Membrane plasmapheresis apparatus and process which utilize a flexible wall to variably restrict the flow of plasma filtrate and thereby stabilize transmembrane pressure

摘要

A membrane plasmapheresis system introduces a flow of whole blood subject to a predetermined inlet pressure into a fluid path across a membrane which is suited for filtering the plasma from the whole blood and across which a predetermined pressure drop occurs. The plasma-poor blood is conducted from the membrane subject to a determinable plasma-poor blood pressure. Likewise, plasma filtrate is conducted from the membrane subject to a determinable plasma-filtrate pressure. The conduction of plasma filtrate is metered in response to the existent plasma-poor blood pressure to achieve and thereafter maintain substantial equilibrium between the plasma-poor blood pressure and the plasma filtrate pressure. A substantially constant transmembrane pressure can thereby be maintained at a level below which hemolysis occurs.