title: Tourniquet use during ankle surgery leads to increased postoperative opioid use.
abstract: OBJECTIVE
  Ankle surgery is often done using a tourniquet. Ischemia/reperfusion injury caused by the tourniquet may increase postoperative pain. The study objective was to investigate the amount of opioids given to patients after ankle surgery with and without tourniquet.
  
  
  METHODS
  We did a cohort study based on data from patient's records between January 2008 and December 2011.
  
  
  METHODS
  Information is gathered from operating room, postanesthetic care unit, and surgical ward in a university hospital.
  
  
  METHODS
  We identified patients undergoing reconstructive ankle fracture surgery from hospital records. We excluded multiple fractures of the same extremity, major trauma, reoperations, arthrodesis of the ankle joint, and missing data on tourniquet use. We included 603 patients.
  
  
  METHODS
  For each patient, we registered for how long (minutes) the tourniquet was inflated.
  
  
  METHODS
  Main outcome was opioid use during first 24 hours postoperatively (in equipotent intravenous morphine doses). Secondary outcomes were the peak pain on a verbal rating scale, time in postanesthetic care unit, and additional antiemetic medicine. We performed multiple regression to analyze the primary outcome.
  
  
  RESULTS
  Three hundred fifty-eight patients underwent surgery with tourniquet. There was a correlation between tourniquet time and postoperative opioid use (P value = .001) after controlling for confounders. The slope of the correlation was 0.04 mg/min (95% confidence interval, 0.02-0.07), which means there is an increase in postoperative opioid use by 0.43 mg for every 10 minutes of tourniquet time.
  
  
  CONCLUSIONS
  We found an increase in postoperative opioid consumption correlated to tourniquet use. Possible preventive measures with antioxidant treatment to prevent ischemia/reperfusion injury should be investigated.
authors.affiliation: Department of Anaesthesia, University Hospital Herlev, Herlev Ringvej 75, 2720 Herlev, Denmark. Electronic address: heidi_kruse@hotmail.com.
authors.forename: Heidi
authors.initials: H
authors.lastname: Kruse
authors.affiliation: Department of Anaesthesia, University Hospital Herlev, Herlev Ringvej 75, 2720 Herlev, Denmark.
authors.forename: Kristian P
authors.initials: KP
authors.lastname: Christensen
authors.affiliation: Department of Anaesthesia, University Hospital Herlev, Herlev Ringvej 75, 2720 Herlev, Denmark.
authors.forename: Ann M
authors.initials: AM
authors.lastname: Møller
authors.affiliation: Department of Surgery, University Hospital Herlev, Herlev Ringvej 75, 2720 Herlev, Denmark.
authors.forename: Ismail
authors.initials: I
authors.lastname: Gögenur
mesh_terms: D000328:Adult; D000368:Aged; D000701:Analgesics, Opioid / Q000008:administration & dosage; D000842:Ankle / Q000601:surgery*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010149:Postoperative Pain / Q000188:drug therapy / Q000209:etiology*; D015427:Reperfusion Injury / Q000209:etiology*; D013997:Time Factors; D014111:Tourniquets / Q000009:adverse effects*
chemical_list: D000701:Analgesics, Opioid
keywords: Anesthesia recovery period; Opioid; Orthopedics; Postoperative pain; Reperfusion injury; Tourniquets