How long should one wait after performing PLR to assess if the patient is fluid responsive?

The appropriate time to wait after performing a Passive Leg Raise (PLR) to assess fluid responsiveness is between 30 to 60 seconds. This time frame allows the hemodynamic changes induced by the PLR maneuver to stabilize, which is essential for an accurate evaluation of whether the patient will benefit from additional fluid administration.

During PLR, blood volume is transiently increased in the intrathoracic space, effectively simulating a fluid bolus. The physiologic response, such as an increase in stroke volume or cardiac output, typically occurs fairly rapidly but may require some time for the full effect to manifest. Waiting at least 30 seconds ensures that any changes in hemodynamic parameters can be properly assessed and that the results are not influenced by immediate postural changes or variations that may occur too soon after initiating the maneuver.

In shorter time frames, such as 15 to 30 seconds, it is possible that the assessment may reflect transient changes rather than a true indication of fluid responsiveness. Conversely, waiting more than 60 seconds may not yield additional relevant information and could lead to unnecessary delays in clinical decision-making regarding fluid therapy. Therefore, the 30 to 60 seconds interval is optimal for evaluating fluid responsiveness effectively after performing the PLR maneuver