When kidney function declines to the point of requiring external support, hemodialysis becomes necessary to filter waste products and excess fluid from the blood. Patients require a reliable, high-flow connection to their bloodstream, known as vascular access, for this life-sustaining procedure to occur regularly. Creating long-term access can take time or may not be possible for every patient. A tunneled hemodialysis catheter, often called a Permacath, serves as a primary method for quickly establishing this connection, providing a durable and secure pathway for blood flow to and from the dialysis machine.
Defining the Permacath and Its Structure
A Permacath is a central venous catheter designed for intermediate to long-term use, constructed from a soft, flexible material like silicone. The device is placed into a large central vein, most commonly the internal jugular vein in the neck, with its tip positioned near the right atrium of the heart, ensuring high blood flow rates. This catheter has two distinct internal channels, or lumens, which allow for the continuous, simultaneous flow needed during dialysis. The arterial lumen withdraws blood from the body to send it to the dialysis filter, while the venous lumen returns the filtered blood back to the patient’s circulation.
The two lumens are staggered at the tip to prevent recirculation, where returning blood is immediately pulled back into the withdrawal line, which would make the treatment less effective. A defining feature of the Permacath is the polyester cuff located beneath the skin in a subcutaneous tunnel. This cuff promotes tissue ingrowth, which anchors the catheter securely and creates a physical barrier to bacteria migration, thereby helping to reduce the risk of infection.
The Role of the Permacath in Dialysis Access Strategy
While the Permacath offers immediate access, it is generally considered a temporary or bridge solution, as the preferred long-term methods are an arteriovenous fistula (AVF) or an arteriovenous graft (AVG). An AVF is the gold standard because it has the lowest rates of infection and clotting, but it requires months of maturation before it can be used. The Permacath fills the critical gap when a patient with new or sudden kidney failure needs to start hemodialysis immediately, before a newly created AVF is ready for cannulation.
The catheter is also used as a bridge to transplantation, offering stable access while a patient awaits a kidney donor. For a significant number of patients, however, the Permacath becomes the only viable option for long-term dialysis access. This occurs when a patient’s peripheral veins have been exhausted by previous procedures or disease, making the creation of a functional AVF or AVG impossible. In these cases, the tunneled catheter provides a necessary alternative for receiving life-saving treatment.
The Insertion Procedure
Permacath placement is typically performed in a sterile environment, such as an interventional radiology suite, and usually requires local anesthesia combined with conscious sedation. The procedure begins with the medical team using ultrasound guidance to locate the intended central vein, usually the internal jugular vein. A small needle is then inserted into the vein, and a guidewire is threaded through it, allowing for the subsequent introduction of the catheter.
The technique involves “tunneling” a section of the catheter under the skin, separating the vein entry point from the skin exit site, often located on the upper chest. The polyester cuff is positioned within this tunnel, allowing tissue to grow into it over the following weeks for stabilization. Fluoroscopy is used throughout the procedure to ensure the catheter tip is correctly positioned within the large vein just above the heart, which is essential for optimal blood flow during dialysis.
Daily Care and Preventing Complications
Proper daily care is necessary to minimize the two main risks associated with a Permacath: infection and malfunction due to clotting. The most serious complication is a Catheter-Related Bloodstream Infection (CRBSI), which occurs when bacteria enter the bloodstream through the catheter tract. Patients and caregivers must inspect the exit site daily for signs of infection, which include redness, swelling, unusual pain, discharge, or an unexplained fever.
Strict hand hygiene is the first line of defense, requiring thorough hand washing before and after touching the catheter or its dressing. The dressing covering the exit site must be kept clean and completely dry, with a sterile technique required for any dressing changes. Patients must avoid submerging the catheter site in water, meaning swimming and tub baths are prohibited, and special waterproof covers are needed for showering.
Preventing Clotting
To prevent clotting within the lumens, which causes catheter malfunction and poor flow, medical staff routinely “lock” the catheter after each dialysis session. This involves flushing the lumens with an anticoagulant solution, such as heparin or a citrate solution, to prevent blood from coagulating inside the device until the next use. If the flow rate is poor during treatment, specialized clot-dissolving medications may be instilled directly into the catheter to restore function. Any signs of tugging, displacement, or difficulty with flushing must be reported to the healthcare team immediately, as these can indicate a serious problem with the device.