Short dialysis with a polyacrylonitrilmembrane (RP 6) without the use of a closed recirculating dialyzate delivery system.

Because of excessive eltrafiltration (UF), the RP 6 dialyzer requires a closed recirculating dialyzate delivery system. The purpose of this study is to present the characteristics of the RP 6 dialyzer on a single needle system which programs the UF rate of this dialyzer. The single needle system consists of one blood pu-mp and two roller pump heads, switched on and off at preselected maximum and minimum out let pressures (OP). It is possible to decrease the UF rate by lowering the OP in the bubble trap chamber. By varying OP from 0 to 100 mm Hg, we obtained an UF rate in vitro of 6.5 ml per minute. The clearance values, in ml/min, obtained at OP 0 to -100 NN Hg, QB 300 and QD 500 are (in ml/min): urea: 160.0, creatinine: 145.0, sucrose-C14: 105.4, sodiumiothalamate-i125: 79.9, cyanocobalamin-co58: 73.7 and inulin-3H: 40.7. The priming volume (corn-oil) at OP 0 to -100 MM Hg, QB 250, QD 500 varies between 140 ml (at the minimum OP) and 150 ml (at the maximum OP). We performed 370 dialyses. The dialysis runs were well tolerated: moderate hypotension occurred in 4% and cramps in 1.6% of the dialyses. In most cases no fluid perfusion was necessary. The residual blood volume (Technetium99m) is estimated at 8.2 ml(n equale 11).