Background: This study aims to investigate the effects of controlled reoxygenation cardiopulmonary bypass on oxidative stress in children undergoing repair of cyanotic congenital heart defect.

Methods: Thirty cyanotic children (mean age 24.2±17.4 month; range 6 month to 5 years) who underwent surgery using cardiopulmonary bypass for congenital heart defect (Tetralogy of Fallot) were included. The patients were randomly allocated into two groups as normoxic (PaO₂: 80-150 mmHg) and hyperoxic (PaO₂: 150-250 mmHg) cardiopulmonary bypass. Blood samples for serum malondialdehyde levels, glutathione peroxidase and glutathione reductase response to cardiopulmonary bypass were collected after induction of anesthesia, and at 30 minutes after placement of aortic cross clamp, and 10 minutes and 12 hours after removal of the aortic cross clamp.

Results: Hyperoxic cardiopulmonary bypass in the group, serum malondialdehyde and antioxidant enzyme levels were found to be high, at 30 minutes after placement of aortic cross clamp, 10 minutes after removal of the aortic cross clamp, indicating a statistical significance.

Conclusion: High level of partial oxygen pressure which is routinely used in cardiopulmonary bypass leads to increased oxyradical damage in cyanotic children. Controlled reoxygenation strategy should be implemented to prevent or minimize this undesired condition.

Keywords : Cardiopulmonary bypass; cyanotic congenital heart defect; hyperoxic; normoxic