title: Respiratory inductive plethysmography accuracy at varying PEEP levels and degrees of acute lung injury.
abstract: OBJECTIVE
  This study was performed to assess the accuracy of respiratory inductive plethysmographic (RIP) estimated lung volume changes at varying positive end-expiratory pressures (PEEP) during different degrees of acute respiratory failure.
  
  
  METHODS
  Measurements of inspiratory tidal volume were validated in eight piglets during constant volume ventilation at incremental and decremental PEEP levels and with increasing severity of pulmonary injury. RIP accuracy was assessed with calibration from the healthy state, from the disease state as the measurement error was assessed, and at various PEEP levels.
  
  
  RESULTS
  Best results (bias 3%, precision 7%) were obtained in healthy animals. RIP accuracy decreased with progressing degrees of acute respiratory failure and was PEEP dependent, unless RIP was calibrated again. When calibration was performed in the disease state as the measurement error was assessed, bias was reduced but precision did not improve (bias -2%, precision 9%).
  
  
  CONCLUSIONS
  RIP accuracy is within the accuracy range found in monitoring devices currently in clinical use. Most reliable results with RIP are obtained when measurements are preceded by calibration in pulmonary conditions that are comparable to the measurement period. When RIP calibration is not possible, fixed weighting of the RIP signals with species and subject size adequate factors is an alternative. Measurement errors should be taken into account with interpretation of small volume changes.
authors.affiliation: Pediatric Intensive Care Unit, University Medical Center Utrecht, Utrecht, The Netherlands. dg.markhorst@vumc.nl
authors.forename: D G
authors.initials: DG
authors.lastname: Markhorst
authors.forename: J P
authors.initials: JP
authors.lastname: Van Gestel
authors.forename: H R
authors.initials: HR
authors.lastname: Van Genderingen
authors.forename: J J
authors.initials: JJ
authors.lastname: Haitsma
authors.forename: B
authors.initials: B
authors.lastname: Lachmann
authors.forename: A J
authors.initials: AJ
authors.lastname: Van Vught
mesh_terms: D000208:Acute Disease; D000818:Animals; D018893:Bronchoalveolar Lavage; D005260:Female; D055370:Lung Injury; D010991:Plethysmography; D011175:Positive-Pressure Respiration; D015203:Reproducibility of Results; D013552:Swine