ARTIFICAL KIDNEY MACHINES AND DIALYSIS

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					ARTIFICAL KIDNEY MACHINES
           AND
        DIALYSIS
ARTIFICAL KIDNEY MACHINES

 MAIN FUNCTION OF THE KIDNEYS
 Form urine out of blood plasma.
 This consists of two process
 1) Removal of waste products from blood
  plasma.
 2)Regulation of the composition of Blood
  plasma.
 These activities leads to
 A) Excretion of non-volatile metabolic
  waste products
 B) To keep a constancy of volume, osmotic
  pressure, PH and electrolyte composition of
  extra-cellular fluids.
 Human body – 2 Kidneys
   Each kidney- 1 million individual units –
    nephrons
                                 NEPHRONS
                                 1. A cluster of capillary
   Kidneys work on plasma.       loops – Glomerulus
                                 2. A tuble
   Erythrocytes supply O2       Each substance in plasma
                                  is handled in ch: manner
                                  by nephrons, involving
                                  combinations of filtration,
                                  re-absorption aand
                                  secretion.
 Glomerular filtrate consists of blood plasma
  without proteins.
 Total amount of glomerular filtrate is
180 l/day
Amount of urine formed – 1- 1.5 litre.
Large amount of water & other substances are
  reabsorbed by kidney tubules.
Re-absorption of water is controlled by ADH
 Absorption of Na & K is controlled by renal
  gland.
 Concentration of cloride & bicarbonate is
  related to acid base balance.
 Urea, Phosphate and sulphates – waste
  products of metabolism- un wanted.
 Un wanted can’t diffuse back to plasma and
  a large portion is excreted into urine.
 Specific gravity of urine rises from 1.015 to
  1.030.
 Other substances – glucose amino acids
  diffuse through tubules and are retuned to
  plasma – active- re-absorption
 Blood plasma & extra cellular fluids are in
  equilibrium with each other.
   Water and electrolyte content of blood
    plasma are controlled by kidneys.

   Kidneys play important role in maintaining
    the acid base balance.
Kidneys
     The EKG
Physiology in action
Principle of dialysis in the artificial
               kidney
        Coil Hemodializer
 Tubular membrane placed between flexible
  support wrapped around a cylinder.
 Coil is immersed in dialyzing bath.
 Membrane may be Cellophane or
  Cuprophane.
 Cellophane thickness 20- 30 Mico meters
 Cuprahane thickness 18- 75 Micro meters
 The coil membrane supports are woven
  screens or un woven lattice.
 Twin coil is made with three layers of
  woven pvc coated fiber glass. Screen
  separated by three 4 narrow strips of the
  same material.
HOLLOW FIBRE DIALYSER
 HOLLOW FIBRE DIALYSER
 Most commonly used
 10,000 hollow de-acetylated cellulose
  diacetate capillaries.
 Capillaries are jacketed in plastic cylinder
  18 cm in length and 7 cm dia.
 Capillaries are sealed on each end into a
  tube sheet with an elostamer.
 Capillaries internal dia 200- 300mm
 Wall thickness 25- 30 Mico meters.
 dialyzing area 9,000 cm sq/unit
 Primary volume 130 ml
 Blood is introduced &removed from the
  hemodylizer through manifold headers.
 Advantages & Disadvantages
    1. Reduction in Infection risk
    2. Reduced operator set up time.
    Sterilization procedure eliminated.
           Disadvantages
1)   Expensive
2)   Cleaning is necessary for dialysate cartridge.
3)   Dializer cleaning process is time consuming, un
     pleasent,& requires technical skills.
KILL DIALYZER SHOWING
PLATES SEPERATED OUT
HAEMODIALYSIS MACHINE
HAEMODIALYSIS MACHINE
   Used for the production of warm dialysate which
    is then circulated through an external dialyser
    assembly.
   It also controls the cycling of the blood from the
    patient through the artificial kidney and back to
    the patient.
   It monitors and controls all important pqarameters,
    automatically halting treatment if parameters
    going out of pre-set limits.
    Hemodialysis M/c performs
        5 basic functions
 1) Mixes the dialysate,
 2) Monitors the dialysate
 3) Pumps the blood & control anti-
  coagulants.
 4) Monitors the blood for the presence of air
  and drip chamber pressure.
 5) Monitors the ultra filtration rate.
   The machine pumps and controls the flow
    of blood from the patient through the
    dialyzer at a pre- determined rate and
    pressure to ensure effective clearances and
    fluid removal in a specified time period.
      MEMBRANES USED FOR
        HAEMODIALYSIS
   Cellulose membrane is used for dialysis

   Cupraphan- is commonly used.
    Characteristics of membranes
          used for dialysis
   Efficiency of dialysis – Permeability ch:
   Ideal membrane should posses high permeability
    to water, organic metabolites and ions, and the
    capability of retaining plasma proteins.
   Sufficient wet strength to resist tearing or bursting
    and non- toxic to blood and all body cells.
   Fresh membrane of each dialysis – inexpensive.
Wearable artificial kidney
      machines
        Wearable artificial kidney
              machines
   A single pump – to pump blood and dialysate.
   Using silastic tubing ventricles with unidirectional
    valves giving pulsatile flow.
   Pump operate on 12V, rechargeable Ni- Cd
    battery.
   Dialyser used – Hollow fiber dialyser.
   A bubble catcher at the outside of the dialyser.
 Blood circuit is on left and dialysing fluid
  circuit on right.
 Blood flow through the patient is simple,
  coming from the patient into the blood
  pump ventricle, to the inflow of the
  dialyzer, out of the dialyzer to the bubble
  catcher and returning to the patient.
Portable dialysis machine
Portable Hemodialysis system
 Developed at Hodge Moor Hospital ,
  Sheffield, UK
 Dialysis time – 6 Hrs, Requires change of
  dialyzing fluid and uses Hollow fiber
  dialyzer.
 Weight 16 Kg, Measure: 570 x 412 x 228
  mm.
 Built in suitcase.
                 Principle
 Dialyzing fluid is prepared in a collapsible
  20 L container by connecting fresh water
  supply to the inlet of preparation circuit.
 Water is purified by passing through
  disposable denomination cartridge.
 Water quality is checked before being
  heated in a temp: controlled chamber.
 41 degree centigrade water passes out of
  the preparation circuit and into the mixture
  container via a sachet of dialyzing fluid
  concentrate.
 Machine senses by weight when the
  container has the required quantity of
  mixture and shuts down automatically.

				
DOCUMENT INFO
Description: MAIN FUNCTION OF THE KIDNEYS Form urine out of blood plasma. This consists of two process 1) Removal of waste products from blood plasma. 2)Regulation of the composition of Blood plasma.