Imposed work of breathing of 16 neonatal CPAP-devices using different mechanisms of CPAP generation

Failure of continuous positive airway pressure (CPAP) in preterm infants may result from respiratory exhaustion, potentially also evoked by the CPAP device's imposed work of breathing (iWOB). This study investigated in-vitro the iWOB of 16 CPAP-devices in four simulated neonatal scenarios with focus on the impact of different mechanisms of CPAP-generation.

A neonatal lung model and 3D-printed nasopharyngeal dummies (representing a 1000 g preterm and a 3000 g term infant, settings: preterm/term: V_tid 4.5/14 ml, rate 80/60 bpm) were used to evaluate common CPAP-devices under various conditions (two levels of positive end-expiratory pressure: 5, 10 cmH₂O).

During 9300 simulated breaths, iWOB differed widely across investigated devices. The lowest inspiratory iWOB were observed in Bubble CPAP, variable-flow devices and constant-flow devices with turbine (0.04/0.15-0.17 mJ/breath for preterm/term model resp. 0.07/0.24-0.33 mJ/breath). Devices with mechanical regulation and with constant resistance require higher inspiratory effort and are therefore not relevant in the low iWOB group. The highest iWOB (0.41/2.92 mJ/breath at 5 cmH₂O) was found in a T-piece device. The mechanism of CPAP generation influenced iWOB levels.

The magnitude of iWOB varied considerably between devices. This should be considered, to optimize non-invasive respiratory support in neonates.

This bench study detected differences in the imposed work of breathing (iWOB) between 16 different CPAP devices. In addition to existing literature, the present study contributes to a more comprehensive understanding of iWOB and the influence of CPAP generation due to the large number of CPAP devices investigated. If the identified differences are confirmed in clinical practice, this could streamline decision-making in CPAP device selection.