User login
SNOWMASS, COLO. – Targeted temperature management maintained at 32-36 degrees Celsius is now a strong class I recommendation for all comatose patients who experience return of spontaneous circulation after out-of-hospital cardiac arrest, including those with nonshockable rhythms, Erin A. Bohula, MD, PhD, said at the annual Cardiovascular Conference at Snowmass sponsored by the American College of Cardiology.
“Our practice is that ,” said Dr. Bohula, a cardiologist and critical care specialist at Brigham and Women’s Hospital and Harvard Medical School, Boston.
The current ACC/AHA guidelines declare: “There are essentially no patients for whom temperature control somewhere in the range between 32 degrees C [89.6 F) and 36 degrees C [96.8 F] is contraindicated.” The writing committee cited “recent clinical trial data enrolling patients with all rhythms, the rarity of adverse effects in trials, the high neurologic morbidity and mortality without any specific interventions, and the preponderance of data suggesting that temperature is an important variable for neurologic recovery” (Circulation. 2015 Nov 3;132[18 Suppl 2]:S465-82).
“That’s a pretty strong statement,” Dr. Bohula observed.
The current guidelines, which date back to 2015, give a class I, level of evidence B recommendation for targeted temperature management (TTM) in patients who are comatose with return of spontaneous circulation (ROSC) after out-of-hospital cardiac arrest involving ventricular fibrillation or pulseless ventricular fibrillation. The bedside definition of comatose is lack of meaningful response to verbal commands to squeeze hands, blink, or move toes.
The current recommendation for TTM in patients resuscitated from out-of-hospital cardiac arrest with a nonshockable rhythm is class I, level of evidence C, meaning it’s based on expert consensus. However, that recommendation is now out of date and due for a level-of-evidence upgrade in light of the recent results of the French HYPERION trial, an open-label randomized trial of 584 patients resuscitated from cardiac arrest with a nonshockable rhythm. Although 90-day mortality was similarly high in the TTM and targeted normothermia groups, the rate of favorable neurologic outcome as assessed by a Cerebral Performance Category scale score of 1 or 2 was 10.2% in the TTM group, significantly better than the 5.7% rate in controls (N Engl J Med. 2019 Dec 12;381[24]:2327-37).
The 2010, ACC/AHA guidelines recommended a TTM range of 32-34 degrees C, but on the basis of subsequent persuasive randomized trial data, that range was broadened to 32-36 degrees C in the 2015 guidelines, with a class IB recommendation. Maintenance of TTM for at least 24 hours has a IIa, level of evidence C recommendation in the current guidelines.
The guidelines emphasize that specific features may favor selection of one temperature for TTM over another. For example, patients with seizures or cerebral edema might be better off with TTM at a lower temperature, while a higher temperature may be best for those with bleeding or severe bradycardia. At Brigham and Women’s Hospital, the default temperature is 33 degrees C. However, TTM with a goal of 36 degrees C is seriously considered in patients with recent head trauma, major surgery within the past 2 weeks, refractory hypotension, severe sepsis, pregnancy, or high bleeding risk. Rewarming is done at a rate of 0.25 degrees C per hour, with sedation maintained until the patient has been returned to 98.6 degrees F, according to Dr. Bohula.
Based on several negative studies of TTM using rapid infusion of chilled fluids in the ambulance en route to the hospital, the guidelines rate that practice class IIIA, meaning don’t do it. Avoidance of a systolic blood pressure below 90 mm Hg and a mean arterial pressure of less than 65 mm Hg gets a class IIb level of evidence C recommendation to lessen the risk of cerebral hypoxia.
TTM a major breakthrough
Prior to the introduction of TTM, comatose patients with ROSC after out-of-hospital cardiac arrest had a dreadful prognosis, with survival rates of 1%-10% in registry studies. In contrast, the survival rate in the landmark TTM clinical trials was 50%-60%. And while that’s a dramatic improvement, ROSC after cardiac arrest remains a high-mortality condition. Dr. Bohula was first author of a report by the Critical Care Cardiology Trials Network, composed of 16 tertiary cardiac intensive care units in the United States and Canada. Cardiac arrest was the primary indication for 8.7% of 3,049 consecutive admissions, and its 38% mortality rate was the highest of all cardiac critical care indications (JAMA Cardiol. 2019 Jul 24;4[9]:928-35).
TTM was developed in response to a recognition that two-thirds of deaths in patients who make it to the hospital after out-of-hospital cardiac arrest are neurologic – the result of brain anoxia – rather than being due to the myocardial ischemia that may have initially brought them to medical attention.
“Time is brain cells, the same way we think of time as cardiac muscle,” Dr. Bohula observed.
The main idea behind therapeutic hypothermia is that it lowers the cerebral metabolic rate of oxygen to reduce the consequences of ongoing anoxia. The brain doesn’t require as much perfusion when cooled.
TTM has other beneficial neurologic effects as well: It reduces cerebral blood volume via autoregulation, decreases intracranial pressure, and blunts the inflammatory response involved in the postcardiac arrest syndrome. In addition, TTM has anticonvulsant properties, an important effect because seizures and/or myoclonus occur in up to 15% of adults who achieve ROSC after cardiac arrest – and in even more of those who are comatose after doing so. And seizures increase the brain’s metabolic rate threefold, resulting in more cerebral ischemic injury, she explained.
Seizure activity can be difficult to distinguish from shivering in a patient on TTM. For this reason Dr. Bohula recommends putting patients on continuous EEG monitoring from the time of admission, as is the routine practice at the Brigham.
She reported serving as a consultant to Daiichi Sankyo, Servier, Lexicon, Kowa, Merck, Novartis, Novo Nordisk, and the National Institutes of Health. In addition, she generates institutional research grants provided by a half-dozen pharmaceutical companies.
SNOWMASS, COLO. – Targeted temperature management maintained at 32-36 degrees Celsius is now a strong class I recommendation for all comatose patients who experience return of spontaneous circulation after out-of-hospital cardiac arrest, including those with nonshockable rhythms, Erin A. Bohula, MD, PhD, said at the annual Cardiovascular Conference at Snowmass sponsored by the American College of Cardiology.
“Our practice is that ,” said Dr. Bohula, a cardiologist and critical care specialist at Brigham and Women’s Hospital and Harvard Medical School, Boston.
The current ACC/AHA guidelines declare: “There are essentially no patients for whom temperature control somewhere in the range between 32 degrees C [89.6 F) and 36 degrees C [96.8 F] is contraindicated.” The writing committee cited “recent clinical trial data enrolling patients with all rhythms, the rarity of adverse effects in trials, the high neurologic morbidity and mortality without any specific interventions, and the preponderance of data suggesting that temperature is an important variable for neurologic recovery” (Circulation. 2015 Nov 3;132[18 Suppl 2]:S465-82).
“That’s a pretty strong statement,” Dr. Bohula observed.
The current guidelines, which date back to 2015, give a class I, level of evidence B recommendation for targeted temperature management (TTM) in patients who are comatose with return of spontaneous circulation (ROSC) after out-of-hospital cardiac arrest involving ventricular fibrillation or pulseless ventricular fibrillation. The bedside definition of comatose is lack of meaningful response to verbal commands to squeeze hands, blink, or move toes.
The current recommendation for TTM in patients resuscitated from out-of-hospital cardiac arrest with a nonshockable rhythm is class I, level of evidence C, meaning it’s based on expert consensus. However, that recommendation is now out of date and due for a level-of-evidence upgrade in light of the recent results of the French HYPERION trial, an open-label randomized trial of 584 patients resuscitated from cardiac arrest with a nonshockable rhythm. Although 90-day mortality was similarly high in the TTM and targeted normothermia groups, the rate of favorable neurologic outcome as assessed by a Cerebral Performance Category scale score of 1 or 2 was 10.2% in the TTM group, significantly better than the 5.7% rate in controls (N Engl J Med. 2019 Dec 12;381[24]:2327-37).
The 2010, ACC/AHA guidelines recommended a TTM range of 32-34 degrees C, but on the basis of subsequent persuasive randomized trial data, that range was broadened to 32-36 degrees C in the 2015 guidelines, with a class IB recommendation. Maintenance of TTM for at least 24 hours has a IIa, level of evidence C recommendation in the current guidelines.
The guidelines emphasize that specific features may favor selection of one temperature for TTM over another. For example, patients with seizures or cerebral edema might be better off with TTM at a lower temperature, while a higher temperature may be best for those with bleeding or severe bradycardia. At Brigham and Women’s Hospital, the default temperature is 33 degrees C. However, TTM with a goal of 36 degrees C is seriously considered in patients with recent head trauma, major surgery within the past 2 weeks, refractory hypotension, severe sepsis, pregnancy, or high bleeding risk. Rewarming is done at a rate of 0.25 degrees C per hour, with sedation maintained until the patient has been returned to 98.6 degrees F, according to Dr. Bohula.
Based on several negative studies of TTM using rapid infusion of chilled fluids in the ambulance en route to the hospital, the guidelines rate that practice class IIIA, meaning don’t do it. Avoidance of a systolic blood pressure below 90 mm Hg and a mean arterial pressure of less than 65 mm Hg gets a class IIb level of evidence C recommendation to lessen the risk of cerebral hypoxia.
TTM a major breakthrough
Prior to the introduction of TTM, comatose patients with ROSC after out-of-hospital cardiac arrest had a dreadful prognosis, with survival rates of 1%-10% in registry studies. In contrast, the survival rate in the landmark TTM clinical trials was 50%-60%. And while that’s a dramatic improvement, ROSC after cardiac arrest remains a high-mortality condition. Dr. Bohula was first author of a report by the Critical Care Cardiology Trials Network, composed of 16 tertiary cardiac intensive care units in the United States and Canada. Cardiac arrest was the primary indication for 8.7% of 3,049 consecutive admissions, and its 38% mortality rate was the highest of all cardiac critical care indications (JAMA Cardiol. 2019 Jul 24;4[9]:928-35).
TTM was developed in response to a recognition that two-thirds of deaths in patients who make it to the hospital after out-of-hospital cardiac arrest are neurologic – the result of brain anoxia – rather than being due to the myocardial ischemia that may have initially brought them to medical attention.
“Time is brain cells, the same way we think of time as cardiac muscle,” Dr. Bohula observed.
The main idea behind therapeutic hypothermia is that it lowers the cerebral metabolic rate of oxygen to reduce the consequences of ongoing anoxia. The brain doesn’t require as much perfusion when cooled.
TTM has other beneficial neurologic effects as well: It reduces cerebral blood volume via autoregulation, decreases intracranial pressure, and blunts the inflammatory response involved in the postcardiac arrest syndrome. In addition, TTM has anticonvulsant properties, an important effect because seizures and/or myoclonus occur in up to 15% of adults who achieve ROSC after cardiac arrest – and in even more of those who are comatose after doing so. And seizures increase the brain’s metabolic rate threefold, resulting in more cerebral ischemic injury, she explained.
Seizure activity can be difficult to distinguish from shivering in a patient on TTM. For this reason Dr. Bohula recommends putting patients on continuous EEG monitoring from the time of admission, as is the routine practice at the Brigham.
She reported serving as a consultant to Daiichi Sankyo, Servier, Lexicon, Kowa, Merck, Novartis, Novo Nordisk, and the National Institutes of Health. In addition, she generates institutional research grants provided by a half-dozen pharmaceutical companies.
SNOWMASS, COLO. – Targeted temperature management maintained at 32-36 degrees Celsius is now a strong class I recommendation for all comatose patients who experience return of spontaneous circulation after out-of-hospital cardiac arrest, including those with nonshockable rhythms, Erin A. Bohula, MD, PhD, said at the annual Cardiovascular Conference at Snowmass sponsored by the American College of Cardiology.
“Our practice is that ,” said Dr. Bohula, a cardiologist and critical care specialist at Brigham and Women’s Hospital and Harvard Medical School, Boston.
The current ACC/AHA guidelines declare: “There are essentially no patients for whom temperature control somewhere in the range between 32 degrees C [89.6 F) and 36 degrees C [96.8 F] is contraindicated.” The writing committee cited “recent clinical trial data enrolling patients with all rhythms, the rarity of adverse effects in trials, the high neurologic morbidity and mortality without any specific interventions, and the preponderance of data suggesting that temperature is an important variable for neurologic recovery” (Circulation. 2015 Nov 3;132[18 Suppl 2]:S465-82).
“That’s a pretty strong statement,” Dr. Bohula observed.
The current guidelines, which date back to 2015, give a class I, level of evidence B recommendation for targeted temperature management (TTM) in patients who are comatose with return of spontaneous circulation (ROSC) after out-of-hospital cardiac arrest involving ventricular fibrillation or pulseless ventricular fibrillation. The bedside definition of comatose is lack of meaningful response to verbal commands to squeeze hands, blink, or move toes.
The current recommendation for TTM in patients resuscitated from out-of-hospital cardiac arrest with a nonshockable rhythm is class I, level of evidence C, meaning it’s based on expert consensus. However, that recommendation is now out of date and due for a level-of-evidence upgrade in light of the recent results of the French HYPERION trial, an open-label randomized trial of 584 patients resuscitated from cardiac arrest with a nonshockable rhythm. Although 90-day mortality was similarly high in the TTM and targeted normothermia groups, the rate of favorable neurologic outcome as assessed by a Cerebral Performance Category scale score of 1 or 2 was 10.2% in the TTM group, significantly better than the 5.7% rate in controls (N Engl J Med. 2019 Dec 12;381[24]:2327-37).
The 2010, ACC/AHA guidelines recommended a TTM range of 32-34 degrees C, but on the basis of subsequent persuasive randomized trial data, that range was broadened to 32-36 degrees C in the 2015 guidelines, with a class IB recommendation. Maintenance of TTM for at least 24 hours has a IIa, level of evidence C recommendation in the current guidelines.
The guidelines emphasize that specific features may favor selection of one temperature for TTM over another. For example, patients with seizures or cerebral edema might be better off with TTM at a lower temperature, while a higher temperature may be best for those with bleeding or severe bradycardia. At Brigham and Women’s Hospital, the default temperature is 33 degrees C. However, TTM with a goal of 36 degrees C is seriously considered in patients with recent head trauma, major surgery within the past 2 weeks, refractory hypotension, severe sepsis, pregnancy, or high bleeding risk. Rewarming is done at a rate of 0.25 degrees C per hour, with sedation maintained until the patient has been returned to 98.6 degrees F, according to Dr. Bohula.
Based on several negative studies of TTM using rapid infusion of chilled fluids in the ambulance en route to the hospital, the guidelines rate that practice class IIIA, meaning don’t do it. Avoidance of a systolic blood pressure below 90 mm Hg and a mean arterial pressure of less than 65 mm Hg gets a class IIb level of evidence C recommendation to lessen the risk of cerebral hypoxia.
TTM a major breakthrough
Prior to the introduction of TTM, comatose patients with ROSC after out-of-hospital cardiac arrest had a dreadful prognosis, with survival rates of 1%-10% in registry studies. In contrast, the survival rate in the landmark TTM clinical trials was 50%-60%. And while that’s a dramatic improvement, ROSC after cardiac arrest remains a high-mortality condition. Dr. Bohula was first author of a report by the Critical Care Cardiology Trials Network, composed of 16 tertiary cardiac intensive care units in the United States and Canada. Cardiac arrest was the primary indication for 8.7% of 3,049 consecutive admissions, and its 38% mortality rate was the highest of all cardiac critical care indications (JAMA Cardiol. 2019 Jul 24;4[9]:928-35).
TTM was developed in response to a recognition that two-thirds of deaths in patients who make it to the hospital after out-of-hospital cardiac arrest are neurologic – the result of brain anoxia – rather than being due to the myocardial ischemia that may have initially brought them to medical attention.
“Time is brain cells, the same way we think of time as cardiac muscle,” Dr. Bohula observed.
The main idea behind therapeutic hypothermia is that it lowers the cerebral metabolic rate of oxygen to reduce the consequences of ongoing anoxia. The brain doesn’t require as much perfusion when cooled.
TTM has other beneficial neurologic effects as well: It reduces cerebral blood volume via autoregulation, decreases intracranial pressure, and blunts the inflammatory response involved in the postcardiac arrest syndrome. In addition, TTM has anticonvulsant properties, an important effect because seizures and/or myoclonus occur in up to 15% of adults who achieve ROSC after cardiac arrest – and in even more of those who are comatose after doing so. And seizures increase the brain’s metabolic rate threefold, resulting in more cerebral ischemic injury, she explained.
Seizure activity can be difficult to distinguish from shivering in a patient on TTM. For this reason Dr. Bohula recommends putting patients on continuous EEG monitoring from the time of admission, as is the routine practice at the Brigham.
She reported serving as a consultant to Daiichi Sankyo, Servier, Lexicon, Kowa, Merck, Novartis, Novo Nordisk, and the National Institutes of Health. In addition, she generates institutional research grants provided by a half-dozen pharmaceutical companies.
EXPERT ANALYSIS FROM ACC SNOWMASS 2020