Experimental evaluation of the V-point heparin-bonding system applied to a dense-membrane artificial lung during 24-hour extracorporeal circulation in beagles.

Heparin was covalently bonded to a hollow-fiber dense-membrane artificial lung and circuit using a silane coupling agent and polyethyleneimine as a spacer. This study investigated whether the novel artificial lung could sustain prolonged extracorporeal lung assist (ECLA) by venoarterial bypass in beagles using minimal anticoagulants. We maintained ECLA for 24 h in 3 groups of minimal systemic heparinization, heparinization with the new anticoagulant nafamostat mesilate, and without any systemic anticoagulant. The results were assessed from the functional performance of the artificial lung and by macroscopic and microscopic examination after the experiments. Artificial lung function, hemodynamics, hemogram, and platelet aggregation activity were well maintained in all groups. There was no plasma leakage from the artificial lung. Although several clots were observed in stagnant areas of the artificial lungs and circuits, there was no clot formation inside the artificial lung in any group. This highly biocompatible, heparin-bonded dense-membrane artificial lung performed well and safely during prolonged ECLA with blood clotting times less than 120 s.