Prognostication in comatose survivors of cardiac arrest: an advisory statement from the European Resuscitation Council and the European Society of Intensive Care Medicine

Objectives: To review and update the evidence on predictors of poor outcome (death, persistent vegetative state or severe neurological disability) in adult\r\ncomatose survivors of cardiac arrest, either treated or not treated with controlled temperature, to identify knowledge gaps and to suggest a reliable\r\nprognostication strategy.\r\nMethods: GRADE-based systematic review followed by expert consensus achieved using Web-based Delphi methodology, conference calls and face-to-face\r\nmeetings. Predictors based on clinical examination, electrophysiology, biomarkers and imaging were included.\r\nResults and conclusions: Evidence from a total of 73 studies was reviewed. The quality of evidence was low or very low for almost all studies. In patients who\r\nare comatose with absent or extensor motor response at ≥72 h from arrest, either treated or not treated with controlled temperature, bilateral absence\r\nof either pupillary and corneal reflexes or N20 wave of short-latency somatosensory evoked potentials were identified as the most robust predictors.\r\nEarly status myoclonus, elevated values of neuron specific enolase at 48–72 h from arrest, unreactive malignant EEG patterns after rewarming, and\r\npresence of diffuse signs of postanoxic injury on either computed tomography or magnetic resonance imaging were identified as useful but less robust\r\npredictors. Prolonged observation and repeated assessments should be considered when results of initial assessment are inconclusive. Although no specific\r\ncombination of predictors is sufficiently supported by available evidence, a multimodal prognostication approach is recommended in all patients.