title: Lung recruitment and breathing pattern during variable versus continuous flow nasal continuous positive airway pressure in premature infants: an evaluation of three devices.
abstract: OBJECTIVE
  To determine whether lung volume changes and breathing pattern parameters differ among 3 devices for delivery of nasal continuous positive airway pressure (CPAP) in premature infants.
  
  
  METHODS
  Thirty-two premature infants receiving nasal CPAP for apnea or mild respiratory distress were enrolled. Birth weight was (mean +/- standard deviation) 1081 +/- 316 g, gestational age 29 +/- 2 weeks, age at study 13 +/- 12 days, and fraction of inspired oxygen (FIO(2)) at study.29 +/-.1. Three devices, applied in random order, were studied in each infant: continuous flow nasal CPAP via CPAP prongs, continuous flow nasal CPAP via modified nasal cannula, and variable flow nasal CPAP. After lung recruitment to standardize volume history, changes in lung volume (DeltaV(L)) were assessed at nasal CPAP of 8, 6, 4, and 0 cm H(2)O using calibrated direct current-coupled respiratory inductance plethysmography.
  
  
  RESULTS
  DeltaV(L) was significantly greater overall with the variable flow device compared with both the nasal cannula and CPAP prongs. However, DeltaV(L) was not different between the cannula and the prongs. Respiratory rate, tidal volume, thoraco-abdominal asynchrony, and FIO(2) were greater with the modified cannula than for either of the other 2 devices.
  
  
  CONCLUSIONS
  Compared with 2 continuous flow devices, the variable flow nasal CPAP device leads to greater lung recruitment. Although a nasal cannula is able to recruit lung volume, it does so at the cost of increased respiratory effort and FIO(2).
authors.affiliation: Robert Wood Johnson Medical School at Camden and the Department of Pediatrics, Division of Neonatology, the Children's Regional Hospital at Cooper Hospital/University Medical Center, Camden, New Jersey 08103, USA. courtnse@umdnj.edu
authors.forename: S E
authors.initials: SE
authors.lastname: Courtney
authors.forename: K H
authors.initials: KH
authors.lastname: Pyon
authors.forename: J G
authors.initials: JG
authors.lastname: Saslow
authors.forename: G K
authors.initials: GK
authors.lastname: Arnold
authors.forename: P B
authors.initials: PB
authors.lastname: Pandit
authors.forename: R H
authors.initials: RH
authors.lastname: Habib
mesh_terms: D001049:Apnea / Q000628:therapy; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature / Q000502:physiology*; D007235:Infant, Premature, Diseases / Q000503:physiopathology / Q000628:therapy; D008170:Lung Compliance; D009666:Nose; D011175:Positive-Pressure Respiration / Q000295:instrumentation* / Q000379:methods; D012119:Respiration; D012131:Respiratory Insufficiency / Q000628:therapy; D014109:Total Lung Capacity