Work of breathing during CPAP and heated humidified high-flow nasal cannula.

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.