Prognostication after cardiac arrest

Abstract

Hypoxic-ischaemic brain injury (HIBI) is the main cause of death in patients who are comatose after resuscitation from cardiac arrest. A poor neurological outcome-defined as death from neurological cause, persistent vegetative state, or severe neurological disability-can be predicted in these patients by assessing the severity of HIBI. The most commonly used indicators of severe HIBI include bilateral absence of corneal and pupillary reflexes, bilateral absence of N₂O waves of short-latency somatosensory evoked potentials, high blood concentrations of neuron specific enolase, unfavourable patterns on electroencephalogram, and signs of diffuse HIBI on computed tomography or magnetic resonance imaging of the brain. Current guidelines recommend performing prognostication no earlier than 72 h after return of spontaneous circulation in all comatose patients with an absent or extensor motor response to pain, after having excluded confounders such as residual sedation that may interfere with clinical examination. A multimodal approach combining multiple prognostication tests is recommended so that the risk of a falsely pessimistic prediction is minimised.

Keywords: Cardiac arrest; Coma; Hypoxic brain damage; Prognosis.

Fig. 1

Definition of poor neurological outcomes in 87 prognostication studies, 1974–2014. Reproduced from [19], with permission. CPC Cerebral Performance Category

Fig. 2

European Resuscitation Council–European Society of Intensive Care Medicine algorithm for neuroprognostication after cardiac arrest. Reproduced from [12] with permission. CI confidence interval, CT computed tomography, EEG electroencephalogram, FPR false-positive rate, M Glasgow Coma Scale Motor score, NSE neuron specific enolase, ROSC return of spontaneous circulation, SSEP short-latency somatosensory evoked potentials