Mild hypothermia treatment in patients resuscitated from non-shockable cardiac arrest.

Objective: Therapeutic hypothermia has proved effective in improving outcome in patients after cardiac arrest due to ventricular fibrillation (VF). The benefit in patients with non-VF cardiac arrest is still not defined.
Methods: This prospective observational study was conducted in a university hospital setting with historical controls. Between 2002 and 2010 387 consecutive patients have been admitted to the intensive care unit (ICU) after cardiac arrest (control n=186; hypothermia n=201). Of those, in 175 patients the initial rhythm was identified as non-shockable (asystole, pulseless electrical activity) rhythm (control n=88; hypothermia n=87). Neurological outcome was assessed at ICU discharge according to the Pittsburgh cerebral performance category (CPC). A follow-up was completed for all patients after 90 days, a Kaplan-Meier analysis and Cox regression was performed.
Results: Hypothermia treatment was not associated with significantly improved neurological outcome in patients resuscitated from non-VF cardiac arrest (CPC 1-2: hypothermia 27.59% vs control 18.20%, p=0.175). 90-Day Kaplan-Meier analysis revealed no significant benefit for the hypothermia group (log rank test p=0.82), and Cox regression showed no statistically significant improvement.
Conclusions: In this cohort patients undergoing hypothermia treatment after non-shockable cardiac arrest do not benefit significantly concerning neurological outcome. Hypothermia treatment needs to be evaluated in a large multicentre trial of cardiac arrest patients found initially to be in non-shockable rhythms to clarify whether cooling may also be beneficial for other rhythms than VF.