Pediatric Anesthesia Found to Damage Rat Brains

A study has found that drugs commonly used to anesthetize children can cause brain damage and long-term learning and memory problems in infant rats. The results were reported in the February 1, 2003, issue of the Journal of Neuroscience.

Researchers anesthetized seven-day-old rats with a combination of three drugs commonly used in pediatric surgery: midazolam, nitrous oxide, and isoflurane. Some rats were examined when a month old and others at adulthood. The researchers found moderately severe cell death had occurred in several brain regions in every brain examined, including brain regions involved in learning and memory such as the hippocampus. They also found that the rats appeared to behave normally in most other ways, and there were no outward signs of brain damage.

"These infant rats were anesthetized during the brain growth spurt period called synaptogenesis, which lasts for the first few weeks of life in rats, but in humans it extends from the third trimester of pregnancy until about age three,” said John W. Olney, M.D., senior investigator and professor of neuropsychopharmacology at Washington (St. Louis, MO, USA). "During this period, nerve cells in the brain make connections with one another and form large networks. But if something interferes with that process, the cells are programmed to kill themselves.”

The researchers suggest that some surgical procedures might not require general anesthesia, or in some cases the duration could be reduced. If the surgery does not have to be performed early in life, they say it would be prudent to postpone it.




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Washington University School of Medicine