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Updated: Jan 20, 2026

Development of a Neonatal Piglet Acute Lung Injury Model Recreating the Early Environment of Preterm Infant Lungs
Published on: October 31, 2025
An in-line high frequency flow interrupter applied to nasal CPAP: Improved carbon dioxide clearance in a premature
Emidio M Sivieri1,2, Eric C Eichenwald1,2,3, David M Rub2,3
1Division of Neonatology, Children's Hospital of Philadelphia Newborn Care at Pennsylvania Hospital, Philadelphia, Pennsylvania.
Background:
Noninvasive respiratory support continues to have high failure rates in small preterm infants. We previously demonstrated significantly improved in vitro CO2 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 (EtCO2 ) 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. EtCO2 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 EtCO2 levels decreased with oscillation (P < .001). BCPAP EtCO2 was significantly dependent on oscillation frequency (P < .001) with decreases of 18% to 47% and maximum effect at 10 Hz. Optimum VCPAP CO2 clearance occurred at 6 Hz with reductions of 30% and 39% at 6 and 8 cm H2 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 H2 O, respectively. Power spectrum analysis of non-oscillated BCPAP showed bubbling-only dominant peaks at 10 to 12 Hz corresponding with the maximum BCPAP EtCO2 reductions.
Conclusion:
Application of high frequency oscillation to NCPAP improves CO2 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.
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