[A new plasma exchange technique : coagulation studies (author's transl)].

Coagulation studies were performed during and after 60 continuous plasma exchanges in 15 patients with neurologic disorders. One or several plasmapheresis were performed on each patient using a new filtration material "Plasmaflo" from Asahi Medical, Tokyo. During each exchange involving massive heparin infusion, two total plasma volumes were removed and replaced isovolumetrically by a material devoid of clotting factors (albumin and Plasmion). The variation of the platelet count was moderate (mean reduction of 19%). An important and rapid fall of all coagulation factors was observed, and during a single exchange procedure the extent of the fall was comparable for all coagulation factors. The mean reduction during plasmapheresis was 70%. However, a difference in the rapidity of normalisation was observed between the various proteins (F.V. : 24 h, A.T.III : 72 h). A particular property was noted concerning factor VIII. In all cases, a normal or high level of VIII : C as well as of VIII R : Ag was reached 3 hours after exchange. In some cases an increase could be observed even during plasmapheresis. No hemorrhagic diathesis was noted despite massive heparin administration to the patients and a striking decrease of blood procoagulant factors. On the other hand, one patient developed femoral vein thrombosis following the 8th exchange.