Anesthesia's influence on the brain

The potential damaging, long-lasting effect of anesthesia on the brain may take its toll on adults alongside pediatric patients, new research from Cincinnati Children’s Hospital Medical Center suggests.

According to trials conducted on mice, anesthesia can have a neurotoxic effect on developing brains depending on the age of the brain neurons, rather than the age of the person/animal under the ether.

"We demonstrate that anesthesia-induced cell death in neurons is not limited to the immature brain, as previously believed," said Andreas Loepke, MD, PhD, a physician and researcher in the Department of Anesthesiology, in a prepared statement. "Instead, vulnerability seems to target neurons of a certain age and maturational stage. This finding brings us a step closer to understanding the phenomenon's underlying mechanism"

Juvenile and newborn rodents were administered the widely used anesthetic isoflurane in doses equivalent to what would be dripped during surgery. As expected, newborn mice experienced extensive neuronal loss in the forebrain region with no significant loss in the dentate gyrus. Meanwhile, juvenile mice had reverse effects, with prominent cell death in the dentate gyrus.

Following study into the age and maturational status of the neurons within each age set and region of the brain, Loepke and team are eager to explore further anesthesia’s impact on brain chemistry, but remain cautious about immediately applying aspects of the study to children and adult humans. Previous studies have shown loose linkage between learning and memory loss congruent with early anesthesia; explicit follow-up has yet to be determined. Nevertheless, it is best to practice caution, Loepke noted.

"Surgery is often vital to save lives or maintain quality of life and usually cannot be performed without general anesthesia," Loepke said. "Physicians should carefully discuss with patients, parents and caretakers the risks and benefits of procedures requiring anesthetics, as well as the known risks of not treating certain conditions."

Researchers from the Pediatric Neuroimaging Research Consortium at Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine and the Children's Hospital of Fudan University, Shanghai, China, were also consulted for the project.

The study appears in the latest edition of the Annals of Neurology.

Image from the U.S. Navy courtesy of Creative Commons licensing.