Initial and recurrent bleeding are the major causes of death following subarachnoid hemorrhage.

BACKGROUND AND PURPOSE: The goal of this study was to determine the causes of mortality and morbidity after subarachnoid hemorrhage. METHODS: We identified all first-ever spontaneous subarachnoid hemorrhages that occurred in the nearly 1.3 million population of greater Cincinnati during 1988. RESULTS: Thirty-day mortality for subarachnoid hemorrhage was 45% (36 of 80 cases). Of the 36 deaths, 22 (61%) died within 2 days of onset; 21 of these deaths were due to the initial hemorrhage, and one death was due to rebleeding documented by computer tomography. Nine of the remaining 14 deaths after day 2 were caused by the initial hemorrhage (2 cases) or rebleeding (7 cases). Volume of subarachnoid hemorrhage was a powerful predictor of 30-day morality (P = .0001). Only 3 of the 29 patients with a volume of subarachnoid hemorrhage of 15 cm3 or less died before 30 days. Two of these 3 patients died from documented rebleeding; the third had 87 cm3 of additional intraventricular hemorrhage. Delayed arterial vasospasm contributed to only 2 of all 36 deaths. CONCLUSIONS: Most deaths after subarachnoid hemorrhage occur very rapidly and are due to the initial hemorrhage. Rebleeding is the most important preventable cause of death in hospitalized patients. In a large representative metropolitan population, delayed arterial vasospasm plays a very minor role in mortality caused by subarachnoid hemorrhage.