Fig 1.
(A) First generation Pumani bCPAP device. In the first generation Pumani bCPAP device, air flows from the flow driver to the bottle and the patient interface in parallel. There is a bleed valve at the patient interface to prevent rebreathing of CO2. (B) Second generation Pumani bubble CPAP device. In the second generation Pumani bubble CPAP device, air flows from the flow driver to the patient interface to the bottle.
Fig 2.
Prongs connected to the airway inlet of the VT650 gas flow analyzer.
Prongs were connected to the device using a silicone Y-connector.
Fig 3.
Pressure at patient interface vs. flow rate for (A) Fisher and Paykel bubble CPAP; (B) Diamedica baby CPAP; (C) second generation Pumani bubble CPAP; (D) Medijet nCPAP generator; (E) first generation Pumani bCPAP.
Relationships are shown at 0 (solid black), 3 (solid gray), 5 (dashed black), and 7 (dotted black) cm of submersion in H2O. For the Medijet, only one value (solid black) is shown. Error bars represent one standard deviation. Data in S1 Table.
Table 1.
Resistance of CPAP systems at 0 cm H2O submersion depth.
Fig 4.
Theoretical contributions of tubing, prongs, and connectors to calculated resistance.
Height of the bars indicates measured resistance of the expiratory limb for each CPAP system. Theoretical contribution of system tubing (solid), prongs (dotted), and connectors (diagonal lines) are shown. Data in S2 Table.
Fig 5.
Imposed work of breathing for Fisher and Paykel bubble CPAP, Diamedica baby CPAP, 2nd generation Pumani bubble CPAP, Medijet nCPAP generator, and 1st generation Pumani bCPAP.
Imposed work of breathing for the Fisher and Paykel, Diamedica and first and second generation Pumani CPAP systems at flow rates of 6, 7, and 8 L/min and 8 cm H2O submersion depth are plotted. For the Medijet nCPAP generator, pressure cannot be set independently; results for the flow rates of 6, 7, and 8 L/min are plotted. (A) Imposed work of breathing for breath profiles of an infant (5.5 kg) (32 mL lung volume, sinusoidal breath pattern, RR = 60); (B) Imposed work of breathing for a term neonate (4 kg) (24 mL lung volume, sinusoidal breath pattern, RR = 67); (C) Imposed work of breathing for a preterm neonate (2.5 kg) (15 mL lung volume, sinusoidal breath pattern, RR = 67). Error bars represent standard deviation. Data in S3 and S4 Tables.