科研之友
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摘要
Background 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 was 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 (E-ES) and end-diastolic stiffness (E-ED) 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); 5 minutes after the stabilizer device was placed for anastomosis on 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: first, hemodynamic variables were measured;, second, right ventricular E-ES and E-ED were calculated; third, 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 generally shifted to the left during OPCAB surgery. Especially, the end-diastolic point shifted upward and to the left at T2-T5 compared with that at T1. 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. The change of E-ES was not statistically significant during operation. Right atrial pressure increased only during coronary anastomoses (T2T4, P <0.05), whereas E-ED increased throughout OPCAB surgery (P <0.05). @@@ Conclusions Right ventricular pressure-volume loops can be constructed using a volumetric PAC. Right ventricular systolic dysfunction occurred during anastomoses on the heart's posterior wall not due to impaired myocardial contractility but as a result of reduced preload and a relative increase in afterload. Right ventricular diastolic function was impaired throughout OPCAB surgery.
- 出版日期2008-5-20
- 单位首都医科大学
