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Author(s): Michael F. Graessler [sup.1], Karin H. Wodack [sup.1], Hans O. Pinnschmidt [sup.2], Sarah Nishimoto [sup.1], Christoph R. Behem, Daniel A. Reuter [sup.3], Constantin J. C. Trepte [sup.1] Author Affiliations: [...], Purpose Dynamic indicators of preload currently only do reflect preload requirements of the left ventricle. To date, no dynamic indicators of right ventricular preload have been established. The aim of this study was to calculate dynamic indicators of right ventricular preload and assess their ability to predict ventricular volume responsiveness. Materials and methods The study was designed as experimental trial in 20 anaesthetized pigs. Micro-tip catheters and ultrasonic flow probes were used as experimental reference to enable measurement of right ventricular stroke volume and pulse pressure. Hypovolemia was induced (withdrawal of blood 20 ml/kg) and thereafter three volume-loading steps were performed. ROC analysis was performed to assess the ability of dynamic right ventricular parameters to predict volume response. Results ROC analysis revealed an area under the curve (AUC) of 0.82 (CI 95% 0.73-0.89; p < 0.001) for right ventricular stroke volume variation (SVV.sub.RV), an AUC of 0.72 (CI 95% 0.53-0.85; p = 0.02) for pulmonary artery pulse pressure variation (PPV.sub.PA) and an AUC of 0.66 (CI 95% 0.51-0.79; p = 0.04) for pulmonary artery systolic pressure variation (SPV.sub.PA). Conclusions In our experimental animal setting, calculating dynamic indicators of right ventricular preload is possible and appears promising in predicting volume responsiveness.

Purpose: In order to assess the occurrence of blood congestion in the liver during liver resection, we aimed to evaluate the influence of a positive-end-expiratory-pressure (PEEP) and positioning of patients on central venous pressure (CVP) and venous hepatic blood flow parameters. We further analyzed correlations between CVP and venous hepatic blood flow parameters.Methods: In 20 patients scheduled for elective liver resection we measured CVP and quantified venous hepatic hemodynamics by ultrasound assessment of flow-velocity and diameter of the right hepatic vein and the portal vein after equilibration following these maneuvers: M1: 0° supine position, PEEP 0 cmH2O; M2: 0° supine position, PEEP 10 cmH2O; M3: 20° reverse-trendelenburg position; PEEP 10 cmH2O; M4: 20° reverse-trendelenburg position, PEEP 0cmH2O.Results: Changing from supine to reverse-trendelenburg position led to a significant decrease in CVP (M3 5.95 ± 2.06 vs. M1 7.35 ± 2.18 mmHg and M2 8.55 ± 1.79 mmHg). A PEEP of 10 cmH2O and reverse-trendelenburg position led to significant reduction of systolic (VsHV) and diastolic (VdHV) flow-velocities of the right hepatic vein (VsHV M3 19.96 ± 6.47 vs. M1 27.81 ± 11.03 cm s-1;VdHV M3 14.94 ± 6.22 vs. M1 20.15 ± 10.34 cm s-1 and M2 20.19 ± 13.19 cm s-1) whereas no significant changes of flow-velocity occurred in the portal vein. No correlations between CVP and diameters or flow-velocities of the right hepatic and the portal vein were found.Conclusions: Changes of central venous pressure due to changes of PEEP and positioning were not correlated with changes of venous hepatic blood flow parameters as measured after equilibration. Strategies aiming for low central venous pressure cannot be supported by these results. However, before ruling out low-CVP-strategies during liver resections these results should be confirmed by further studies. [ABSTRACT FROM AUTHOR]