Average duration of treatment and hospital stay (+/− standard deviation) for eligible subjects and survivors versus treatment group.

<p>Average duration of treatment and hospital stay (+/− standard deviation) for eligible subjects and survivors versus treatment group.</p

Flow chart summarizing study procedure and outcome groups.

<p>Flow chart summarizing study procedure and outcome groups.</p

Number of study participants and demographic data for subjects meeting eligibility criteria.

*<p>Difference in group receiving nasal oxygen and bCPAP significantly different (p = 0.015).</p

Survival of participants with RDS and sepsis receiving nasal oxygen vs. bCPAP.

<p>(Left) Fraction of eligible study subjects with a primary diagnosis of respiratory distress syndrome (RDS) who survived to discharge and received nasal oxygen or bCPAP. (Right) Fraction of eligible study subjects with a co-morbidity of sepsis who survived to discharge and received nasal oxygen or bCPAP.</p

Overall survival of eligible study participants receiving nasal oxygen vs. bCPAP.

<p>(Left) Fraction of eligible study participants who survived to discharge and received nasal oxygen or bCPAP. When treated with bCPAP, the survival rate of infants with severe respiratory distress is significantly higher than for those treated with nasal oxygen (p = 0.018). Without adjustment, bCPAP is associated with a 3.1-fold increase in odds of survival (confidence interval 1.2–8.1, significance = 0.02). (Right) Kaplan-Meier survival curves showing cumulative survival vs. days since treatment initiation for infants with severe respiratory distress treated with bCPAP (n = 62) and those treated with nasal oxygen (n = 25).</p

bCPAP device operating specifications.

<p>bCPAP device operating specifications.</p

Vital signs for 6-month old patient with bronchiolitis (a) and a neonate with respiratory distress (b) immediately before and after initiation of bCPAP.

<p>(A) Time course immediately before treatment (large symbols) and after initiation of therapy (small symbols). The patient received CPAP treatment with gradually decreasing oxygen flow for 4 days, was then transitioned to nasal oxygen, and finally transitioned to room air. The patient was discharged on day 6. (B) Time course immediately before treatment (large symbols) and after initiation of therapy (small symbols). The patient received CPAP treatment for 3.5 days. The fraction of oxygen was gradually decreased to room air during the first 2 ½ days.</p

Comparison of reference standard and low-cost bCPAP output pressure under different flow and pressure settings.

<p>Each bCPAP system was assembled and nasal prong pressure was measured for 60 seconds of operation and mean pressures were calculated; results were then averaged for 10 independent trials of each system. (A) The mean pressure (mid-point of bar) and peak low and high pressures at a flow rate of 7 L/min at varying pressure settings. (B) The mean pressure (mid-point of bar) and peak low and high pressures at a pressure of 6 cm H₂O and varying flow rates.</p

Block diagram and photograph of bCPAP system.

<p>The system consists of: (1) an adjustable flow generator; (2) a pressure-regulated delivery system; and (3) a patient interface. Flow is generated by two air pumps that can be blended with oxygen from a tank or concentrator. The total flow rate and fraction of oxygen delivered are controlled by two flow regulators. The output of the flow generator is connected to the pressure-regulated delivery system. Pressure is controlled by submerging a pressure control tube in a column of water; the mean pressure in the system is determined by the height of the water column. The patient interface is also connected to the pressure control tube, ensuring that the pressure in the patient interface and the pressure control tube are equivalent. The pressurized air mix is delivered to the patient's nostrils via a set of binasal prongs terminated at the distal end.</p

Pressure vs. time at the nasal prongs for two bCPAP devices.

<p>(Left) a reference standard bCPAP device used clinically in the US and (Right) the low-cost bCPAP device. Dotted lines show the mean and average peak pressures, averaged across 60 seconds of data collection. The pressure waveforms of the two devices are similar, indicating delivery of equivalent therapeutic pressure. In both devices, the mean pressure is controlled by adjusting the height of water in the pressure control tube, and the high frequency oscillations about the mean are associated with the formation of bubbles at the distal tip of the pressure control tube. There were no statistically significant differences between the pressures generated by the two devices (Student t-test, p<0.01).</p