Dialysis catheter



A dialysis catheter is a catheter used for exchanging blood to and from the hemodialysis machine from the patient.

The dialysis catheter contains two lumens: This is a confusing terminology for layperson, because both lumens are in the vein. The arterial lumen (typically red) withdraws blood from the patient and carries it to dialysis machine, while the venous lumen (typically blue) returns blood to the patient (from the dialysis machine). Flow rates of dialysis catheters range between 200 to 500 ml/min.
 * Venous
 * Arterial

If a patient requires long-term dialysis therapy, a chronic dialysis catheter will be inserted. Chronic catheters contain a dacron cuff that is tunneled beneath the skin approximately 3-8 cm. The tunnel is thought to add a barrier to infection. The most popular dialysis catheter sold on the market today is the split-tip dialysis catheter. This catheter comprises two free floating tips.

Catheter placement
The catheter is placed in one of the large veins. A common site is superior vena cava or SVC. An SVC catheter is placed by puncturing the internal jugular vein in the neck (often on the left side), and the catheter is then advanced downwards toward the chest. Alternatively an SVC catheter can be inserted via subclavian veins right behind the clavicle (the collar bone), often on the right. If the access of SVC is difficult, the femoral veins can be used. This is an inferior option, however, because the groin site is more prone to infection and also because patient cannot sit upright.

Complications
Some common malfunctions of dialysis catheters include: clotting, infection, and kinking.

Fistulas versus catheters
Surgically created arteriovenous fistulas are preferred over catheters for patients with chronic renal failure, as the risk of infections (e.g. endocarditis, bacteremia), hospitalization and death are lower.