Sequential measurements of cerebral blood flow in the acute phase of subarachnoid hemorrhage.

Cerebral blood flow (CBF) measurements were made at predetermined intervals over the first 20 days after a subarachnoid hemorrhage (SAH) by the method of 133Xe inhalation clearance in 39 patients, Hunt and Hess degrees I, II or III. Mean hemispheral and regional blood flow showed a similar pattern of behavior over time: namely an initial hypoperfusion, being more marked in patients with consistent or thick blood deposition at CT scanning, followed by transient improvement and subsequent deterioration in the second week, this being especially conspicuous in patients who developed vasospasm; deterioration, at any rate, was distributed widely regardless of the initial CBF readings or magnitude of bleeding. Patients developing later neurological deficit (23% of the total) were those who showed a statistically significant increase of hemispheric asymmetries and regional hypoperfusion at the time when deterioration occurred. Accordingly, the Author calls attention to the practical value of CBF measurements in SAH patients, in view of the relationships that obtain between certain CBF patterns and the emergence of late neurologic deficits.