Efficacy of Changes in Pulse Pressure Variation During Tidal Volume Challenge Test to Predict Fluid Responsiveness in Low Tidal Volume Ventilated Critically ill Patients

Background: Fluid administration is one of the first-line therapy interventions used to reverse tissue hypoperfusion during acute circulatory failure. Nevertheless, fluid administration is not free of adverse effects, especially when fluids are excessively administered. Assessment of fluid responsiveness might limit fluid administration, potentially reducing the risk of fluid overload, avoiding complications derived from tissue oedema, and increasing mechanical ventilation-free days, among others. Aim and objectives: Aiming to predict preload response in low tidal volume ventilation by analyzing pulse pressure variation (PPV) fluctuations during a one-minute tidal volume challenge (TVC). Subjects and methods: From March 2023 through August 2024, sixty patients admitted to the intensive care unit at Al-Azhar University Hospitals were part of this correlational clinical study. After receiving signed informed consents, the study procedure was approved by the department's Ethics Committee. Results: The responders' PPV increased significantly with TVC, reaching 91.9% specificity and 95.7% sensitivity at the optimal cutoff value of 4. With a statistically best threshold value of 2% decrease in PPV, the changes in PPV induced by the PLR test were 87% sensitive and 86.5% specific. Conclusion: In critically ill patients ventilated with a low tidal volume of 6ml/kg IBW or less, the variations in PPV can accurately predict preload response when PPV rises to 4 or more during TVC and falls to 2 or less during PLR. There is no need to employ continuous cardiac output monitoring to evaluate the effects of either test; they are both straightforward.