原位肝移植非静-静脉转流围术期肺氧合及肺内分流的变化

目的观察非体外静静脉转流术下原位肝移植(OLT)围术期肺氧合功能及肺内分流的改变。方法对19例晚期肝病行OLT手术的患者采用静吸复合麻醉,无肝期均未使用体外静静脉转流术。常规经右颈内静脉放置SwanGanz导管持续监测心排血量(CO),测定肺氧合功能及肺内分流率。分别在麻醉诱导后、无肝前30min、无肝30min、新肝30min和术毕抽取桡动脉血和肺动脉血进行血气分析,记录不同时期的动脉血氧分压(PaO2)、动脉血二氧化碳分压(PaCO2)和心排血指数(CI),计算肺泡动脉氧分压差(PAaO2)。根据肺内分流标准模型公式计算肺内分流率(Qs/Qt)。结果麻醉诱导后吸入氧浓度(FiO2)1.00情况下,PaO2为(385.0±56.4)mmHg(1mmHg=0.133kPa),PAaO2和Qs/Qt均明显高于正常参考值。麻醉诱导后各项指标与无肝前30min相比差异均无显著性;无肝30minCO和CI明显下降(P均<0.01),Qs/Qt明显下降(P<0.05);新肝30minPaO2、PaCO2均明显升高(P均<0.05),PAaO2明显下降(P<0.05),CO和CI均明显升高(P均<0.01);术毕CO和CI也均明显升高(P均<0.05),并维持在较高的水平,Qs/Qt明显下降(P<0.05),但PaO2、PaCO2、PAaO2则均无明显变化。结论OLT患者非静静脉转流术前和术中均存在明显的肺氧合功能障碍。

Changes in pulmonary gas exchange and intrapulmonary shunt during orthotopic liver transplantation with non-venovenous bypass

OBJECTIVE: To study the changes in pulmonary gas exchange and intrapulmonary shunt during orthotopic liver transplantation (OLT) with non-venovenous bypass. METHODS: Nineteen American Society of Anesthesiologists (ASA) III-IV patients (male 17, female 2) with terminal liver diseases were enrolled for study. Their age ranged from 25-67 years. Anesthesia was induced with midazolam 0.05 mg/kg, propofol 0.5-1.0 mg/kg, fentanyl 4 microg/kg, with vecuronium 0.1 mg/kg, and it was maintained with isoflurane inhalation, fentanyl and vecuronium. All patients were mechanically ventilated with 100% O(2) during operation. After induction of anesthesia, Swan-Ganz catheter was inserted via right internal jugular vein. Cardiac output (CO), mixed venous oxygen saturation and core venous temperature were continuously monitored with continuous cardiac output monitor, and electrocardiogram (ECG), central venous pressure (CVP), pulmonary arterial wedge pressure (PAWP), pulse oxygen saturation (SpO(2)) and end-tidal carbon dioxide tension (P(ET)CO(2)) were also continuously monitored during operation. Radial artery was cannulated for continuous direct blood pressure monitoring. Arterial and mixed venous blood samples were taken after induction of anaesthesia, and partial pressure of oxygen (PaO(2)), partial pressure of carbon dioxide (PaCO(2)), and cardiac index(CI) were determined after induction of anaesthesia, 30 minutes before anhepatic stage, 30 minutes during anhepatic stage, 30 minutes during neohepatic stage and at the end of operation. Alveolar-arterial oxygen partial pressure difference (P(A-a)O(2)) and intrapulmonary shunt (Qs/Qt) were calculated according to the standard formula. RESULTS: After induction of anaesthesia, when the inspired oxygen flow (FiO(2)) was 1.00, PaO(2) was only (385.0+/-56.4) mm Hg (1 mm Hg=0.133 kPa), P(A-a)O(2) and Qs/Qt were all higher than normal values. There were no significant changes 30 minutes before anhepatic stage as compared with that after induction of anaesthesia. CO, CI and Qs/Qt were decreased significantly during anhepatic stage compared with that after induction of anaesthesia. PaO(2), PaCO(2), CO and CI were increased and P(A-a)O(2) decreased significantly, but there were no significant changes in Qs/Qt 30 minutes during neohepatic stage. CI and CO increased and Qs/Qt decreased significantly at the end of operation, but there were no significant difference in PaO(2), PaCO(2) and P(A-a)O(2). CONCLUSION: There are obvious changes in pulmonary gas exchange and intrapulmonary shunt during OLT with nonvenovenous bypass.