Abstract 1850 Poster Session I, Saturday, 5/1 (poster 30)

Physical model studies have indicated that the Aladdin/Infant Flow ® NCPAP device (A-IF) provides more stable volume recruitment (ΔVL) with less imposed WOB compared to conventional NCPAP (CONV) (Klausner et al, Pediatr Pulmonol 1996;22:188-94). However, corroborating infant data are lacking. METHODS: 15 preterm infants with minimal lung disease [(means ± SD) birth weight 1.1 ± 0.24 kg, gestational age 29 ± 1.8 wks, age 13 ± 11 days, FiO2 0.31 ± 0.11, CONV NCPAP 5.6 ± 1cmH20] were studied. A-IF and CONV were applied in random order. We measured ΔVL and tidal ventilation (VT) by DC-coupled/calibrated respiratory inductance plethysmography (RIP) as well as esophageal pressures (Pes) during NCPAP of 8, 6, 4 and 0 cmH20. WOB and lung compliance (CL) were calculated from the Pes and VT data using standard methods. RESULTS: Baseline measurements at NCPAP=0 were assumed to be equivalent for the two devices, and were used for subsequent comparisons of WOB and CL. WOB decreased at all NCPAP levels with A-IF, with a maximal decrease at NCPAP=4 (p=0.04, Fig). WOB increased at all NCPAP levels with CONV. An increase in CL was observed at all NCPAP levels with A-IF, while CL increased only at NCPAP=8 with CONV. When compared to CONV, ΔVL with A-IF was significantly higher at all NCPAP levels

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CONCLUSION: WOB is decreased with A-IF compared to CONV. At NCPAP>4, the relative increase in WOB and decrease in CL with A-IF may be explained by lung overdistension. The increase in WOB with CONV at NCPAP 4-8, relative to NCPAP=0, indicates the presence of appreciable imposed WOB with this device. This result, combined with the reduced WOB seen with A-IF, is consistent with the physical model studies. Our study, performed in neonates with little lung disease, indicates the possibility of lung overdistension at NCPAP 6-8 with A-IF. Further study is necessary to determine the efficacy of A-IF, as compared to CONV, in neonates with significant lung disease and as well as its use over extended periods of time.

Supported in part by a grant from Cooper Faculty Practice, Hamilton Medical, and EME Ltd.