Figure 7-8 Left ventricular (LV) pressure versus LV volume diagrams during inferior vena caval occlusion and the definition of LV-arterial coupling. The LV maximal elastances of each pressure-volume diagram are used to calculate the slope (E_ES ) of the end-systolic pressure-volume relationship. Effective arterial elastance (E_A ) is determined as the ratio of end-systolic arterial pressure and stoke volume during steady-state hemodynamic conditions. In the pressure-volume plane, E_A represents the magnitude of the slope connecting end-systole to end-diastole. (Adapted from Hettrick DA, Pagel PS, Warltier DC: Desflurane, sevoflurane, and isoflurane impair canine left ventricular-arterial coupling and mechanical efficiency. Anesthesiology 85:403–413, 1996.)