In 2002 two published articles in the New England Journal of Medicine changed ICU management of out of hospital arrests profoundly. According to these two articles (cited below) the American Heart Association labeled this to be good evidence (Level1) to recommend induced hypothermia in comatose survivors of out of hospital cardia arrest caused by VF. The target temperature was recommended to be between 32-34°C and to be maintained for 12-24 hours.
And now this… Nielsen et al. present the Targeted Temperature Management Trial showing, that there is NO difference between patients cooled to 33°C and patients kept at 36°C. Is this the end of the cooling era, should we change our management?
I personally think think that this trial basically adds up to our knowledge in the field of post cardiac arrest care, but not necessarily contradicts the previous two trials. We now have one trial showing that there seems to be no difference between 33°C and 36°C but we also know, that hyperthermia (pyrexia) is troublesome and associated with worse neurological outcome.
So, as pronounced hypothermia (33°C) makes no difference to ‘mild’ hypothermia (36°C) and pyrexia is proven to be harmful… the question is: What is the right temperature? We seem to head towards normothermia or mild hypothermia in order to provide best management for our patients. It’s going to be interesting to see how recommendations will change in the near future.
The Targeted Temperature Management Trial: Nielsen N, et al. New Engl J Med. 2013 Dec;369(23):2197-206
The 2 trials that introduced therapeutic hypothermia into ICU practice:
Review article on therapeutic hypothermia for non-VF/VT cardiac arrest:
Pyrexia and neurological outcome: