title: Life-threatening critical respiratory events: a retrospective study of postoperative patients found unresponsive during analgesic therapy.
abstract: OBJECTIVE
  To identify risk factors for life-threatening critical respiratory events occurring during parenteral analgesic therapy for acute postoperative pain.
  
  
  METHODS
  Retrospective, observational, cohort study.
  
  
  METHODS
  University hospital.
  
  
  METHODS
  The electronic records of patients with sudden-onset, life-threatening critical respiratory events during analgesic therapy for postoperative pain were studied. Critical respiratory event data were identified from the hospital risk management database between 8/1/2000 and 7/31//2007. Patients required rescue treatment with naloxone, endototracheal intubation, or cardiopulmonary resusucitation. Pediatric patients were excluded from the study. In addition to the event description (type of analgesia, opioid dose, patient monitoring data, time of day, and time from surgery), each patient's record was reviewed to extract co-morbidities and outcome data.
  
  
  RESULTS
  Over the 6-year period, 32 patients experienced a postoperative critical respiratory event. Twenty-six events and three deaths occurred within the first 24 hours of opioid therapy. Four of 32 patients died. Congestive heart failure, postoperative acute renal failure, obstructive sleep apnea, cardiac dysrhythmia, diabetes mellitus, coronary artery disease, and hypertension were significant associations in adult patients.
  
  
  CONCLUSIONS
  The first 24 hours after commencing opioid-based analgesic therapy represents a high risk period. Obstructive sleep apnea, deep levels of sedation, nocturnal presentation, and postoperative acute renal failure were seen in patients who died as a result of these critical respiratory events.
authors.affiliation: Department of Anesthesiology, University of Michigan Medical Center, Ann Arbor, MI 48109-0048, USA. rsatyak@med.umich.edu
authors.forename: Satya Krishna
authors.initials: SK
authors.lastname: Ramachandran
authors.forename: Naeem
authors.initials: N
authors.lastname: Haider
authors.forename: Kelly A
authors.initials: KA
authors.lastname: Saran
authors.forename: Michael
authors.initials: M
authors.lastname: Mathis
authors.forename: Joyce
authors.initials: J
authors.lastname: Kim
authors.forename: Michelle
authors.initials: M
authors.lastname: Morris
authors.forename: Michael
authors.initials: M
authors.lastname: O'Reilly
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000701:Analgesics, Opioid / Q000009:adverse effects* / Q000627:therapeutic use; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010149:Postoperative Pain / Q000188:drug therapy*; D012131:Respiratory Insufficiency / Q000139:chemically induced*; D012189:Retrospective Studies; D020181:Sleep Apnea, Obstructive / Q000139:chemically induced
chemical_list: D000701:Analgesics, Opioid