Neurological benefit of therapeutic hypothermia following return of spontaneous circulation for out-of-hospital non-shockable cardiac arrest

Background: Although therapeutic hypothermia is an effective therapy for comatose adults experiencing out-of-hospital shockable cardiac arrest, there is insufficient evidence that is also applicable for those with out-of-hospital non-shockable cardiac arrest.

Methods and results: Of 452 comatose adults treated with therapeutic hypothermia after return of spontaneous circulation (ROSC) subsequent to an out-of-hospital cardiac arrest of cardiac etiology, 372 who had a bystander-witnessed cardiac arrest, target core temperature of 32-34°C and cooling duration of 12-72 h were eligible for this study (75 cases of non-shockable cardiac arrest, 297 cases of shockable cardiac arrest). The median collapse-to-ROSC interval was significantly longer in the non-shockable group than in the shockable group (30 min vs. 22 min, P=0.008), resulting in a significantly lower frequency of 30-day favorable neurological outcome in the non-shockable group compared with the shockable group (32% vs. 66%, P<0.001). However, an analysis of data in quartiles assigned to varying lengths of collapse-to-ROSC interval revealed a similar frequency of 30-day favorable neurological outcome among both groups when the collapse-to-ROSC interval was ≤16 min (90% non-shockable group vs. 92% shockable group; odds ratio 0.80, 95% confidence interval 0.09-7.24, P=0.84).

Conclusions: Post-ROSC cooling is an effective treatment for patients with non-shockable cardiac arrest when the time interval from collapse to ROSC is short.