title: Respiratory variations in pulse oximetry plethysmographic waveform amplitude to predict fluid responsiveness in the operating room.
abstract: BACKGROUND
  Respiratory variations in pulse oximetry plethysmographic waveform amplitude (DeltaPOP) are related to respiratory variations in pulse pressure (DeltaPP) and are sensitive to changes in preload. The authors hypothesized that DeltaPOP can predict fluid responsiveness in mechanically ventilated patients during general anesthesia.
  
  
  METHODS
  Twenty-five patients referred for cardiac surgery were studied after induction of general anesthesia. Hemodynamic data (cardiac index, central venous pressure, pulmonary capillary wedge pressure, DeltaPP, and DeltaPOP) were recorded before and after volume expansion (500 ml hetastarch, 6%). Fluid responsiveness was defined as an increase in cardiac index of 15% or greater.
  
  
  RESULTS
  Volume expansion induced changes in cardiac index (2.0+/-0.4 to 2.3+/-0.5 mmHg; P<0.05), DeltaPP (11+/-7 to 6+/-5%; P<0.05), and DeltaPOP (12+/-9 to 7+/-5%; P<0.05). DeltaPOP and DeltaPP were higher in responders than in nonresponders (17+/-8 vs. 6+/-4 and 14+/-7 vs. 6+/-4%, respectively; P<0.05 for both). A DeltaPOP greater than 13% before volume expansion allowed discrimination between responders and nonresponders with 80% sensitivity and 90% specificity. There was a significant relation between DeltaPOP before volume expansion and percent change in cardiac index after volume expansion (r=0.62; P<0.05).
  
  
  CONCLUSIONS
  DeltaPOP can predict fluid responsiveness noninvasively in mechanically ventilated patients during general anesthesia. This index has potential clinical applications.
authors.affiliation: Hospices Civils de Lyon, Department of Anesthesiology and Intensive Care, Louis Pradel Hospital, Claude Bernard Lyon I University, France. maxime_cannesson@hotmail.com
authors.forename: Maxime
authors.initials: M
authors.lastname: Cannesson
authors.forename: Yassin
authors.initials: Y
authors.lastname: Attof
authors.forename: Pascal
authors.initials: P
authors.lastname: Rosamel
authors.forename: Olivier
authors.initials: O
authors.lastname: Desebbe
authors.forename: Pierre
authors.initials: P
authors.lastname: Joseph
authors.forename: Olivier
authors.initials: O
authors.lastname: Metton
authors.forename: Olivier
authors.initials: O
authors.lastname: Bastien
authors.forename: Jean-Jacques
authors.initials: JJ
authors.lastname: Lehot
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000768:Anesthesia, General; D001794:Blood Pressure / Q000187:drug effects*; D001026:Coronary Artery Bypass; D005260:Female; D006801:Humans; D006895:Hydroxyethyl Starch Derivatives / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D010092:Oximetry; D010952:Plasma Substitutes / Q000494:pharmacology*; D010991:Plethysmography; D012119:Respiration / Q000187:drug effects*; D012121:Respiration, Artificial
chemical_list: D006895:Hydroxyethyl Starch Derivatives; D010952:Plasma Substitutes