Ing MK, Hegarty JW, Perkins AJO et al.
British Journal of Anaesthesia 2017; 119 (3): 532–40
https://doi.org/10.1093/bja/aew413
Aim of Study
There are few clinical trials looking at the association between exposure to volatile anaesthetic agents and neurotoxicity in children; of the few studies that have been done, some have found an increased risk of learning difficulties and decreased academic achievements. This study was based on previous data looking at the relationship between anaesthesia and long term neurological changes, focusing on language and cognition. It looked at children undergoing an anaesthetic before the age of three, and their cognitive function aged ten.
Design and Location
Retrospective observational study, Perth, Australia.
Methodology
Ethical approval was gained. Data obtained from Raine study, which collected information about almost 3000 children born within a specific time period, looking at various characteristics, medical procedures and cognitive function. Anaesthetic charts examined including exposure to volatile agents and duration. Neuropsychological testing carried out by trained research staff.
Primary Outcome
Scores for neuropsychological testing – cognitive function, language and abstract reasoning.
Secondary Outcomes
Long term neurological changes.
Statistics
Linear regression
Results
148 children had anaesthetic record information and test scores.
These were split into quartiles based on the duration of the anaesthetic – mean duration from 19 to 160min.
Children in 4th quartile had higher percentage of lower birth weight and more exposure to health services during their childhood.
Types of GA: 99% nitrous, 91% halothane, 15% isoflurane and 13% enflurane.
Lower neurological test scores seen in quartiles with longer exposure.
1st and 2nd quartiles had similar test scores to unexposed children
3rd and 4th quartiles had scores 6 points lower than unexposed children (95% CI)
Conclusions/Discussions
Results suggest an association between duration of exposure to volatile agents and cognitive function.
Total number of exposures may also play a role – need for multiple procedures.
Short exposures <30min do not appear to have long term effects
Stated Limitations from the Study
Only an association: patient co-morbidity confounding factor.
Unable to determine causal nature.
Only observational study – unethical and logistical difficulties to perform clinical trials
Retrospective data – changes in medicine since study
Missing data/anaesthetic charts
Agents used in study much less used today
Effect of IV agents not included.
Discussion from Journal Club Meeting (?Change of Practice)
Value of study: carried out 3 decades ago using different techniques and anaesthetic agents – should we be using this as a reason not to expose children to volatile agents?
Need more studies and trials looking at this – very difficult to determine relationship as nature and nurture likely to play a huge role in development of cognitive function.
What do we tell parents who ask about long term effects of anaesthetics on children? – We still do not know!
Summary by Dr A. Allana. Journal Club 25 January 2018.
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