title: Recurrent hypoxemia in children is associated with increased analgesic sensitivity to opiates.
abstract: BACKGROUND
  Postsurgical administration of opiates in patients with obstructive sleep apnea (OSA) has recently been linked to an increased risk for respiratory complications. The authors have attributed this association to an effect of recurrent oxygen desaturation accompanying OSA on endogenous opioid mechanisms that, in turn, alter responsiveness to subsequent administration of exogenous opiates. In a retrospective study, the authors have shown that oxygen desaturation and young age in children with OSA are correlated with a reduced opiate requirement for postoperative analgesia.
  
  
  METHODS
  The current study was designed to test that conclusion prospectively in 22 children with OSA scheduled to undergo adenotonsillectomy. The children were stratified to those having displayed < 85% or > or = 85% oxygen saturation nadir during sleep preoperatively. Using a blinded design, the children were given morphine postoperatively to achieve an identical behavioral pain score.
  
  
  RESULTS
  As compared with children in the > or = 85% group, the < 85% oxygen saturation nadir group required one half the total analgesic morphine dose postoperatively, indicating heightened analgesic sensitivity to morphine after recurrent hypoxemia.
  
  
  CONCLUSIONS
  Previous recurrent hypoxemia in OSA is associated with increased analgesic sensitivity to subsequent morphine administration. Therefore, opiate dosing in children with OSA must take into account a history of recurrent hypoxemia.
authors.affiliation: Division of Pediatric Anesthesia, Department of Pediatrics, McGill University Health Centre/The Montreal Children's Hospital, 2300 Tupper Street, Montreal, Quebec H3H 13P, Canada. roula.cacolyris@muhc.mcgill.ca
authors.forename: Karen A
authors.initials: KA
authors.lastname: Brown
authors.forename: André
authors.initials: A
authors.lastname: Laferrière
authors.forename: Indrani
authors.initials: I
authors.lastname: Lakheeram
authors.forename: Immanuela Ravé
authors.initials: IR
authors.lastname: Moss
mesh_terms: D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000627:therapeutic use*; D001049:Apnea / Q000453:epidemiology; D002245:Carbon Dioxide / Q000378:metabolism; D002648:Child; D002675:Child, Preschool; D003627:Data Interpretation, Statistical; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D000860:Hypoxia / Q000150:complications*; D007223:Infant; D008297:Male; D009020:Morphine / Q000008:administration & dosage / Q000627:therapeutic use; D010149:Postoperative Pain / Q000188:drug therapy*; D011446:Prospective Studies; D012008:Recurrence; D015656:Respiratory Mechanics / Q000187:drug effects; D014068:Tonsillectomy
chemical_list: D000701:Analgesics, Opioid; D002245:Carbon Dioxide; D009020:Morphine