title: The effects of anaesthesia on the developing brain: a summary of the clinical evidence.
abstract: BACKGROUND
  There is data amassing in the literature regarding the potentially adverse effects of anaesthesia exposure on the developing human brain. The purpose of this article is to summarise current relevant data from clinical studies in this area.
  
  
  METHODS
  Articles from journals written in English were searched for using PubMed, Ovid and Medline. Keywords used included: brain (newborn, infant, child and neonate), neurodegeneration, apoptosis, toxicity, neurocognitive impairment (developmental impairment and learning disorders) and anaesthesia (intravenous, inhalational and sedation).
  
  
  RESULTS
  From the initial search, 23 articles were identified as potentially relevant, with publication dates spanning from 1978 to 2012.  Twelve studies were deemed irrelevant to the research questions. The results of neurocognitive assessment from eight of the remaining eleven studies had showed some differences in the performances of children exposed to anaesthesia. The control population in these studies was highly variable. The age at which the subjects were exposed to anaesthesia ranged from prenatal to 4 years in the majority of studies with one including children aged up to 12 years when exposed.
  
  
  CONCLUSIONS
  Although there is clinical data suggesting a possible detrimental effect, the evidence is best considered preliminary and inconclusive at this stage. Many of the outcome measures were lacking in specificity and standardization in most cases. Parents should be counselled to not avoid necessary invasive procedures for fear of a currently ill-defined risk.  However, deferral of elective procedures beyond the first few years of life should be contemplated.
authors.affiliation: Department of Anaesthesiology, Queen Mary Hospital, Hong Kong.
authors.forename: Clara Ky
authors.initials: CK
authors.lastname: Yu
authors.affiliation: Department of Anaesthesiology, Queen Mary Hospital, Hong Kong.
authors.forename: Vivian Man Ying
authors.initials: VM
authors.lastname: Yuen
authors.affiliation: Department of Anaesthesiology, University of Hong Kong, Hong Kong.
authors.forename: Gordon Tc
authors.initials: GT
authors.lastname: Wong
authors.affiliation: Department of Anaesthesiology, University of Hong Kong, Hong Kong.
authors.forename: Michael G
authors.initials: MG
authors.lastname: Irwin