Most patients who are comatose a few hours after a period of global cerebral ischemia have a poor prognosis. In a series of studies selected with strict criteria for study design, the median prevalence of death or survival in a vegetative state was 78% (range, 56-90%) (Zandbergen et al., 1998). Most nonsurvivors die within the first weeks, not from brain damage, but from cardiac or pulmonary complications. Uncertainty about treatment and nontreatment decisions is therefore most critical during this period. To reduce this uncertainty among caregivers, and the related anxiety among family members, early identification of patients with such a poor prognosis is desirable.