Predicting the outcome of a comatose patient at the bedside

Abstract

The call to the bedside and the prognostication of a comatose patient—telling family members what to expect—commonly falls to neurologists. The assessment is often confounded by the treatment paradigms of modern intensive care (ie, drugs, drug interactions and targeted temperature management). Patients may be too unstable to leave the intensive care unit for neuroimaging; thus, repeated clinical examinations are decisive. Despite diverse causes, certain principles do apply: (1) Many patients can improve, although with significant abnormalities; (2) Neuroimaging and electrodiagnostic tests can help but are rarely definitive; (3) Secondary involvement of the upper brainstem marks a tipping point with much lower probability for an independent outcome; (4) We rarely predict mortality or diagnose brain death; usually the major concern is anticipated neurological deficits; and (5) Prior comorbidity and permanent organ dysfunction are critical factors in making decisions about de-escalation or escalation of care. This review provides a practical approach to evaluating outcome of a comatose patient. Prognostication is difficult, and we should only attempt it when the diagnosis is confirmed and appropriate (often aggressive) medical or surgical treatment has been tried.