Objective: To compare the work of breathing (WOB) in premature neonates supported with high-flow nasal cannula (HFNC) and nasal continuous positive airway pressure (NCPAP).Study Design: Eighteen preterm neonates <2.0 kg on HFNC or NCPAP support were studied in a random order. A ventilator was used to deliver 6 cm H 2 O of NCPAP with nasal prongs. High-flow nasal cannula delivered with Vapotherm (VAPO) at 3, 4 and 5 l/min was used. Tidal ventilation was obtained using respiratory inductance plethysmography calibrated with face-mask pneumotachography. An esophageal balloon estimated pleural pressure from which changes in end distending pressure were calculated. Inspiratory, elastic and resistive WOB and respiratory parameters were calculated.Results: No differences were found in the WOB for all settings. Changes in end distending pressure did not vary significantly over all device settings except VAPO at 5 l/min. Conclusion:In these preterm infants with mild respiratory illness, HFNC provided support comparable to NCPAP.

WOB(I) is decreased with variable-flow NCPAP compared with constant-flow NCPAP. The increase in WOB(I) with constant-flow NCPAP indicates the presence of appreciable imposed WOB with this device. Our study, performed in neonates with little lung disease, indicates the possibility of lung overdistention at CPAP of 6 to 8 cm H(2)O with the variable-flow device. Further study is necessary to determine the efficacy of variable-flow NCPAP in neonates with significant lung disease and its use over extended periods of time.continuous-flow and variable-flow NCPAP, work of breathing, premature neonates, lung compliance.

Synchronized nasal intermittent positive pressure ventilation (SNIPPV) is non-invasive respiratory support that delivers ventilator breaths via the nasal prongs. We hypothesized that SNIPPV is more effective than nasal continuous positive airway pressure (NCPAP) in premature neonates due to decreased work of breathing (WOB). Fifteen infants (BW: 1,367 +/- 325 g, GA: 29.5 +/- 2.4 weeks) were studied on (a) NCPAP at 5 cmH(2)O (NCPAP5) and (b) three increasing SNIPPV settings achieved by NCPAP5 with additional delivered peak inspiratory pressures (PIP) of 10, 12, and 14 cmH(2)O. Tidal volumes and transpulmonary pressures were estimated via calibrated respiratory inductance plethysmography (RIP) and esophageal pressures, respectively. Inspiratory (WOB(insp)), resistive (RWOB), and elastic (WOB(E)) components of WOB were calculated using standard methods. Compared to NCPAP5, (a) WOB(insp) and RWOB were significantly lower with SNIPPV12, and were similarly lower with SNIPPV14 and (b) WOB(E) was significantly lower only with SNIPPV14. WOB components did not differ significantly for the three SNIPPV settings. Tidal volume, respiratory rate (RR), minute ventilation, compliance, and phase angle were similar for all four measurements. In conclusion, compared to NCPAP, the addition of ventilator-delivered PIP during SNIPPV decreases WOB in premature infants.

Compared with 2 continuous flow devices, the variable flow nasal CPAP device leads to greater lung recruitment. Although a nasal cannula is able to recruit lung volume, it does so at the cost of increased respiratory effort and FIO(2).