Upload
debarati-saha
View
163
Download
4
Tags:
Embed Size (px)
Citation preview
HEMODIALYSIS ANDARTIFICIAL KIDNEY
INTRODUCTION
Dialysis is the artificial replacement of lost
kidney functions.
Used in Chronic Kidney Disease(CKD) stage 5
or End Stage Renal Disease(ESRD).
Typically needed when 90% or more kidney
function is lost.
Artificial Kidney 2
DAILY WASTE PRODUCTION IN A NORMAL AND URIMIC PERSON
Component Normal man(g/day)
Uremic patient(g/day)
Water 1500 300
Urea 30 12
Creatinine 0.6 0.2
Uric acid 0.9 0.4
Na+ 5 0.4
Cl- 10 1.2
Ca2+ 0.2 0.1
PO4 3- 3.7 1.8
K+ 2.2 0.5
HSO4+ 8.2 -
Artificial Kidney 3
KIDNEY FAILURE :CAUSES
Diabetes mellitus
Hypertension
Glomerulonephritis(GN)
Polycystic kidney
Overuse of common drugs such as aspirin,
ibuprofen, codeine
Artificial Kidney 4
TREATMENT: ARTIFICIAL WASTE REMOVAL
A body fluid is contacted with a “dialysate” solution
across a semipermiable membrane.
Dialysate contains no waste material.
Body fluid will loose those materials to dialysate via
diffusion through SPM.
Clean body fluid is returned back to the body.
Component g/liter Component Meq/liter
NaCl 5.8 Na+ 132
NaHCO3 4.5 K+ 2.0
KCl 0.15 Cl- 105
CaCl2 0.18 HCO3- 33
MgCl2 0.15 Ca2+ 2.5
Glucose 2.0 Mg2+ 1.5
DIFFERENT METHODS OF WASTE DISPOSAL
A. Internal method
1. Peritoneal dialysis.
2. Gastro dialysis.
3. Intestinal dialysis.
4. Pleural dialysis.
B. External Method
1. Filter Bed absorption column
2. Ultrafiltration method
Artificial Kidney 6
ADVANTAGES AND DISADVANTAGES OF INTERNAL DEVICES
Advantages: Avoidance of handling blood Simplicity of equipment
Disadvantages:Poor efficiency in most casesUncomfortablenessLoss of proteinMembrane infectionThe necessity that the dialysate must be extremely sterile
HEMODIALYSIS
It is the most commonly used process
Purpose - removal of wastes from the body
Water retention / removal
Salt retention / removal
Protein retention
Artificial Kidney 8
HEMODIALYSIS MACHINE
DESIGN CRIETERIONS
1. Efficient to remove nitrogenous & toxic waste and
excess ionic species.
2. Efficient in removing excess water.
3. Small internal blood-side volume(~500ml or less).
4. low blood-side flow resistance.
5. Constructed of blood-compatible material.
6. Reliable, repeatable and easy to operate.
Artificial Kidney 10
DIALYZER
It is called an artificial kidney
It is 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).
Artificial Kidney 11
Types of hemodialyzer:
i. Flat plate
ii. Coil type
iii. Tubular
iv. Hollow fiber
FLAT PATE TYPE OF HEMODIALYSER
The assembled unit consists of parallel epoxy boards having lengthwise channels and grooves.
Two cellophane sheets are inserted between each board-to-board joint.
Headers direct blood to the channels between two cellophane sheets and dialysate to the gap between cellophane and board.
Flow is normal counter-current.
Artificial Kidney 13
COIL TYPE OF HEMODIALYSER Most popular type is called
Kolff Twin Coil.
The membrane consists of two cellophane tubes flattened and placed on a support screen and tightly wound around a plastic core.
Flow is “cross-flow”.
Limitation:Coil design don’t produceuniform dialysate flow.
Artificial Kidney 14
HOLLOW FIBRE DEVICES This is the most effective
type of dialysis unit consisting up to 11000 capillaries made of regenerated cellulose.
No blood pump in needed.
It provides low blood flow resistance and high efficiency.
Artificial Kidney 15
RECIRCULATION OF DIALYSATE SYSTEM (ReDy)
A recirculating dialysate system is used with artificial kidney to eliminate toxic substance from the dialysate solution.
It is used to maintain continuously a normal dialysate solution.
Artificial Kidney 16
Recirculating dialysis system consist of several layers:
1. Urease: it converts urea
into ammonium carbonate
2. Zirconium phosphate:
absorbs ammonium ion.
3. Hydrated zirconium oxide:
absorbs phosphate ion.
4. Activated carbon: absorbs
uric acid, creatinine and
other organic waste
MASS TRANSFER EQUATION OF THE DIALYZER
BBDD
DBo
dCQdCQdW
dACCKdW
and
WALL
MEMBRANE
Mass transfer in a differential length of a dialyzer
D
B
DBB
DBBDBBD
B
DBBBD
B
DBDDD
B
D
B
QQCCd
QdW
CCdQdCdCQQ
QdW
dCQdCQdWQ
QdW
dCQdCQQ
QdW
Q
Q
1
1
&
dA
QQK
CC
CCd
dACCK
QQCCd
Q
DBo
DB
DB
DBo
D
B
DBB
11
1
Artificial Kidney 20
Equating the dW’s,
Integrate assuming constant Ko
meano
DiBo
DoBi
DiBoDoBio
DiDoBoBi
DB
DBo
DiBo
DoiB
CAKW
CC
CC
CCCCAKW
W
CC
W
CC
QQSince
AQQ
KCC
CC
log
ln
11
11ln
REFERENCES
Lysaght MJ. Maintenance dialysis population dynamics: current trends and long-term implications. J Am Soc Nephrol 2002; 13: 37–40
Moeller S, Gioberge S, Brown G. ESRD patients in 2001: global overview of patients, treatment modalities and development trends. Nephrol Dial Transplant 2002; 17: 2071–2976
PRESENTED BY
Debarati Saha4th year,7th semRoll No.071090131013
Artificial Kidney 23