Hydergine effect on cerebral circulation in cerebrovascular disease

Regional cerebral blood flow in patients with ruptured intracranial aneurysms

Eighty-five studies of regional cerebral blood flow (rCBF) were performed on 49 patients with ruptured intracranial aneurysms. The changes in rCBF were analyzed under various pathophysiological conditions, The degree of flow abnormalities correlated well with the clinical severity of neurological deficits. All of the patients with diffuse vasospasm of severe grade, to less than half of their control value, showed focal areas of decreased flow below 30 ml/100 gm/min, in addition to a reduction in mean CBF. The relief or disappearance of vasospasm in angiograms was followed by the increase of rCBF in the ischemic focus and mean CBF. Marked reduction in rCBF was found in patients with intracerebral hematoma and ventricular dilatation. Impaired CO2 response and autoregulation were found in patients with severe neurological deficits, a severe degree of vasospasm and marked depression of CBF. In this series direct operation was delayed in patients with impaired vascular reactivity as well as marked decrease of mean CBF below 30 ml/100 gm/min; good clinical results were obtained in thses patients.

Cerebral vasodilator therapy in stroke

Cerebral vasodilating agents have been questioned as an effective form of therapy for the stroke patient and even have been considered by some to be harmful. Animal studies show that often vasodilating agents will cause an intracerebral steal, but such a reaction has rarely been demonstrated in stroke patients. Several studies measuring cerebral blood flow in man have shown that vasodilating agents will increase cerebral blood flow even in ischemic regions in some patients. Significant clinical studies have not been carried out to determine whether these agents will alter the natural history of the disease. On the basis of reported studies of the effect of vasodilating agents on the cerebral circulation, it is suggested that further laboratory and clinical studies be performed. These agents could potentially be an effective form of therapy in some patients with occlusive cerebrovascular disease.

Oxygen availability in ischemic brain following hypocarbia and hypercarbia. Polarographical depth electrode recordings in evolving and completed experimental stroke in the monkey

Acutely implanted oxygen-recording polarographical depth electrodes were used to appraise changes in oxygen availability (O 2 a) in the brain of the Rhesus monkey. Modifications of oxygen availability induced by hypocarbia and hypercarbia in the normal and the infarcted brain are described. The most consistent finding was a reversal of the expected effects of low and high Paco 2 values during the acutely ischemic period (evolving stroke) and an incomplete return to the normal response by five days (completed stroke).