title: Spontaneously Breathing Preterm Infants Change in Tidal Volume to Improve Lung Aeration Immediately after Birth.
abstract: OBJECTIVE
  To examine the temporal course of lung aeration at birth in preterm infants <33 weeks gestation.
  
  
  METHODS
  The research team attended deliveries of preterm infants <33 weeks gestation at the Royal Alexandra Hospital. Infants who received only continuous positive airway pressure were eligible for inclusion. A combined carbon dioxide (CO2) and flow-sensor was placed between the mask and the ventilation device. To analyze lung aeration patterns during spontaneous breathing, tidal volume (VT), and exhaled CO2 (ECO2) were recorded for the first 100 breaths.
  
  
  RESULTS
  Thirty preterm infants were included with a total of 1512 breaths with mask leak <30%. Mean (SD) gestational age and birth weight was 30 (1) weeks and 1478 (430) g. Initial VT and ECO2 for the first 30 breaths was 5-6 mL/kg and 15-22 mm Hg, respectively. VT and ECO2 increased over the next 20 breaths to 7-8 mL/kg and 25-32 mm Hg, respectively. For the remaining observation period VT decreased to 4-6 mL/kg and ECO2 continued to increase to 35-37 mm Hg.
  
  
  CONCLUSIONS
  Preterm infants begin taking deeper breaths approximately 30 breaths after initiating spontaneous breathing to inflate their lungs. Concurrent CO2 removal rises as alveoli are recruited. Lung aeration occurs in 2 phases: initially, large volume breaths with poor alveolar aeration followed by smaller breaths with elimination of CO2 as a consequence of adequate aeration.
authors.affiliation: Center for the Studies of Asphyxia and Resuscitation, Neonatal Research Unit, Royal Alexandra Hospital, Edmonton, Canada; Department of Pediatrics, University of Alberta, Edmonton, Canada.
authors.forename: Qaasim
authors.initials: Q
authors.lastname: Mian
authors.affiliation: Center for the Studies of Asphyxia and Resuscitation, Neonatal Research Unit, Royal Alexandra Hospital, Edmonton, Canada; Department of Pediatrics, University of Alberta, Edmonton, Canada.
authors.forename: Po-Yin
authors.initials: PY
authors.lastname: Cheung
authors.affiliation: Center for the Studies of Asphyxia and Resuscitation, Neonatal Research Unit, Royal Alexandra Hospital, Edmonton, Canada; Department of Pediatrics, University of Alberta, Edmonton, Canada.
authors.forename: Megan
authors.initials: M
authors.lastname: O'Reilly
authors.affiliation: Department of Pediatrics, Medical University Graz, Graz, Austria.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Pichler
authors.affiliation: Center for the Studies of Asphyxia and Resuscitation, Neonatal Research Unit, Royal Alexandra Hospital, Edmonton, Canada.
authors.forename: Sylvia
authors.initials: S
authors.lastname: van Os
authors.affiliation: Center for the Studies of Asphyxia and Resuscitation, Neonatal Research Unit, Royal Alexandra Hospital, Edmonton, Canada.
authors.forename: Karin
authors.initials: K
authors.lastname: Kushniruk
authors.affiliation: Center for the Studies of Asphyxia and Resuscitation, Neonatal Research Unit, Royal Alexandra Hospital, Edmonton, Canada; Department of Pediatrics, University of Alberta, Edmonton, Canada.
authors.forename: Khalid
authors.initials: K
authors.lastname: Aziz
authors.affiliation: Center for the Studies of Asphyxia and Resuscitation, Neonatal Research Unit, Royal Alexandra Hospital, Edmonton, Canada; Department of Pediatrics, University of Alberta, Edmonton, Canada.
authors.forename: Georg M
authors.initials: GM
authors.lastname: Schmölzer
mesh_terms: D002170:Canada; D002245:Carbon Dioxide / Q000378:metabolism*; D045422:Continuous Positive Airway Pressure; D005260:Female; D005865:Gestational Age; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007234:Infant, Premature / Q000502:physiology*; D008168:Lung / Q000378:metabolism / Q000502:physiology*; D008297:Male; D012119:Respiration; D013990:Tidal Volume / Q000502:physiology
chemical_list: D002245:Carbon Dioxide