Pulmonary Effective Elastance Research Articles

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] ) ; 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). 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. Key words: Right ventricle ; Pressure-volume relationship ; Systolic function ; Diastolic function ; Orthotopie liver transplantation ; Pulmonary artery catheter ;

Effects of Dobutamine on Right Ventricular Function and Pulmonary Circulation in Pulmonary Hypertension During Liver Transplantation

Introduction In the setting of orthotopic liver transplantation (OLT), pulmonary hypertension (PH) affects right ventricular (RV) function. When RV failure occurs, reducing RV afterload, optimizing RV preload, and preserving coronary perfusion through maintenance of systemic blood pressure are the primary goals of intraoperative treatment. Patients and methods To verify the effect of dobutamine on RV function and RV-arterial coupling, we compared a group of 9 cirrhotic patients with mild PH treated with OLT to a group of 20 patients with normal mean pulmonary artery pressure (MPAP). All patients received dobutamine (5–10 μg/kg/min) to maintain a cardiac index (CI) >3 L/min/m 2, during the anhepatic phase. Hemodynamic profile, using a pulmonary artery catheter, was performed before and during dobutamine infusion, studying MPAP, CI, and RV end-diastolic volume index (RVEDVI). RV stroke work index (RVSWI), RV end-systolic elastance (Ees), pulmonary effective elastance (Ea), and RV-arterial coupling efficiency as the Ees/Ea ratio were also calculated. Results RV contractility (Ees and RVSWI) and afterload (Ea) were significantly higher among the PH group. In both groups, all the studied variables improved with dobutamine: RV contractility increased, afterload decreased, and thus Ees/Ea coupling markedly increased. Conclusion Cirrhotic patients with mild PH who were undergoing OLT still have a reserve of RV contractile performance and pulmonary vasodilation.

Portopulmonary Hypertension and Liver Transplantation: Hemodynamic Consequences at Reperfusion

Background The absence of portopulmonary hypertension (PH) upon preoperative evaluation for liver transplantation (OLT) does not exclude the occasional occurrence of an acquired PH while awaiting a graft. We sought to estimate hemodynamic changes and right ventriculoarterial coupling during reperfusion. Methods We studied 11 cirrhotic patients diagnosed with mild PH, according to the current classification: mean pulmonary artery pressure (MPAP)-25 to 34 mm Hg. These patients underwent OLT, using the piggyback technique (group PH). None of them had exhibited criteria for PH on preoperative echocardiography. This cohort was compared with 20 consecutive cirrhotic patients with normal MPAP at OLT. We performed a complete hemodynamic profile using a pulmonary artery catheter (RVEF, Baxter-Edwards, Calif, USA) before and 5 minutes after reperfusion. The variables were MPAP and right ventricular (RV) end-diastolic volume index (RVEDVI). Using standard formulas we calculated RV stroke work index (RVSWI), RV end-systolic elastance (Ees), pulmonary effective elastance (Ea), and RV-arterial coupling efficiency as the Ees/Ea ratio. Systolic ventricular function was expressed as RVSWI versus RVEDVI. Results During the anhepatic phase, MPAP, Ees, Ea, and RVSWI were higher in the PH group; but RVEDVI was lower. After reperfusion the pressure (MPAP), contractility (RVSWI) and preload (RVEDVI) increased in both groups. However, afterload (Ea) decreased in the non-PH group; accordingly, Es/Ea increased only in these patients. Discussion At reperfusion, the expansion in preload and cardiac output, without a similar afterload decrease, is responsible for the steady increase in pressure. Our results have shown that in the PH patient group, systolic ventricular function improves during reperfusion by a Frank-Starling mechanism; however, ventricular-arterial uncoupling is maintained (Ees/Ea < 1) because ventricular contractility is not appropriately balanced by simultaneous declines in afterload.