[Cerebral blood flow and meningeal hemorrhage. An aid to the surgical decision].

One hundred and eleven measurements of cerebral blood flow (C.B.F.) were performed using the Xenon 133 inhalation method in 80 cases of spontaneous subarachnoid hemorrhage of which 59 were due to ruptured aneurysms. This method is non-traumatic, reproducible and dependable. A correlation was found between clinical condition and C.B.F. values, but in a number of cases which cannot be dismissed, very low mean C.B.F. values or ischemic foci were revealed where clinical state gave no indication. A poor correlation appeared between vasospasm seen by angiography and ischemic foci detected by isotopic technique. Patients' age influenced C.B.F. values but not clinical evolution. No correlation was found between C.B.F. values and cisternal blood seen on CT scan. C.B.F. values, measured in the first two weeks of illness, were significantly higher in those patients having favorable outcome, whatever their clinical state at the time of C.B.F. measurement (comas excluded). The figure of 60 ml/100 g/min for mean cortical flow seemed to be a critical level below which the risk of complication was greater. Below this level or in cases or ischemic foci, surgery was delayed. Thus, C.B.F. measurement promises to be a valuable prognostic tool, playing an important role in the therapeutic strategy for this type of patients.