Effect of sleep state on chest wall movements and gas exchange in infants with resolving bronchopulmonary dysplasia.

During active sleep, neonates exhibit asynchronous chest wall movements, which have been associated with a small but significant decrease in oxygenation. To determine the effects of maturation and residual chronic lung disease on both these phenomena, we studied 11 preterm infants with resolving bronchopulmonary dysplasia (BPD) and compared these infants to ten healthy preterm infants all at time of discharge. Synchrony of chest wall (upper rib cage and abdominal) movements, sleep state, O2 saturation, and transcutaneous CO2 (TcPCO2) were recorded during both active (AS) and quiet sleep (QS). Sleep state was determined by electroencephalographic and behavioral criteria. Normal preterm infants displayed asynchronous chest wall movements only in AS, whereas, in infants with BPD, asynchrony predominated in both sleep states, although O2 saturation and TcPCO2 did not differ between sleep states in either group. The O2 saturation during AS was lower in the BPD group than in the group of normal infants (92% vs 96%; P less than 0.02), whereas TcPCO2 was higher in the BPD group unrelated to sleep state. We conclude that infants with resolving BPD exhibit asynchronous chest wall movements in both AS and QS, and that change in sleep state from QS to AS is not associated with a detrimental fall in oxygenation in these infants.