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Medline ® Abstract for Reference 61

of 'Evaluation of suspected obstructive sleep apnea in children'

Sleep-disordered breathing does not affect nocturnal dipping, as assessed by pulse transit time, in preschool children: evidence for early intervention to prevent adverse cardiovascular effects?
Nisbet LC, Nixon GM, Yiallourou SR, Biggs SN, Davey MJ, Trinder J, Walter LM, Horne RS
Sleep Med. 2014;15(4):464. Epub 2014 Feb 10.
OBJECTIVE: Sleep-disordered breathing (SDB) is associated with reduced nocturnal dipping of blood pressure (BP) and sleep disruption in adults, and these features confer an increased risk of cardiovascular events. As SDB prevalence in children peaks during the preschool years, we investigated nocturnal dipping and sleep fragmentation in preschool children with SDB.
METHODS: Children (3-5 years; n=163) grouped by obstructive apnoea hypopnoea index (OAHI): control, no snoring history and OAHI≤1 event/h; primary snoring, OAHI≤1 event/h; mild SDB,>1-≤5 events/h; moderate-severe SDB,>5 events/h. Pulse transit time (PTT), an inverse continuous indicator of BP changes, and heart rate (HR) during total sleep time and the first period of rapid eye movement (REM), non-REM (NREM)1/2 and NREM3/4 sleep were expressed as percentage change from wake before sleep onset. The sleep fragmentation index (SFI) was calculated as the number of sleep stage transitions or awakenings per hour of sleep.
RESULTS: There were no group differences in the change in PTT or HR from wake to total sleep time or to individual sleep stages or in the proportion of children in the quartile with the smallest change in PTT during total sleep. Children with moderate-severe SDB had higher SFI than primary snoring (PS) or mild SDB groups (p<0.05 for both) and controls (p=0.07).
CONCLUSIONS: In contrast to adults, nocturnal dipping is preserved in young children with SDB, despite increased sleep fragmentation. As there is evidence that nocturnal dipping is similarly preserved at the school age, childhood may pose a window of opportunity for resolution of SDB when the cardiovascular effects are less marked.
The Ritchie Centre, Monash Institute of Medical Research, Monash University, Melbourne, Victoria, Australia.