title: Combined general and neuraxial anesthesia versus general anesthesia: a population-based cohort study.
abstract: OBJECTIVE
  To determine whether combining spinal or epidural anesthesia with general anesthesia (combined anesthesia) reduces major medical complications of elective surgery compared with general anesthesia alone.
  
  
  METHODS
  We conducted a propensity-matched population-based historical cohort study using large healthcare databases from Ontario, Canada. We identified patients undergoing 21 different elective procedures that were amenable to either combined anesthesia or general anesthesia alone in 108 hospitals from 2004 to 2011. We assessed the following four outcomes together as a composite and individually in the 30 days following surgery: acute kidney injury, stroke, myocardial infarction, and all-cause mortality.
  
  
  RESULTS
  Prior to matching, we identified 21,701 patients receiving general anesthesia and 8,042 patients receiving combined anesthesia. After matching, our cohort included 12,379 patients. Twenty-eight baseline characteristics were well-matched between the combined (n = 4,773) and general anesthesia groups (n = 7,606). Mean patient age was 66 yr. Relative to general anesthesia alone, combined anesthesia was not associated with a reduced risk for the composite outcome [104/4,773 (2.2%) vs 162/7,606 (2.1%); odds ratio (OR) 0.97; 95% confidence interval (CI) 0.75 to 1.24] or for any of the four component outcomes when examined separately: acute kidney injury (OR 0.93; 95% CI 0.58 to 1.51), stroke (OR 0.79; 95% CI 0.36 to 1.73), myocardial infarction (OR 1.04; 95% CI 0.69 to 1.57), and all-cause mortality (OR 0.91; 95% CI 0.59 to 1.42).
  
  
  CONCLUSIONS
  The addition of spinal or epidural anesthesia to general anesthesia was not associated with a reduced risk of major medical complications among 21 different elective procedures when compared with general anesthesia alone.
authors.affiliation: Institute for Clinical Evaluative Sciences Western, London Health Sciences Centre, 800 Commissioners Rd. E, Room ELL-113A, London, ON, N6A 4G5, Canada, danielle.nash@ices.on.ca.
authors.forename: Danielle M
authors.initials: DM
authors.lastname: Nash
authors.forename: Reem A
authors.initials: RA
authors.lastname: Mustafa
authors.forename: Eric
authors.initials: E
authors.lastname: McArthur
authors.forename: Duminda N
authors.initials: DN
authors.lastname: Wijeysundera
authors.forename: J Michael
authors.initials: JM
authors.lastname: Paterson
authors.forename: Sumit
authors.initials: S
authors.lastname: Sharan
authors.forename: Christopher
authors.initials: C
authors.lastname: Vinden
authors.forename: Ron
authors.initials: R
authors.lastname: Wald
authors.forename: Blayne
authors.initials: B
authors.lastname: Welk
authors.forename: Daniel I
authors.initials: DI
authors.lastname: Sessler
authors.forename: P J
authors.initials: PJ
authors.lastname: Devereaux
authors.forename: Michael
authors.initials: M
authors.lastname: Walsh
authors.forename: Amit X
authors.initials: AX
authors.lastname: Garg
mesh_terms: D058186:Acute Kidney Injury / Q000453:epidemiology; D000368:Aged; D000767:Anesthesia, Epidural / Q000009:adverse effects / Q000379:methods*; D000768:Anesthesia, General / Q000009:adverse effects / Q000379:methods*; D000775:Anesthesia, Spinal / Q000009:adverse effects / Q000379:methods*; D015331:Cohort Studies; D016208:Databases, Factual; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000453:epidemiology; D009864:Ontario; D020521:Stroke / Q000453:epidemiology