Comparison of two different CPAP systems by tidal breathing parameters

OBJECTIVE: Comparison of tidal breathing and pressure fluctuation of the continuous positive airway pressure (CPAP) associated with the use of the valveless Infant Flow System versus the conventional constant-flow CPAP (Babylog 8000) in preterm infants. DESIGN: Randomized cross-over trial. SETTING: Neonatal intensive care unit level III. PATIENTS: Twenty infants; median (range): birth weight 1,035 g (640-4,110 g), actual weight 1,165 g (820-4,250 g), gestational age at birth 27 (26-40) weeks. INTERVENTIONS: After extubation two CPAP devices (Infant Flow System vs Babylog 8000) were applied in a random order to the same infant. Fluctuations of the applied pressure during the breathing cycle and tidal breathing parameters were measured by the flow-through technique. MAIN RESULTS: Using the Infant Flow System the mean (standard deviation) inspiratory flow 1.5 (0.1) vs 1.3 (0.1) l.min(-1).kg(-1), P<0.05] and tidal volume were significantly increased 5.3 (1.3) vs 4.7 (1.3) ml/kg(-1), P<0.05] compared to Babylog 8000. The fluctuations of the applied pressure of the Infant Flow System during the breathing cycle were significantly lower 0.1 (0.03) kPa vs 0.15 (0.08) kPa, P<0.05] compared to Babylog 8000. No differences were seen in the duration of inspiration and expiration and the time to peak tidal flow. In the Infant Flow System pressures during expiration remained stable whereas they increased during the use of Babylog 8000. CONCLUSIONS: Within-subject comparisons of tidal breathing parameters of the two CPAP devices Infant Flow System and Babylog 8000 show: (1) a significant influence of the system used; and (2) that the valveless Infant Flow System increases air flow and tidal volume with less fluctuations in CPAP pressures during the breathing cycle.