Feasibility of bubble non-invasive positive pressure ventilation, a first-in-human study.

PURPOSE: Infant respiratory distress is  a significant cause of mortality globally. Bubble continuous positive airway pressure (CPAP) is a simple and effective therapy, but sicker infants may require additional support such as non-invasive positive-pressure ventilation (NIPPV). We investigated the feasibility of a simple, low-cost, non-electric bubble NIPPV device. METHODS: In this cross-over feasibility study, seven newborns with moderate respiratory distress (Downes score ≥ 3), weight > 1500 g and gestational age > 32 weeks were randomized to  4 h of treatment with bubble CPAP (5-8 cm H2O) vs. bubble NIPPV (Phigh 8-10 cm H2O/Plow 5-8 cm H2O) followed by 4 h of the alternate treatment. Treatment order (CPAP vs. NIPPV) was randomized. Outcome measures included hourly vital signs, Downes score and O2 saturation. Adverse events including pneumothorax, nasal septal necrosis, necrotizing enterocolitis and death before discharge were also recorded. RESULTS: It took nurses 39 (7.3) s to assemble the bubble NIPPV device. Patients had similar vital signs and Downes scores on both treatments; median (IQR) values on bubble CPAP vs. bubble NIPPV were: heart rate 140 (134.5, 144), 140 (134.5, 144); respiratory rate 70 (56, 80), 65 (58, 82), Downes score 4 (3, 5.75), 4 (3, 5), O2 96 (94, 98), 97 (96, 98). All newborns survived to discharge and there were no adverse events. . CONCLUSIONS: A simple, low-cost, non-electric method of providing NIPPV for newborns with respiratory distress is feasible in limited resource settings. Randomized-controlled trials comparing bubble CPAP and bubble NIPPV are justified.

Bubble bilevel ventilation facilitates gas exchange in anesthetized rabbits.

BACKGROUND: Bubble continuous positive airway pressure is an established therapy for infants in respiratory distress. In resource-limited settings, few treatment options exist for infants requiring further respiratory support. A bubble bilevel device has been developed to provide nonelectric, time-cycled, pressure-limited respiratory support. We compared the efficacy of bubble bilevel ventilation with conventional mechanical ventilation in sedated rabbits. METHODS: Six adult rabbits under inhaled isoflurane general anesthesia were ventilated by alternating intervals of conventional and bubble bilevel ventilation for three 10-15-min periods. During each period, interval arterial blood gas (ABG) measurements were obtained after at least 10 min on the respective mode of ventilation. RESULTS: The bubble bilevel system was able to deliver the following pressures: 20/7, 15/5, 12/5, 8/5 cm H2O. The estimated differences in arterial blood gas values on bubble bilevel vs. ventilator were as follows (normalized values): pH 7.41 vs. 7.40, pCO2 37.7 vs. 40, pO2 97.6 vs. 80. In addition, the bubble bilevel ventilation delivered consistent pressure waveforms without interruption for over 60 min on two rabbits. CONCLUSION: This study demonstrates promising in vivo results on the efficacy of a novel bubble bilevel device, which may prove useful for infants in respiratory distress. IMPACT: Given the lack of personnel, funds or infrastructure to provide neonatal mechanical ventilation in resource-limited settings, additional low-cost, low-tech treatments are necessary to save infant lives. Bubble bilevel ventilation reliably delivers two levels of airway pressure to anesthetized rabbits resulting in normalization of blood gases comparable to those achieved on a traditional ventilator. If proven effective, simple technologies like this device have the potential to significantly impact neonatal mortality due to respiratory distress globally.

The BCPAP Score: Five Questions to Assess the Effectiveness of a Bubble CPAP Circuit.

Respiratory illnesses are a leading cause of infant mortality worldwide. Bubble CPAP is a simple and effective treatment for infants in respiratory distress. Across resource-limited settings, various bubble CPAP setups have been used with widely varying results. Based on fundamental fluid dynamics principles and clinical experience, the BCPAP score has been developed to gauge effectiveness of bubble CPAP delivery in different settings. Five questions addressing Bubbles, Circuit, Prongs, Airway and Pressure allow clinicians to rapidly determine whether they are delivering effective bubble CPAP. This article describes how to calculate a BCPAP score and explains the rationale behind the BCPAP score.

Bench Testing of a Bubble Noninvasive Ventilation Device in an Infant Lung Simulator.

BACKGROUND: Infant respiratory distress remains a significant problem worldwide, leading to more than one million neonatal deaths each year. The cost, maintenance, energy, and personnel required to implement ventilators have proven to be a barrier in many resource-limited settings. To address these barriers, a nonelectric bubble noninvasive positive pressure ventilation (NIV) device was developed. This study aims to benchmark the performance of this bubble NIV device against commercially available ventilators. METHODS: The delivered pressure waveforms and tidal volumes of the bubble NIV device were compared with those of 2 conventional ventilators (ie, Dräger Evita Infinity V500 and Hamilton G5) at the following pressure settings: 8/5, 12/5, and 15/5 cm H2O. To simulate the lung mechanics of an infant in respiratory distress, tests were conducted on the IngMar ASL 5000 Test Lung simulator. Resistance was set at 100 cm H2O/L/s, and compliance was tested at 0.5, 1.0, and 2.0 mL/cm H2O to simulate 3 different patients. RESULTS: The delivered pressure waveforms and compliance curves of the bubble NIV device are similar to those of the Hamilton and Dräger ventilators. The mean ± SD differences between delivered versus set pressure gradient (ie, the difference between the high delivered pressure and the low delivered pressure) for each treatment modality across the various values of compliance were -2 ± 8% for the bubble NIV device, 3 ± 4% for the Dräger ventilator, and 7 ± 10% for the Hamilton ventilator. CONCLUSIONS: The similarity of pressure waveforms and delivered tidal volumes in this simulated clinical scenario suggest that the bubble NIV device may provide comparable efficacy compared with traditional ventilator treatment for a range of patients. This may provide clinicians in resource-limited settings with an additional, simple, nonelectric treatment modality for the management of infant respiratory distress.

Development and Testing of a Bubble Bi-Level Positive Airway Pressure System.

BACKGROUND: Neonatal respiratory distress results in > 1 million annual deaths worldwide. Bubble CPAP is a simple, effective, and widely used therapy for infants in respiratory distress. In low-resource settings, more advanced respiratory support is limited by cost, technical expertise, and sporadic electricity. We sought to develop a safe, inexpensive, and simple solution to provide further respiratory support for these infants. METHODS: A standard bubble CPAP system was modified to provide 2 levels of positive airway pressure (bi-level positive airway pressure) by attaching a novel device. To demonstrate reliability, the system was run with continuous pressure monitoring on full-term and preterm neonatal mannikins with pressure targets of 8/5 cm H2O and 15/5 cm H2O to simulate 2 different modes of noninvasive ventilation (NIV). RESULTS: At a ventilation rate set between 30 and 45 cycles/min, by adjusting the leak rate of the device, the following mean pressures ± SD were demonstrated: term mannikin low-pressure NIV, 7.9 ± 0.2/5.3 ± 0.2 cm H2O; term mannikin high-pressure NIV, 15.1 ± 0.1/6.1 ± 0.1 cm H2O; preterm mannikin low-pressure NIV, 7.9 ± 0.2/5.3 ± 0.2 cm H2O; preterm mannikin high-pressure NIV, 16.5 ± 0.4/5.1 ± 0.1 cm H2O. CONCLUSIONS: The modified bubble CPAP system reliably provided alternating pressures similar to bi-level positive airway pressure modes of respiratory support in neonatal mannikins. The dual-pressure technology is a simple, single connection add-on that can readily be applied to existing bubble CPAP systems.