title: Baroreflex gain in children with obstructive sleep apnea.
abstract: BACKGROUND
  We previously demonstrated that children with obstructive sleep apnea have increased blood pressure associated with changes in left ventricular mass index. Others have shown in adults that blood pressure variability is an important predictor of changes in left ventricular mass. The baroreflex system buffers blood pressure changes by varying heart rate. We have thus hypothesized that (1) baroreflex system gain is increased during sleep, improving blood pressure buffering; (2) children with obstructive sleep apnea lack this baroreflex gain increase; and (3) reduced blood pressure buffering results in exaggerated blood pressure variability that is associated with end-organ damage.
  
  
  OBJECTIVE
  Compare measures of left ventricular mass index and nighttime baroreflex gain of healthy children to those of children with obstructive sleep apnea.
  
  
  METHODS
  A total of 169 children (50 control subjects, 63 with mild obstructive sleep apnea, and 56 with severe obstructive sleep apnea) with a mean age of 9.9 years (+/-2.2) underwent echocardiography followed by polysomnography with continuous blood pressure measurement. Baroreflex gain was calculated in time and frequency domains.
  
  
  RESULTS
  Healthy children demonstrated a nighttime pattern of increasing baroreflex gain. Children with obstructive sleep apnea had decreased nighttime baroreflex gain compared with control subjects. Nighttime blood pressure and blood pressure variability were significantly correlated with left ventricular mass index.
  
  
  CONCLUSIONS
  Obstructive sleep apnea is associated with a decrease in nighttime baroreflex gain and an increase in blood pressure variability. This increase is correlated with changes in left ventricular mass index.
authors.affiliation: Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.
authors.forename: Keith
authors.initials: K
authors.lastname: McConnell
authors.forename: Virend K
authors.initials: VK
authors.lastname: Somers
authors.forename: Thomas
authors.initials: T
authors.lastname: Kimball
authors.forename: Stephen
authors.initials: S
authors.lastname: Daniels
authors.forename: Rhonda
authors.initials: R
authors.lastname: VanDyke
authors.forename: Matthew
authors.initials: M
authors.lastname: Fenchel
authors.forename: Aliza
authors.initials: A
authors.lastname: Cohen
authors.forename: Paul
authors.initials: P
authors.lastname: Willging
authors.forename: Abu
authors.initials: A
authors.lastname: Shamsuzzaman
authors.forename: Raouf
authors.initials: R
authors.lastname: Amin
mesh_terms: D017704:Baroreflex / Q000502:physiology*; D001794:Blood Pressure / Q000502:physiology*; D016022:Case-Control Studies; D002648:Child; D004452:Echocardiography; D005260:Female; D006801:Humans; D017379:Hypertrophy, Left Ventricular / Q000209:etiology; D008297:Male; D017286:Polysomnography; D020181:Sleep Apnea, Obstructive / Q000503:physiopathology*