Temperature control after cardiac arrest: friend or foe.

Abstract

Most patients who are successfully resuscitated after cardiac arrest are initially comatose and require mechanical ventilation and other organ support in an ICU. Best practice has been to cool these patients and control their temperature at a constant value in the range of 32-36 oC for at least 24 h. But the certainty of the evidence for this practice is increasingly being challenged. This review will summarize the evidence on key aspects of temperature control in comatose postcardiac arrest patients. The Targeted Temperature Management 2 (TTM-2) trial documented no difference in 6-month mortality among comatose postcardiac arrest patients managed at 33 oC vs. targeted normothermia. A systematic review and meta-analysis completed by the Advanced Life Support (ALS) Task Force of the International Liaison Committee on Resuscitation (ILCOR) concluded that temperature control with a target of 32-34 °C did not improve survival or favourable functional outcome after cardiac arrest. Two observational studies have documented an association between predicted moderate hypoxic-ischaemic brain injury and better outcome with temperature control at 33-34 oC compared with 35-36 oC. We suggest actively preventing fever by targeting a temperature 37.5 oC or less for those patients who remain comatose following return of spontaneous circulation (ROSC) after cardiac arrest.