非体外循环冠状动脉旁路移植术对右心室血流动力学的影响

Hemodynamic changes of the right ventricle during off-pump coronary bypass grafting

目的应用连续心排血量测定的方法,观察在进行非体外循环冠状动脉旁路移植术(OPCABG)中右心功能的变化. 方法冠状动脉粥硬化性心脏病178例,均为2～3支血管病变需行冠状动脉旁路移植术.术前心功能Ⅱ级72例,Ⅲ级84例,Ⅳ级22例.左心室射血分数0.35～0.82,平均搭桥数3.3根.所有病人均行Swan-Ganz漂浮导管,用连续心输出量监测仪连续监测血流动力学指标,包括心率(HR),平均动脉压(MAP),中心静脉压(CVP),平均肺动脉压(MPAP),右房压(RAP),肺毛细血管楔压(PCWP),心输出量(CO),心脏指数(CI),每搏容量指数(SVI),体循环阻力指数(SVRI),肺循环阻力指数(PVRI),混合静脉血饱和度(SvO2),右室射血分数(RVEF),右室收缩末容量(RVESV),右室舒张末容量(RVEDV),右室收缩末容量指数(RVESVI),右室舒张末容量指数(RVEDVI).设定时间点观察血流动力学指标:麻醉诱导后血流动力学稳定后,准备搬动心脏前(T1),吻合前降支前(T2),吻合回旋支或对角支前(T3),吻合右冠状动脉或后降支前(T4),心脏回位后,关胸前(T5).结果 4例死亡,其中2例为术前急性心肌梗死急诊手术,术后3天死于严重低心排血量综合征,1例术后7天死于严重呼吸衰竭,1例于术后4天死于急性肺栓塞.与T1相比,T2时,MPAP,PCWP,RAP和PVRI明显增加而SvO2明显降低;T3时,血流动力学变化明显,MPAP,PCWP,RAP和PVRI明显增加,SvO2明显降低,CI,SVI,RVEF明显下降,SVRI明显增加;T4时,HR,RAP明显增加而SvO2明显降低;T5时未恢复正常水平. 结论在进行纯缘支吻合时,右心功能有所下降,主要是CI及RVEF有明显的变化,而在前降支及右冠状动脉的吻合时,对右心血流动力学影响不大,因此,在OPCABG中监护右心功能具有重要意义,尤其是对右心功能受到损害的患者.

Objective To observe functional changes of the right ventricle (RV) during off-pump coronary bypass grafting (OPCABG) by using a continuous cardiac output (CCO) monitoring. Methods The study included 178 patients with 2~3 vessel disease requiring a coronary bypass grafting. Preoperative cardiac functions were classified as New York Heart Association (NYHA) class Ⅱ in 72 patients, class Ⅲ in 84 patients and class Ⅳ in 22. The ejection fraction of the left ventricle was 0.35~0.82. The mean number of bypassed vessel was 3.3. A Swan-Ganz catheter was inserted for continuous monitoring of cardiac output by thermodilution. Parameters measured were heart rate (HR), mean arterial pressure (MAP), central venous pressure (CVP), mean pulmonary artery pressure (MPAP), right atrial pressure (RAP), pulmonary capillary wedge pressure (PCWP), cardiac output (CO), cardiac index (CI), stroke volume index (SVI), systemic vascular resistance index (SVRI), pulmonary vascular resistance index (PVRI), mixed venous saturation value (SvO_2), right ventricular ejection fraction (RVEF), right ventricular end-systolic volume (RVESV), right ventricular end-diastolic volume (RVEDV), right ventricular end-systolic volume index (RVESVI), and right ventricular end-diastolic volume index (RVEDVI). The hemodynamic parameters were measured at time-points when a stable hemodynamics was obtained after the induction of general anesthesia and before the heart would be moved (T1), when the anterior descending branch would be anastomosed (T2), when the circumflex branch or the diagonal branch would be anastomosed (T3), when the right coronary artery or the posterior descending branch would be anastomosed (T4), and when the heart had been repositioned before the thoracic cavity would be closed (T5), respectively. Results There were 4 fatal cases: 2 patients received an emergency surgery for acute myocardial infarction and died with severe low cardiac output syndrome 3 days after the surgery, 1 patient ended with severe respiratory failure 7 days after the surgery, and 1 succumbed to acute pulmonary embolism 4 days after the surgery. As compared with the time-point of T1: the MPAP, PCWP, RAP and PVRI were significantly elevated and the SvO_2 was significantly reduced at the time-point of T2; the MPAP, PCWP, RAP, PVRI and SVRI were significantly elevated and the SvO_2, CI, SVI and RVEF were significantly depressed at the time-point of T3; the HR and RAP significantly went up and the SvO_2 significantly dropped at the time-point of T4; the parameters didn’t recover to normal levels at the time-point of T5. Conclusions When the obtuse marginal (OM) branch is anastomosed, right ventricular functions may decrease, particularly in CI and RVEF levels, while when the left anterior descending branch or right coronary artery is anastomosed, hemodynamics of the right ventricle vary within narrow limits. Therefore, a monitoring of right ventricular functions during OPCABG is of great significance, especially for those with right ventricular insufficiency.