Methods of assessing fluid responsiveness in septic shock patients: a narrative review

A growing body of evidence shows that some septic patients experience fluid overload, which leads to an increased number of serious complications and death. This is because the majority of septic patients are fluid non-responders. Therefore, a reliable distinction of which patient would benefit from fluid boluses is crucial in current sepsis mana-gement. Several methods used to assess fluid responsiveness have been developed. The principle of "dynamic" measurements (in contrast to static indices such as central venous pressure) involves the induction of a change in cardiac preload and the measurement of its effect on stroke volume. Dynamic methods are based on either heart-lung interaction during mechanical ventilation or on an assessment of change in cardiac stroke volume in response to fluid provocative stimuli such as rapid fluid administration, passive leg raising, or the end-expiratory occlusion test. Most dynamic measurements are easy to perform and interpret as well as being available at the bedside. However, they vary in their invasiveness, difficulty in performance, reliability, and limitations. In this study, we provide an overview of various methods for assessing fluid responsiveness and indicate those that potentially lead to haemodynamically guided fluid restrictive treatment that would prevent fluid overload in septic patients.