Cystatine C biochemical marker for renal dysfunction in coronary artery bypass randomized double blinded comparison between the effects of sevoflurane and isoflurane

ABSTRACT

Volatile anesthetics exert significant protection against myocardial ischemia and excitotoxic cardiomyocyte death. One of the mechanisms by which volatile anesthetics induce protection in myocytes is pharmacological preconditioning, the activation of a potent endogenous protective mechanism in cardiac tissue against a variety of important stressors. Laboratory investigations further stress the concept that volatile anesthetics may protect endothelial and smooth muscle cells, implying that anesthetic protection might beneficially affect a much wider variety of tissues including the brain, spinal cord, liver, and kidneys. After written informed consents were obtained from all patients, 40 patients scheduled for elective CABG, they were divided into 2 groups, 20 patients each group, group I [isoflurane group], group II [sevoflurane group]. All patients received midazolam for premedication. Anesthesia was induced in all patients with propofol, fentanyl and the muscle relaxant vecuronium. Blood samples were obtained preoperatively, at arrival in the intensive care unit, and 24, 48, and 72h after surgery; they were stored at -20°C until analysis. Creatinine level and Cystatine C [CysC] assays were used as markers for renal dysfunction. Sevoflurane-treated patients required significantly more phenylephrine than did isoflurane-treated patients to maintain blood pressure above 50mmHg. However, there was no difference in mean arterial blood pressure between both groups. CysC concentrations significantly increased immediately postoperatively and peaked at 48 h after surgery for both groups [time effect, p<0.001]. Cystatine C concentrations were markedly higher for isoflurane-treated patients than for sevoflurane-treated patients. Plasma creatinine concentrations were slightly, but not significantly, increased in isoflurane-treated patients. The study concluded that, sevoflurane could be administered safely during CABG without affecting renal function. Because this study only evaluated immediate perioperativc effects of sevoflurane, we can only speculate on potential beneficial long-term effects of this treatment. Future studies should address this important issue