Single-needle membrane plasmapheresis. In vivo comparison of plasma separator performances.

Plasma filtration characteristics of three hollow fiber plasma separation filters (Plasmaflo Hi-05, Extraplex BL 550 and CPS-10) were studied in a single-needle setting by means of the double headpump. Plasma exchange was carried out in 12 patients during a total number of 59 sessions. For each filter, a mean total ultrafiltration volume of +/- 3,000 ml was obtained over a period from 92 to 121 min. The lowest and highest obtained mean filtration flows were 26.7 +/- 2.5 and 36.6 +/- 1.7 ml/min for Extraplex BL 550 and CPS-10, respectively (p less than 0.01). The pre- and postplasmapheresis pressures, measured in the bubble trap chamber as an indirect estimation of transmembrane pressure, were lower for the Plasmaflo Hi-05 than for the two other filters under study; pressures remained unaltered during the session. Blood pressure showed a minor but significant decline during plasmapheresis with the Plasmaflo filter. A reduction after plasmapheresis by more than 40% of the immunoglobulins IgE, IgG, IgM and IgA, and of complement factors C3 and C4 was seen for each of the filters and no significant differences between the filters were observed. An additional study on 6 filters with constant blood flow and TMP showed minor differences in the transmembrane pressure necessary to obtain a given filtration volume per unit of time and similar sieving coefficients for immunoglobulins. This study demonstrates that with this single-needle technique a satisfying immunoglobulin extraction performance was obtained for each of the filter types studied; however, there existed minor but significant differences in the patient hemodynamic status according to the membrane used.