Progressive Change in Cerebral Blood Flow during the First Three Weeks after Subarachnoid Hemorrhage

Abstract

Cerebral blood flow (CBF) was estimated from each cerebral hemisphere by the 133Xe inhalation method. Daily estimates were made during the first 3 weeks after subarachnoid hemorrhage (1265 studies in 116 patients). Some of the patients were taking adrenergic blocking drugs (propranolol and phentolamine), others were taking tranexamic acid, and the rest were taking no drugs. CBF was also studied in 67 normal subjects. The resting CBF was related inversely to age not only for normal subjects but also for patients after subarachnoid hemorrhage (SAH). The CBF fell progressively during the first 2 weeks after SAH and was abnormally low throughout the 3 weeks after hemorrhage. For any 1 day after SAH, those patients who were fully alert had the smallest reduction in CBF. The progressive changes in CBF occurred whether or not an aneurysm was present on angiograms. For aneurysms situated to one side of the midline, the changes in CBF affected both sides of the brain. The progressive decline in CBF was least in those patients who subsequently made the best clinical recovery. Arterial pCO2 seemed to influence CBF throughout the 3 weeks after SAH. During the 2nd week, CBF was especially low in SAH patients treated with tranexamic acid. The serial changes in CBF are discussed in relation to current views concerning the timing of operation for ruptured aneurysms.

Reversal of delayed vasospasm by an inhibitor of the synthesis of 20-HETE

“…In summary, the present study indicates that rats subjected to the dual-hemorrhage model of SAH exhibit biphasic changes in CBF and the diameter of cerebral arteries that closely mimic the time course and magnitude of the response previously reported in humans (30,54) and the dual-hemorrhage dog and monkey models of SAH (29,52). Acute blockade of the synthesis of 20-HETE fully reversed cerebral vasospasm in this model.…”

“…Previous studies have documented that there are biphasic changes in the diameter of cerebral arteries in humans after SAH (30,54). The acute phase lasts several hours.…”

Neurological impairment in rats after subarachnoid hemorrhage—A comparison of functional tests

“…High intracranial pressure and vasospasm lead to cerebral ischemia with concomitant neuronal damage in various neuronal territories involved in the processing of sensor and motor information [6]. A variety of clinical and experimental studies demonstrated a close correlation between the severity of bleeding, the extent of the ischemic damage and the clinical status of the patient [4,5,[7][8][9][10][11].…”

Risk Profile of Patients with Poor-Grade Aneurysmal Subarachnoid Hemorrhage Using Early Perfusion Computed Tomography

“…Also, the initial severity of the hemorrhage and CBF reduction during the early SAH period are the major determinants of imminent morbidity and mortality (3,17). A more pronounced initial decrease in CBF has also been found in patients with a higher Hunt and Hess grade (5,12,19). Acute hypoperfusion is caused by various cellular and structural changes, but the theory that acute vasospasms are a major factor has gained widespread acceptance (20).…”