A new apparatus to decrease rebreathing of exhaled carbon dioxide in preterm infants. † 1148

Abstract

The rebreathing of carbon dioxide in vulnerable infants has been proposed as a hypothesis for Sudden Infant Death Syndrome (SIDS). A new device, Infant Crib Air (ICA), provides a continuous flow of filtered air to an infant's mouth and nose and was shown to decrease rebreathing of carbon dioxide in 21 healthy full term infants in their own cribs at home (Amer J Perinat 12:1995). Because these were infants at low risk for SIDS and the environment for each infant was so different, we chose to study preterm infants in a more controlled setting (using the same crib, same sleep position, same equipment, same room). Thirteen preterm infants of 30.2 ± 2.7 weeks gestational age (mean ± SD) who had successfully weaned from the incubator isolette for at least 2 days and projected to be ready for discharge within one week were enrolled. Infants were studied at 35.8 ± 1.9 weeks corrected age. Based on the previous report, we determined that 11 infants were necessary to obtain a 50% decrease in inspiratory carbon dioxide using ICA. All infants were placed on their side in the crib with the ICA manifold placed 20cm from their nose. An Ohmeda 5200 measured carbon dioxide levels. Inspiratory carbon dioxide, end tidal carbon dioxide, skin temperature, and room temperature were regularly measured for 30 minutes before and after starting the ICA device. We found that the mean inspiratory carbon dioxide significantly fell (p < 0.05) from a baseline of 4.5 torr to 2.6 torr and 2.1 torr when the air speed from the device was set at 0.5 mile per hour and 1 mile per hour respectively(p = N.S. 0.5 vs 1 mile per hour). There was no significant difference in the end tidal carbon dioxide levels on ICA. We found no significant difference in the room temperature (mean = 23.5° C) or the infant's skin temperature after 16 continuous hours of ICA exposure at one mile per hour air speed. We conclude that the ICA significantly lowers the inspiratory carbon dioxide in preterm infants. We speculate that this device may help reduce the risk of SIDS by decreasing the frequency of rebreathing exhaled air and may prevent overheating by continuously blowing air onto an infant's head and face.