The new study, in the British journal The Lancet, is a randomized controlled trial involving more than 700 infants who needed hernia repairs. The babies, at 28 hospitals in seven countries, were randomly assigned to receive either general anesthesia or regional (spinal) anesthesia for these short operations — the mean duration of general anesthesia was 54 minutes. The study, called the GAS study — for general anesthesia compared to spinal — compared neurodevelopmental outcomes at 5 years of age, and found no significant difference in the children’s performance in the two groups.

Dr. Andrew Davidson, a professor in the department of anesthesia at the Royal Children’s Hospital of Melbourne and one of the two lead investigators on the trial, said that this prospective, randomized design allows researchers to avoid many confounding factors that have complicated previous studies, and answer a very specific question.

Preliminary data from testing the children at age 2 had shown no significant differences between the groups, and the children were then evaluated at the age of school entry. “If you have an hour of anesthesia as a child, then you are at no greater risk of deficits of cognition at the age of 5,” Dr. Davidson said. “It doesn’t increase the risk of poor neurodevelopmental outcome.”

As a pediatrician, I can tell you that pediatric anesthesiologists tend to have excellent people skills. They’re the ones talking to you and to your child right before surgery, reassuring parents, answering questions, and are highly skilled at explaining scary stuff like surgery, anesthesia and pain. They can talk to children at their different developmental levels, and to parents at their different pitches of anxiety. And they acknowledged and took on this globally scary question of whether a little anesthesia leaves a little patient with a changed brain.

General anesthesia is one of the great blessings of medical science, making surgery possible without the agonies suffered in the past. The drugs that temporarily erase awareness have always seemed both miraculous and frightening, not least because with all the research of modern medicine, we still don’t understand exactly how and why they do what they do to our brains.