Effect of low-dose methyl prednisolone on serum cytokine levels following extracorporeal circulation

The systemic inflammatory response to cardiopulmonary bypass (CPB) is assoc iated with increased production of cytokines. This systemic inflammatory re sponse characterized by the activation of interleukin-6 (IL-6) and interleu kin-8 (IL-8) during and after CPB is well documented. A prospective, random ized, double-blind study was performed so as to understand the effects of l ow-dose methyl prednisolone sodium succinate (MPSS) on the circulating leve ls of serum cytokines and clinical outcome. Twenty patients were randomly divided into two groups on the basis of the a dministration of low-dose(1 mg/kg) MPSS in = 10) and placebo in = 10) into the pump prime solution. All patients were scheduled to undergo a primary; elective coronary artery bypass grafting operation. Patients receiving conc urrent corticosteroids, salicylates, dipyridamol or anticoagulants were exc luded from the study. Other exclusion criteria were concurrent chronic obst ructive pulmonary disease, chronic renal failure, insulin-dependent diabete s, congestive cardiac failure, peptic ulcer history, prior cardiac operatio ns, recent tin a one-month period) myocardial infarction and steroid depend ency. Mild systemic hypothermia (30-32 degrees C, rectal) was assured durin g the CPB. Four blood samples were drawn from the radial artery catheter im mediately before starting CPB (T1), following protamine administration (T2) and at 24 (T3) and 48 h (T4) after completion of CPB. In each sample, crea tine kinase-myocardial band (CK-MB), white blood cell (WBC), IL-6 and IL-8 levels were measured. IL-6 and IL-8 concentrations were measured by enzyme immunoassay and enzyme-linked immunoabsorbant assay methods.