Anesthetic preconditioning in cardiac surgery

Abstract

The problem of myocardial protection in cardiac surgery is a challenge due to an increased number of interventions and severity of their complications related to the patient's status, pathophysiology of the artificial circulation and the used techniques for replacement of vital functions. Oxidative stress and formation of active oxygen species, as a consequence of the above mentioned processes, may result in systemic injury, such as acute heart failure, central nervous system dysfunction and acute renal injury. Short ischemic episodes before prolonged hypoxia with subsequent reperfusion can decrease cardiomyocyte injury. This phenomenon has been referred to as ischemic preconditioning. A similar effect is caused by inhalation anesthetics. Experimental and clinical data on anesthetic preconditioning suggest that inhalation anesthesia with halogen-containing agents may be used as a method to protect the myocardium from damage by active oxygen species produced during the periods of oxidative stress in cardiac surgery. Studies analyzed in this review have shown benefits of inhalation anesthetics, compared to total intravenous anesthesia, such as effective cardiac protection and, what is most important, in potential reduction of mortality after coronary bypass grafting. The level of evidence for the effects of anesthetic preconditioning on long-term mortality in these studies was not high enough; therefore, a large multicenter randomized controlled trial is needed to confirm these results.