DESFLURANE AND ISOFLURANE HAVE SIMILAR EFFECTS ON CEREBRAL BLOOD-FLOWIN PATIENTS WITH INTRACRANIAL MASS LESIONS

Background. Before desflurane is advocated for patients undergoing neu rosurgical procedures, it is necessary to determine the effect of desf lurane on cerebral blood flow (CBF). In this study, CBF values are com pared between desflurane and isoflurane at two doses. In addition, CBF reactivity to CO2 and the effect of prolonged exposure were compared between the two agents. Methods. Cerebral blood flow measurements with intravenous Xe-133 were performed in 24 patients undergoing craniotom y for mass lesions, randomized to receive either isoflurane or desflur ane in oxygen and air. Cerebral blood flow was determined at 1 and 1.5 MAC concentrations at Pa(CO2) of 25 mmHg in the absence of surgical s timulation. intraoperatively, with 1.25 MAC anesthesia, CBF was determ ined at target Pa(CO2) of 25 and 35 mmHg. In 15 patients, an additiona l measurement at 1.25 MAC was made before closure. Results: At 1.0 MAC , mean +/- SD CBF values for the desflurane and isoflurane groups were 18 +/- 2 and 20 +/- 3 ml . 100 g-1. min-1, respectively. At 1.5 MAC, CBF values were the same for the two anesthetics; 17 +/- 3 ml . 100 g- 1 . min-1 for isoflurane and 19 +/- 4 ml . 100 g-1 . min-1 for desflur ane. During 1.25 MAC anesthesia, there were no differences between gro ups, with CO2 reactivity 1.3 +/- 1.2 ml . 1 00 g-1 . min-1 . mmH g-1 f or desflurane and 1.6 +/- 0.6 ml . 100 g-1. min-1. mmHg-1 for isoflura ne. There was no demonstrable decrease in CBF with prolonged exposure to either agent. Conclusions: Desflurane and isoflurane are similar in terms of absolute CBF, the response to increasing doses, and the pres ervation of CO2 reactivity.