Figure 4

Representative waveforms of airway pressure, airway flow, end tidal carbon dioxide, and signal of plethysmograph. Airway pressure: In the nCPAP group, PIP did not reach the target pressure during any of the ventilator settings (PIP/PEEP of 20/0, 20/5, and 20/10 cm H₂O) and PEEP was not maintained at the set level during 20/5 and 20/10 cm H₂O. In the FmCPAP group, airway pressure reached and maintained the target pressure. Airway flow: In the nCPAP group, while airway flow during inspiration was almost the same among the three ventilator settings, expired flow was detected in only the 20/0 setting. In the FmCPAP group, airway flow was not detected or very low values were detected during both inspiration and expiration at all three ventilator settings. ETCO₂: In the nCPAP group, ETCO₂ was detected in only the 20/0 settings. In the FmCPAP group, ETCO₂ was not detected or very low values were detected with each of the three ventilator settings. Plethysmograph: In the nCPAP group, the signal of plethysmograph was detected with each of three ventilator settings. In the FmCPAP group, the plethysmograph was not detected with any of the three ventilator settings. The values of plethysmograph are presented as the mean values of the movement of rib cage and abdomen. The mean value was calculated by using the sum of readings from the movement of the rib cage and abdomen and then divided by 2. ETCO₂, end tidal carbon dioxide; FmCPAP, continuous positive airway pressure via a full face mask and ventilation; nCPAP, continuous positive airway pressure via a nasal mask and ventilation.