[Changes in serum lipid peroxide concentration in open heart surgery].

During open heart surgery, the release of oxygen free radicals as a result of ischemia and reperfusion often induces post-operative low cardiac output, arrhythmias or cardiac re-performance failure. Changes in serum lipid peroxide (LPO) concentrations were studied in 72 patients undergoing open heart surgery, to quantitate the rhythm of changes, and to seek for proper measures in myocardial protection. Blood samples were drawn before induction of anesthesia, just before aortic cross-clamping, 5 min after the release of aortic cross-clamping, immediately after rewarming to 35 degrees C, 30 min after cardiac performance, and at the end of the procedure. Fluorescent spectrophotometric method was used to detect the variation of LPO concentrations. The results showed that intraoperative serum LPO concentrations were significantly lower than pre-induction serum LPO concentrations (P < 0.01). It seems probable that methods of myocardial protection, hypothermia and hemodilution may induce lower concentrations of LPO. Serum LPO concentrations at the end of the procedure were smaller than those of the pre-induction concentrations (P > 0.05). This phenomena was caused by numerous factors that reduce serum LPO concentration.