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Work of breathing during CPAP and heated humidified high-flow nasal cannula
  1. Sandeep Shetty1,2,
  2. Ann Hickey1,
  3. Gerrard F Rafferty2,
  4. Janet L Peacock3,4,
  5. Anne Greenough2,4
  1. 1Neonatal Intensive Care Centre, King's College Hospital, London, UK
  2. 2Division of Asthma, Allergy and Lung Biology, MRC Centre for Allergic Mechanisms in Asthma, King's College London, London, UK
  3. 3Division of Health and Social Care Research, King's College London, London, UK
  4. 4NIHR Biomedical Research Centre at Guy's and St Thomas’ NHS Foundation Trust and King's College London, London, UK
  1. Correspondence to Professor Anne Greenough, Neonatal Intensive Care Centre, 4th Floor Golden Jubilee Wing, King's College Hospital, Denmark Hill, London SE5 9RS, UK; anne.greenough{at}


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).

Design Randomised crossover study.

Setting Tertiary neonatal unit.

Patients 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).

Interventions 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.

Main outcome measures 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).

Conclusion 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.

  • high flow nasal cannula
  • continuous positive airway pressure
  • bronchopulmonary dysplasia
  • work of breathing

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