Is This Patient Dead, Vegetative, or Severely Neurologically Impaired?: Assessing Outcome for Comatose Survivors of Cardiac Arrest

Abstract

CONTEXT: Most survivors of cardiac arrest are comatose after resuscitation, and meaningful neurological recovery occurs in a small proportion of cases. Treatment can be lengthy, expensive, and often difficult for families and caregivers. Physical examination is potentially useful in this clinical scenario, and the information obtained may help physicians and families make accurate decisions about treatment and/or withdrawal of care. OBJECTIVE: To determine the precision and accuracy of the clinical examination in predicting poor outcome in post-cardiac arrest coma. DATA SOURCES AND STUDY SELECTION: We searched MEDLINE for English-language articles (1966-2003) using the terms coma, cardiac arrest, prognosis, physical examination, sensitivity and specificity, and observer variation. Other sources came from bibliographies of retrieved articles and physical examination textbooks. Studies were included if they assessed the precision and accuracy of the clinical examination in prognosis of post-cardiac arrest coma in adults. Eleven studies, involving 1914 patients, met our inclusion criteria. DATA EXTRACTION: Two authors independently reviewed each study to determine eligibility, abstract data, and classify methodological quality using predetermined criteria. Disagreement was resolved by consensus. DATA SYNTHESIS: Summary likelihood ratios (LRs) were calculated from random effects models. Five clinical signs were found to strongly predict death or poor neurological outcome: absent corneal reflexes at 24 hours (LR, 12.9; 95% confidence interval [CI], 2.0-68.7), absent pupillary response at 24 hours (LR, 10.2; 95% CI, 1.8-48.6), absent withdrawal response to pain at 24 hours (LR, 4.7; 95% CI, 2.2-9.8), no motor response at 24 hours (LR, 4.9; 95% CI, 1.6-13.0), and no motor response at 72 hours (LR, 9.2; 95% CI, 2.1-49.4). The proportion of individuals' dying or having a poor neurological outcome was calculated by pooling the outcome data from the 11 studies (n = 1914) and used as an estimate of the pretest probability of poor outcome. The random effects estimate of poor outcome was 77% (95% CI, 72%-80%). The highest LR increases the pretest probability of 77% to a posttest probability of 97% (95% CI, 87%-100%). No clinical findings were found to have LRs that strongly predicted good neurological outcome. CONCLUSIONS: Simple physical examination maneuvers strongly predict death or poor outcome in comatose survivors of cardiac arrest. The most useful signs occur at 24 hours after cardiac arrest, and earlier prognosis should not be made by clinical examination alone. These data provide prognostic information, rather than treatment recommendations, which must be made on an individual basis incorporating many other variables.