Literature
Clinical Pearls & Morning Reports
Published March 8, 2023
How did 36 hours of temperature control after out-of-hospital cardiac arrest compare with 72 hours of the same in the trial by Hassager et al.?
Hassager et al. randomly assigned comatose patients who had been resuscitated after an out-of-hospital cardiac arrest of presumed cardiac cause to device-based temperature control targeting 36°C for 24 hours followed by targeting of 37°C for either 12 or 48 hours (for total intervention times of 36 and 72 hours, respectively) or until the patient regained consciousness. Read the NEJM Original Article here.
Clinical Pearls
Q: What are the postulated harms of fever in patients who have had an out-of-hospital cardiac arrest?
A: Fever is prevalent among critically ill patients and is caused by an increase in the set point for the core body temperature. Fever may have harmful effects, such as increasing oxygen demand, and in patients who have had an out-of-hospital cardiac arrest, observational studies have suggested that fever after cessation of temperature control by physical cooling is associated with worse neurologic outcomes.
Q: What do current guidelines recommend regarding temperature management after an initial 24 hours of temperature control in patients with an out-of-hospital cardiac arrest?
A: Contemporary European and American guidelines recommend targeted temperature management for the initial 24 hours and active fever prevention with a temperature target of 37.7°C or lower for at least 72 hours in patients who have been resuscitated after an out-of-hospital cardiac arrest and remain comatose. Nevertheless, data from randomized trials on the duration of active fever prevention to be used after the initial 24 hours of temperature control have been lacking.
Morning Report Questions
Q: How did 36 hours of temperature control after out-of-hospital cardiac arrest compare with 72 hours of the same in the trial by Hassager et al.?
A: The authors found no significant difference between the two durations with respect to the percentages of patients who died or had severe disability or coma. The primary outcome was a composite of death from any cause or discharge from the hospital with a Cerebral Performance Category (CPC) of 3 or 4 (indicating severe disability or coma or vegetative state) within 90 days after randomization. Death from any cause or a CPC of 3 or 4 at hospital discharge within 90 days occurred in 127 of 393 patients (32.3%) in the 36-hour group and 133 of 396 patients (33.6%) in the 72-hour group (hazard ratio, 0.99; 95% CI, 0.77 to 1.26; P = 0.70).
Q: What were some of the limitations of this trial?
A: This trial has several limitations. The temperature intervention was not masked and was only modestly effective for the prevention of low-grade fewer. Follow-up in this trial was challenging as a result of Covid-19 pandemic restrictions, including a temporary pause in research-related follow-up visits and a subsequent reluctance among patients to visit a hospital. As a result, the number of patients available for follow-up visits and assessment of cognitive testing was lower than expected. Furthermore, the trial involved a patient cohort with a relatively good prognosis: almost 85% of the patients had a shockable primary rhythm, and almost 90% had received bystander cardiopulmonary resuscitation. Trial findings may not be generalizable to other populations with a higher risk of more severe brain injury.