Too cold may not be so cool: spontaneous hypothermia as a marker of poor outcome after cardiac arrest

In a recent issue of Critical Care, Den Hartog and colleagues show an association between spontaneous hypothermia, defined by an admission body temperature <35 C, and poor outcome in patients with coma after cardiac arrest (CA) treated with therapeutic hypothermia (TH) [1]. Previous studies have shown that spontaneous hypothermia is associated with increased mortality after severe trauma and haemorrhage [2]. Given that TH has improved prognosis of hypoxic-ischemic encephalopathy [3], studies aiming to identify early markers of injury severity and outcome are welcome, since they may contribute overall to optimize the management of comatose CA patients [4]. Den Hartog and colleagues identify spontaneous hypothermia as a new prognostic marker of CA: their study provide an important message to clinicians involved in post-resuscitation care and raises important questions which need to be taken into account in future studies.