应用心室压力-容量关系探讨肝移植术中右心室收缩和舒张功能的变化

目的 用容量性肺动脉导管收集右心室收缩末期和舒张末期的压力、容量数据,并计算心室收缩末期弹性(end-systolic elagtance,Ees)、舒张未僵硬度(end-diastolic stiffness,EED)、有效动脉弹性(arterial effective elastance,Ea)、Ees/Ea,借以评价肝移植术中右心室收缩和舒张功能的变化.方法 12例拟行同种异体原位肝移植术的终末期肝病患者.ASA Ⅱ-Ⅳ级;无心脏病史,心功能Ⅰ或Ⅱ级;不合并肺动脉高压[以插入漂浮导管后平均肺动脉压(MPAP)25 mm Hg为标准]及其他肺部疾病.全麻后行右侧颈内静脉穿刺,放置容量性肺动脉导管.于切皮前麻醉稳定时、无肝期10 min、新肝期10 min、术毕缝皮时,4个时点收集数据,包括①记录右心血流动力学参数;②计算Ees、EED、Ea、Ees/Ea.结果 与切皮前相比,无肝期心指数(cardiac index,CI)、右心室舒张末期容积指数(RV ejection fraction,RVEF)、右心室作功指数(fight ventricular stroke work index,RVSWI)、肺动脉楔压(pulmonary artery wedge pressure,PAWP)、中心静脉压(central verous pressure,CVP)、MPAP、每博指数(stroke volume index,SVI)、右心室舒张末期容积指数(RV end-diastolic volume index,RVEDVI)、平均动脉压(mean arterial blood pressure,MAP)等指标均明显下降(P<0.05),新肝期均相应增加.术毕时恢复至切皮前水平.Ees在4个时期未见明显变化(P0.05).EED无肝期显著下降(P<0.05),新肝期显著升高(P<0.05),术毕时恢复至切皮前水平.PVRI与Ea变化趋势一致,无肝期和新肝期增加,但没有显著性.与切皮前相比,无肝期的Ees/Ea比下降(P<0.05).结论 不合并肺动脉高压的肝移植患者术中无肝期和新肝期RVEF下降与前负荷剧降及后负荷增加有关,不代表心肌收缩能力降低.新肝期右心室舒张功能下降,表现为室壁僵硬度增加,EED下降.术毕时,右心室收缩和舒张功能均可恢复至术前水平,并且右心室功能与肺循环的状态能够匹配.

Assessment of right ventricular function by pressure-volume relationships in orthotopic liver transplantation

Objective To evaluate right ventricular function during orthotopic liver transplantation (OLT) by Ees (end-systolic elastance) and EED (end-diastolic stiffness) with right ventricular end-systolic and end-diastolic pressure/volume data measured using volumetric pulmonary artery catheter. Methods Twelve cirrhotic patients without pulmonary hypertension (mean pulmonary arterial pressure [MPAP] < 25 mm Hg) who underwent OLT were included. After anesthesia induction, a volumetric thermodilution pulmonary artery catheter was placed via the right internal jugular vein. Hemodynamic parameters were recorded during the 4 phases: anesthesia steady-state before skin incision (T1) ; 10 rain after the anhepatic phase (T2) ; 10 rain after graft reperfusion (T3>) ; at the end of surgery (T4). Two sets of data were collected at each phase : first, right ventricular hemodynamic variables were measured ; second, right ventricular Ees, EED, pulmonary effective elastance (Ea), and right ventricle-arterial coupling efficiency as the Ees/Ea ratio were calculated. Results Compared with values at T1, CI,RVEF,RVSWI,PAWP,CVP,MPAP,SVI,RVEDVI,MAP decreased significantly at T2(P < 0.05) and increased gradually after graft reperfusion and recovered at the end of surgery. The change of Ees was not statistically significant during the operation (P > 0.05). EED increased significantly after reperfusion (P < 0. 05) and recovered at the end of surgery compared with that at T,. There were no significant changes in Ea during the operation, which had the same trend as the change of PVRI. Ees/Ea ratio declined at T2 (P < 0.05) compared with that at other time points. Conclusion Right ventricular myocardial contractility (Ees) was maintained in cirrhotic patients without pulmonary hypertension during OLT. Right ventricular systolic dysfunction (down-regulation in RVEF) occurred during the anhepatic phase and after reperfusion not due to impaired contractility but as a result of reduced stroke volume, preload and a relative increase in afterload. Right ventricular compliance was impaired after reperfusion and recovered at the end of the surgery.