title: Neurodevelopmental Assessment in Kindergarten in Children Exposed to General Anesthesia before the Age of 4 Years: A Retrospective Matched Cohort Study.
abstract: BACKGROUND
  Animal studies demonstrate general anesthetic (GA) toxicity in the developing brain. Clinical reports raise concern, but the risk of GA exposure to neurodevelopment in children remains uncertain.
  
  
  METHODS
  The authors undertook a retrospective matched cohort study comparing children less than 4 yr of age exposed to GA to those with no GA exposure. The authors used the Early Development Instrument (EDI), a 104-component questionnaire, encompassing five developmental domains, completed in kindergarten as the outcome measure. Mixed-effect logistic regression models generated EDI estimates for single versus multiple GA exposure and compared both single and multiple exposures by the age of 0 to 2 or 2 to 4 yr. Known sociodemographic and physical confounders were incorporated as covariates in the models.
  
  
  RESULTS
  A total of 18,056 children were studied: 3,850 exposed to a single GA and 620 exposed to two or more GA, who were matched to 13,586 nonexposed children. In children less than 2 yr of age, there was no independent association between single or multiple GA exposure and EDI results. Paradoxically, single exposure between 2 and 4 yr of age was associated with deficits, most significant for communication/general knowledge (estimate, -0.7; 95% CI, -0.93 to -0.47; P < 0.0001) and language/cognition (estimate, -0.34; 95% CI, -0.52 to -0.16; P < 0.0001) domains. Multiple GA exposure at the age of 2 to 4 yr did not confer greater risk than single GA exposure.
  
  
  CONCLUSIONS
  These findings refute the assumption that the earlier the GA exposure in children, the greater the likelihood of long-term neurocognitive risk. The authors cannot confirm an association between multiple GA exposure and increased risk of neurocognitive impairment, increasing the probability of confounding to explain the results.
authors.affiliation: From the Department of Anesthesia (M.R.G.) and Department of Community Health Sciences, Manitoba Centre for Health Policy (M.B., D.G.C., R.D.D., C.B., R.R.F.), University of Manitoba, Winnipeg, Manitoba, Canada.
authors.forename: M Ruth
authors.initials: MR
authors.lastname: Graham
authors.forename: Marni
authors.initials: M
authors.lastname: Brownell
authors.forename: Daniel G
authors.initials: DG
authors.lastname: Chateau
authors.forename: Roxana D
authors.initials: RD
authors.lastname: Dragan
authors.forename: Charles
authors.initials: C
authors.lastname: Burchill
authors.forename: Randal R
authors.initials: RR
authors.lastname: Fransoo