Two membrane oxygenators and a bubbler: a clinical comparison.

We compared the hemocompatibility of the Polystan bubble oxygenator and the Travenol TMO and SciMed spiral-coil membrane oxygenators in 43 patients undergoing aortic valve replacement. In a subgroup of 27 patients, we collected hematological data and correlated platelet behavior with hemostasis. We found no differences in blood loss or blood (product) requirements among the groups. Platelet and erythrocyte damage was less in the membrane oxygenator groups than in the bubble oxygenator group. Differences in adenosine diphosphate-induced platelet aggregation were equivalent. Drops in this function concurred with intensified cardiotomy suction and administration of protamine. Leukocytosis after bypass was most marked in the SciMed group. Duration of bypass correlated with blood loss and blood requirements in the operating theater. Platelet counts shortly after bypass correlated negatively with duration of bypass and blood loss in the intensive care unit. Platelet function correlated with none of the factors just mentioned. We conclude that platelets and erythrocytes are preserved better by the membrane oxygenator than by the bubbler. The TMO system causes more erythrocyte damage than the SciMed oxygenator, probably due to TMO's dual-pump system. Clinical evidence for these improvements was not found, and this will be possible only when the other factors responsible for blood damage can be controlled.