Cardiac Surgical Transfusions Linked to Infection Risk

FT. LAUDERDALE, FLA. – Transfusion of packed red blood cells during cardiac surgery is independently associated with increased risk of major infection, researchers reported, and – in a related study – pneumonia was found to be the most common infection associated with cardiac surgery.

Cardiac procedures with transfusions were associated with a significant risk of infection, such that "with every unit of blood, you had a significant increase in the risk of infection for the patient. It appears that there might be some sort of threshold in the 2- to 4-unit range, whereafter the risk really seems to increase. But statistically, even that first drop of blood carried an additional infectious risk," Dr. Keith A. Horvath said at the annual meeting of the Society of Thoracic Surgeons.

In a related study, researchers found pneumonia to be the most common infection associated with cardiac surgery. "Pneumonia, surprisingly, was the most common infection, at 2.4%. This was much more common than other infections that we certainly worry about and get a fair amount of press and literature on, specifically sternal wound infections," said Dr. Gorav Ailawadi of the University of Virginia in Charlottesville.

Data for 5,184 adult cardiac patients were used for both studies. The patients were prospectively enrolled in a 10-center infection registry between February and September, 2010. Captured data included infection occurrence, type, and organism. Adjudication was performed by an independent panel of infectious diseases experts.

Major infections evaluated in the study included deep incisional surgical (chest), deep incisional surgical (second incisions), empyema, endocarditis, mediastinitis, myocarditis, pneumonia, bloodstream infections, Clostridium difficile colitis, and cardiac device infections. Infections were defined by a combination of clinical, laboratory, and/or radiologic evidence (according to Centers for Disease Control and Prevention surveillance definitions) for a follow-up of 65 days.

The researchers included several types of surgical interventions: isolated coronary artery bypass graft (CABG), isolated valve surgery, CABG with valve surgery, surgery for heart failure, thoracic aortic surgery, and other procedures.

The mean patient age was 64 years, mean bypass time was 115 minutes, two-thirds (67%) were men, 71% had heart failure, a quarter (27%) had diabetes, 14% had chronic obstructive pulmonary disease (COPD), and 19% had prior cardiac surgery. Mean hemoglobin was 13.2 mg/dL.

There was a significant dose-dependent association between quantity of packed red blood cells (PRBCs) and risk of infection, with the crude risk increasing by an average of 29% with each PRBC unit.

Several factors increased the risk of infection, including severe COPD (relative risk, 1.85), preoperative creatinine levels greater than 1.5 mg/dL (RR, 1.72), heart failure (RR, 1.49), mild to moderate COPD (RR, 1.36), PRBCs per unit (RR, 1.24), and surgery time per 60 minutes (RR, 1.19).

Platelet transfusion occurred in 31% of patients. However, the use of platelets was associated with a decreased risk of infection (RR, 0.71). Cell Saver use was not related to infection.

Creatinine levels greater than 1.5 mg/dL (RR, 2.40) and PRBCs per unit (RR, 1.23) significantly increased the risk of death. Many factors significantly increased the length of stay, including creatinine levels greater than 1.5 mg/dL (RR, 1.26), severe COPD (RR, 1.41), mild to moderate COPD (RR, 1.14), heart failure (RR, 1.36), PRBCs (RR, 1.12), surgery time per 60 minutes (RR, 1.11), age of 65-79 years (RR, 1.21), and age older than 80 years (RR, 1.44). The use of platelets was associated with a decreased length of stay (RR, 0.71).

All risks of transfusion must be weighed against toleration anemia, which is also associated with adverse outcomes, according to Dr. Horvath, who is the director of the Cardiothoracic Surgery Research Program for the National Heart, Lung, and Blood Institute and a member of the Cardiothoracic Surgery Trials Network.

Efforts to reduce PRBC transfusions may significantly reduce major postoperative infections. Cell salvage and ultrafiltration could be viable alternatives, he noted.

In the second study, the researchers used the same dataset. Captured data included infection occurrence, type, timing, and organisms. Infections were adjudicated by an independent panel of infectious disease experts. The risk of pneumonia, mortality, and length of stay (time to discharge) were analyzed.

Major infections included bloodstream, pneumonia, C. difficile, deep sternal incisional, mediastinitis, deep groin/leg incisional, endocarditis, and empyema.

Pneumonia was diagnosed using the 2010 surveillance criteria from the CDC/National Healthcare Safety Network, including chest x-ray with new or progressive and persistent infiltrate; fever greater than 38° C; leukopenia (defined as fewer than 4,000 leukocytes per cc); leukocytosis (at least 12,000 leukocytes per cc); or altered mental status. At least two of the following must have been present as well: purulent sputum or change; cough, dyspnea, or tachypnea; rales or bronchial breath sounds; or worsening gas exchange. Duration of follow-up was 65 days.

In all, 31% had isolated CABG, 30% had isolated valve surgery, 11% had CABG and valve surgery, 6% had thoracic aortic surgery, 2% had left ventricular assist device (LVAD) implantation/heart transplant, and 20% were categorized as other.

Overall, 2.4% of patients in the registry had pneumonia, 1.1% had blood stream infection, 1% had C. difficile colitis, and 0.5% had deep sternal infections.

The overall mean time to infection was 19 days and the median was 14 days. The mean time to infection for pneumonia was 15 days. Overall, more than 40% of infections occurred after the index hospitalization. However, 68% and 66% of pneumonias and blood stream infections, respectively, occurred during hospitalization. The three most common organisms were Pseudomonas aeruginosa (12%), Enterobacter cloacae (8%), and Klebsiella pneumoniae (7%).

Increased risk of pneumonia was associated with surgery time (RR, 1.42), a creatinine level of at least 1.5 mg/dL (RR, 1.94), mild to moderate COPD (RR, 1.78), severe COPD (RR, 4.12), and heart failure (RR, 1.76). The reference category was those without COPD.

In terms of process-of-care factors, only nasal decontamination with mupirocin was associated with reduced risk of pneumonia (RR, 0.77). Nasal decontamination with other agents (RR, 1.44); antibiotics given within 24 hours after surgery (RR, 1.26) and within 48 hours postop (RR, 2.70); ventilator use of 24-48 hours (RR, 2.31) and more than 48 hours (RR, 4.58); nasogastric tube (RR, 2.07); and use of PRBCs (RR, 1.10) were all associated with increased risk of pneumonia.

In terms of mortality, "pneumonia, among all the factors analyzed, had the greatest association with mortality, with an odds ratio greater than seven ... which was far and away greater than anything else that was examined," said Dr. Ailawadi.

Pneumonia was significantly associated with an increased risk of mortality (RR, 7.07), as were heart failure (RR, 1.87), creatinine levels of at least 1.5 mg/dL (RR, 2.97), and surgery duration (1.27). However, black race appeared to be protective, with a significantly decreased risk of pneumonia (RR, 0.43).

Pneumonia significantly increased the length of stay by a median of 13 days (19 days with pneumonia and 6 days without). A number of factors – mild to moderate COPD, severe COPD, heart failure, creatinine levels of at least 1.5 mg/dL, surgery time, age of 65-79 years, age 80 years and older, and black or Hispanic race – were significantly associated with increased risk of longer length of stay. Male sex was significantly associated with decreased length of stay (RR, 0.79).

Both Dr. Horvath and Dr. Ailawadi reported that they have no relevant financial disclosures.

FT. LAUDERDALE, FLA. – Transfusion of packed red blood cells during cardiac surgery is independently associated with increased risk of major infection, researchers reported, and – in a related study – pneumonia was found to be the most common infection associated with cardiac surgery.

Cardiac procedures with transfusions were associated with a significant risk of infection, such that "with every unit of blood, you had a significant increase in the risk of infection for the patient. It appears that there might be some sort of threshold in the 2- to 4-unit range, whereafter the risk really seems to increase. But statistically, even that first drop of blood carried an additional infectious risk," Dr. Keith A. Horvath said at the annual meeting of the Society of Thoracic Surgeons.

In a related study, researchers found pneumonia to be the most common infection associated with cardiac surgery. "Pneumonia, surprisingly, was the most common infection, at 2.4%. This was much more common than other infections that we certainly worry about and get a fair amount of press and literature on, specifically sternal wound infections," said Dr. Gorav Ailawadi of the University of Virginia in Charlottesville.

Data for 5,184 adult cardiac patients were used for both studies. The patients were prospectively enrolled in a 10-center infection registry between February and September, 2010. Captured data included infection occurrence, type, and organism. Adjudication was performed by an independent panel of infectious diseases experts.

Major infections evaluated in the study included deep incisional surgical (chest), deep incisional surgical (second incisions), empyema, endocarditis, mediastinitis, myocarditis, pneumonia, bloodstream infections, Clostridium difficile colitis, and cardiac device infections. Infections were defined by a combination of clinical, laboratory, and/or radiologic evidence (according to Centers for Disease Control and Prevention surveillance definitions) for a follow-up of 65 days.

The researchers included several types of surgical interventions: isolated coronary artery bypass graft (CABG), isolated valve surgery, CABG with valve surgery, surgery for heart failure, thoracic aortic surgery, and other procedures.

The mean patient age was 64 years, mean bypass time was 115 minutes, two-thirds (67%) were men, 71% had heart failure, a quarter (27%) had diabetes, 14% had chronic obstructive pulmonary disease (COPD), and 19% had prior cardiac surgery. Mean hemoglobin was 13.2 mg/dL.

There was a significant dose-dependent association between quantity of packed red blood cells (PRBCs) and risk of infection, with the crude risk increasing by an average of 29% with each PRBC unit.

Several factors increased the risk of infection, including severe COPD (relative risk, 1.85), preoperative creatinine levels greater than 1.5 mg/dL (RR, 1.72), heart failure (RR, 1.49), mild to moderate COPD (RR, 1.36), PRBCs per unit (RR, 1.24), and surgery time per 60 minutes (RR, 1.19).

Platelet transfusion occurred in 31% of patients. However, the use of platelets was associated with a decreased risk of infection (RR, 0.71). Cell Saver use was not related to infection.

Creatinine levels greater than 1.5 mg/dL (RR, 2.40) and PRBCs per unit (RR, 1.23) significantly increased the risk of death. Many factors significantly increased the length of stay, including creatinine levels greater than 1.5 mg/dL (RR, 1.26), severe COPD (RR, 1.41), mild to moderate COPD (RR, 1.14), heart failure (RR, 1.36), PRBCs (RR, 1.12), surgery time per 60 minutes (RR, 1.11), age of 65-79 years (RR, 1.21), and age older than 80 years (RR, 1.44). The use of platelets was associated with a decreased length of stay (RR, 0.71).

All risks of transfusion must be weighed against toleration anemia, which is also associated with adverse outcomes, according to Dr. Horvath, who is the director of the Cardiothoracic Surgery Research Program for the National Heart, Lung, and Blood Institute and a member of the Cardiothoracic Surgery Trials Network.

Efforts to reduce PRBC transfusions may significantly reduce major postoperative infections. Cell salvage and ultrafiltration could be viable alternatives, he noted.

In the second study, the researchers used the same dataset. Captured data included infection occurrence, type, timing, and organisms. Infections were adjudicated by an independent panel of infectious disease experts. The risk of pneumonia, mortality, and length of stay (time to discharge) were analyzed.

Major infections included bloodstream, pneumonia, C. difficile, deep sternal incisional, mediastinitis, deep groin/leg incisional, endocarditis, and empyema.

Pneumonia was diagnosed using the 2010 surveillance criteria from the CDC/National Healthcare Safety Network, including chest x-ray with new or progressive and persistent infiltrate; fever greater than 38° C; leukopenia (defined as fewer than 4,000 leukocytes per cc); leukocytosis (at least 12,000 leukocytes per cc); or altered mental status. At least two of the following must have been present as well: purulent sputum or change; cough, dyspnea, or tachypnea; rales or bronchial breath sounds; or worsening gas exchange. Duration of follow-up was 65 days.

In all, 31% had isolated CABG, 30% had isolated valve surgery, 11% had CABG and valve surgery, 6% had thoracic aortic surgery, 2% had left ventricular assist device (LVAD) implantation/heart transplant, and 20% were categorized as other.

Overall, 2.4% of patients in the registry had pneumonia, 1.1% had blood stream infection, 1% had C. difficile colitis, and 0.5% had deep sternal infections.

The overall mean time to infection was 19 days and the median was 14 days. The mean time to infection for pneumonia was 15 days. Overall, more than 40% of infections occurred after the index hospitalization. However, 68% and 66% of pneumonias and blood stream infections, respectively, occurred during hospitalization. The three most common organisms were Pseudomonas aeruginosa (12%), Enterobacter cloacae (8%), and Klebsiella pneumoniae (7%).

Increased risk of pneumonia was associated with surgery time (RR, 1.42), a creatinine level of at least 1.5 mg/dL (RR, 1.94), mild to moderate COPD (RR, 1.78), severe COPD (RR, 4.12), and heart failure (RR, 1.76). The reference category was those without COPD.

In terms of process-of-care factors, only nasal decontamination with mupirocin was associated with reduced risk of pneumonia (RR, 0.77). Nasal decontamination with other agents (RR, 1.44); antibiotics given within 24 hours after surgery (RR, 1.26) and within 48 hours postop (RR, 2.70); ventilator use of 24-48 hours (RR, 2.31) and more than 48 hours (RR, 4.58); nasogastric tube (RR, 2.07); and use of PRBCs (RR, 1.10) were all associated with increased risk of pneumonia.

In terms of mortality, "pneumonia, among all the factors analyzed, had the greatest association with mortality, with an odds ratio greater than seven ... which was far and away greater than anything else that was examined," said Dr. Ailawadi.

Pneumonia was significantly associated with an increased risk of mortality (RR, 7.07), as were heart failure (RR, 1.87), creatinine levels of at least 1.5 mg/dL (RR, 2.97), and surgery duration (1.27). However, black race appeared to be protective, with a significantly decreased risk of pneumonia (RR, 0.43).

Pneumonia significantly increased the length of stay by a median of 13 days (19 days with pneumonia and 6 days without). A number of factors – mild to moderate COPD, severe COPD, heart failure, creatinine levels of at least 1.5 mg/dL, surgery time, age of 65-79 years, age 80 years and older, and black or Hispanic race – were significantly associated with increased risk of longer length of stay. Male sex was significantly associated with decreased length of stay (RR, 0.79).

Both Dr. Horvath and Dr. Ailawadi reported that they have no relevant financial disclosures.

FT. LAUDERDALE, FLA. – Transfusion of packed red blood cells during cardiac surgery is independently associated with increased risk of major infection, researchers reported, and – in a related study – pneumonia was found to be the most common infection associated with cardiac surgery.

Cardiac procedures with transfusions were associated with a significant risk of infection, such that "with every unit of blood, you had a significant increase in the risk of infection for the patient. It appears that there might be some sort of threshold in the 2- to 4-unit range, whereafter the risk really seems to increase. But statistically, even that first drop of blood carried an additional infectious risk," Dr. Keith A. Horvath said at the annual meeting of the Society of Thoracic Surgeons.

In a related study, researchers found pneumonia to be the most common infection associated with cardiac surgery. "Pneumonia, surprisingly, was the most common infection, at 2.4%. This was much more common than other infections that we certainly worry about and get a fair amount of press and literature on, specifically sternal wound infections," said Dr. Gorav Ailawadi of the University of Virginia in Charlottesville.

Data for 5,184 adult cardiac patients were used for both studies. The patients were prospectively enrolled in a 10-center infection registry between February and September, 2010. Captured data included infection occurrence, type, and organism. Adjudication was performed by an independent panel of infectious diseases experts.

Major infections evaluated in the study included deep incisional surgical (chest), deep incisional surgical (second incisions), empyema, endocarditis, mediastinitis, myocarditis, pneumonia, bloodstream infections, Clostridium difficile colitis, and cardiac device infections. Infections were defined by a combination of clinical, laboratory, and/or radiologic evidence (according to Centers for Disease Control and Prevention surveillance definitions) for a follow-up of 65 days.

The researchers included several types of surgical interventions: isolated coronary artery bypass graft (CABG), isolated valve surgery, CABG with valve surgery, surgery for heart failure, thoracic aortic surgery, and other procedures.

The mean patient age was 64 years, mean bypass time was 115 minutes, two-thirds (67%) were men, 71% had heart failure, a quarter (27%) had diabetes, 14% had chronic obstructive pulmonary disease (COPD), and 19% had prior cardiac surgery. Mean hemoglobin was 13.2 mg/dL.

There was a significant dose-dependent association between quantity of packed red blood cells (PRBCs) and risk of infection, with the crude risk increasing by an average of 29% with each PRBC unit.

Several factors increased the risk of infection, including severe COPD (relative risk, 1.85), preoperative creatinine levels greater than 1.5 mg/dL (RR, 1.72), heart failure (RR, 1.49), mild to moderate COPD (RR, 1.36), PRBCs per unit (RR, 1.24), and surgery time per 60 minutes (RR, 1.19).

Platelet transfusion occurred in 31% of patients. However, the use of platelets was associated with a decreased risk of infection (RR, 0.71). Cell Saver use was not related to infection.

Creatinine levels greater than 1.5 mg/dL (RR, 2.40) and PRBCs per unit (RR, 1.23) significantly increased the risk of death. Many factors significantly increased the length of stay, including creatinine levels greater than 1.5 mg/dL (RR, 1.26), severe COPD (RR, 1.41), mild to moderate COPD (RR, 1.14), heart failure (RR, 1.36), PRBCs (RR, 1.12), surgery time per 60 minutes (RR, 1.11), age of 65-79 years (RR, 1.21), and age older than 80 years (RR, 1.44). The use of platelets was associated with a decreased length of stay (RR, 0.71).

All risks of transfusion must be weighed against toleration anemia, which is also associated with adverse outcomes, according to Dr. Horvath, who is the director of the Cardiothoracic Surgery Research Program for the National Heart, Lung, and Blood Institute and a member of the Cardiothoracic Surgery Trials Network.

Efforts to reduce PRBC transfusions may significantly reduce major postoperative infections. Cell salvage and ultrafiltration could be viable alternatives, he noted.

In the second study, the researchers used the same dataset. Captured data included infection occurrence, type, timing, and organisms. Infections were adjudicated by an independent panel of infectious disease experts. The risk of pneumonia, mortality, and length of stay (time to discharge) were analyzed.

Major infections included bloodstream, pneumonia, C. difficile, deep sternal incisional, mediastinitis, deep groin/leg incisional, endocarditis, and empyema.

Pneumonia was diagnosed using the 2010 surveillance criteria from the CDC/National Healthcare Safety Network, including chest x-ray with new or progressive and persistent infiltrate; fever greater than 38° C; leukopenia (defined as fewer than 4,000 leukocytes per cc); leukocytosis (at least 12,000 leukocytes per cc); or altered mental status. At least two of the following must have been present as well: purulent sputum or change; cough, dyspnea, or tachypnea; rales or bronchial breath sounds; or worsening gas exchange. Duration of follow-up was 65 days.

In all, 31% had isolated CABG, 30% had isolated valve surgery, 11% had CABG and valve surgery, 6% had thoracic aortic surgery, 2% had left ventricular assist device (LVAD) implantation/heart transplant, and 20% were categorized as other.

Overall, 2.4% of patients in the registry had pneumonia, 1.1% had blood stream infection, 1% had C. difficile colitis, and 0.5% had deep sternal infections.

The overall mean time to infection was 19 days and the median was 14 days. The mean time to infection for pneumonia was 15 days. Overall, more than 40% of infections occurred after the index hospitalization. However, 68% and 66% of pneumonias and blood stream infections, respectively, occurred during hospitalization. The three most common organisms were Pseudomonas aeruginosa (12%), Enterobacter cloacae (8%), and Klebsiella pneumoniae (7%).

Increased risk of pneumonia was associated with surgery time (RR, 1.42), a creatinine level of at least 1.5 mg/dL (RR, 1.94), mild to moderate COPD (RR, 1.78), severe COPD (RR, 4.12), and heart failure (RR, 1.76). The reference category was those without COPD.

In terms of process-of-care factors, only nasal decontamination with mupirocin was associated with reduced risk of pneumonia (RR, 0.77). Nasal decontamination with other agents (RR, 1.44); antibiotics given within 24 hours after surgery (RR, 1.26) and within 48 hours postop (RR, 2.70); ventilator use of 24-48 hours (RR, 2.31) and more than 48 hours (RR, 4.58); nasogastric tube (RR, 2.07); and use of PRBCs (RR, 1.10) were all associated with increased risk of pneumonia.

In terms of mortality, "pneumonia, among all the factors analyzed, had the greatest association with mortality, with an odds ratio greater than seven ... which was far and away greater than anything else that was examined," said Dr. Ailawadi.

Pneumonia was significantly associated with an increased risk of mortality (RR, 7.07), as were heart failure (RR, 1.87), creatinine levels of at least 1.5 mg/dL (RR, 2.97), and surgery duration (1.27). However, black race appeared to be protective, with a significantly decreased risk of pneumonia (RR, 0.43).

Pneumonia significantly increased the length of stay by a median of 13 days (19 days with pneumonia and 6 days without). A number of factors – mild to moderate COPD, severe COPD, heart failure, creatinine levels of at least 1.5 mg/dL, surgery time, age of 65-79 years, age 80 years and older, and black or Hispanic race – were significantly associated with increased risk of longer length of stay. Male sex was significantly associated with decreased length of stay (RR, 0.79).

Both Dr. Horvath and Dr. Ailawadi reported that they have no relevant financial disclosures.