To The Question of Safety of Neonatal Anesthesia

Copyright: © 2012 Martynyuk AE, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. A rapidly increasing number of prematurely born and sick babies with different pathophysiological conditions survive due to the progress of modern medicine. Clinical procedures for most of these patients require general anesthesia; frequently repeated exposures are needed. Although, the advances in pediatric anesthesiology play a crucial role in this success, numerous laboratory studies provide evidence that exposure to general anesthesia of even healthy animals during the early postnatal period may result in immediate and long-term brain related abnormalities, such as neurodegeneration and impaired cognition [1-5]. Even though these adverse effects of neonatal anesthesia were demonstrated across various species, from rodents to non-human primates, the results of human studies are not conclusive at this time. Thus, on the one hand, signs of learning disabilities, developmental and behavioral complications have been detected in children who were exposed to general anesthetics before 4 years of age [6-8]. On the other hand, other human studies were not able to find significant differences in cognitive performance in children that were exposed to general anesthesia early after birth and when compared to age-matched counterparts that did not have such exposure [9-12]. All these human studies were retrospective epidemiological assessments, and for this reason suffer from lack of detailed planning and other weaknesses discussed in detail in recent excellent reviews [13-15]. Specifically designed human studies are definitely needed to better assess the risk of long-term consequences that the youngest patients may face after exposure to general anesthesia. It is plausible that neonates with (or predisposed to) certain diseases that share mechanisms with the side effects of general anesthetics are more vulnerable to the harmful effects of general anesthetics than patients with other conditions. The problem is that the mechanisms that mediate the adverse actions of general anesthetics in the early stages after birth and the pathophysiological conditions, which, in combination with the anesthetic actions, may produce synergistic or additive adverse effects, are essentially unknown even in animal models. A better understanding of such additive and synergistic effects may allow the identification of groups of neonatal patients to whom general anesthesia, especially with certain types of anesthetics, may not be safe, and, on the other hand, may give a green light to other patients who are tolerant of the long-term effects of the anesthetics. Therefore, new laboratory investigations that identify the whole spectrum of the side effects of neonatal anesthesia and their underlying mechanisms can be an important component in the combined efforts to answer the question whether neonatal anesthesia is safe to human patients. One of the weaknesses of the published animal studies investigating the side effects of general anesthetics is that they all, almost exclusively, focus on neurodegeneration, neurogenesis, synaptogenesis and a limited number of behavioral paradigms. Given that pharmacologic targets for general anesthetics are present not only in the central nervous system, it is plausible that the side effects that the general anesthetics may cause in neonates and pathophysiological conditions that specifically interact with those side effects are not necessarily restricted to the brain.