[Influence of cardiopulmonary bypass on plasma lipid peroxides]

In 22 patients who underwent cardiac surgery with cardiopulmonary bypass (CPB), we studied the influence of CPB on the level of lipid peroxides (LPO) in plasma by means of measuring the time course of plasma LPO level during and after CPB. We expressed LPO level, which was measured by thiobarbituric acid reaction, as the level of malondialdehyde. In our preliminary study, it was found necessary to correct the plasma LPO level diluted by priming fluids of CPB machine and the concentration of plasma protein was fitted for its correction. In the following study, we used the plasma LPO level corrected by the concentration of plasma protein. LPO were significantly decreased since the initiation of CPB (1.669 +/- 0.208 versus pre-CPB 1.785 +/- 0.158 log nmol MDA/gm protein, p less than 0.05) to the post CPB 30 minutes, except around 60 minutes after initiation of CPB (1.735 +/- 0.242 log nmol MDA/gm protein, p greater than 0.05). As the initial change (the values at 30 minutes after CPB initiation) may express the effect of CPB directly in this time course of LPO, we analyzed the initial change on different background factors. By ordinary analysis of the initial change, as to the effect of type of disease (congenital and acquired), LPO were decreased in the acquired group (1.617 +/- 0.197 versus pre-CPB 1.779 +/- 0.163 log nmol MDA/gm protein, p less than 0.05). At that time the acquired group was significantly different from the congenital group (1.799 +/- 0.191 versus pre-CPB 1.800 +/- 0.157 log nmol MDA/gm protein, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)