Technical and clinical aspects of cascade filtration plasma exchange (CFPE).

Cascade filtration plasma exchanges (CFPE) were realized using an hemofiltration system (HFS) coupled to 2 filters with different pore sizes. The first one (F1 = plasma-separator; Asahi plasmaflo HI-05) separates plasma from whole blood, the second one (F2 = plasma filter; Asahi XK-60, Kuraray EVAL 2A or 4A) filtrates high molecular weight (MW) components from the separated plasma. F2 filtrate returns to patient mixed with blood cells and 4% Albumin solution or Plasmion R replacing plasma discarded (about 0.5-0.8 I for 1-1.5 plasma mass (PM) treated). The HFS is able i) to modulate the different pressures (venous pressure, F1 and F2 transmembrane pressures (TMp] using pumps speed variators, ii) to recirculate and concentrate extracted plasma and iii) to know F2 treated PM. Blood pressure, pulse rate and electrocardiogram were monitored during each CFPE session. Nineteen CFPE were performed for 8 patients selected among our PE indications, this selection taking into account presence or not of risk factors linked to disease e and/or to patient. Anti-histamine drugs were always infused before CFPE session. On a biological point of view, the problem lies into F2 selectivity which is relatively good for low (as Albumin) and high (as IgM) MW molecules which are returned to patient or discarded, but should be improved for the intermediate ones (as IgG). On a technical point of view, the plasma substitute quantity is reduced about six times. But the control of F2 TMp is not perfectly and the PM to be treated has to be investigated.(ABSTRACT TRUNCATED AT 250 WORDS)