Repeated exposure to anesthesia in early life may alter emotional behaviour that may persist for years, a study has found.
The team from Icahn School of Medicine at Mount Sinai University in New York and the Yerkes National Primate Research Centre exposed 10 nonhuman primates (rhesus monkeys) to a common pediatric anesthetic for four hours - a comparable length of time required for a significant surgical procedure in humans.
The stage of neurodevelopment of rhesus monkeys at birth is more similar to that of human infants compared to neo-natal rodents.
The monkeys were exposed to the anesthetic at post-natal day seven and then again two and four weeks later.
Researchers evaluated the socio-emotional behaviour of exposed monkeys compared with that of healthy controls at six months of age using a mild social stressor (an unfamiliar human).
They found the anesthesia-exposed infants expressed significantly more anxious behaviours overall compared with controls.
"Events that impact the developing brain have the potential to affect a wide range of later-developing behaviours," said study co-investigator Maria Alvarado from Yerkes National Primate Research Centre.
Retrospective birth-cohort studies of children have found an association between learning problems and multiple exposures to anesthesia early in life.
Previous research in animal models, mainly rodents, has shown that early anesthesia exposure causes cell death in the brain and cognitive impairments later in life.
"The major strength of the new study is its ability to separate anesthesia exposure from surgical procedures, which is a potential complication in the studies conducted in children," noted Mark Baxter, professor at the Icahn School of Medicine.
The results confirm that multiple anesthesia exposures alone result in emotional behaviour changes in a highly translational animal model.
"This raises concerns about whether similar phenomena are occurring during clinical anesthesia exposure in children," the authors noted in a paper published in the journal Anesthesiology.
