title: Relation between respiratory variations in pulse oximetry plethysmographic waveform amplitude and arterial pulse pressure in ventilated patients.
abstract: BACKGROUND
  Respiratory variation in arterial pulse pressure is a reliable predictor of fluid responsiveness in mechanically ventilated patients with circulatory failure. The main limitation of this method is that it requires an invasive arterial catheter. Both arterial and pulse oximetry plethysmographic waveforms depend on stroke volume. We conducted a prospective study to evaluate the relationship between respiratory variation in arterial pulse pressure and respiratory variation in pulse oximetry plethysmographic (POP) waveform amplitude.
  
  
  METHODS
  This prospective clinical investigation was conducted in 22 mechanically ventilated patients. Respiratory variation in arterial pulse pressure and respiratory variation in POP waveform amplitude were recorded simultaneously in a beat-to-beat evaluation, and were compared using a Spearman correlation test and a Bland-Altman analysis.
  
  
  RESULTS
  There was a strong correlation (r2 = 0.83; P < 0.001) and a good agreement (bias = 0.8 +/- 3.5%) between respiratory variation in arterial pulse pressure and respiratory variation in POP waveform amplitude. A respiratory variation in POP waveform amplitude value above 15% allowed discrimination between patients with respiratory variation in arterial pulse pressure above 13% and those with variation of 13% or less (positive predictive value 100%).
  
  
  CONCLUSIONS
  Respiratory variation in arterial pulse pressure above 13% can be accurately predicted by a respiratory variation in POP waveform amplitude above 15%. This index has potential applications in patients who are not instrumented with an intra-arterial catheter.
authors.affiliation: Service de Réanimation Médicale, Centre Hospitalier Lyon Sud, Pierre Bénite, France. maxime_cannesson@hotmail.com
authors.forename: Maxime
authors.initials: M
authors.lastname: Cannesson
authors.forename: Cyril
authors.initials: C
authors.lastname: Besnard
authors.forename: Pierre G
authors.initials: PG
authors.lastname: Durand
authors.forename: Julien
authors.initials: J
authors.lastname: Bohé
authors.forename: Didier
authors.initials: D
authors.lastname: Jacques
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001794:Blood Pressure / Q000502:physiology*; D001810:Blood Volume; D004812:Epidemiologic Methods; D005260:Female; D005440:Fluid Therapy; D006801:Humans; D007385:Intermittent Positive-Pressure Ventilation; D008297:Male; D008875:Middle Aged; D010092:Oximetry / Q000379:methods*; D010991:Plethysmography / Q000379:methods*