title: Relation between pulse oximetry plethysmographic waveform amplitude induced by passive leg raising and cardiac index in spontaneously breathing subjects.
abstract: BACKGROUND
  Previous studies suggested that variation of pulse oximetric plethysmographic (POP) waveform amplitude (Delta POP) could predict fluid responsiveness in mechanically ventilated patients. Our objective was to correlate the variations of Delta POP and the variations of cardiac index (CI) induced by passive leg raising (PLR) in spontaneously breathing volunteers.
  
  
  METHODS
  We studied 26 spontaneously breathing volunteers using a pulse oximeter attached to the middle finger. We assessed hemodynamic variables, including Delta POP (%) (POP(max) - POP(min))/[(POP(max) + POP(min))/2] and CI determined by transthoracic echocardiography at baseline (eg, semirecumbent position), during PLR at 60 degrees, and back to baseline.
  
  
  RESULTS
  Cardiac index significantly increased from 2.2 to 2.5 L/min x m(2) (P < .01) at 60 degrees PLR. Conversely, Delta POP significantly decreased from 22% to 15% (P < .01) at 60 degrees PLR. There was a weak correlation between CI and Delta POP variations at 60 degrees PLR (r = 0.40; P < .01). The area under curve of the receiver operating characteristic curve for Delta POP as a predictor of an increase of CI of 15% was not significant (0.67 +/- 0.10; P = .16).
  
  
  CONCLUSIONS
  The variation of Delta POP induced by PLR is not an accurate predictor of increase in CI.
authors.affiliation: Department of Emergency Medicine and Surgery, Center Hospitalo-Universitaire Pitié-Salpêtrière, 75013 Paris, UPMC Paris 6, France.
authors.forename: Samuel
authors.initials: S
authors.lastname: Delerme
authors.forename: Samuel
authors.initials: S
authors.lastname: Castro
authors.forename: Yonathan
authors.initials: Y
authors.lastname: Freund
authors.forename: Pierre
authors.initials: P
authors.lastname: Nazeyrollas
authors.forename: Marie-Odile
authors.initials: MO
authors.lastname: Josse
authors.forename: Béatrice
authors.initials: B
authors.lastname: Madonna-Py
authors.forename: Edwin
authors.initials: E
authors.lastname: Rouff
authors.forename: Bruno
authors.initials: B
authors.lastname: Riou
authors.forename: Patrick
authors.initials: P
authors.lastname: Ray
mesh_terms: D000328:Adult; D001794:Blood Pressure; D002302:Cardiac Output / Q000502:physiology; D005260:Female; D005440:Fluid Therapy; D006321:Heart / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D007866:Leg; D008297:Male; D008875:Middle Aged; D010092:Oximetry; D010991:Plethysmography; D011187:Posture / Q000502:physiology; D012372:ROC Curve; D012119:Respiration; D013318:Stroke Volume / Q000502:physiology; D055815:Young Adult