A NEW HEPARIN-BONDED DENSE MEMBRANE LUNG COMBINED WITH MINIMAL SYSTEMIC HEPARINIZATION PROLONGED EXTRACORPOREAL LUNG ASSIST IN GOATS

Heparin was covalently bonded to a new hollow-fiber dense membrane art ificial lung and extracorporeal circuit using a silane coupling agent and polyethyleneimine. This study investigated whether prolonged, veno arterial bypass extracorporeal lung assist (V-A bypass ECLA) could be sustained in a goat by the combination of the new membrane lung and mi nimal systemic heparinization. We maintained ECLA with the hallow-fibe r lungs (surface area, 0.8 m(2)) and circuits by titrating the activat ed clotting time (ACT) to below 150 s with minimal systemic hepariniza tion in 5 goats. The outcome was assessed from the function of the art ificial lung via macro and microscopic examinations after the experime nts and the incidence of systemic complications. The 5 goals were main tained on ECLA for 6 to 27 days. The bypass flow rate, blood gases at the return and drainage sites, platelet counts, and platelet aggregati on activity were well maintained, Although the hemoglobin concentratio n, hematocrit, and plasma protein at the start of the ECLA were signif icantly lower than the pre-ECLA values due to hemodilution, the values remained stable during ECLA, A cerebral infarction occurred in 1 goat . However, in the other 4 goats, no complications such as bleeding, th rombosis, or plasma leakage from the artificial lung were observed. Al though several thrombi were observed in the stagnant area of the artif icial lung, these local thrombi did not cause the function of the arti ficial lung to deteriorate. We found that this new type of highly bioc ompatible, dense membrane artificial lung, when combined with minimal systemic heparinization, prolonged ECLA without the deterioration of t he artificial lung unction and was suitable for prolonged ECLA.