Pulse Pressure Variation Helps to Predict Fluid Responsiveness in Patients Ventilated With Low Tidal Volumes

Objective: To determine the value of pulse pressure variation (ΔRESPPP) to predict fluid responsiveness in patients ventilated with low tidal volumes (VT), and to investigate whether a lower ΔRESPPP cut-off point should be used when patients are ventilated with low tidal volumes. Methods: This cross-sectional, observational study included 37 critically ill patients with acute circulatory failure requiring fluid challenge. They were sedated and mechanically ventilated with Tidal Volume (VT) 6-7 ml/kg IBW (ideal body weight), monitored by pulmonary artery catheter and arterial line. Mechanical ventilation and hemodynamic parameters, including ΔRESPPP, were measured before and after fluid challenge with 1,000 ml crystalloids or 500 ml colloids. Fluid responsiveness was defined as an increase of at least 15% in cardiac index. The present study was designed to (1) determine the value of ΔRESPPP to predict fluid responsiveness in patients ventilated with low tidal volumes, and (2) to investigate whether a lower ΔRESPPP cut-off point should be used when patients are ventilated with low tidal volumes. The study hypothesis is not a good predictor of fluid responsiveness in patients ventilated with low tidal volumes.