Counties Manukau Health Vascular Surgery Service
Renal Access Surgery
Patients who have kidney failure need to dialyse to clear their blood of products that would normally be cleared by functioning kidneys. There are two main ways to do this:
Continuous Ambulatory Peritoneal Dialysis
Continuous Ambulatory Peritoneal Dialysis (CAPD) which involves exchanging fluid through a special catheter (Tenkhoff catheter) that goes into the peritoneal cavity (abdomen). This must be done everyday.
The other major form of dialysis is haemodialysis via a needle in a fistula vein or graft. Blood is sucked out from the body and spun through a dialysis machine and then returned to the body via another needle into the fistula.
The fistula vein or graft is created by taking a vein and joining it to an artery. This means that the strong pulsatile flow of an artery is directed straight into a vein which dilates and can be easily ‘needled’ by the dialysis nurses. The flow in the so called fistula vein is now much greater so that the blood can be drained off to the dialysis machine and returned without clotting (thrombosing). The increased flow in the fistula vein causes vibrations to develop in the blood which can be heard by listening to the vein with a stethoscope (bruit) or palpated by gently placing fingers on the vein (twill).
The increased blood supply and constant needling puts a strain on the veins and fistulas are often maintained by performing angioplasties and corrective surgery.