Experiments in developing animals, including primates, have shown that general anesthetic agents can be toxic to the developing brain, with long-lasting neurocognitive or behavioral deficits. For this reason, a recent research project sought to pinpoint conclusively the effect of anesthesia in causing neurodevelopmental impairment or death in low-birth-weight infants who undergo surgery. But conclusive findings on those effects remained elusive.
The study, “Surgery and Neurodevelopmental Outcome of Very Low-Birth-Weight Infants,” published in JAMA Pediatrics, looks at data on more than 12,000 such infants from 1998 through 2009. The data were collected by the National Institute of Child Health and Human Development Neonatal Research Network Generic Database.
The children with neurodevelopmental impairment were evaluated at 18 to 22 months’ corrected age (calculated by subtracting from the chronological age the number of weeks that a baby was born before 40 weeks gestation).
The infants’ birth-weights were 401 to 1,500 grams. They had to survive at least 12 hours.
Surgery was classified as major if performed under general anesthesia, minor if under nongeneral anesthesia — and, in general, the latter didn’t last as long. (Spinal anesthetics have not been associated with neurodevelopmental impairment.)
“The bottom line is that for all surgery patients compared with those who had no surgery, there was a 50% increase in the risk of neurodevelopmental impairment, but not all surgical procedures have the same increased risk,” says Frank H. Morriss Jr., MD, MPH, the study’s corresponding author.
“For patients who had major surgery compared to those who had minor surgery, there was a 45% increase of death or neurodevelopmental impairment. However, there was no increased risk for patients in the minor surgery category.”
The authors conclude, “It is difficult to determine whether an adverse effect associated with surgery results from the anesthetic drug or from noxious effects of other perioperative drugs and/or events unrelated to the anesthetic. The role of general anesthesia is implicated but remains unproven.”