MEMBRANE PLASMAPHERESIS APPARATUS AND PROCESS UTILIZING A FLUID FLOW CONTROL DEVICE TO 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 (12) 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 by means of a fluid flow control device (52) 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.