肝纤维化兔最低肺泡有效浓度

背景七氟醚广泛应用于外科手术患者，其可能会影响肝功能和肝血流。然而，肝纤维化对七氟醚最低肺泡有效浓度（minimum alveolar concentration，MAC）的影响仍不清楚。因此我们设计了这个研究，以测定肝纤维化兔的MAC。方法30只雄性新西兰白兔，体重约2．5kg，随机分为两组：肝纤维化组（n=20）和正常对照组（n=10）。肝纤维化组兔用50％的四氯化碳处理12周，以诱导肝纤维化。麻醉前测定血清总蛋白、白蛋白、球蛋白、总胆汁酸、丙氨酸氨基转移酶、门冬氨酸氨基转移酶、碱性磷酸酶、γ-谷氨酰转肽酶、总胆红素、直接胆红素和间接胆红素浓度。两组麻醉诱导和维持均用七氟醚。实验中运用标准的钳尾技术来测定兔自主呼吸时的七氟醚MAC。麻醉后处死兔子，取出肝脏做病理检查。结果肝纤维化组经过12周四氯化碳处理后，20只兔子中有14只存活；对照组10只兔子有9只存活。肝纤维化组存活的14只兔子均发展为中至重度的肝纤维化。其中14只兔子中有3只兔子由于其他疾病或对疼痛刺激无反应而被排除。与对照组相比，肝纤维化组的球蛋白、门冬氨酸氨基转移酶和γ-谷氨酰转肽酶的水平显著增高。然而，白蛋白和碱性磷酸酶的水平明显低于对照组。七氟醚麻醉期间，两组动物平均动脉血压、心率、呼气末二氧化碳和温度均稳定。肝纤维化组的七氟醚MAC显著低于对照组（3．52％和4．10％，P=0．018）。结论肝纤维化兔的七氟醚MAC显著降低。

BACKGROUND： Sevoflurane is widely used in patients undergoing surgical procedures, which could affect both the liver function and hepatic blood flow. However, the effects of liver fibrosis on minimum alveolar concentration （MAC） of sevoflurane are still unclear. Therefore, we designed this study to determine the MAC of sevoflurane in rabbits with liver fibrosis. METHODS： Thirty male New Zealand white rabbits weighing approximately 2.5 kg were divided randomly into 2 groups： fibrosis （n = 20） and normal control group （n = 10）. The rabbits in the fibrosis group were treated with 50% carbon tetrachloride for 12 weeks to induce liver fibrosis. The serum concentration of total protein, albumin, globulin, total bile acids, alanine aminotransferase, aspartame aminotransferase, alkaline phosphatase, γ-glutamyl transpeptidase, total bilirubin, direct bilirubin, and indirect bilirubin were measured before anesthesia. The anesthesia for animals that survived in both groups was induced and maintained with sevoflurane. A standard tail-clamp technique was used to determine the MAC of sevoflurane in spontaneously breathing rabbits. After anesthesia, animals were killed for liver pathologic examination. RESULTS： Twelve weeks after 50% carbon tetrachloride administration, 14 of 20 rabbits survived in the fibrosis group, and 9 of 10 survived in the control group. All surviving animals in the fibrosis group had developed moderate to severe liver fibrosis. Three rabbits that survived after the fibrosis challenge were excluded for other diseases or no response to pain stimulation. The levels of globulin, aspartame aminotransferase, and γ-glutamyl transpeptidase significantly increased in fibrosis animals compared with controls. However, the albumin and alkaline phosphatase levels were significantly lower in the fibrosis group than in the control group. Mean arterial blood pressure, heart rate, end-tidal CO2, and temperature were stable in both groups during sevoflurane anesthesia. The MAC of sevoflurane was significantly less in the fibrosis group than in the control group （3.52% vs 4. 10%, P = 0. 018）. CONCLUSIONS： The MAC of sevoflurane decreased significantly in rabbits with liver fibrosis.