[Changes in platelets and blood coagulation during prolonged ECLA with a heparin bonded hollow fiber membrane lung]

Effects of the heparin bonded artificial membrane lung and circuit on blood coagulation were investigated during prolonged extracorporeal lung assist on goats. A veno-venous bypass ECLA was performed on 18 goats up to 10 days. Twelve of them (Group I) were with a heparin bonded device and the other six (Group II) were with the usual device. In Group I, heparin was continuously infused at a rate of 15.2 units.kg-1.hr-1 to maintain the activated coagulation time, ACT, at around 130 sec., while in Group II, 25.5 units.kg-1.hr-1 of heparin was necessary to maintain ACT at about 200 sec. to prevent blood coagulation in the bypass circuit. Platelets decreased significantly in Group I (by 50% of pre ECLA value) as well as in Group II, but aggregation activity in Group I was higher than in Group II. Fibrinopeptide A and antithrombin III showed no significant difference between the two groups. Autopsy showed no significant pathological findings. ECLA, with a heparin bonded surface, showed excellent blood compatibility and required only a little systemic administration of heparin. The heparin bonded bypass circuit will enable safer ECLA even in patients with some bleeding sites.