Dialysis is a medical treatment that performs the functions of failing kidneys, filtering waste products and excess fluid from the blood. For individuals requiring this life-sustaining therapy, access to the bloodstream is a primary consideration. A tunneled dialysis catheter provides a pathway for blood to be exchanged with a dialysis machine, serving as a direct connection for this process. This catheter offers either temporary or long-term access, depending on patient needs.
Understanding Tunneled Dialysis Catheters
A tunneled dialysis catheter is a soft, flexible tube, typically made from silicone or polyurethane, inserted into a large vein. These catheters are characterized by having two distinct internal pathways, known as lumens, which are usually color-coded: one red for drawing blood from the body to the dialysis machine, and one blue for returning cleaned blood to the body. The term “tunneled” refers to how the catheter is placed; a portion of the tube is passed under the skin before it enters the vein. This tunneling creates a barrier that helps minimize the risk of infection.
Many tunneled catheters also feature a “cuff,” often made of Dacron, located within the tunneled portion beneath the skin. Tissue grows around this cuff, helping to secure the catheter in place and further reducing the chance of bacteria entering the bloodstream.
When Tunneled Catheters Are Necessary
Tunneled dialysis catheters are chosen for several reasons, often when immediate access to the bloodstream for dialysis is required. They are frequently used as a temporary measure when a patient needs urgent dialysis, such as in cases of acute kidney injury. Another common scenario involves patients awaiting the maturation of a more permanent access, like an arteriovenous (AV) fistula or graft, which can take weeks to months to become ready for use.
For some individuals, tunneled catheters may become a long-term solution when other permanent access options, such as fistulas or grafts, are not feasible due to factors like unsuitable blood vessels or previous access failures. Fistulas and grafts are preferred due to lower complication rates, but tunneled catheters provide a reliable alternative for patients with limited vascular access.
How a Tunneled Catheter Facilitates Dialysis
The tunneled catheter functions as a direct bridge between the patient’s bloodstream and the hemodialysis machine. During a dialysis session, blood is drawn from the patient through one lumen, filtered by the machine to remove waste and excess fluid, and then returned to the body through the other lumen. This continuous circulation allows for efficient removal of toxins and maintains the balance of fluids and electrolytes in the body. The design of these catheters aims to achieve high blood flow rates, typically ranging from 200 to 500 milliliters per minute, which is important for effective dialysis treatment.
Insertion Procedure and Placement Sites
The insertion of a tunneled dialysis catheter is a surgical procedure, usually performed by a specialist in interventional radiology or surgery. It is typically done under local anesthesia, which numbs the insertion area, along with conscious sedation to help the patient relax. The most common placement site is the internal jugular vein in the neck, which offers a straightforward path to a large vein near the heart. Other possible sites include the subclavian vein in the chest or, less commonly, the femoral vein in the groin.
During the procedure, two small incisions are typically made: one at the site where the catheter enters the vein and another a few inches away where the catheter exits the skin. The catheter is then passed under the skin between these two points before its tip is advanced into the large central vein, often guided by imaging. The catheter is then secured in place with sutures at the exit site.
Daily Life and Care with a Tunneled Catheter
Living with a tunneled dialysis catheter requires careful daily attention to prevent complications, with infection being a primary concern. Patients must keep the catheter exit site clean and dry, often involving regular dressing changes by healthcare professionals or trained caregivers. It is important to avoid immersing the catheter site in water, meaning activities like swimming and taking baths are generally not advised. Showering may be possible with a waterproof dressing to protect the site.
Despite diligent care, complications can arise. Infection at the exit site or within the bloodstream is the most common issue, often signaled by fever, chills, redness, or drainage around the catheter. Another potential problem is clotting within the catheter, which can reduce blood flow and make dialysis less effective. Patients are educated on recognizing these signs and reporting them promptly to their healthcare team to ensure timely intervention and maintain the catheter’s function.