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Exposure to halogenated ethers causes neurodegeneration and behavioural changes in young healthy experimental
Carlijn R Hooijmans1, Marije Buijs2, Frederique Struijs2
1Department of Anesthesiology, Pain and Palliative Medicine, Radboud University Medical Center, Geert Grooteplein-Noord 21, route 126, 6525 GA, Nijmegen, The Netherlands. carlijn.hooijmans@radboudumc.nl.
Insights
Inhalational anesthetics like sevoflurane and isoflurane can harm young children's brains, causing neurodegeneration and behavioral issues even after one use. Further research is needed to understand long-term effects.
Area of Science:
- Neuroscience
- Toxicology
- Anesthesiology
Background:
- The FDA warns that prolonged exposure to inhaled anesthetics in young children may cause neurological damage, but clinical evidence is limited.
- Preclinical studies on the neurotoxic potential of common anesthetics like sevoflurane, isoflurane, and desflurane are needed to assess risks.
Approach:
- A systematic review and meta-analysis of preclinical studies on isoflurane, sevoflurane, and desflurane exposure in young animals was conducted.
- Data on neurodegeneration (Caspase-3, TUNEL) and behavioral outcomes (Morris water maze, Elevated plus maze, Open field, Fear conditioning) were extracted and analyzed.
Key Points:
- Sevoflurane, isoflurane, and desflurane exposure significantly increased markers of neurodegeneration (Caspase-3, TUNEL).
- Sevoflurane and isoflurane exposure impaired learning and memory and increased anxiety in animal models.
- Even single exposure to sevoflurane or isoflurane negatively impacted brain development and behavior.
Conclusions:
- Preclinical evidence indicates that common inhaled anesthetics, particularly sevoflurane and isoflurane, can cause neurodegeneration and behavioral changes in young animals.
- These effects, including impaired learning, memory, and increased anxiety, are evident after single exposures.
- The findings suggest that the use of sevoflurane and isoflurane in young children should be minimized pending further research on long-term impacts.
Abstract:
The FDA issued a warning that repeated and prolonged use of inhalational anaesthetics in children younger than 3 years may increase the risk of neurological damage. Robust clinical evidence supporting this warning is however lacking. A systematic review of all preclinical evidence concerning isoflurane, sevoflurane, desflurane and enflurane exposure in young experimental animals on neurodegeneration and behaviour may elucidate how severe this risk actually is PubMed and Embase were comprehensively searched on November 23, 2022. Based on predefined selection criteria the obtained references were screened by two independent reviewers. Data regarding study design and outcome data (Caspase-3 and TUNEL for neurodegeneration, Morris water maze (MWM), Elevated plus maze (EPM), Open field (OF) and Fear conditioning (FC)) were extracted, and individual effect sizes were calculated and subsequently pooled using the random effects model. Subgroup analyses were predefined and conducted for species, sex, age at anesthesia, repeated or single exposure and on time of outcome measurement. Out of the 19.796 references screened 324 could be included in the review. For enflurane there were too few studies to conduct meta-analysis (n = 1). Exposure to sevoflurane, isoflurane and desflurane significantly increases Caspase-3 levels and TUNEL levels. Further, sevoflurane and isoflurane also cause learning and memory impairment, and increase anxiety. Desflurane showed little effect on learning and memory, and no effect on anxiety. Long term effects of sevoflurane and isoflurane on neurodegeneration could not be analysed due to too few studies. For behavioural outcomes, however, this was possible and revealed that sevoflurane caused impaired learning and memory in all three related outcomes and increased anxiety in the elevated plus maze. For isoflurane, impaired learning and memory was observed as well, but only sufficient data was available for two of the learning and memory related outcomes. Further, single exposure to either sevoflurane or isoflurane increased neurodegeneration and impaired learning and memory. In summary, we show evidence that exposure to halogenated ethers causes neurodegeneration and behavioural changes. These effects are most pronounced for sevoflurane and isoflurane and already present after single exposure. To date there are not sufficient studies to estimate the presence of long term neurodegenerative effects. Nevertheless, we provide evidence in this review of behavioral changes later in life, suggesting some permanent neurodegenerative changes. Altogether, In contrast to the warning issued by the FDA we show that already single exposure to isoflurane and sevoflurane negatively affects brain development. Based on the results of this review use of sevoflurane and isoflurane should be restrained as much as possible in this young vulnerable group, until more research on the long term permanent effects have been conducted.
