DOI: 10.1177/19433654261472943 ISSN: 1943-3654

In Vitro Comparison of a Low-Cost Bubble-NIV and Ventilator-Driven NIV

Josephine U. Pierce Pucci, Bradley T. Pierce, Lisa M. Pierce, Nicholas L. Shriver, Alicyn F. Grete, Alex M. Burgess, Emily S. Minner, Dante M. DiAngelis, Margaret A. Nowicki, David Ayer, Jason C. Barnhill, Christopher A. Naun

Background:

Almost 2.5 million neonatal deaths occur annually, disproportionately affecting low- and middle-income countries. Respiratory support devices remain largely inaccessible in these regions because of prohibitive costs and infrastructure requirements. The WHO-style bubble CPAP provides accessible continuous positive pressure but cannot deliver bi-level support when CPAP alone is insufficient. We hypothesized that a low-cost bubble noninvasive ventilatory (Bubble-NIV) system, meant to augment the WHO-style bubble CPAP, would perform non-inferiorly to the ventilator-driven RAM-NIV in delivering positive pressure across variable nasal interface conditions in bench testing.

Methods:

We developed a low-cost Bubble-NIV system (∼$50) with a servo motor-driven lever to drive bi-level pressures via variable distal tubing water submersion depths. Performance was compared with ventilator-driven RAM-NIV in a static in vitro model across 3 nasal cannula fits (80%, 70%, 60% nostril occlusion). Primary outcome was mean airway pressure Paw (should be a line over P) measured in the nasopharynx.

Results:

Bubble-NIV maintained bi-level pressures and delivered pressures closer to target (mean airway pressure, mean goal: 15 cm H 2 O) than ventilator-driven RAM-NIV across all nasal interface scenarios: 15.1 versus 13.4 cm H 2 O at 80% occlusion ( P < .001), 12.6 versus 7.4 cm H 2 O at 70% occlusion ( P < .001), and 5.6 versus 1.8 cm H 2 O at 60% occlusion ( P < .001). The performance advantage increased with worsening leak (1.1-fold to 3.1-fold). Optimal Bubble-NIV pressures occurred with flows set within 2 L/min of minimal bubbling. Oscillatory waveforms of Bubble-NIV were greater than RAM-NIV.

Conclusions:

A low cost Bubble-NIV system demonstrated superior nasal leak tolerance compared with ventilator-driven RAM-NIV in bench testing. The low-cost, nonproprietary design addresses accessibility barriers to delivering bi-level noninvasive respiratory support for neonates in resource-limited settings.

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