title: Obstructive sleep apnea, pain, and opioids: is the riddle solved?
abstract: OBJECTIVE
  Perioperative opioid-based pain management of patients suffering from obstructive sleep apnea (OSA) may present challenges because of concerns over severe ventilatory compromise. The interaction between intermittent hypoxia, sleep fragmentation, pain, and opioid responses in OSA, is complex and warrants a special focus of perioperative outcomes research.
  
  
  RESULTS
  Life-threatening opioid-related respiratory events are rare. Epidemiologic evidence suggests that OSA together with other serious renal and heart disease, is among those conditions predisposing patients for opioid-induced ventilatory impairment (OIVI) in the postoperative period. Both intermittent hypoxia and sleep fragmentation, two distinct components of OSA, enhance pain. Intermittent hypoxia may also potentiate opioid analgesic effects. Activation of major inflammatory pathways may be responsible for the effects of sleep disruption and intermittent hypoxia on pain and opioid analgesia. Recent experimental evidence supports that these, seemingly contrasting, phenotypes of pain-increasing and opioid-enhancing effects of intermittent hypoxia, are not mutually exclusive. Although the effect of intermittent hypoxia on OIVI has not been elucidated, opioids worsen postoperative sleep-disordered breathing in OSA patients. A subset of these patients, characterized by decreased chemoreflex responsiveness and high arousal thresholds, might be at higher risk for OIVI.
  
  
  CONCLUSIONS
  OSA may complicate opioid-based perioperative management of pain by altering both pain processing and sensitivity to opioid effect.
authors.affiliation: aDepartment of Anaesthesia, Toronto Western Hospital, University Health Network, University of Toronto, Toronto, Canada bDepartment of Anesthesiology, Perioperative and Pain Medicine, Stanford University School of Medicine, Stanford, California, USA.
authors.forename: Karen K
authors.initials: KK
authors.lastname: Lam
authors.forename: Samuel
authors.initials: S
authors.lastname: Kunder
authors.forename: Jean
authors.initials: J
authors.lastname: Wong
authors.forename: Anthony G
authors.initials: AG
authors.lastname: Doufas
authors.forename: Frances
authors.initials: F
authors.lastname: Chung
mesh_terms: D000701:Analgesics, Opioid / Q000009:adverse effects* / Q000627:therapeutic use; D006801:Humans; D010149:Postoperative Pain / Q000188:drug therapy*; D020181:Sleep Apnea, Obstructive / Q000139:chemically induced*
chemical_list: D000701:Analgesics, Opioid