Summarizing our data we can say, that some hematologic disorders during extracorporeal circulation can be diminished by the use of new oxygenator types like the membrane and the Hollowfiber oxygenator. This correlates to the results of other research teams. In contrast to that the activation of the complement cascade is caused by the three systems in a similar way. Although we know, that the activation of the complement systems is only one of numerous reasons for postoperative pulmonary complications, we still must regard this as an important factor, so that the aim of further investigations should be to reduce complement activation during long term ECC.