Plasma Exchange

WHAT IS THERAPEUTIC PLASMA EXCHANGE (TPE)?

Therapeutic Plasma Exchange (TPE) also referred to as plasmapheresis or plasma exchange is a procedure that removes plasma from the blood and replaces it with new plasma fluid. Using the Asahi Plasmaflo® Plasma Separator, blood is drawn from the patient, during which time the plasma is separated and discarded. The red and white blood cells and the platelets are returned to the patient, along with a replacement fluid. An anti-coagulant is added to the blood to help avoid clotting.

PRINCIPLE

The Plasmaflo® AP-05H(L) plasma separator from Asahi Kasei Kuraray Medical Co., Ltd. is used for separating plasma from whole blood. As shown in the schematic above, whole blood flows through the hollow fibers while plasma flows through the pores in the fiber walls. The hollow fiber functions as a membrane, with the pore size allowing penetration by plasma while retaining the other blood components.

REASON FOR TPE

There are some diseases which may cause harmful substances to circulate in the blood. Plasma exchange allows these harmful substances to be removed by replacing the plasma which contains them.

METHODS FOR PERFORMING MEMBRANE TPE

Blood is removed via a compatible blood pump capable of monitoring pressures and detecting air and sent through the Plasmaflo filter fibers, which separates whole blood from plasma. The holes in the wall of the filter fibers are too small to allow blood cells to pass through, so the plasma is 'sieved out' and removed by the PlasmaPro® dual track pump for discard. Simultaneously, replacement fluid is infused into the blood circuit by the PlasmaPro® and the whole blood is returned to the patient. A typical set-up for membrane TPE is shown to the right.

ADVANTAGES OF PERFORMING TPE BY MEMBRANE

No loss of cellular components No citrate used Can be performed using available existing blood pumps with the addition of the PlasmaPro® dual track pump; no need to purchase additional bulky expensive machines to perform TPE

Can be performed by hemodialysis staff Training usually consists of one day (4-5 hour in-service) Small Extracorporeal volume (190ml.) Platelet-free plasma

TYPICAL SETTING FOR MEMBRANE TPE

Membrane TPE is mainly performed in hospital settings such as the ICU or an acute dialysis unit.