Anesthesia and Neurodevelopment in Children – perhaps the end of the beginning.

Exposure of young animals to most clinically-utilized anesthetics in sufficient doses changes brain structure and affects cognition and behavior in later life. The question of whether these findings can be translated to children has spurred numerous studies, reviews of these studies, and commentaries. In the current issue, two of the leading investigators in this field provide an excellent critical review of the literature about children, including recent studies that have contributed significantly to our understanding. As rightly noted by the review authors, the concerns about whether anesthetics may be “neurotoxic” in children, and indeed the Food and Drug Administration’s warning about the potential neurotoxic effects of most anesthetics, were driven primarily by observations in animals, not by an “obvious clinical problem.” Concerns about adverse neurodevelopmental outcomes after major neonatal and cardiac surgery are longstanding, but any such effects were typically attributed to the underlying conditions necessitating surgery and other perioperative factors, rather than anesthesia, per se. The potential for relatively short-term postoperative changes in behavior is well recognized, but few suspected that anesthesia itself could have long-term neurodevelopmental effects. This lack of suspicion has been used to argue against any significant effects of anesthesia exposure, as surely if this was a real problem, then we would have noticed it by now. Why have we not, other than the possibility that there is no problem?