[The effect of cerebral perfusion pressure on cerebral blood flow in the rhesus monkey during sevoflurane anesthesia].

The effect of cerebral perfusion pressure on cerebral blood flow (CBF) was studied under the normocapnic condition in the rhesus monkey under sevoflurane anesthesia. CBF was measured by means of positron emission tomography technique. After the measurement of CBF at 0.5% sevoflurane as control, the measurement was repeated at 2.0% sevoflurane (1 MAC), when blood pressure was kept at a half of the control value. The measurement was also repeated at the same sevoflurane concentration, when the mean blood pressure was restored with the infusion of angiotensin II. Average CBF as well as regional CBFs were compared between two different mean blood pressures at 2.0% sevoflurane. Average CBF increased significantly (+35%), when the mean arterial pressure was increased by the angiotensin II infusion. All the regional CBFs except at frontal cortex increased significantly (+ about 30%) in response to the increase in the mean arterial pressure. The increase in occipital CBF was greatest (+52%). We conclude that CBF during sevoflurane anesthesia up to 2.0% might become dependent on the cerebral perfusion pressure, indicating the compromised autoregulation of CBF in the rhesus monkey.