Ondracek AS, Hofbauer TM, Wurm R, et al. - Almost half of out-of-hospital cardiac arrest (OHCA) patients do not survive up to hospital discharge despite an increased rate of return of spontaneous circulation (ROSC) in these patients. Given that deoxyribonuclease (DNase) degrades double-stranded (ds) DNA that is released into circulation, exerting pro-inflammatory effects, researchers here examined the role of DNase activity in OHCA survivors and impact on clinical outcome. They conducted a prospective, single-center study determining dsDNA and DNase activity at hospital admission (acute phase) and 24 h (subacute phase) after ROSC in 64 OHCA survivors. Of these patients, 26.6% (n = 17) died within 30 days. Observations revealed that disproportionally raised dsDNA levels uncompensated by DNase activity are a strong predictor of mortality in OHCA survivors. This study indicates a potentially protective effect of DNase activity in cases undergoing cardiac arrest. .