TOTAL ANTIOXIDANT STATUS EVALUATED BY TROLOX EQUIVALENT ANTIOXIDANT CAPACITY (TEAC) IN CABG PATIENTS

Abstract

S208 INTRODUCTION: TEAC measures antioxidants within physiological fluids [1]. This method is suitable for automation and permits rapid throughput of samples. TEAC has been used previously to measure the total antioxidant activity (TAA) in various clinical situations [2]. Studies are in progress to identify patients whom the measurement of TAA may be an important prognostic or diagnostic guide; patients with atherosclerosis, reperfusion injury, septic shock. In this prospective study, TEAC was used to measure peroperative antioxidant status of CABG patients under a narcotic based anesthesia. METHODS: After IRB approval, informed consent was obtained from 16 adult patients scheduled' for CABG with good ventricular function (EF>50%). Patients with diabetes mellitus and smokers were excluded. Anesthetic protocol: Fentanyl (10 [micro sign]g/kg), midazolam for induction, intubation facilitated by vecuronium and maintained with fentanyl (30-50 [micro sign]g/kg) and midazolam. Standard technique of systemic hypothermia at 28-32[degree sign]C, nonpulsatile cardiopulmonary bypass, membrane oxygenator, crystalloid prime and hypercalemic cardioplegic was used. Blood samples via internal jugular catheter were obtained preinduction (I) (baseline), after sternotomy closure (II), 24 hours postoperatively (III). Serum was obtained from centrifuged samples of blood and kept in deionized test tubes at -20[degree sign]C before analysis. 'Total Antioxidant Status Kit' (Randox Labs. Ltd. UK.) was used. Liver, kidney function tests, CK MB isoenzyme and CPK were measured, whole blood count and blood-gas analyses were performed and hemodynamic parameters were recorded at the same intervals. Results were analyzed by paired samples t-test, Correlation by simple regression analysis. Values are expressed as mean +/- SD. RESULTS: Mean age was: 54 +/- 8 yr., total cardiopulmonary bypass duration was 110 +/- 24 min. Total antioxidant status levels were; (I): 1.09 +/- 0.2, (II): 1.48 +/- 0.3 (p<0.01), (III): 1.78 +/- 0.22 (p<0.05). Uric acid, albumin, total and direct bilirubin levels, neutrophil and lymphocyte counts were increased at intervals II and III (p<0.05). Positive correlation was found between TEAC and each of the following parameters; uric acid (r=0.61, p<0.05), albumin (r=0.58, p<0.05), total bilirubin (r=0.88, p<0.01) and direct bilirubin (r=0.82, p<0.01) DISCUSSION: Assessment of TAA in CABG patients has not been performed before. Parameters that have a positive correlation with TEAC in this study (bilirubin, albumin and uric acid) are components of extracellular fluid antioxidant defense system [1]. Anesthetic protocol used in this study does not have any known antioxidant activity, therefore the significant increase of TEAC detected on the 2nd and 3rd intervals is due to multifactorial origin including increased response of endogenous antioxidant mechanisms. As a result TEAC can be regarded as a promising method to estimate TAA in CABG patients.