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Published on: January 20, 2023
Assessing Fluid Responsiveness in Spontaneously Breathing Patients
Joseph Miller1,2, Chuan-Xing Ho2, Joy Tang2
1Department of Emergency Medicine, Henry Ford Hospital, Detroit, MI.
Objectives:
The primary objective of this study was to test if fasting volunteers exhibit fluid responsiveness using noninvasive hemodynamic measurements. The secondary objective was to test a passive leg raise (PLR) maneuver as a diagnostic predictor of fluid responsiveness.
Methods:
This was a quasi-experimental design involving healthy volunteers. Subjects were excluded for pregnancy and congestive heart failure. Following a 12-hour fast, subjects had baseline hemodynamic monitoring recorded using noninvasive, continuous pulse contour analysis. Subjects then had a PLR maneuver performed, followed by an intravenous bolus of crystalloid. A rise in stroke volume ≥ 10% from baseline with the bolus was considered consistent with fluid responsiveness, and the same rise with a PLR was consistent with a positive PLR maneuver. The primary outcome was the change in stroke volume with a fluid bolus. Univariate analysis assessed changes in hemodynamic parameters. Logistic regression analysis determined the test characteristics of the PLR in predicting subjects who were ultimately fluid responsive.
Results:
Forty subjects completed the study. The mean change in stroke volume with a crystalloid bolus was 19% (95% confidence interval [CI] = 16% to 21%). Thirty-six (90%) subjects were fluid responsive. The mean PLR response for the overall cohort was 16% (95% CI = 12% to 19%), and 26 (65%) subjects had a positive PLR maneuver. The PLR was 72% sensitive (95% CI = 55% to 85%) and 100% specific (95% CI = 40% to 100%) for predicting the presence of fluid responsiveness.
Conclusions:
Noninvasive assessment of fluid responsiveness in healthy volunteers and prediction of this response with a PLR maneuver is achievable. Further work is indicated to test these methods in acutely ill patients.
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