Work of breathing during nasal continuous positive airway pressure in preterm infants: a comparison of bubble vs variable-flow devices.
OBJECTIVE
To compare work of breathing and breathing asynchrony during bubble nasal continuous positive airway pressure (NCPAP) vs variable-flow (VF)-NCPAP in premature infants.


METHODS
We studied 18 premature infants of birth weight <1500 g who required NCPAP for mild respiratory distress. Each infant was studied on bubble and VF-NCPAP at 8, 6, 4, and 0 cm H2O. 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 cm H2O.


RESULTS
Provision of NCPAP with either device decreased inspiratory work of breathing, tidal volume, and minute ventilation relative to NCPAP of 0 cm H2O. Bubble NCPAP did not decrease resistive work of breathing relative to 0 cm H2O. 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.


CONCLUSIONS
The more labored and asynchronous breathing seen with bubble NCPAP may lead to higher failure rates over the long term than with VF-NCPAP.
Liptsen
Ellina
E
Department of Pediatrics, Schneider Children's Hospital, North Shore Long Island Jewish Health System, New Hyde Park, NY 11040, USA.
Aghai
Zubair H
ZH
Pyon
Kee H
KH
Saslow
Judy G
JG
Nakhla
Tarek
T
Long
Jennifer
J
Steele
Andrew M
AM
Habib
Robert H
RH
Courtney
Sherry E
SE
D045422:Continuous Positive Airway Pressure / Q000295:instrumentation*; D018592:Cross-Over Studies; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D019102:Infant, Very Low Birth Weight; D008170:Lung Compliance / Q000502:physiology; D012127:Respiratory Distress Syndrome, Newborn / Q000503:physiopathology* / Q000628:therapy; D015656:Respiratory Mechanics / Q000502:physiology; D013990:Tidal Volume / Q000502:physiology; D014939:Work of Breathing / Q000502:physiology*