title: Work of breathing during CPAP and heated humidified high-flow nasal cannula.
abstract: OBJECTIVE
  To determine whether continuous positive airway pressure (CPAP) compared with heated humidified, high-flow nasal cannula (HHFNC) in infants with evolving or established bronchopulmonary dysplasia (BPD) reduced the work of breathing (WOB) and thoracoabdominal asynchrony (TAA) and improved oxygen saturation (SaO2).
  
  
  METHODS
  Randomised crossover study.
  
  
  METHODS
  Tertiary neonatal unit.
  
  
  METHODS
  20 infants (median gestational age of 27.6 weeks (range 24.6-31.9 weeks)) were studied at a median postnatal age of 30.9 weeks (range 28.1-39.1 weeks).
  
  
  METHODS
  Infants were studied on 2 consecutive days. On the first study day, they were randomised to either CPAP or HHFNC each for 2 h, the order being reversed on the second day.
  
  
  METHODS
  The WOB was assessed by measuring the pressure time product of the diaphragm (PTPdi). PTPdi, TAA and SaO2 were assessed during the final 5 min of each 2 h period and the results on the two study days were meaned.
  
  
  RESULTS
  There were no significant differences in the results on CPAP versus HHFNC: mean PTPdi 226 (range 126-294) versus 224 cm H2O/s/min (95% CI for difference: -27 to 22; p=0.85) (range 170-318) (p=0.82), mean TAA 13.4° (range 4.51°-23.32°) versus 14.01° (range 4.25°-23.86°) (95% CI for difference: -3.9 to 2.8: p=0.73) (p=0.63) and mean SaO2 95% (range 93%-100%) versus 95% (94%-99%), (95% CI for difference -1.8 to 0.5; p=0.25) (p=0.45).
  
  
  CONCLUSIONS
  In infants with evolving or established BPD, CPAP compared with HHFNC offered no significant advantage with regard to the WOB, degree of asynchrony or oxygen saturation.
authors.affiliation: Neonatal Intensive Care Centre, King's College Hospital, London, UK Division of Asthma, Allergy and Lung Biology, MRC Centre for Allergic Mechanisms in Asthma, King's College London, London, UK.
authors.forename: Sandeep
authors.initials: S
authors.lastname: Shetty
authors.affiliation: Neonatal Intensive Care Centre, King's College Hospital, London, UK.
authors.forename: Ann
authors.initials: A
authors.lastname: Hickey
authors.affiliation: Division of Asthma, Allergy and Lung Biology, MRC Centre for Allergic Mechanisms in Asthma, King's College London, London, UK.
authors.forename: Gerrard F
authors.initials: GF
authors.lastname: Rafferty
authors.affiliation: Division of Health and Social Care Research, King's College London, London, UK NIHR Biomedical Research Centre at Guy's and St Thomas' NHS Foundation Trust and King's College London, London, UK.
authors.forename: Janet L
authors.initials: JL
authors.lastname: Peacock
authors.affiliation: Division of Asthma, Allergy and Lung Biology, MRC Centre for Allergic Mechanisms in Asthma, King's College London, London, UK NIHR Biomedical Research Centre at Guy's and St Thomas' NHS Foundation Trust and King's College London, London, UK.
authors.forename: Anne
authors.initials: A
authors.lastname: Greenough
mesh_terms: D045422:Continuous Positive Airway Pressure / Q000379:methods*; D018592:Cross-Over Studies; D006358:Hot Temperature; D006801:Humans; D006813:Humidity; D007234:Infant, Premature / Q000502:physiology*; D014939:Work of Breathing
keywords: bronchopulmonary dysplasia; continuous positive airway pressure; high flow nasal cannula; work of breathing