The role of the tidal volume challenge test in volume responsiveness assessment: a narrative review

The accurate prediction of volume responsiveness is fundamental to goal-directed fluid administration. Targeted fluid administration during surgery is critical to avoid hypervolemia or hypovolemia and their associated postoperative complications. Recently, lung-protective ventilation strategies with tidal volumes of less than 8 mL/kg of ideal body weight have been recommended as standard practice during surgeries. Nevertheless, these reduced tidal volumes diminish the reliability of dynamic indices, such as pulse pressure variation, for predicting volume responsiveness. To address this limitation, the tidal volume challenge has proven to be a reliable method. This challenge involves increasing the tidal volume from 6 to 8 mL/kg of ideal body weight and observing the impact on hemodynamic parameters. Multiple studies have validated the efficacy of this test in both surgical patients and critically ill patients in the intensive care unit. The tidal volume challenge effectively improves the accuracy of predicting fluid responsiveness by increasing both sensitivity and specificity. Established threshold values for changes in pulse pressure variation and stroke volume variation offer precise clinical recommendations. However, additional cohorts and randomized controlled trials are imperative to validate the efficacy of the tidal volume challenge and advance fluid management strategies.