554 - Bubble Continuous Positive Airway Pressure (bCPAP): Enhanced Vibratory Ventilation using a Multi Bubble PAP Valve

Publication Number: 1533.554

Mitchell R. Goldstein, Loma Linda Publishing Company, Rancho Cucamonga, CA, United States

Background: Early bubble CPAP (bCPAP) has been associated with a reduction in the incidence and severity of bronchopulmonary dysplasia (BPD). Early application of bCPAP supports the transition to extrauterine life by maintaining functional residual capacity, reducing atelectotrauma, and minimizing the need for invasive ventilation. Unlike continuous-flow CPAP, bCPAP produces oscillations in the circuit. These small-amplitude fluctuations occur around the mean airway pressure established by the water column in the chamber. The oscillations are transmitted back through the circuit and into the infant's airways, creating a dynamic pressure environment that enhances gas exchange and provides a form of "high-frequency ventilation." The properties of bCPAP can improve alveolar recruitment, stabilize the airways, and promote uniform lung inflation. Additionally, the simplicity of the system, reduced dead space, and work of breathing make bCPAP an appealing strategy. The advantages of this oscillatory pattern may explain the association between bCPAP and reduced BPD rates compared to infants managed with continuous-flow CPAP or early intubation.

Objective: We hypothesized that modifying bubble and flow dynamics could enhance the vibratory component of airway pressure in bubble CPAP (bCPAP), specifically an enhanced CPAP delivery device (Babi.Plus, Respiralogics) featuring multi-bubble orifices and a central orifice positioned at the base of the drop tube, adjusted below the water surface. Using a flow rate of 8 lpm, we set up mean airway pressures of 4, 5, 6, 7, 8, and 9 cm H₂O. We propose that this configuration can generate an enhanced vibratory waveform.

Design/Methods: The Multi-bubble device (Babi.Plus) was connected in series to a test lung of known compliance, and then to a Fleisch pneumotachograph integrated at the proximal airway, equipped with Validyne flow and pressure sensors, and a calibrated flow meter. Using Easy Sense for IBM PC, we sampled the devices at 1000 Hz at CPAP levels 4-8 cm H₂O and 8 lpm.

Results: The pressure amplitude at each PEEP was increased with the Multi Bubble (p < 0.05). Please see the Box and Whisker and scaler plots.

Conclusion(s): bCPAP Multi Bubble (Babi.Plus) generates enhanced vibratory pressure. The design provides a greater amplitude of the pressure wave. This may facilitate CO₂ clearance. These findings suggest that this mode of noninvasive respiratory support may reduce the risk of CPAP failure. Clinical trials comparing Multi Bubble (Babi.Plus) with bCPAP and other forms of CPAP are necessary to determine if this enhanced vibratory mechanism translates into improved outcomes.

Box and Whisker Plot
Note the increased standard deviation associated with the Multi bubble technology

Scaler Graph
The bold lines correspond to the Multi Bubble CPAP, and the corresponding non-bolded lines are traditional bCPAP.