Children who received general anesthesia for surgery before age 4 had diminished language comprehension, lower IQ and decreased gray matter density in posterior regions of their brain, according to a new study from researchers at Cincinnati Children’s Hospital Medical Center. The team recommend additional studies to determine anesthesia’s precise molecular effects on the brain and contribution to diminished brain function and composition. Researchers say this knowledge could make it possible to develop mitigating strategies for what the authors describe as a potential dilemma for child health.
The team state that the ultimate goal of the clinical research is to improve safety and outcomes in young children who have no choice but to undergo surgery with anesthesia to treat their serious health concerns. The current study also provides a better understanding as to what extent anesthetics and other factors contribute to learning abnormalities in children before making drastic changes to current practices, which by all measures has become very safe.
The researchers have published previous studies showing widespread cell death, permanent deletion of neurons and neurocognitive impairment in laboratory rats and mice after exposure to general anesthesia. Those studies have raised concerns about similar effects in young children during a particularly sensitive neurodevelopmental period in early life, which the researchers say could interfere with the refinement of neuronal networks and lead to long-term functional abnormalities.
For the current retrospective study the team compared the scores of 53 healthy participants of a language development study (ages 5 to 18 years with no history of surgery) with the scores of 53 children in the same age range who had undergone surgery before the age of 4.
The group stress that average test scores for all 106 children in the study were within population norms, regardless of surgical history. Still, compared with children who had not undergone surgery, children exposed to anesthesia scored significantly lower in listening comprehension and performance IQ. The data findings also showed that decreased language and IQ scores were associated with lower gray matter density in the occipital cortex and cerebellum of the brain.
The current study used extensive analysis of surgical and other medical records, matching the children for age, gender, handedness and socioeconomic status, all confounding factors of cognition and brain structure. The team also factored into their calculations the types of surgeries and length of exposure to anesthetics. The anesthetics used during the surgeries included common agents such as sevoflurane, isoflurane or halothane (used alone or in combination) and nitrous oxide.
Children included in the study did not have a history of neurologic or mental illness, head trauma or any other associated conditions. Neurocognitive assessments included the Oral and Written Language Scales and the Wechsler Intelligence Scale. Brain structural comparisons were conducted by MRI scans.
Although data in the current study highlight the need to look for improved methods of administering anesthesia, the team emphasize that current methods are very safe. The researchers advise parents who are concerned to discuss with their pediatrician and surgeon the risks of a surgical procedure, and the potential risk of anesthetic exposure, versus the risks of not having a surgery.
The team stress that it is important to note that no surgeries are truly elective in young children. They go on to add that many surgical procedures early in life treat life-threatening conditions, avert serious health complications, or improve quality of life. These cannot be easily postponed or avoided.
Cincinnati Children’s Hospital are now actively looking for alternative anesthetic techniques in their ongoing laboratory studies. Drugs are being tested that show potential for lessening the harmful effects of anesthetics in laboratory rats and mice, and this research is ongoing. Additionally, the medical center is participating in an international clinical trial to test an alternative anesthetic regimen in young children undergoing urological procedures.