title: Reliability of Displayed Tidal Volume in Healthy and Surfactant-Depleted Piglets.
abstract: BACKGROUND
  Volutrauma has been established as the key factor in ventilator-induced lung injury and can only be avoided if tidal volume (VT) is accurately displayed and delivered. The purpose of this study was to investigate the accuracy of displayed exhaled VTin a ventilator commonly used in small infants with or without a proximal flow sensor and using 3 methods to achieve a target VTin both a healthy and lung-injured neonatal pig model.
  
  
  METHODS
  This was a prospective animal study utilizing 8 male pigs, approximately 2.0 kg (range 1.8-2.2 kg). Intubated, sedated, neonatal pigs were studied with both healthy and injured lungs using the Servo-i ventilator. In pressure-regulated volume control, both with and without a proximal flow sensor, we used 3 methods to set VT: (1) circuit compliance compensation (CCC) on, set VT6-8 mL/kg; (2) CCC off, calculated VTusing the manufacturer's circuit compliance factor; and (3) CCC off, set VT10-12 mL/kg to approximate a target VTof 6-8 mL/kg. Ventilator-displayed exhaled VTmeasurements were compared with exhaled VTmeasured at the airway opening by a calibrated pneumotachograph. Bland-Altman plots were constructed to show the level of agreement between the two.
  
  
  RESULTS
  CCC improved accuracy and precision of displayed exhaled VTwhen the sensor was not used, more markedly in the lung-injured model. Without CCC, the sensor improved accuracy and precision of displayed exhaled VT, again more markedly in the lung-injured model.
  
  
  CONCLUSIONS
  When the Servo-i ventilator is used in neonates, CCC or the in-line sensor should be employed due to the large positive bias and imprecision seen with CCC off and no sensor in-line.
authors.affiliation: Neonatology Section.|The Women's Hospital, Newburgh, Indiana.
authors.forename: A Cecilia
authors.initials: AC
authors.lastname: Mendiondo Luedloff
authors.affiliation: Critical Care Medicine Section.|Translational Research Institute, UAMS, Little Rock, Arkansas.
authors.forename: Tracy L
authors.initials: TL
authors.lastname: Thurman
authors.affiliation: Respiratory Care Department, Arkansas Children's Hospital, Little Rock, Arkansas.
authors.forename: Shirley J
authors.initials: SJ
authors.lastname: Holt
authors.affiliation: Biostatistics Section, Department of Pediatrics, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, Arkansas.
authors.forename: Shasha
authors.initials: S
authors.lastname: Bai
authors.affiliation: Critical Care Medicine Section.|Spence and Becky Wilson Baptist Children's Hospital, Memphis, Tennessee.
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Heulitt
authors.affiliation: Neonatology Section scourtney@uams.edu.
authors.forename: Sherry E
authors.initials: SE
authors.lastname: Courtney
mesh_terms: D000818:Animals; D016022:Case-Control Studies; D004195:Disease Models, Animal; D045853:Exhalation; D008170:Lung Compliance; D008297:Male; D008991:Monitoring, Physiologic / Q000295:instrumentation / Q000379:methods; D011446:Prospective Studies; D015203:Reproducibility of Results; D012121:Respiration, Artificial / Q000295:instrumentation* / Q000379:methods; D013552:Swine; D013990:Tidal Volume; D055397:Ventilator-Induced Lung Injury / Q000209:etiology / Q000517:prevention & control*; D012122:Ventilators, Mechanical / Q000009:adverse effects*
keywords: mechanical ventilation; neonatal ventilation; respiratory care