Aladj L J, Croughwell N, Smith L R, Reves J G
Heart Center, Duke University Hospital, Durham, North Carolina.
Anesth Analg. 1991 Jan;72(1):48-52. doi: 10.1213/00000539-199101000-00008.
In 21 patients undergoing elective coronary artery bypass surgery, cerebral blood flow (CBF) was measured during hypothermic nonpulsatile cardiopulmonary bypass to test the hypothesis that isoflurane abolished the mean arterial pressure-CBF relation (pressure-flow autoregulation). Cerebral blood flow was determined by 133Xe clearance. The patients were randomly divided into three groups according to anesthesia during cardiopulmonary bypass: group 1 received midazolam and fentanyl; group 2 received, in addition to midazolam and fentanyl, 0.6% isoflurane; and group 3 received, in addition to midazolam and fentanyl, 1.2% isoflurane. The groups were maintained at a constant temperature, PaO2, PaCO2, and pump flow during CBF measurements. Mean arterial pressure was increased by phenylephrine greater than or equal to 25% after the first CBF determination. Isoflurane decreased mean arterial pressure significantly (P less than 0.05) and was associated with lower CBF. Increasing the mean arterial pressure 29% in group 1, 25% in group 2, and 34% in group 3 had no effect on CBF. We conclude that, within the range studied, pressure-flow CBF autoregulation is preserved during isoflurane anesthesia administered for cardiopulmonary bypass.
在21例行择期冠状动脉搭桥手术的患者中，在低温非搏动性体外循环期间测量脑血流量（CBF），以检验异氟烷消除平均动脉压与CBF关系（压力-流量自动调节）这一假设。脑血流量通过133Xe清除率测定。根据体外循环期间的麻醉方式将患者随机分为三组：第1组接受咪达唑仑和芬太尼；第2组除接受咪达唑仑和芬太尼外，还接受0.6%异氟烷；第3组除接受咪达唑仑和芬太尼外，还接受1.2%异氟烷。在测量CBF期间，各组维持恒定的体温、动脉血氧分压（PaO2）、动脉血二氧化碳分压（PaCO2）和泵流量。在首次测定CBF后，用去氧肾上腺素将平均动脉压升高≥25%。异氟烷显著降低平均动脉压（P<0.05），并伴有较低的CBF。第1组平均动脉压升高29%，第2组升高25%，第3组升高34%，对CBF均无影响。我们得出结论，在所研究的范围内，在用于体外循环的异氟烷麻醉期间，压力-流量CBF自动调节功能得以保留。
