CHANGES IN PLASMA-LEVELS OF OXYGEN RADICAL SCAVENGING ENZYMES DURING EXTRACORPOREAL MEMBRANE-OXYGENATION IN A LAMB MODEL

We studied levels of superoxide dismutase, glutathione, reductase, glu tathione peroxidase and lipoperoxides in 12 healthy lambs below 1 year of age (8-19 kg) under therapy with extracorporeal membrane oxygenati on (ECMO). Plasma levels of these,free oxygen radical scavenging enzym es and lipoperoxides were taken 1 day before the ECMO experiment, at t he beginning of ECMO after the first rotations of the roler pump, duri ng, and after ECMO. The pre-ECMO results of days 1 and 2 were compared with the during-ECMO results and those with the post-ECMO results usi ng the t test for paired samples. We found a significant decrease of b oth superoxide dismutase and glutathione reductase on ECMO, a trend to increased lipoperoxide levels, and unchanged levels of glutathione pe roxidase. After discontinuing bypass the levels began to normalize aga in. We conclude that ECMO reduces some oxygen radical scavenging enzym e levels and exhibits a trend to increased lipoperoxide levels. Near t otal lung collapse with consecutive reperfusion injury might be harmfu l considering these results. However, the nonsignificant increase in l ipoperoxide levels excludes considerable oxygen toxicity during this s hort ECMO trial.