title: Pulse rate and pulse rate variability decrease after adenotonsillectomy for obstructive sleep apnea.
abstract: BACKGROUND
  Data suggest that obstructive sleep apnea syndrome (OSA) results in sympathetic stimulation, brady/tachycardia and cardiac stress. Heart rate variability, but not baseline heart rate, is known to be elevated in pediatric OSA. Our patients with moderate to severe OSA (McGill Oximetry Scores of 3 or 4) have been re-evaluated with pulse oximetry after adenotonsillectomy (T&A). We hypothesized that pulse rate (PR) and pulse rate variability (PRV) would decrease after treatment of OSA with T&A.
  
  
  METHODS
  This retrospective before-after study comprised pre- and post-operative oximetries and parental questionnaires of children 1-18 years old with moderate to severe OSA from September 2004 to August 2005, inclusive. We excluded patients with significant comorbidities.
  
  
  RESULTS
  In 25 subjects, age at surgery was 4.3 +/- 3.6 years (mean +/- SD). OSA symptoms decreased or resolved, saturation metrics improved, and parental concern about breathing during sleep decreased following T&A. PR decreased in 21 of 25 patients after T&A (mean PR from 99.7 +/- 11.2 to 90.1 +/- 10.7 bpm, P < 0.001; maximum PR from 150.6 +/- 14.5 to 137.4 +/- 15.6 bpm, P < 0.001). PRV, as measured by the standard deviation of the PR, decreased in 23 of 25 patients after T&A (from 10.3 +/- 2.1 to 8.2 +/- 1.6 bpm, [P < 0.001]). Pulse accelerations greater than 6, 7, 8 bpm also decreased post-operatively.
  
  
  CONCLUSIONS
  Nocturnal pulse oximetry complements clinical history to document improvement and/or resolution of moderate to severe OSA in children. Resolution of tachycardia and diminished PRV after T&A illustrate the stress that recurrent airway obstruction during sleep places on the cardiovascular system. Further work will be required to determine if PR and PRV as measured by pulse oximetry would be useful in the diagnosis and follow-up of OSA in children.
authors.affiliation: Department of Pediatrics, Montreal Children's Hospital, McGill University Health Centre, Montreal, Quebec, Canada. evelyn.constantin@muhc.mcgill.ca
authors.forename: Evelyn
authors.initials: E
authors.lastname: Constantin
authors.forename: Christine D
authors.initials: CD
authors.lastname: McGregor
authors.forename: Valerie
authors.initials: V
authors.lastname: Cote
authors.forename: Robert T
authors.initials: RT
authors.lastname: Brouillette
mesh_terms: D000233:Adenoidectomy; D000293:Adolescent; D000402:Airway Obstruction / Q000209:etiology / Q000503:physiopathology / Q000601:surgery; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D006339:Heart Rate; D006801:Humans; D007223:Infant; D008297:Male; D008991:Monitoring, Physiologic / Q000379:methods / Q000706:statistics & numerical data; D010092:Oximetry / Q000706:statistics & numerical data; D011182:Postoperative Care / Q000379:methods / Q000706:statistics & numerical data; D011300:Preoperative Care / Q000379:methods / Q000706:statistics & numerical data; D012189:Retrospective Studies; D012720:Severity of Illness Index; D020181:Sleep Apnea, Obstructive / Q000503:physiopathology / Q000601:surgery*; D011795:Surveys and Questionnaires; D013610:Tachycardia / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control; D014068:Tonsillectomy; D016896:Treatment Outcome