Indications
When a patient with Chronic Kidney Disease requires hemodialysis, it is usually preferable for them to receive their dialysis through an AV graft or fistula. However, there are many situations in which we turn to catheter placement to enable patients to receive dialysis. A catheter is essentially a tube with two sections (or lumens) which is placed directly into a large vein (usually either the internal jugular, subclavian, or common femoral vein). By convention, one of the lumens is considered the arterial (red) lumen and the other is considered the venous (blue) lumen. During dialysis, blood is removed from the body through the red lumen and returned to the body through the blue lumen.
Catheters are most commonly used when patients first present with renal failure. In that setting, the catheter serves as a bridge between initial presentation and the time that either an AV graft or fistula is placed and is ready to use. Catheters are also used in patients experiencing a failure of an AV graft or fistula.
Procedural Details
Catheters that are used for dialysis are usually classified into one of two categories: tunneled or non-tunneled catheters. A non-tunneled catheter passes from the skin directly into the target vein. A tunneled-catheter is passed through the skin and then runs in the soft tissue under the skin for a variable distance until it enters the target vein. In general, non-tunneled catheters are utilized in the hospital on a short-term basis in patients requiring acute treatment whereas tunneled catheters are utilized in patients requiring dialysis for a longer period of time.
The DuraMax Chronic HemoDialysis Catheter, manufactured by Angiodynamics, is an example of a tunneled dialysis catheter.
The catheter placement procedure is done under sedation and with local anesthesia to ensure that the patients are comfortable throughout the procedure. The procedure begins with gaining access into a suitable vein in the body. The vein that is used is typically a large vein either in the neck (internal jugular vein) or the chest (subclavian vein). At times, we may use a vein in the arm or the leg based on a patient's individual circumstances. Once a small needle is placed into that vein, a guidewire is advanced further into the vein to maintain position within the vein. If we are placing a non-tunneled catheter, we advance the catheter over the guidewire and position its tip right near the heart. We then remove the guidewire and place some stitches to help hold the catheter to the skin.
If we are placing a tunneled catheter, we direct our attention to the site on the chest where the catheter will be exiting. A small incision is made at that site, and the catheter is advanced through that incision to the vein access site. The catheter is then advanced into the vein and positioned with its tip right near the heart. We determine the exact position of the catheter tubing using x-rays. Once the catheter is appropriately positioned, we place some stitches to help hold the catheter to the skin. Over time, there is a cuff on the catheter that is able to attach itself to the tissue under the skin, which helps keep it in place for a longer period of time. Following the procedure, you will spend 1-2 hours in our recovery area.
Post-Procedure Care
It is important to take care of a dialysis catheter after it is placed so that it can continue to work for as long as it is needed. The exit site for the catheter as well as the dressing over the catheter should be kept clean and dry. Patients can take a bath, but the catheter should be kept covered and dry.
It is possible that the blood flow through the catheter can change with time. One reason for this is the development of clot, which can form inside the catheter or immediately outside the catheter. If this occurs, blood flow through the catheter will diminish and dialysis treatments will be less effective. You will know this if the system frequently alarms during dialysis. This is usually treated by putting clot-dissolving medication called tissue plasminogen activator (tPA) directly inside the catheter. Another potential cause for diminished blood through a catheter is something called a fibrin sheath. As the body adapts to the catheter being present, a small film of tissue may form inside the body over the tip of the catheter. This can interfere with blood flow and may also be treated with clot-dissolving medication. At times, the presence of a fibrin sheath may require the catheter to be changed.
If the area around a catheter feels sore or looks red, it is possible that it may represent an infection of the catheter. This may especially be the case if there is fever, chills, or drainage from the catheter exit site. An antibiotic ointment may be used if the infection is limited to the catheter exit site. If there is drainage from the exit site or if the infection has spread throughout the body, antibiotics may be required.