title: Impaired blood pressure control in children with obstructive sleep apnea.
abstract: BACKGROUND
  Obstructive sleep apnea (OSA) in adults has been associated with hypertension, low baroreflex sensitivity (BRS), a delayed heart rate response to changing blood pressure (heart period delay [HPD]), and increased blood pressure variability (BPV). Poor BRS may contribute to hypertension by impairing the control of blood pressure (BP), with increased BPV and HPD. Although children with OSA have elevated BP, there are scant data on BRS, BPV, or HPD in this group.
  
  
  METHODS
  105 children ages 7-12 years referred for assessment of OSA and 36 nonsnoring controls were studied. Overnight polysomnography (PSG) was performed with continuous BP monitoring. Subjects were assigned to groups according to their obstructive apnea-hypopnea index (OAHI): primary snoring (PS) (OAHI ≤1event/h), mild OSA (OAHI>1- ≤5events/h) and moderate/severe (MS) OSA (OAHI>5events/h). BRS and HPD were calculated using cross spectral analysis and BPV using power spectral analysis.
  
  
  RESULTS
  Subjects with OSA had significantly lower BRS (p<.05 for both) and a longer HPD (PS and MS OSA, p<.01; mild OSA, p<.05) response to spontaneous BP changes compared with controls. In all frequencies of BPV, the MS group had higher power compared with the control and PS groups (low frequency [LF], p<.05; high frequency [HF], p<.001).
  
  
  CONCLUSIONS
  Our study demonstrates reduced BRS, longer HPD, and increased BPV in subjects with OSA compared to controls. This finding suggests that children with OSA have altered baroreflex function. Longitudinal studies are required to ascertain if this dampening of the normal baroreflex response can be reversed with treatment.
authors.affiliation: The Ritchie Centre, Monash Institute of Medical Research, Monash University, Melbourne, Australia. lisa.walter@monash.edu
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Walter
authors.forename: Stephanie R
authors.initials: SR
authors.lastname: Yiallourou
authors.forename: Anna
authors.initials: A
authors.lastname: Vlahandonis
authors.forename: Scott A
authors.initials: SA
authors.lastname: Sands
authors.forename: Candice A
authors.initials: CA
authors.lastname: Johnson
authors.forename: Gillian M
authors.initials: GM
authors.lastname: Nixon
authors.forename: Margot J
authors.initials: MJ
authors.lastname: Davey
authors.forename: John
authors.initials: J
authors.lastname: Trinder
authors.forename: Adrian M
authors.initials: AM
authors.lastname: Walker
authors.forename: Rosemary S C
authors.initials: RS
authors.lastname: Horne
mesh_terms: D001341:Autonomic Nervous System / Q000502:physiology; D017704:Baroreflex / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology*; D002648:Child; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D006973:Hypertension / Q000150:complications* / Q000503:physiopathology*; D008297:Male; D017286:Polysomnography; D012720:Severity of Illness Index; D020181:Sleep Apnea, Obstructive / Q000150:complications* / Q000503:physiopathology*; D012894:Sleep Stages / Q000502:physiology*; D012913:Snoring / Q000150:complications / Q000503:physiopathology
keywords: Baroreflex sensitivity; Blood pressure variability; Heart period delay; Pediatric; Sleep; Sleep apnea; Sleep-disordered breathing