Anesthesia plays a significant role in surgeries. Without it, it is less likely that patients survive a major operation. However, in a recent finding, it may not be beneficial if pediatric patients continue to receive anesthesia, as prolonged exposure to it could lead to long-term behavioral changes.
There are approximately one million children at the age of four and below who undergo surgery with general anesthesia every year, based on the records of the US Food and Drug Administration. There are already some established correlations drawn from retrospective studies on children, majority of which have linked learning problems to repeated anesthesia exposure.
Researchers at the Mount Sinai's Icahn School of Medicine and the Yerkes National Primate Research Center were able to investigate the effects of anesthesia to humans. The team was also able to measure the duration of the effects and see how long changes in emotional behavior persist.
As reported in the press release, Mark Baxter, Ph.D., professor in the Department of Neuroscience and Anesthesiology at the Icahn School of Medicine at Mount Sinai, highlighted the major strength of the study. According to him, the research design eliminated the possible influence of surgical procedures to the actual effects of anesthesia. The impact would have affected the results should they conduct the study in human children.
In the study, researchers designed a method that involved rhesus monkey models as the treatment group. The team came up with using this species, knowing that they are highly comparable to humans in terms of the genetic makeup. Concerning brain development, a six-week-old rhesus monkey also resembles that of an infant that is seven to 12 months old.
The researchers exposed ten rhesus monkeys to a common pediatric anesthesia called sevoflurane with a dose effective for four hours. Also, the subjects were also treated with the same dosage of anesthesia at postnatal days seven, 14 and 28 to indicate repeated exposure.
After applying the treatment, researchers observed the primates (both the exposed and the control) at their sixth month. Emotional behavior was evaluated using an unfamiliar human as a mild social stressor. According to Jessica Raper, Ph.D. of YNPRC, such method was designed in a way similar to that used in assessing behavioral inhibition and dispositional anxiety in children.
Researchers found that infant rhesus monkeys exposed to anesthesia exhibited significantly more anxious behaviors overall as compared to the control group. Moreover, the study also found that the observed alterations in emotional expression were long-term. The effects observed in the subjects persisted at no less than five months after anesthesia exposure. However, the study team plans to keep on studying the treated subjects so as to determine the length of time that the behavioral changes continue to manifest.
With the gathered data, researchers believe that the study leads to new research that focuses on finding the best anesthesia that does not anymore alter emotional behavior.
The study appears in the Online First edition of Anesthesiology.