Cerebral pial vascular responses to brain ischemia-reperfusion under sevoflurane or propofol anesthesia in rabbits.

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We investigated the effects of sevoflurane and propofol on cerebral pial arteriolar and venular diameter changes after brain ischemia using cranial window in rabbits. Pial microcirculation was visualized using a closed cranial window technique in 30 Japanese white rabbits. Before the experiments, we determined the effects of propofol on cerebral pial arterioles and venules in rabbits (n=14). We confirmed that propofol has no effect on pial arterioles and venules. Then 30 rabbits were randomly assigned to one of three groups on a basis of anesthetic methods. P group received propofol, S group received sevoflurane, and SI group received sevoflurane and Intralipid. Global brain ischemia was produced by the 15 min clamp of brachiocephalic artery, left common carotid artery, and left subclavian artery. Diameters of selected pial arterioles and venules were visualized with a microscope-video capture unit combination and subsequently measured with a digital video analyzer. Data were collected … More at the following time-points: just before clamping (control), 10 min after clamping, and at 5, 10, 20, 40, 60, 80, 100, 120 min after unclamping. Of 30 rabbits in the study, 5 rabbits were excluded from the data analysis. Two rabbits in the P group did not survive because of developing pulmonary edema and severe hypoxemia. Acute brain swelling occurred in two rabbits in the P group and one in the SI group. Mean arterial blood pressure and plasma glucose concentration were stable in the S and SI groups compared with the P group. During the ischemia, pial arteriolar and venular diameters were significantly reduced in all groups. After unclamping, pial large and small arteriolar and venular diameters increased temporarily and significant pial arteriolar and venular dilation was observed at 10 min after the unclamping in the S and SI group. Then, pial arteriolar and venular diameters reduced until the end of the study period. Significant large and small arteriolar constriction was detected after the reperfusion period only in the P group.After the ischemia-reperfusion period, pial arteriolar diameter increased temporarily and then decreased continuously especially in propofol-anesthetized rabbits. Ischemia-induced adverse effects such as pulmonary edema and acute brain swelling were observed only in propofol-anesthetized rabbits. In addition, during ischemia-reperfusion period, blood pressure, heart rate, and plasma glucose were stable in sevoflurane-anesthetized rabbits. Sevoflurane may be preferable for surgeries in which brain ischemia is anticipated. Less