The surge in heart rate and blood pressure at respiratory event termination is dampened in children with down syndrome

Abstract

BackgroundChildren with Down syndrome (DS) have a high prevalence of sleep disordered breathing (SDB) and altered cardiovascular autonomic control. We aimed to analyze the effect of DS on the surge in heart rate (HR) and pulse transit time (PTT, an inverse surrogate measure of blood pressure change) at respiratory event termination. Methods44 children (3–19 y) with DS and 44 typically developing (TD) children matched for SDB severity, age and sex underwent overnight polysomnography. Multilevel modelling determined the effect of DS on HR and PTT changes between a 10s pre-event to the latter half of each respiratory event (late-event) and 15s post-event during NREM and REM, accounting for SDB severity and event length. ResultsThe children with DS had a significantly smaller % change in HR late-event to post-event (NREM: DS 26.4 % ± 17.5 % (mean ± SD), TD 30.7 % ± 21.0 %; REM DS 16.9 % ± 15.3 %, TD 21.0 % ± 14.0 %; p < 0.05 for both) compared with TD children for obstructive events, and central events (13.2 % ± 17.0 %, TD 18.8 % ± 17.0 %; p < 0.01) during REM. %change in PTT was significantly smaller in the DS group during NREM and REM from pre-event and late-event to post-event compared with TD children for obstructive and central events. ConclusionThese results suggest children with DS have dampened HR and BP responses to respiratory events compared with TD children. Whether this is symptomatic of autonomic dysfunction or a protective factor for the cardiovascular system in children with DS remains to be elucidated.