SOURCES: Andreas Loepke, M.D., Ph.D., F.A.A.P., professor of clinical anesthesia and pediatrics, University of Cincinnati College of Medicine and Cincinnati Children's Hospital Medical Center; Raafat S. Hannallah, M.D., pediatric anesthesiologist, Children's National Health System, Washington, D.C.; July 2015, Pediatrics
MONDAY, June 8, 2015 (HealthDay News) -- Having general anesthesia during surgery at a very young age may be linked to poorer brain development, new research suggests.
Children who had received general anesthesia during surgery before they turned 4 years of age later scored slightly lower on listening comprehension and parts of an IQ test, compared to children who had never had general anesthesia, the researchers found. The children's overall IQ scores, however, remained within the normal range.
"It is difficult to see whether this decrease had any functional effect for an individual child," said study author Dr. Andreas Loepke, a professor of clinical anesthesia and pediatrics at the University of Cincinnati College of Medicine.
But, he added, "these concerns make it obvious that a lot more research is needed to better understand the effects of anesthetics on brain development."
The findings, published online June 8 and in the July print issue of the journal Pediatrics, echo those of earlier studies that have pointed to a similar link.
Loepke and his colleagues compared 53 children who had undergone surgery using general anesthesia before they were 4 years old with 53 children who had never been exposed to general anesthesia. Each child from the first group was matched to a child in the second group according to age, sex, socioeconomic status and being left- or right-handed.
All of the children underwent IQ and language development testing as well as imaging with an MRI. The scores for all the children in both groups were within the normal range.
But the children with a history of surgery had listening comprehension and performance IQ scores that averaged 3 to 6 points lower than the kids without surgery. Performance IQ refers to several combined components from an overall IQ test. A score of 100 is considered average.
In addition, those with a lower performance IQ and listening comprehension had slightly less gray matter in two areas at the back of their brains, the researchers found.
"The very receptors that anesthetics act on to produce unconsciousness during surgery are also important for stimulating neurons to form proper connections and to survive," Loepke said. "Anesthetic exposure may interfere with normal brain development."
However, one expert cautioned, this small study only shows a link between lower scores and a history of general anesthesia. It cannot show that anesthesia caused brain development problems, said Dr. Raafat Hannallah, a pediatric anesthesiologist at Children's National Health System in Washington, D.C.
"Studies in children have limitations that prevent experts from understanding whether the harmful effects, if any, were due to the anesthetic drugs or to other factors, such as the surgery or related illness," Hannallah said.
Loepke also mentioned other factors that can occur during surgery that might have unknown effects, such as inflammation, pain or the underlying medical problem being treated.
"Hence, our study cannot conclusively identify any of these factors to be the cause for the reported findings," he said.
In addition, skipping surgery may lead to similar or worse concerns about brain development, Loepke pointed out.
"Surgery is only performed to save lives or to prevent serious health complications," Loepke said. "So not performing these crucial surgeries may put the child at greater risk for developmental complications than the theoretical risk linked to the anesthetic exposure."
The majority of children in this study underwent surgery for ear, nose or throat conditions, especially hearing conditions. General surgery and urology comprised the other two common surgery types.
"Concerns regarding the unknown risk of a surgical procedure and anesthetic exposure to a child's brain development must be weighed against the potential harm associated with canceling or delaying a needed surgical or diagnostic procedure," Hannallah said. "The child's doctors, including the physician anesthesiologist, are best able to provide this advice."
For those children who need surgical procedures, anesthesia and surgery today are "safer than ever," Loepke added. "Survival is much improved even for critically ill babies and procedures that were unthinkable just two or three decades ago," he said.
At least two previous studies, one from Australia and the other from the Mayo Clinic, also published in Pediatrics in 2011 and 2012, also found a potential link between anesthesia in young children undergoing surgery and language deficits.
Researchers are continuing to study both animals and children to learn more about whether anesthetics have any effect on brain development, Loepke said, but these findings should not be used to delay a necessary procedure.
"Bottom line, kids do not undergo anesthesia for the fun of it," Hannallah said. "They do because they need a surgical or diagnostic procedure to keep them healthy or cure an existing condition. This should not change based on current knowledge."
For more on preparing children for anesthesia, visit the American Society of Anesthesiologists.