Dialyzer

1. DIALYZER

2. INTRODUCTION
 A dialyzer is an artificial kidney designed to
provide controllable transfer of solutes and water
across a semi -permeable membrane separating
flowing blood and dialysate streams.
 The transfer processes are diffusion (dialysis)
and convection (ultrafiltration).

3. COMPONENTS OF DIALYZER
 BLOOD COMPARTMENT
 DIALYSATE
COMPARTMENT
 the fluid pumped into the canister
to surround the hollow fibers
 dialysate helps remove uremic
wastes, it also helps maintain a
proper balance of electrolytes –
sodium, chloride, and magnesium
– in the blood.
 SEMI PERMEABLE
MEMBRANE
 MEMBRANE SUPPORT
STRUCTURE

4. TYPES OF DIALYZERS
 Kiil dialyzer
 Coil dialyzer
 Parallel Plate Dialyzer
 Hollow Fiber Dialyzer

5. KIIL DIALYZER
Used by HKL 1964
Assemble by dialysis staff
before HD session
Treatment time
 8 hrs to 10 hrs
Problem - massive blood
leak
High mortality rate

6. COIL DIALYZER
An early design in which the
blood compartment consisted
of one or two long membrane
tubes placed between support
screens and then tightly wound
around a plastic core. This
design had serious performance
limitations, which gradually
restricted its use as better
designs evolved.
The coil design did not
produce uniform dialysate flow
distribution across the
membrane. More efficient
devices have replaced the coil
design.

7. PARALLEL PLATE DIALYZER
Sheets of membrane are mounted on plastic support screens, and then
stacked in multiple layers ranging from 2 to 20 or more.
This design allows multiple parallel blood and dialysate flow channels
with a lower resistance to flow.
The physical size of the parallel plate dialyzers has been greatly
reduced since their introduction.
There have been major improvements which provide (1) thinner blood
and dialysate channels with uniform dimensions, (2) minimal masking
or blocking of membranes on the support, and (3) minimal stretching or
deformation of membranes across the supports.

8. HOLLOW FIBER DIALYZER
 This is the most effective
design for providing low-
volume high efficiency
devices with low resistance
to flow.
The fibers in the device are
termed the fiber bundle.
The fibers are potted in
polyurethane at each end of
the fiber bundle in the tube
sheet, which serves as the
membrane support.

9. HOLLOW FIBER DIALYZER
 The hollow fiber dialyzer is the most popular of
the above four types and is composed of group
of between 8000 to 12,000 fibre like structures
(capillaries) with an internal diameter of 200
microns.

10. Anatomy of a Hollow Fiber
Dialyzer
Hollow Fibre membrane
Blood in
Blood out
Dialysate in
Dialysate Out
Cross Section
Outside the Fibre (effluent)
Inside the Fibre (blood)

11. ADVANTAGES OF HOLLOW
FIBER DIALYZER
 LOW OR SMALL PRIMING VOLUME
 HANDY, SMALL AND COMPACT
 INCREASE CLEARANCE OF MIDDLE MOLECULES
 GOOD ULTRAFILTRATION RATE (UFR)
 NO REBUILDING
 REDUCED RISK OF LEAKAGE

12. CONCLUSION
 Depending upon the manufacturer, the fibers are
made from such biocompatible materials as
cellulose acetate or polysulfone.
 The fibers have a microporous structure that permit
the diffusion of small molecular weight species from
the blood to the dialysate.
 The diffusion rate can be expressed in terms of the
dialyzer clearance of the molecule.

13. ….. IS JUST A NEW BEGINNING
THE END