New research suggests that multiple exposures to anesthesia during infancy could have an impact on emotional behavior, leading to alterations such as an increase in anxious behaviors that persist into later life.
The study, published in Anesthesiology, was a collaboration between researchers from the Icahn School of Medicine at Mount Sinai in New York City, NY, and the Yerkes National Primate Research Center in Atlanta, GA.
“Events that impact the developing brain have the potential to affect a wide range of later-developing behaviors,” states co-investigator Maria Alvarado, of the Yerkes National Primate Research Center.
According to the US Food and Drug Administration (FDA), approximately 1 million children under the age of 4 undergo surgery involving general anesthetic each year.
Some retrospective studies investigating the effects of anesthesia on children have observed a possible relation between learning problems and multiple exposures to anesthesia during infancy. Other animal studies have also demonstrated that exposure to anesthesia early on in life can cause cell death and future cognitive impairment.
Despite these findings, experts are unsure as to the extent anesthesia poses a risk to humans when compared with other factors associated with anesthesia and surgery.
To investigate, the researchers exposed 10 infant rhesus monkeys to a common pediatric anesthetic for 4 hours – a length of time comparable to that required for a significant surgical procedure in humans.
Rhesus monkeys were selected as the stage of their neurodevelopment at birth is comparable to that observed in human infants. The study was also conducted in the absence of a surgical procedure so that the researchers could isolate the influence of anesthesia.
“The major strength of this study is its ability to separate anesthesia exposure from surgical procedures, which is a potential complication in the studies conducted in children,” explains study author Mark Baxter, a professor in the Departments of Neuroscience and Anesthesiology at the Icahn School of Medicine.
The rhesus monkeys were exposed to anesthetic three times – at 7 days, 2 weeks and 4 weeks after birth – as previous research indicates repeat exposure to anesthesia results in a greater risk of learning disabilities compared with a single exposure.
Using an unfamiliar human as a mild stressor, the researchers then assessed the socioemotional behavior of the monkeys exposed to anesthetic and compared them with healthy control monkeys aged 6 months.
- General anesthesia is typically produced by a combination of intravenous drugs and inhaled gasses
- While under general anesthesia, a patient’s breathing is assisted and controlled
- Anesthetic is administered by a specially trained doctor known as an anesthesiologist.
This method of assessment was designed to be similar to the task used for assessing dispositional anxiety and behavioral inhibition in children, explains first author Jessica Raper, a research associate in the Division of Developmental and Cognitive Neuroscience at Yerkes National Primate Center.
Infant monkeys exposed to anesthetic were found by the researchers to exhibit significantly more anxious behaviors than the healthy controls.
In addition, they found that these alterations in emotional behavior also persisted for at least 5 months after exposure to the anesthetic. This study will continue so that the team can determine how long these changes persist for and whether or not they eventually resolve in time.
As a large proportion of pediatric surgical cases involving anesthetic are procedures that need to be carried out, it may be necessary for a novel anesthetic agent to be developed that negates the impact of anesthesia on the emotional behavior of children.
Future research into this area will also be needed to identify the mechanisms behind the findings of the study.
Previously, Medical News Today reported on a study finding that people born very prematurely or with a very low birth weight are at an increased risk of being introverted or neurotic as an adult.