CEREBRAL BLOOD-FLOW VELOCITIES AFTER SUBARACHNOID HEMORRHAGE IN RELATION TO THE AMOUNT OF BLOOD-CLOTS IN THE INITIAL COMPUTED-TOMOGRAPHY

In 72 patients with acute subarachnoid haemorrhage (SAH) the relations hip between the amount of subarachnoid blood clots detected by initial cranial computed tomography (CCT) up to 48 hours after bleeding and t he later development of vasospasm established by blood flow velocity m easurement with transcranial Doppler ultrasound (TCD) was investigated . The serial Doppler examinations started within the first 72 hours af ter SAH and were carried out every second day up to three weeks. Each Doppler recording was accompanied by a neurological examination. Patie nts classified as Hunt and Hess grade V were excluded from the study. All patients with remarkable brain oedema in CCT or with intracranial pressure above 25 mmHg were also excluded. Because of the well known a ge-dependence of vasospasm after SAH, two age groups were formed. A st atistically significant correlation (p > 0.05) between blood flow velo cities and blood load after SAH was not found. The mean age of the inv estigated 72 individuals was 48.9 years (14 up to 76 years). 47 patien ts were younger than 56 years. Linear regression analysis indicated a correlation with a quite low significance level (r = 0.350, p < 0.025) between TCD blood flow velocities and blood load in CCT in these youn ger subjects. No significant correlation (p > 0.05) between these two variables could be established in the 25 patients older than 55 years. In a second step an intra-individual comparison of side-to-side diffe rences in TCD and CCT was made. There were no significant differences in blood how velocities between subjects with or without side-to-side differences in cisternal blood load. It is concluded that the amount o f brood visible on initial CCT after SAH is not a powerful predictor o f cerebral blood flow velocities measured by TCD.