[Plasma proteins and other substances in membrane plasmapheresis. Relation to possibilities and limitations of this therapeutic method].

The authors investigated the effectiveness of therapeutic membrane plasmapheresis and its influence on plasma concentrations of 17 proteins, cholesterol, triacylglycerols, urea, creatinine and uric acid. To this end they made 30 operations on monitors A 2008 PF with filters Plasmaflux P 2, where they exchanged one volume of plasma and replaced it with isooncotic albumin. They assessed the plasma concentrations of the investigated substances before, in the course of and after the operation, estimated sieving coefficients during the 15th and 90th minute and the clearance. Under conditions in vivo they confirmed that the sieving coefficients of the investigated substances approach the value of "1" and the clearance of the filtration rate, i.e. that the investigated substances pass easily through the plasmafilter and that plasmapheresis removes the substances non-selectively. They demonstrated that the assessment of plasma concentrations alone can lead to underestimation of the effectiveness of the operation. Assessment of sieving coefficients and clearance makes more adequate evaluation of the effectiveness of the procedure possible. Assessment of sieving coefficients and clearance made it obvious that plasma concentrations do not depend only on the amount of substance removed by plasmapheresis but also on other factors which must be investigated. The authors' findings support efforts to introduce methods for the selective removal of pathogenetic substances.