Pleth Variability Index

Pulse pressure variation (PPV) and pleth variability index (PVI) are widely used in clinical practice as indicators of the responsiveness to fluid therapy in patients receiving mechanical ventilation. PPV, which measures changes in arterial pressure, requires arterial puncture, which is invasive, and PVI, which detects subtle changes in oxygen saturation, requires an expensive, commercial monitoring equipment. In this study, we aimed to measure peripheral venous pressure variation using less invasive waveform variation in peripheral veins and to determine whether this indicator can be clinically used to predict the responsiveness to fluid therapy. In addition, the investigators aimed to confirm the superiority of the indicators by comparing them with the responsiveness to fluid therapy of the PPV and PVI.