RESUMO
Autoregulation of cerebral blood flow is altered by volatile anesthetics and vasodilators such as nitroglycerin. Forty patients with cerebral aneurysm were anesthetized with halothane or isoflurane, and hypotension (mean arterial pressure: 55 mmHg) was induced with nitroglycerin. Blood gas analysis of radial artery and internal jugular vein during normotension and hypotension was performed. The results were as follows 1) There were no significant changes in juqular venous oxygen saturation, difference of arterial and venous oxygen content and extration rate of oxygen between normotension and hypotension. 2) There were no differences in SjvO2, CaO2, CjvO2, and O2ER between halothane and isoflurane. There is no possibility of cerebral ischemia in induced hypotension by nitroglycerin during halothane and isoflurane anesthesia.