title: Assessing Fluid Responsiveness in Spontaneously Breathing Patients.
abstract: OBJECTIVE
  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.
authors.affiliation: Department of Emergency Medicine, Henry Ford Hospital, Detroit, MI.|Wayne State University School of Medicine, Detroit, MI.
authors.forename: Joseph
authors.initials: J
authors.lastname: Miller
authors.affiliation: Wayne State University School of Medicine, Detroit, MI.
authors.forename: Chuan-Xing
authors.initials: CX
authors.lastname: Ho
authors.affiliation: Wayne State University School of Medicine, Detroit, MI.
authors.forename: Joy
authors.initials: J
authors.lastname: Tang
authors.affiliation: Wayne State University School of Medicine, Detroit, MI.
authors.forename: Richard
authors.initials: R
authors.lastname: Thompson
authors.affiliation: Department of Emergency Medicine, Henry Ford Hospital, Detroit, MI.
authors.forename: Jared
authors.initials: J
authors.lastname: Goldberg
authors.affiliation: Department of Emergency Medicine, Henry Ford Hospital, Detroit, MI.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Amer
authors.affiliation: Lincoln Medical and Mental Health Center, Weill Cornell Medical College, New York, NY.
authors.forename: Bashar
authors.initials: B
authors.lastname: Nahab
mesh_terms: D000328:Adult; D005215:Fasting; D005260:Female; D005440:Fluid Therapy / Q000379:methods*; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D007866:Leg; D008297:Male; D008991:Monitoring, Physiologic / Q000379:methods*; D013318:Stroke Volume