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

采用开颅窗法观察了七氟醚和异丙酚对兔脑缺血后软脑膜、小动脉和小静脉内径的影响。用闭合颅窗技术对30只日本大白兔的软脑膜微循环进行了可视化研究。实验前，我们测定了异丙酚对兔脑软膜小动脉和小静脉的影响(n=14)。我们证实异丙酚对软脑膜小动脉和小静脉没有影响。然后将30只兔按麻醉方法随机分为3组。P组为异丙酚组，S组为七氟醚组，SI组为七氟醚加Intralipid组。夹闭头臂动脉、左颈总动脉、左锁骨下动脉15min造成全脑缺血模型。选择的软脑膜小动脉和小静脉的直径用显微镜-视频采集单元组合进行可视化，然后用数字视频分析仪测量。数据收集自…在以下时间点：夹紧前(对照)、夹紧后10分钟和松开后5、10、20、40、60、80、100、120分钟。30只兔中有5只排除在数据分析之外。P组有2只兔因发生肺水肿和严重低氧血症而死亡。P组有2只兔出现急性脑肿胀，SI组有1只发生急性脑肿胀。与P组相比，S组和SI组的平均动脉压和血糖浓度稳定。在缺血期间，所有组的软膜小动脉和小静脉直径均显著减小。松开后，S组和SI组松开后10min，软脑膜大小动脉和静脉直径一过性增加，软脑膜微动静脉明显扩张。然后，软膜小动脉和小静脉直径减小，直到研究期结束。再灌注期后仅P组可见明显的大小动脉收缩，缺血再灌注期后软膜小动脉内径暂时增大，而后持续减小，异丙酚组尤为明显。缺血引起的不良反应，如肺水肿和急性脑肿胀，仅在异丙酚麻醉的兔中观察到。此外，七氟醚麻醉的兔在缺血再灌注期血压、心率和血糖均保持稳定。七氟醚可能更适用于可预见脑缺血的手术。较少

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