【作者】 赵洪伟；

【导师】 岳云；

【作者基本信息】 首都医科大学 ， 麻醉学， 2008， 博士

【摘要】 目目的心室压力-容量环(pressure-volume loop, P-V环)是评估心功能变化的非负荷依赖性的方法,不仅适用于左心室,同样也适用于右心室。本研究旨在:一方面,探讨通过容量性肺动脉导管(pulmonary artery catheter,PAC)获取右心室心动周期内几个特殊时刻的压力、容量数据,并据此绘制右心室P-V环的方法和临床可行性;另一方面,通过右心室收缩末弹性(end-systolic elastance, Ees)和舒张末僵硬度(end-diastolic stiffness, EED),评估非停跳冠状动脉搭桥术(off-pump coronary artery bypass surgery, OPCAB)术中右心室收缩和舒张功能的变化。方法择期行OPCAB术的三支病变冠心病患者28例(男19例,女9例),年龄(67.3±6.5)岁,术前左室射血分数为(61.4±10.7)%,心功能NYHA分级为Ⅰ～Ⅲ,各系统无严重并发症。麻醉诱导后经右侧颈内静脉放置容量性PAC,连接普通监护仪和Vigilance监测系统。数据记录时点包括:T1,切皮前麻醉稳定时(术前水平);T2,心脏前壁血管搭桥、心肌固定器放置后5min;T3,心脏侧壁血管远端搭桥、心肌固定器放置后5min;T4,心脏后壁血管远端搭桥、心肌固定器放置后5min;T5,关胸后(术毕)。每个时点共收集三组数据:⑴记录右心血流动力学参数;⑵计算右室Ees和EED:Ees为右室收缩期末压力/容量之比;EED为右室舒张期末压力/容量之比;⑶将心动周期内几个主要时刻(舒张期末、等容收缩期末、射血峰压期、收缩期末、等容舒张期末)的压力、容量数据输入计算机,绘制右室P-V环。结果根据舒张期末、等容收缩期末、射血峰压期、收缩期末、等容舒张期末等5个时刻的压力、容量数据,可以绘制出右室P-V环,P-V环大致呈三角形。OPCAB术中不同时点P-V环明显向左侧移动,特别是舒张末时点向左上方移动,提示右室被动舒张功能受损。不同时点Ees的变化未达统计学差异(P>0.05),但T4、T5时升高。与T1相比,EED在T2～T4明显升高(P<0.05),T5虽然有所恢复,但并未恢复到T1水平(P<0.05)。与T1比较,RVEF值在T4明显下降(P<0.05)。RVEDVI呈降低趋势,T3、T4、T5下降明显(P<0.05)。SVI与RVEDVI变化相似,但与T1比较,T4时SVI下降程度(18%)大于RVEDVI(10%)。与T1比较,术中PVRI明显降低(P<0.05),但T2～T4却是逐渐升高的趋势,T5又下降(P<0.05)。与T1相比,T2～T4的RAP明显升高(P<0.05),T5又恢复到T1水平。各时点间PAWP没有明显变化(P<0.05),MAP在T3和T4明显下降。结结论利用容量性PAC可以获得右心室心动周期内几个特殊时刻的压力、容量数据,根据这些数据可以生成右室P-V环,并计算Ees和EED,据此可以评价右心室心肌收缩性和被动舒张能力的变化。结果表明,OPCAB术中心脏后壁血管搭桥时,右心室收缩功能(RVEF下降)的降低不代表心肌收缩性(Ees)下降,而是每搏量和前负荷下降,以及后负荷相对升高的结果,至术毕收缩功能恢复。术中右室舒张功能降低,表现为室壁僵硬度(EED)增加,顺应性下降,且至术毕未能恢复。更多还原

【Abstract】 Objective Right ventricular function plays an important role in the hemodynamic derangement during off-pump coronary artery bypass (OPCAB) surgery. Pressure-volume loops have been shown to provide load-independent information of cardiac function. Therefore, the aim of this study is to investigate the feasibility of construction of right ventricular pressure-volume loops with pressure and volume data measured by a volumetric pulmonary artery catheter (PAC) and to evaluate right ventricular systolic and diastolic function by end-systolic elastance (Ees) and end-diastolic stiffness (EED) in OPCAB surgery.Methods Twenty-eight patients who underwent OPCAB surgery were included. After anesthesia induction, a volumetric PAC was placed via the right internal jugular vein. Data were recorded at: anesthesia steady-state before skin incision (T1); 5min after stabilizer device placed for anastomosis of the heart’s anterior wall (T2), lateral wall (T3), posterior wall (T4), respectively; after sternal closure (T5). Three sets of data were collected at each time point: firstly, hemodynamic variables were measured; secondly, right ventricular end-systolic elastance (Ees) was estimated by end-systolic pressure divided by end-systolic volume, and end-diastolic stiffness (EED) was estimated by end-diastolic pressure divided by end-diastolic volume; thirdly, right ventricular pressure-volume loops were constructed with pressure and volume data measured from end-diastole point, end-isovolumic systole point, peak-ejection point, end-systole point and end-isovolumic diastole point.Results Right ventricular pressure-volume loops were constructed successfully with pressure/volume data measured from several specific time-points by a volumic PAC, and they generally shifted to the left during OPCAB surgery. Especially, shift upward and to the left in end-diastole point indicated that right ventricular passive relaxation properties were impaired compared with that at T1. The change of Ees was not statistically significant during operation (P>0.05), whereas EED increased throughout the OPCAB surgery (P<0.05). Decrease in right ventricular ejection fraction, stroke volume index and end-diastolic volume index occurred (P<0.05) at T4 compared with values at T1. Pulmonary vascular resistance index at T4 increased relatively compared with that at T2 and T3. Right atrial pressure increased only during coronary anastomoses (P<0.05)Conclusion Right ventricular pressure-volume loops can be constructed and Ees and EED can be estimated using a volumetric PAC. Right ventricular systolic dysfunction occurred during anastomoses on the heart’s posterior wall not due to impaired contractility but as a result of reduced stroke volume and preload and a relative increase in afterload. Right ventricular diastolic function was impaired throughout OPCAB surgery.更多还原