title: Effect of nasal continuous and biphasic positive airway pressure on lung volume in preterm infants.
abstract: OBJECTIVE
  To monitor regional changes in end-expiratory lung volume (EELV), tidal volumes, and their ventilation distribution during different levels of nasal continuous positive airway pressure (nCPAP) and nasal biphasic positive airway pressure (BiPAP) in stable preterm infants.
  
  
  METHODS
  By using electrical impedance tomography and respiratory inductive plethysmography, we measured changes in EELV and tidal volumes in 22 preterm infants (gestational age 29.7 ± 1.5 weeks) during 3 nCPAP levels (2, 4, and 6 cmH2O) and unsynchronized BiPAP (nCPAP = 6 cmH2O; pressure amplitude = 3 cmH2O; frequency = 50/min; inspiration time = 0.5 seconds) at 10-minute intervals. We assessed the distribution of these volumes in ventral and dorsal chest regions by using electrical impedance tomography.
  
  
  RESULTS
  EELV increased with increasing nCPAP with no difference between the ventral and dorsal lung regions. Tidal volume also increased, and a decrease in phase angle and respiratory rate was noted by respiratory induction plethysmography. At the regional level, electrical impedance tomography data showed a more dorsally oriented ventilation distribution. BiPAP resulted in a small increase in EELV but without changes in tidal volume or its regional distribution.
  
  
  CONCLUSIONS
  Increasing nCPAP in the range of 2 to 6 cmH2O results in a homogeneous increase in EELV and an increase in tidal volume in preterm infants with a more physiologic ventilation distribution. Unsynchronized BiPAP does not improve tidal volume compared with nCPAP.
authors.affiliation: Department of Neonatology, Emma Children's Hospital, Academic Medical Center, Amsterdam, The Netherlands. m.miedema@amc.uva.nl
authors.forename: Martijn
authors.initials: M
authors.lastname: Miedema
authors.forename: Pauline S
authors.initials: PS
authors.lastname: van der Burg
authors.forename: Sabine
authors.initials: S
authors.lastname: Beuger
authors.forename: Frans H
authors.initials: FH
authors.lastname: de Jongh
authors.forename: Inez
authors.initials: I
authors.lastname: Frerichs
authors.forename: Anton H
authors.initials: AH
authors.lastname: van Kaam
mesh_terms: D002138:Calibration; D045422:Continuous Positive Airway Pressure / Q000379:methods*; D017097:Electric Impedance; D004562:Electrocardiography / Q000379:methods; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D008168:Lung / Q000473:pathology* / Q000502:physiology; D008297:Male; D010991:Plethysmography / Q000379:methods; D011175:Positive-Pressure Respiration / Q000379:methods*; D011312:Pressure; D013990:Tidal Volume / Q000502:physiology; D014054:Tomography / Q000379:methods; D014691:Ventilation