Altered nocturnal cardiovascular control in children with sleep-disordered breathing

Study objectives To assess cardiovascular control during sleep in children with sleep-disordered breathing (SDB) and the effect of adenotonsillectomy in comparison to healthy nonsnoring children. Methods Cardiorespiratory signals obtained from overnight polysomnographic recordings of 28 children with SDB and 34 healthy nonsnoring children were analyzed. We employed an autoregressive closed-loop model with heart period (RR) and pulse transit time (PTT) as outputs and respiration as an external input to obtain estimates of respiratory gain and baroreflex gain. Results Mean and variability of PTT were increased in children with SDB across all stages of sleep. Low frequency power of RR and PTT were attenuated during non–rapid eye movement (REM) sleep. Baroreflex sensitivity was reduced in children with SDB in stage 2 sleep, while respiratory gain was increased in slow wave sleep. After adenotonsillectomy, these indices normalized in the SDB group attaining values comparable to those of healthy children. Conclusions In children with mild-to-moderate SDB, vasomotor activity is increased and baroreflex sensitivity decreased during quiet, event-free non-REM sleep. Adenotonsillectomy appears to reverse this effect.