von Auenmueller KI, et al. – The authors explored whether arterial blood gas parameters correlated with mortality of patients after out–of–hospital cardiac arrest. They demonstrated that after out–of–hospital resuscitation, several arterial blood gas parameters correlated with mortality of patients. pH and lactate were the most relevant parameters as they were strongly and independently associated with mortality within the first 5 days after resuscitation. None of these parameters by oneself was strong enough to allow an early prognostication despite this correlation. These parameters, however, could contribute as part of a multimodal approach to assessing the patients' prognosis.