularly those on chemotherapeutic agents and the T-cell-depleting agent alemtuzumab.^29–31

Italian clinical practice guidelines for the use of tumor necrosis factor antagonists in inflammatory bowel disease recommend consideration of PCP prophylaxis in patients who are also on other immunosuppressants, particularly high-dose glucocorticoids.³²

Prophylaxis has been shown to increase life expectancy and quality-adjusted life-years and to reduce cost for patients on immunosuppressive therapy for granulomatosis with polyangiitis.²¹ The European Society of Clinical Microbiology and Infectious Diseases recently produced consensus statements recommending PCP prophylaxis for patients on rituximab with other concomitant immunosuppressants such as the equivalent of prednisone 20 mg daily for more than 4 weeks.³³ Prophylaxis was not recommended for other biologic therapies.^34,35

THE RISKS OF PROPHYLAXIS

The risk of PCP should be weighed against the risk of prophylaxis in patients with rheumatic disease. Adverse reactions to sulfonamide antibiotics including disease flares have been reported in patients with systemic lupus erythematosus.^36,37 Other studies have found no increased risk of flares in patients taking trimethoprim-sulfamethoxazole for PCP prophylaxis.^12,38 A retrospective analysis of patients with vasculitis found no increased risk of combining methotrexate and trimethoprim-sulfamethoxazole.³⁹

KEY POINTS

• PCP is an opportunistic infection with a high risk of death.
• PCP has been reported with biologics used as immunomodulators in rheumatic disease.
• PCP prophylaxis should be considered in patients at high risk of PCP, such as those who have granulomatosis with polyangiitis, underlying pulmonary disease or who are concomitantly taking glucocorticoids.