Work of breathing during nasal continuous positive airway pressure in preterm infants: A comparison of bubble vs variable-flow devices

Abstract

Objective: To compare work of breathing and breathing asynchrony during bubble nasal continous positive airway pressure (NCPAP) vs variable-flow (VF)-NCPAP in premature infants. Study designs: We studied 18 premature infants of birth weight <1500g who required NCPAP for mild respiratory distress. Each infant was studied on bubble and VF-NCPAP at 8, 6, 4, and 0 cmH2O. Tidal volumes were obtained by calibrated respiratory inductance plethysmography. Esophageal pressure estimated intrapleural pressure. Inspiratory and resistive work of breathing were calculated from pressure-volume data. Breathing asynchrony was assessed with phase angle. The results at all NCPAP levels were referenced to VF-NCPAP values at 8 cmH2O. Results: Provision of NCPAP with either device decreased inspiratory work of breathing, tidal volume, and minute ventilation relative to NCPAP of 0 cmH2O. Bubble NCPAP did not decrease resistive work of breathing relative to 0 cmH2O. Resistive work of breathing (p = 0.01), respiratory rate (p < 0.03), and phase angle (p = 0.002) were all greater with bubble compared to VF-NCPAP. Conclusion: The more labored and asynchronous breathing seen with bubble NCPAP may lead to higher failure rates over the long term than with VF-NCPAP. © 2005 Nature Publishing Group All rights reserved.