“…10,16 Pulse pressure variation (PPV) and systolic pressure variation (SPV)-both derived from analysis of the arterial waveform-, stroke volume variation (SVV), and the variation of the amplitude of the pulse oximeter plethysmographic waveform are predictive of fluid responsiveness. 7,21,22 These techniques use heart-lung interactions during mechanical ventilation. During inspiration, pleural pressure increases, causing a reduction in RV preload and an increase in RV afterload.…”