Each year millions of infants, toddlers and preschool children require anesthesia or sedation for various procedures and a new review suggest caution about their use.

A team of anesthesiology investigators and toxicologists writing in the New England Journal of Medicine reviewed existing animal and human studies for the impact of anesthetics on developing brains. 

Observational studies of children have been weak, but they still suggested a correlation between children who had received anesthetics and long-term cognitive impairments such as learning disabilities. Children between the ages of one and three appeared to be at a higher risk of adverse effects.

Animal studies provided evidence of brain injury and long-term behavioral deficits but clinical studies had many serious limitations that prevented University of Toronto Professor Beverley Orser and colleagues from determining whether anesthetics actually caused the impairment in children. For example, other factors such as trauma from surgery or pre-existing conditions could contribute to the behavioral deficits.

Regardless, they still suggest there's enough evidence to suggest the need for specific clinical research.

"Anesthetics are generally assumed to be safe for children, and are important for conducting life- saving or other essential procedures. However, our analysis of the available data raised some red flags," said Orser. "The next step is to start targeted large clinical trials. That's the only way we can determine if or how these drugs are having an impact on a child's developing brain." 

Their Consensus Statement recommends avoiding anesthetics for children three years and under unless they are needed for surgeries that will lead to better outcomes. Obviously, early interventions through surgical procedures can help children lead healthier lives in the long run and anesthetics are administered by highly trained medical professionals who make decisions about anesthesia and surgery very carefully.

A review of weak observational studies and animal models of varying quality can be a justification for better studies, but should not raise any alarms for parents.

Orser suggests that parents who are concerned talk to their child's physicians about the risks and benefits associated with anesthesia.