Inducing hypothermia after out of hospital cardiac arrestBMJ 2014; 348 doi: https://doi.org/10.1136/bmj.g2735 (Published 11 April 2014) Cite this as: BMJ 2014;348:g2735
- Stephen Bernard, senior specialist
- 1Intensive Care Unit, The Alfred Hospital, Melbourne, VIC 3004, Australia
Out of hospital cardiac arrest is common and is associated with a high rate of mortality.1 With early ambulance treatment, about 30% of these patients have a return of spontaneous circulation and are transported to hospital. However, many patients remain comatose owing to hypoxic brain injury, and this is the leading cause of death after hospital admission.
Over the past decade, there has been considerable interest in the use of therapeutic hypothermia, where patients are cooled to a target temperature of 32-34°C and this temperature is maintained for 12-24 hours. This approach is based on the results of two clinical trials published in 2002.2 3
More recently, a larger trial compared a target temperature of 36°C with that of 33°C.4 The Targeted Temperature Management (TTM) trial randomised 939 patients who remained comatose after resuscitation from out of hospital cardiac arrest at hospitals in Europe and Australia. The primary outcome measure was all cause mortality at the end of the trial. Overall, 50% of the patients in the group allocated to 33°C for 24 hours died compared with 48% of those allocated to the 36°C group (hazard ratio 1.06, 95% confidence interval 0.89 to 1.28; …