[Organ protective effects of volatile anesthetics and perioperative outcomes]

Anesthetic agents, especially, volatile anesthetics are considered to exert organ toxicity such as nephrotoxicity and hepatotoxicity; however, recent aggressive researches explored the beneficial effects of volatile anesthetics as an organ protectant. Ischemic preconditioning is a phenomenon in which single or multiple brief periods of ischemia have been shown to protect the myocardium and brain against prolonged ischemic insult. General anesthesia showed the protection against both ischemic myocardial and brain reperfusion injuries. This phenomenon is called anesthetic preconditioning. Regarding the organ protection, anesthetic preconditioning is one of the useful ways to diverse the organ protective effects not only to heart but also brain. Nowadays, ischemic postconditioning, consisting of repeated brief cycles of ischemia-reperfusion performed immediately after reperfusion following a prolonged ischemic insult, dramatically reduces infarct size in experimental models and such clinical studies are reported. Both preconditioning and postconditioning share the same signal transduction pathway and inhibit the mitochondrial permeability transition (MPT) that leads to either apoptosis or necrosis of myocardium and neuronal cell. Both phenomena look very promising, but we still lack the real evidence for human reserach in terms of the clinical outcome and further analysis is necessary. Neurotoxicities of anesthetic agents are very crucial problems for the patient and they are considered to be due to the activation of IP3 receptor in ER after exposure to volatile anesthetics. Massive release of Ca2+ from ER induces Ca2+ overload leading to mitochondria permeability transition (MPT) and induces apoptosis in the brain or aggravates the neurodegenerative disease. Susceptible mechanisms and beneficial treatment for the toxicity of general anesthesia is considered as a critical subject to discuss and challenge to solve for our future.