BACKGROUND: Patients undergoing orthotopic liver transplantation(OLT) may develop significant hemodynamic instability. This study was performed to assess the role of right ventricular function in the hemodynamic alteration during 23 cases of OLT. METHODS: A thermodilution ejection fraction catheter was used to measure ejection fraction(EFrv), allowing for calculation of right ventricular(RV) end-diastolic volume index(EDVIrv), end-systolic volume index(ESVIrv), stroke volume index(SVIrv). RV stroke work index(SWIrv), maximum elastance (Emaxrv) and performance index(PIrv) as the functions of contractility were also calculated. Those RV hemodynamic measures were taken during preanhepatic phase(stage I), anhepatic phase (stage II), after reperfusion of the grafted liver and postanhepatic phase (stage III). All of measures in each surgical stage were statistically analyzed for their differences by repeated measured ANOVA. And correlation between changes from baseline of RV hemodynamic variables was determined by polynomial regression analysis. RESULTS: EFrv, SVIrv, SWIrv appeared to be well preserved throughout the prdegrees Cedure during stage I, II, III and much higher 5 min after reperfusion. No correlation was observed between right atrial pressure(Pra) and EDVIrv. There were significant correlation between EDVIrv and SVIrv, SWIrv and EFrv, Emaxrv and EFrv. CONCLUSION: RV function was well preserved during uncomplicated OLT using venovenous bypass. EDVIrv were more reliable determinants of RV preload than Pra for assessing RV contractility under conditions of this operation.