Cerebral blood flow following induced subarachnoid hemorrhage in the monkey
✓ The acute effects of experimental subarachnoid hemorrhage on cerebral blood flow were investigated in 14 adult rhesus monkeys injected with fresh autogenous blood through a needle positioned within the subfrontal subarachnoid space. Cerebral blood flow was measured by the xenon133 tissue clearance method before hemorrhage, and afterward at 30-minute intervals for a 3-hour period. Post-anesthetic neurological status was graded according to Botterell's classification. Twelve monkeys showed a significant decrease in cerebral perfusion, eight displayed focal neurological deficits, and four were moribund. There was a correlation between the degree of impaired circulation and the severity of neurological deficit. Four additional monkeys subjected to subarachnoid acidic saline injection showed no reduction in cerebral blood flow. In three animals cerebral perfusion was increased during the first hour after injection. It is suggested that measurement of cerebral blood flow may be a more valuable prognostic indication of cerebral function and survival than the angiographic demonstration of arterial vasospasm.