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An in‐line high frequency flow interrupter applied to nasal CPAP: Improved carbon dioxide clearance in a premature infant lung model
Author(s) -
Sivieri Emidio M.,
Eichenwald Eric C.,
Rub David M.,
Abbasi Soraya
Publication year - 2019
Publication title -
pediatric pulmonology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.866
H-Index - 106
eISSN - 1099-0496
pISSN - 8755-6863
DOI - 10.1002/ppul.24505
Subject(s) - medicine , interrupter , anesthesia , continuous positive airway pressure , nasal cannula , respiratory system , washout , cannula , surgery , physics , quantum mechanics , obstructive sleep apnea
Background Noninvasive respiratory support continues to have high failure rates in small preterm infants. We previously demonstrated significantly improved in vitro CO 2 washout by applying oscillations to a high flow nasal cannula system. Objective To develop a high frequency flow interrupter that could be applied to commonly used nasal continuous positive airway pressure (NCPAP) devices and to determine the effect of oscillations on end‐tidal carbon dioxide (EtCO 2 ) levels in an infant lung model. Design/Methods NCPAP was applied to a premature infant lung simulator using either bubble (BCPAP) or variable‐flow (VCPAP) CPAP. Supply gas was interrupted with a solenoid pinch valve. EtCO 2 was measured before and during oscillation and repeated at 4, 6, 8, 10, and 12 Hz oscillation and CPAP pressures of 4, 6, and 8 cm H 2 O. Results BCPAP and VCPAP EtCO 2 levels decreased with oscillation ( P < .001). BCPAP EtCO 2 was significantly dependent on oscillation frequency ( P < .001) with decreases of 18% to 47% and maximum effect at 10 Hz. Optimum VCPAP CO 2 clearance occurred at 6 Hz with reductions of 30% and 39% at 6 and 8 cm H 2 O CPAP respectively. BCPAP and VCPAP mean airway pressures remained unchanged transitioning from nonoscillation to oscillation. Oscillated BCPAP and VCPAP average amplitudes were 8.3 ± 0.5 and 8.4 ± 2.3 SD cm H 2 O, respectively. Power spectrum analysis of non‐oscillated BCPAP showed bubbling‐only dominant peaks at 10 to 12 Hz corresponding with the maximum BCPAP EtCO 2 reductions. Conclusion Application of high frequency oscillation to NCPAP improves CO 2 clearance in a premature infant lung model. This simple modification to NCPAP delivery devices may prove to be an effective enhancement of this mode of noninvasive respiratory support.