1. GRAFT OF DIALYSIS
The three most common types of access are:
Internal arterio-venous fistula (AV fistula)
Internal arterio-venous graft (AV graft)
Central venous catheter (also called central venous “line” or hemodialysis catheter)
The AV graft An AV graft is a strong artificial tube inserted by a surgeon underneath the skin of your forearm, upper arm or thigh.
One end of the tube connects to one of your arteries, and the other end connects to one of your veins (in the same limb).
The graft may be straight or in the shape of a horseshoe.

2. Benefits of an AV graft „ A graft is usually the access method of choice if your veins are not suitable for a fistula. „ The graft can usually be used for hemodialysis two to four weeks after surgery.
„ Once the incision is healed, there are no restrictions regarding showering or swimming.
Surgery to create an AV graft
A surgical procedure is needed to create the AV graft. An anesthetist will talk to you about the anesthetic that will be best for you during your surgery.
After the surgery, it usually takes two to four weeks for the graft to be ready for use. Then, each time you have a hemodialysis treatment the dialysis nurse will insert two needles into your graft
Care of your AV graft After the surgery, follow your surgeon’s instructions about your dressing and when the stitches (sutures) will be taken out.
„ Check for a “thrill” which is the sensation like a vibration caused by blood flowing through your graft and can be felt just above your incision line. The “thrill” indicates the AV graft is working.

3. ARTERIOVENOUS (AV) FISTULA FOR HEMODIALYSIS
Fistula—the gold standard access
The National Kidney Foundation (NKF), Centers for Medicare and Medicaid Services (CMS) and Dialysis Patient Citizens (DPC) agree fistulas are the best type of vascular access.
A fistula used for haemodialysis is a direct connection of an artery to a vein.
Once the fistula is created it’s a natural part of the body.
Once the fistula properly matures, it provides an access with good blood flow that can last for decades.
It can take weeks to months before the fistula  is ready to be used for haemodialysis.
A fistula is the “gold standard” because:
It has a lower risk of infection
It has a lower tendency to clot
It allows for greater blood flow and reduces treatment time
It stays functional longer than other access types
It’s usually less expensive to maintain
While the AV fistula is the preferred access, some people are unable to have a fistula. If the vascular system is greatly compromised, a fistula may not be attempted.
Some of the drawbacks of fistulas are:
A bulge at the access site
Lengthy maturation time or never maturing at all

4. Fistula care
Cleanliness
Cleanliness is one way someone on hemodialysis can keep their fistula uninfected.
Keep an eye out for infections, which can often be detected when there is pain, tenderness, swelling or redness around the access area.
If you notice fever, contact your doctor. .
Unrestricted blood flow
Any restriction of blood flow can cause clotting. Here are some tips to help avoid restriction:
Avoid tight clothing or jewelry over your access area.
Don’t carry heavy items over your access area.
Have your blood pressure taken and blood drawn from your non-access arm.
Don’t sleep with your access arm under your head or pillow.
Check the pulse in your access daily.

5. CENTRAL VENOUS CATHETER
To start hemodialysis treatment immediately, central venous catheter insertion is the most common and effective method.
This method of vascular access is ideal for short-term use until a fistula or graft is ready.
For hemodialysis, catheter is inserted into a large vein in either neck, chest, or leg near the groin (internal jugular, subclavian and femoral veins respectively). With this catheter more than 300 ml/min blood can be withdrawn for dialysis.
Catheters are flexible, hollow tubes with two lumens. Blood is withdrawn from one lumen, enters the dialysis circuit, and is returned to the body via the other lumen.
Venous catheters are commonly used for temporary access because of the risk of infection and clotting.
Two types of venous catheters are available, tunnelled (usable for months) and non-tunnelled (usable for weeks).

6. DIALYZER

7. TYPES OF DIALYZERS
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 (ultra-filtration).
There are three basic dialyzer designs:
coil,
parallel plate, and
hollow fiber configurations
Coil dialyzer
 This artificial kidney was the first to be mass produced.
It 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.

8. Hollow Fiber for Dialyzer
Hollow Fiber for Dialyzer, Polysulfone Membrane Images
Internal detail