[Effect of sevoflurane on blood flow velocity in the vertebral artery]

Blood flow velocity in the vertebral artery was measured using transcranial Doppler sonography during sevoflurane anesthesia in 12 patients in the knee-chest position. The correlation between mean arterial blood pressure (MBP) and mean blood flow velocity in the vertebral artery (Vmean) was significant in each patient. Normalized data expressed as a percentage of the individual arithmetic means permitted a composite analysis of data from all patients. Linear regression of normalized MBP (%MBP) on normalized Vmean (%Vmean) showed %Vmean = 24.8 +/- 0.75 %MBP (r = 0.78, P < 0.01). The results of the present study suggest that fluctuations in systemic blood pressure may lead to fluctuations in cerebral blood flow. Therefore, the use of sevoflurane anesthesia must be accompanied by careful management of blood pressure during surgery.