Prediction of fluid responsiveness in critical care: Current evidence and future perspective

Background: Fluid responsiveness is a crucial concept in the management of critically ill patients, guiding fluid resuscitation to optimize hemodynamics while avoiding fluid overload. Various methods have been proposed to predict fluid responsiveness, but their applicability and accuracy vary. Objectives: To provide a comprehensive review of the different methods used to assess fluid responsiveness in critically ill patients, including their principles, clinical applications, and limitations. Methods: A narrative review of the literature was conducted, focusing on both static and dynamic indices of fluid responsiveness, as well as their advantages and disadvantages. Results: Static indices, such as central venous pressure and pulmonary artery occlusion pressure, have limited accuracy in predicting fluid responsiveness. Dynamic indices, including stroke volume variation, pulse pressure variation, and respiratory changes in inferior vena cava diameter, have demonstrated better predictive value in mechanically ventilated patients. Passive leg raising and end-expiratory occlusion tests are useful in both spontaneously breathing and mechanically ventilated patients. Carotid flow time has been shown to predict fluid responsiveness in both mechanically ventilated and spontaneously breathing patients but may be influenced by factors such as arterial compliance and operator skill. Conclusions: Dynamic indices are more accurate predictors of fluid responsiveness than static indices in critically ill patients. However, each method has its limitations, and a comprehensive understanding of the principles, clinical applications, and potential confounding factors is essential for optimal patient management. Individualized assessment and a multimodal approach should be considered in the evaluation of fluid responsiveness.