0415

EFFECTS OF A NEW CPAP DEVICE ON WORK OF BREATHING

AND BLOOD GASES IN NEWBORNS WITH PNEUMONIA

Xu FS, Zhou ZX, Zhang XM, Dong SH.

Capital Institute of Pediatrics, Beijing, China

Objective: To study the effects of a new nasal CPAP device (Hamilton Medical, Reno. NV. U.S.A.) on work of breathing and blood gases in newborns with pneumonia and compare with a conventional CPAP cannula.

Methods: 8 newborns with moderate pneumonia were involved in the study of work of breathing. It is evaluated by changes of O₂ consumption (V_O2) and resting energy expenditure (REE) with Diaferometer when each baby was on new device, conventional cannula (gas flow 8 L/min, pressure 4 cmH₂O) and breathing naturally without CPAP. Arterial blood gases were measured in another 8 newborns with pneumonia when they were on conventional cannula and new device successively.

Results: V_O2 of conventional cannula, new device and breathing naturally were 7.59±0.50, 7.14±0.55 and 6.64±1.17 ml/kg/min, REEs were 50.23±3.35, 47.28±3.66 and 44.86±6.90 kcal/kg/24h respectively. Comparing with conventional cannula the V_O2 and REEs were slightly lower (0.45±0.46 ml/kg/min, P<0.05 and 2.95±2.90 kcal/kg/24h, P<0.05) in new device. When babies were on conventional cannula and new device mean PaO₂ were 89.79±6.86 and 95.23±9.41 mmHg, PaCO₂ were 48.03±7.17 and 47.71±5.71 mmHg respectively. Comparing with conventional cannula the PaO₂ increased 5.44±5.44 mmHg(P<0.05) in new device. There were no significant changes in mean PaCO₂.

Conclusion: Both new and conventional CPAP devices need more work of breathing than breathing naturally. Comparing with conventional CPAP cannula the new CPAP device needs less work of breathing in newborns with moderate pneumonia, shows better oxygenation and no significant changes in ventilation.