General anesthesia is typically used during surgeries to put patients in an unconscious state, meaning that it interrupts their cognitive networks1. This interruption can be harmful when the brain is in early stages of development and new neural networks are still forming1. For instance, much of the data on the effects of anesthesia on young animals revealed that anesthesia can cause neurocognitive impairments2. This has thus prompted researchers to study these effects in young human children in order to understand whether or not it is truly safe to administer anesthesia during surgeries for children2.
Backeljauw et al. (2015) conducted a prominent correlational study by assessing language development and intelligence in children who had been exposed to anesthesia before the age of four1. They compared these assessments with those of children who had not been exposed to any anesthesia1. Using the results of various tests, the researchers found that children who had been exposed to anesthesia at a young age had lower scores on both IQ and learning tests1. Backeljauw et al. (2015) took this a step further by looking at brain structure using MRI scans, which revealed “lower grey matter density in the occipital cortex and cerebellum” of children exposed to anesthesia, a pattern commonly associated with decreased learning 1. Despite these concerning findings, much of this work is correlational; therefore, a deeper understanding of how early exposure to anesthesia disrupts brain development is necessary.
To gain more insight into this issue, Sun et al. (2016) did a sibling-matched cohort study, which allowed the researchers to control various external factors2. In this study, one sibling had early exposure to anesthesia, whereas the other sibling had not, and the researchers then investigated various aspects of cognition and behavior of the siblings, including memory, visuospatial function and language2. Interestingly, there were no significant differences between the two groups of children. One reason why this may be is because the study only looked at anesthesia exposure before 36 months2. It might be worthwhile to study different times of exposure in future studies to fully understand the risks of early exposure.
With an FDA warning in 2017 regarding exposure to anesthesia for young children, there was increased research on the topic3. Davidson and Sun (2018) conducted a large-scale review to assess this research, finding mostly mixed results3. A majority of the research did not show a strong association between anesthesia exposure in young children and subsequent neurocognitive impairment, and in cases where there was some association, it was fairly weak in that the risk of impairment was considered to be very minimal3. Given these results, Davidson and Sun (2018) suggested that increased research is needed to further understand the cases in which there is some risk of developing cognitive impairments by exploring different extrinsic and intrinsic factors that make these cases different3.
With the FDA warning as well as mixed results of current research, it is still difficult for medical professionals to be sure of the extent to which administering anesthesia to young children is dangerous. More in-depth investigations are needed to fully understand the risks of exposing young children to anesthesia during surgery.
References:
(1) Backeljauw B, Holland SK, Altaye M, Loepke AW. Cognition and Brain Structure Following Early Childhood Surgery with Anesthesia. Pediatrics. 2015;136(1):e1‐e12. doi:10.1542/peds.2014-3526
(2) Sun LS, Li G, Miller TL, et al. Association Between a Single General Anesthesia Exposure Before Age 36 Months and Neurocognitive Outcomes in Later Childhood. JAMA. 2016;315(21):2312‐2320. doi:10.1001/jama.2016.6967
(3) Andrew J. Davidson, Lena S. Sun; Clinical Evidence for Any Effect of Anesthesia on the Developing Brain. Anesthesiology 2018;128(4):840-853. doi: https://doi.org/10.1097/ALN.0000000000001972