Nocturnal dipping of blood pressure and heart rate is not altered in school aged children with sleep disordered breathing regardless of severity.

Introduction: Sleep disordered breathing (SDB) in adults has been associated with loss of the nocturnal dipping in blood pressure (BP) and heart rate (HR), however, there have been limited studies in children. We measured BP non-invasively and continuously during overnight polysomnography in 105 children aged 7-12 with a range of severities of SDB and 36 non-snoring controls to examine nocturnal dipping proiles. Method(s): Children with SDB were divided into three severity groups according to the obstructive apnea hypopnea index (OAHI). BP and HR data were categorised into Wake (before sleep onset), total overnight Sleep, NREM 1/2, SWS and REM. Nocturnal dipping proiles were calculated both as % of children exhibiting a >= 10% fall in systolic BP (SAP) and HR from Wake to Sleep and according to SAP Sleep / SAP Wake ratio as extreme dippers ratio <= 0.8, dippers < 0.8 ratio <= 0.9, non dippers < 0.9 ratio <=1.0 and reverse dippers ratio > 1.0. Result(s): Over the whole night BP dipped during Sleep, reaching statistical signiicance for SAP in the Control group (p<0.05). We also found that the fall in BP between wake before sleep onset and NREM 1/2, SWS and REM sleep was not different between the groups. In addition, when children were grouped according to their nocturnal dipping proile there were no differences between the proportions of children in each group across severities of SDB or between sleep states. Conclusion(s): All severities of SDB were associated with similar nocturnal dipping patterns of BP and HR, a inding which may suggest that the cardiovascular system of these young children has not been signiicantly affected. However, further studies are required to determine if the elevated BP we have previously reported in this group will have long term effects on the cardiovascular system.