Cardiac preload is traditionally considered to be represented by its filling pressures, but more recently, estimations of end diastolic volume of the left or right ventricle have been shown to better reflect preload. One method of determining volumes is the evaluation of the continuous right ventricular end diastolic volume index (cRVEDVI) on the basis of the cardiac output thermodilution technique. Because preload and myocardial contractility are the main factors determining cardiac output during liver transplantation (LTx), accurate determination of preload is important. Thus, monitoring of cRVEDVI and cRVEF should help with fluid management and with the assessment of the need for inotropic and vasoactive agents. In this multicenter study, we looked for possible relationships between the stroke volume index (SVI) and cRVEDVI, cRVEF, and filling pressures at 4 predefined steps in 244 patients undergoing LTx. Univariate and multivariate autoregression models (across phases of the surgical procedure) were fitted to assess the possible association between SVI and cRVEDVI, pulmonary artery occlusion pressure (PAOP), and central venous pressure (CVP) after adjustment for cRVEF (categorized as < or =30, 31-40, and >40%). SVI was strongly associated with both cRVEDVI and cRVEF. The model showing the best fit to the data was that including cRVEDVI. Even after adjustment for cRVEF, there was a statistically significant (P < 0.05) relationship between SVI and cRVEDVI with a regression coefficient (slope of the regression line) of 0.25; this meant that an increase in cRVEDVI of 1 mL m(-2) resulted in an increase in SVI of 0.25 mL m(-2). The correlations between SVI and CVP and PAOP were less strong. We conclude that cRVEDVI reflected preload better than CVP and PAOP.