Objective: 

Oxidant stress generated through extracorporeal circulation (EC) applied for cardiopulmonary bypass (CBP) is the main cause of morbidity and mortality encountered after surgery. The mechanisms that occur during these processes are not clear yet. In this study we aimed to investigate the effects of extracorporeal circulation on oxidant, antioxidant parameters and plasma viscosity.

Methods: 

The study was performed on 22 patients. Blood samples were taken from patients at seven different stages of operation. These stages were in the order of (A) preoperative intensive care, (B) anesthesia, (C) entering pump, (D) after aortic cross clamping, (E) after release of aortic cross clamping, (F) after pump out,(G) post operative intensive care. In all stage plasma Malondialdehyde (MDA), NOx (Nitrate and Nitrite), total sulfhydryl group (RSH) levels and plasma viscosity were determined.

Results: 

MDA and NOx levels began to increase and RSH levels began to decrease at the A and B stages together with C stage. The lowest level of RSH and highest levels of MDA and NOx were determined at the F stage. Viscosity values also decreased with starting at the C stage and increased at the F stage.

Conclusions: 

The data obtained from the MDA and RSH levels were compatible with the oxidant stress and with lowered antioxidant capacity caused by surgical trauma and nonphysiologic EC circulation surface. Increased NOx levels may be the results of the mechanical effect of extracorporeal circulation on endothelium because of the surgery and the expression of eNOS by red blood cells exposed to mechanical stress.