Cardiovascular Autonomic Control Is Altered in Children Born Preterm with Sleep Disordered Breathing

Background To assess if the effects of sleep disordered breathing (SDB) on heart rate (HR) and HR variability, as a measure of autonomic control, were more severe in a group of children born preterm compared with a group of children born at term referred to our sleep laboratory for assessment of SDB. Study design Children (3-12 years of age) referred for polysomnographic assessment of SDB were recruited; 50 born preterm (<37 weeks of gestation) and 50 at term, matched for age and SDB severity. The mean HR and HR variability using power spectral analysis were calculated for each child for wake and sleep, and stages N1, N2, N3, and rapid eye movement sleep. Results Ex-preterm children were born between 23 and 35 weeks of gestational age (29.3 +/- 3.6; mean +/- SEM). There were no differences in the demographic, sleep, or respiratory characteristics between the groups. High-frequency power (reflecting parasympathetic activity) was greater in the ex-preterm children in both N2 and N3 (P < .05 for both) and total power was greater in N3 (P < .05). When the children were divided by SDB severity, these effects were most marked in those preterm born children with moderate to severe disease. Conclusions Preterm born children matched for age and SDB severity with children born at term showed no differences in sleep characteristics; however, they did exhibit increased parasympathetic tone during non-rapid eye movement sleep.