Anesthesia issues in central nervous system disorders

Every year, millions of people affected by disorders of the central nervous system (CNS) undergo various diagnostic, therapeutic and surgical procedures requiring administration of anesthetic agents. Anesthetics exert their anesthetic, amnesic and analgesic effects by acting on multiple neuronal membrane proteins in the CNS. While some of the causal anesthetic targets have been identified, a large number of anesthetic targets remain unknown. The consequent longterm effect of anesthetic agents on expression of these various molecular targets has been implicated in mediating potentially long-lasting adverse effects. Recent work suggested that the effects of general anesthetics may not be entirely reversible, with animal studies demonstrating persistent changes in CNS protein expression post recovery from anesthesia. Age-associated or disease-induced alterations in the CNS can profoundly alter multiple aspects of brain structure, biochemistry, and function. Such maladaptive changes in the brain can render it increasingly vulnerable to the effects of various anesthetics. The selection of appropriate anesthesia drugs and protocol is mandatory, especially in individuals with pre-existing CNS disorders, so as to maximize anesthesia efficiency, avoid occurrence of adverse events, and ensure patient safety. This review aims to summarize and consider the effects and potential risks of commonly used anesthetic agents in patients with compromised CNS function. We provide a comprehensive review of the established as well as the implicated effects of anesthetic agents on the elderly as well as on the pathology and progression of common neurological conditions.