dialyzer and their types

1. DIALYZER
Yousaf khan
Renal dialysis lecturer
IPMS-KMU

2. DIALYZER
 Dialyzer shell
(polyurethane) is a box or
tube with four port (2
blood and 2 dialysis)
 Dialyzer – blood and
dialysis solution
 Movement of molecule
across semipermeable
membrane

3. DIALYZER
An ideal dialyzer should have
 High clearance of small and medium MW toxins
 Adequate UF
 Negligible losses of protiens and amino acids
 Non toxic composition
 Minimal activation of cell or thrombotic pathways
 Minimal blood volume
 Reliability
 Reusability
 Low cost

4. DIALYZER TECHNICAL SPECIFICATION
 Priming volume very from 40-150 ml.
 Surface area vary from 0.5-2.2m2
 KUF from 2.5 to 85ml/h/mmHg
 KoA urea varies from 200 to 1200 (<300 represents a low
efficiency dialyzer and >600 a high efficiency dialyzer)
 Specification sheets also provide clearance for urea and
vitamin B12.
 Dialyzer are sterilzed by gamma irradiation, ethylene oxide or
by steam
 Must be pre rinsed with >2L rinsing solution prior to
connecting to patient to prevent release of fragments from the
dialysis circuit

5. DIALYZER MEMBRANE
Cellulose:
 Obtained form processed cotton (regenerated cellulose,
cuprammonium cellulose, cuprammonium rayon and
saponified cellulose)
Substituted cellulose:
 Cellulose polymer has a large number of free hydroxyl group
at its surface
 Free hydroxyl group are responsible for blood cell activation
causing bio-incompatibiltiy of the dialyzer (cellulose acetate,
cellulose diacetate, triacetate)

6. DIALYZER MEMBRANE
Cellulosynthetic:
 A synthetic material ( a tertiary amino compound) is added to
liquefied cellulose during formation of the membrane as result
the surface of the membrane is altered and biocompatibility is
increased (cellosyn or hemphan)
Synthetics:
 Not cellulose based but are synthetic plastics and materials
used include polyacrylonitrile (PAN) polysulfone,
polycarbonate, polyamide and polymethyl-methacrylate
(PMMA)

7. DIALYZER TYPES
Coil dialyzer:
 Flattened cellulose tubing wrapped as a coil and through
which patients blood flow during dialysis.
 The blood channels was long to obtain the needed surface
area, and resistance was high
 UF was unpredictable and blood leak were frequent.

8. PARALLEL PLATE DIALYZER
 Sheets of membrane are placed between supporting plates.
 The plates have ridges and grooves to support the membrane and
allow flow of dialysate along it
 Resistance to blood flow is low. The surface area vary from 0.25 to
1.5 msq.
Advantage:
 Blood volume is about 50-100 ml at 100 mmHg increase with high
TMP
 Heparin requirement usually low, minimal clotting in the blood
compartment
 Ultrafiltration is reasonably predictable and controllable
Disadvantage:
 Formation of local thrombi around inlet and outlet ports and corners
 May lead to bacterial growth and endotoxin formation therefore
plates are not often reused

9. HOLLOW FIBER DIALYZER
 Numerous hollow fiber
 Hollow fiber are tiny its diameter 150-250um
 Number of fiber20000 or more, depending upon length, kind of
membrane and surface area of dialyzer
Advantage :
 Low blood volume 60-90ml
 Resistance to blood flow is low
 Ultrafiltration can be precisely controlled
 Well adapted to reuse
Disadvantage:
 Deaeration of fiber predialysis is necessary to prevent air lock of the
fibers
 More heparin is required for most of the patients
 Adverse patient reaction

10. DIALYZER TYPE

11. REACTION TO MEMBRANES
Type A reaction
 Within minutes of starting
dialysis with
 Dyspnoea, wheeze
 A feeling of warmth,
urticaria
 Cough, hypotension
 Collapse or cardiac arrest
Type B reaction
 More common but much
milder often occur 20-40
min after starting dialysis
 Usually cause back and
chest pain

12. Thank you