Vascular Access For Hemodialysis
Vascular access for hemodialysis
Blood passes through the dialyzer at a rate of 200 to 400 ml/ minute. To establish such a high blood flow a vascular access needs to be established which can be temporary or permanent.
- Temporary vascular access is a soft catheter which is placed in a large vein, such as the jugular vein in the neck, the subclavian vein just below the collar bone or the femoral vein in the groin. Temporary vascular access should be removed as soon as possible i.e. either at the functioning of the permanent vascular access in case of End Stage Kidney Disease or when there is no need for further dialysis as in Acute Renal Failure on improvement of kidney functions.
- Permanent Vascular Access is meant for End Stage Kidney Disease and should be constructed a month or two before the start of regular hemodialysis.
- Arterio-Venous Fistula (AVF) is the first choice among permanent vascular access options.
IN constructing an AVF a vein is joined with an artery, usually in the forearm or in the arm. The blood flows directly from the artery to the vein and with the passage of time the walls of the vein become thicker & thicker and can be pricked easily with the needle. This is called maturation of a fistula.
- A/V fistula
- Arterio-Venous Graft is the second choice as permanent vascular access and is made when no appropriate artery or vein is available for fistula formation.
Here the artery and vein are bridged by means of a synthetic tube and this tube is pricked with the needle for blood access.