Cerebral blood flow velocity changes under nitrous oxide halothane anesthesia in patients with frontotemporal gliomas: a comparison of the normal and abnormal cerebral hemispheres.

BACKGROUND: Regional differences in vascular response to anesthetic agents in brain areas with and without tumors have not been investigated till now. The existence of such differences may influence the regional distribution of cerebral blood flow under anesthesia. MATERIAL AND METHODS: In 8 patients with frontotemporal gliomas, middle cerebral artery blood flow velocity (VMCA), pulsatality index (PI) and resistance index (RI) were determined in the normal and pathological cerebral hemispheres before and after stable nitrous oxide-halothane anesthesia. RESULTS: During halothane anesthesia, there was an increase in VMCA both in the normal cerebral hemisphere (69 +/- 11 to 100 +/- 38 cm/s; P = 0.05) and the hemisphere with tumor (65 +/- 17 to 83 +/- 28 cm/s; P = 0.04). A significant decrease in the pulsatality index and the resistance index was also observed in both the hemispheres (P < 0.05). The percentage changes of VMCA, PI and RI in both the hemispheres after anesthesia were not significantly different. CONCLUSIONS: In patients with cerebral tumors, nitrous oxide-halothane anesthesia causes comparable changes of cerebral blood flow velocities in the hemisphere with tumor and the normal hemisphere.