Spontaneous plasma exchange by gravity

Lysagth et al have reported a semplified model of spontaneous plasmapheresis by placing between an A-V shunt a conventional plasmafilter. On the basis of this experience we tried to make a further semplification of this apparatus using a single venous puncture, obtaining by gravity sufficient transmembrane pressure for plasma separation. By alternatively lowering and elevating the system, plasma is separated from the blood and packed red cells are reinfused after a new pass through the filter with FFP or plasma substitutes.