Neurological Prognostication After Cardiac Arrest in the Era of Hypothermia

Abstract

Despite recent improvements in resuscitation techniques and post-resuscitation care, cardiac arrest still has a poor prognosis. Mortality exceeds 80 %–90 % and more than one quarter of those who survive to hospital discharge have severe persistent neurological dysfunction [1]. Prediction of poor neurological outcome in comatose survivors of cardiac arrest is important, both to give correct information to their relatives and to avoid futile care. In 2006, the criteria for prediction of poor outcome in those patients were codified in the landmark review from the Quality Standards Subcommittee of the American Academy of Neurology (AAN) [2]. According to that review, myoclonus status epilepticus on day 1 after cardiac arrest, an absent N20 wave of somatosensory evoked potentials (SSEP) or a serum neuron specific enolase (NSE) > 33 µg/l from day 1 to day 3, and absent pupillary or corneal reflexes or an extensor or absent motor response on day 3 accurately predicted a poor outcome, defined as death or unconsciousness after 1 month, or unconsciousness or severe disability after 6 months. In that review, electroencephalogram (EEG) and imaging techniques, such as magnetic resonance imaging (MRI), were considered promising, but not ready for routine clinical use.