What Is a Tunneled Catheter and How Is It Used?

A tunneled catheter is a long, flexible tube inserted into a large vein and threaded so its tip rests near or inside the heart, with part of the catheter running through a short path, or “tunnel,” under the skin before exiting the body. This subcutaneous tunnel is the defining feature: it creates a physical barrier between where the catheter enters the vein and where it exits the skin, which reduces the chance of bacteria migrating from the surface into the bloodstream. Tunneled catheters are built for the long haul, often staying in place for months or even years, and they serve as a lifeline for people who need hemodialysis, chemotherapy, long-term intravenous antibiotics, or parenteral nutrition.

What Makes a Tunneled Catheter Different From Other Central Lines

All central venous catheters share the same basic idea: a tube that delivers medications or draws blood from one of the body’s large central veins. But central lines come in several flavors, and they differ in how long they stay, how they’re anchored, and how prone they are to problems. Non-tunneled central venous catheters are typically placed for short stretches of about two to three weeks. Peripherally inserted central catheters (PICCs) can last up to around three months. Tunneled catheters are expected to remain functional for over a month, and in many cases for years. Fully implanted ports, which are themselves tunneled devices placed entirely under the skin, can also last for years with the additional benefit of being invisible from the outside.¹

The feature that sets a tunneled catheter apart is a small cuff made of polyester or similar material, located along the catheter inside the subcutaneous tunnel. Over the weeks following placement, the patient’s tissue grows into this cuff, anchoring the catheter securely. That tissue ingrowth serves two purposes: it holds the catheter in place without stitches, and it creates a biological seal that helps block bacteria from tracking along the outside of the catheter toward the vein. The best-known designs are the Hickman catheter, which typically has two lumens (channels), and the Broviac catheter, which has a single lumen. Both were developed in the 1970s and remain in wide clinical use.²

How Tunneled Catheters Are Placed

Placement is a minor procedure, but it requires precision. The catheter is most commonly inserted into the internal jugular vein in the neck, though the subclavian or femoral veins are sometimes used. With the patient under local anesthesia and light sedation, a clinician uses ultrasound to locate the vein and guide the needle puncture, then threads the catheter through the vein toward the heart. A separate small incision on the chest wall creates the tunnel; the catheter is pulled through this tunnel so that the cuff sits within the soft tissue and the external portion of the catheter exits the skin several centimeters away from the vein entry point.

Fluoroscopy, a form of real-time X-ray, is typically used alongside ultrasound to confirm that the catheter tip lands in the right spot. Modern imaging guidance has made the procedure both safer and more successful.³ In one series of ultrasound-guided placements for hemodialysis catheters, the primary success rate for achieving correct tip position and good catheter function was about 98%, with no immediate procedure-related complications.⁴ Similarly, combined ultrasound and fluoroscopic guidance has yielded high technical success with low complication rates for large-bore tunneled catheters used in bone marrow transplant patients.⁵

What Tunneled Catheters Are Used For

The most common reason for a tunneled catheter is hemodialysis. When a person’s kidneys fail, they need dialysis several times a week, and each session requires a way to rapidly move blood out of the body, through the dialysis machine, and back again. An arteriovenous fistula (a surgically created connection between an artery and a vein in the arm) is the preferred long-term access because it’s associated with fewer infections and hospitalizations. But creating a fistula takes weeks or months to mature, and not every patient’s blood vessels are suitable for one. In the interim, or when a fistula is not an option at all, a tunneled dialysis catheter provides reliable vascular access.

Beyond dialysis, tunneled catheters are widely used in oncology. Patients undergoing chemotherapy may need reliable intravenous access over many months for drug infusions, blood draws, and supportive care. Stem cell transplant recipients often receive Hickman catheters because of the high volume and variety of infusions they require. Tunneled lines are also used for long courses of intravenous antibiotics (such as treating endocarditis or osteomyelitis) and for total parenteral nutrition in patients who cannot absorb food through their gut.

Infection Risk and Biofilm

Infection is the biggest worry with any central line, and tunneled catheters are no exception. The three main types of infection are exit-site infections (redness and pus where the catheter exits the skin), tunnel infections (infection along the subcutaneous track), and catheter-related bloodstream infections, which are the most serious.⁶

A key driver of these infections is biofilm. Bacteria colonize the catheter’s surfaces and embed themselves in a protective layer of slime-like material that makes them very difficult for the immune system or antibiotics to reach. Bloodstream infections in hemodialysis patients are primarily driven by this microbial colonization and biofilm formation, and they remain a major cause of illness and death in patients with end-stage kidney disease.⁷

Research on removed tunneled catheters has shown that biofilm is present even when there is no clinical infection. In one study, about 30% of catheters removed for non-infection reasons still had positive cultures. In patients who had bloodstream infections, that rate climbed to over 60%. Interestingly, the outer surface of the catheter segment sitting under the skin was the most common site of bacterial growth in both groups, and patients with active bloodstream infections had significantly thicker biofilm on all catheter surfaces compared to those without infection.⁸ This means that the catheter is never truly sterile once it has been in place for a while; the clinical question is whether the bacterial burden stays manageable or crosses a line into active infection.

Non-Infectious Complications

Tunneled catheters can also malfunction in ways that have nothing to do with bacteria. The most common mechanical problem is catheter occlusion, where one or both lumens become partially or fully blocked. This is often caused by a fibrin sheath, a sleeve of protein that forms around the catheter’s intravascular portion. Fibrin sheaths can act like a one-way valve, allowing fluid to be infused but preventing blood from being drawn back, or they can block flow in both directions. Other causes of malfunction include the catheter tip drifting out of position and thrombosis inside or around the catheter.

When a catheter becomes occluded, the first-line treatment is usually a thrombolytic drug such as alteplase, which dissolves the clot or fibrin causing the blockage. One study of hemodialysis patients found that alteplase cleared the blockage after a single dose about 82% of the time, and an additional 15% of cases were resolved with a second dose.⁹ The median time before the catheter clotted again after successful thrombolytic treatment was roughly nine months, though patients with a history of prior catheter thrombosis were more likely to need retreatment.¹⁰

Central Vein Stenosis

A less visible but potentially serious long-term complication is central vein stenosis, a narrowing of the large veins where the catheter sits. This matters especially for dialysis patients because narrowed central veins can sabotage future vascular access options, making it harder to create a working fistula in that arm. In a study of hemodialysis patients who underwent catheter exchange with imaging, about 13% had significant central vein narrowing. The risk was strongly tied to how long the catheter had been in place: patients who had a catheter for six months or more had roughly three times the odds of developing stenosis compared to those with shorter catheter use.¹¹ This is one of the main reasons clinical guidelines emphasize transitioning dialysis patients away from tunneled catheters to fistulas as soon as feasible.

Keeping the Catheter Working

Between uses, tunneled catheters are “locked” by filling the lumens with a solution that prevents clotting and discourages bacterial growth. The choice of lock solution has been an active area of research for years. A traditional approach is heparin, an anticoagulant, but evidence that heparin flushing outperforms simple saline flushing for preventing occlusion is weak, and there is no evidence that heparin locks reduce bloodstream infections.¹²

Newer lock solutions aim to tackle both clotting and infection simultaneously. One that has shown real promise is taurolidine, an antimicrobial agent. In a randomized trial comparing a taurolidine-based lock (combined with heparin and urokinase) against a standard 4% citrate lock, the taurolidine group experienced catheter-related infections at a rate of about 0.67 per 1,000 catheter-days, compared to 2.7 per 1,000 catheter-days with citrate, roughly a 75% reduction. The taurolidine regimen also turned out to be more cost-efficient overall.¹³ Research into anti-biofilm catheter coatings and surface modifications is also advancing, with the goal of building catheters that resist bacterial colonization from the start.¹⁴

Day-to-day catheter care at home matters too. Patients are typically instructed to keep the exit site clean and dry, change dressings regularly, and avoid submerging the catheter site in water. Some dialysis programs have experimented with allowing patients to shower using specific protocols rather than relying solely on occlusive dressings. The rationale is that better hygiene and greater patient comfort could improve adherence to care routines, which in turn helps prevent infections.¹⁵

Tunneled Catheters Versus Implanted Ports in Cancer Care

In oncology, the main alternative to a tunneled external catheter is a totally implanted port, a small reservoir placed under the skin (usually on the upper chest) that connects to a catheter threaded into a central vein. Ports are accessed by pushing a special needle through the skin into the reservoir, and between uses the port sits entirely beneath the skin with nothing visible or protruding. For children with cancer, this choice has been studied extensively.

A systematic review and meta-analysis comparing tunneled external catheters with implanted ports in pediatric oncology found that tunneled external lines were associated with roughly twice the risk of systemic infection and about two and a half times the risk of mechanical complications. Children with tunneled external lines were also over three times more likely to need premature device removal. There was no significant difference in local infection rates at the exit or port site.¹⁶

So why would anyone choose a tunneled external catheter over a port? Ports require a needle stick for every access, which can be distressing for some patients, particularly young children. Tunneled catheters allow blood draws and infusions without needles, which is a real advantage during intensive treatment phases when the line is being used daily. Ports are better suited for less frequent access schedules and for patients who want the device to be invisible between treatments. The choice often comes down to treatment intensity, expected duration, and patient preference.

The Dialysis Access Hierarchy

For hemodialysis specifically, clinical guidelines consistently place arteriovenous fistulas at the top of the access hierarchy, followed by arteriovenous grafts, with tunneled catheters as the last resort. The reason is straightforward: tunneled catheters carry higher rates of infection, hospitalization, and mortality compared to fistulas.

In one study, hemodialysis patients using tunneled catheters had significantly more hospitalizations than those with fistulas, and catheter use was the only independent predictor of being hospitalized. Mortality was also higher in the catheter group, though when other factors like the total duration of dialysis were accounted for, the catheter itself was no longer a statistically independent mortality predictor.¹⁷ A separate study painted a starker picture: the mortality rate for patients with tunneled catheters was roughly 171 per 1,000 patients compared to 14 per 1,000 for those with fistulas, with infection as the leading cause of death and hospitalization in the catheter group.¹⁸

These numbers reflect a reality that nephrologists wrestle with constantly: many patients start dialysis with a tunneled catheter because there was not enough time or suitable anatomy to create a fistula. The catheter gets them through the acute phase, but converting to a fistula as soon as possible is a clinical priority. The longer a tunneled catheter stays in place, the greater the cumulative risk of infection, thrombosis, and central vein stenosis.

Tunneled PICCs and a Newer Hybrid Approach

An interesting development in recent years is the tunneled peripherally inserted central catheter, or tunneled PICC. A standard PICC goes into a vein in the arm and is held in place with an adhesive dressing at the skin surface. A tunneled PICC adds a short subcutaneous tunnel in the upper arm, giving it some of the stability and infection-resistance benefits of a traditional tunneled catheter with the less invasive insertion of a PICC.

A study in adult cancer patients compared tunneled PICCs with conventional PICCs and found that the tunneled version significantly reduced long-term complications. Rates of catheter-related bloodstream infection, thrombosis, catheter dislodgement, local infection, skin irritation, and non-infectious oozing were all lower in the tunneled group. Unplanned catheter removal dropped from about 7% with conventional PICCs to about 2% with the tunneled version.¹⁹ This suggests that the tunneling principle itself, not just the choice of vein, contributes meaningfully to catheter longevity and safety.

Pediatric and Neonatal Considerations

Using tunneled catheters in very small patients presents unique challenges. In neonates, the vessels are tiny, and the catheter has to be proportionally smaller. Researchers have explored using small 6-French tunneled catheters as an alternative to standard hemodialysis catheters in neonates needing continuous kidney replacement therapy. These smaller tunneled catheters lasted significantly longer (a median of 28 days versus 10 days) and required fewer revisions. However, they came with a trade-off: infection rates were higher with the smaller tunneled lines, possibly because the reduced catheter diameter makes flushing less effective or because the smaller lumen creates areas where bacteria can accumulate.²⁰

In pediatric oncology, the decision between a tunneled external catheter and an implanted port, as discussed above, often hinges on the child’s age and the treatment protocol. Very young children or those on extremely intensive regimens may benefit from an external catheter that avoids repeated needle sticks, while older children on maintenance chemotherapy with less frequent access needs may do better with a port.

How Tunneled Catheters Are Removed

Removal is generally straightforward but is not always as simple as it sounds. The tissue ingrowth into the cuff, which is an asset during the catheter’s life, becomes the main obstacle at removal. The standard technique involves locating the cuff under the skin, injecting local anesthetic, making a small incision over the cuff, and using a blunt dissection tool to free the cuff from the surrounding tissue. Once the cuff is freed, the intravascular portion is pulled out through the incision while pressure is held over the vein entry point for several minutes to prevent bleeding. The remaining external segment is then pulled out through the original exit site, and the incision is closed with a few stitches.²¹

Complications during removal are uncommon but they do happen, especially with catheters that have been in place for a long time. The cuff can become heavily scarred in, making dissection difficult. Rarely, a catheter tip can adhere to the vein wall or the heart, requiring more involved techniques. The fact that removal is described in the medical literature as “an underappreciated problem, not always simple and safe” is itself telling: it is a procedure that looks minor on paper but deserves careful attention from an experienced clinician.

Cost and Practical Trade-Offs

Tunneled catheters and implanted ports both cost more to place than a standard PICC line. A retrospective analysis of vascular access in stem cell transplant patients found that PICC placement costs averaged around $500, compared to roughly $2,500 for tunneled catheters or ports. Patient compliance was also better with PICCs, with fewer dressing complaints and easier outpatient management.²² But upfront cost does not tell the whole story. A cheaper device that fails or gets infected, requiring replacement, emergency treatment, and extra hospital days, can easily become more expensive in the long run. The taurolidine lock study mentioned earlier found that a more expensive lock solution actually reduced overall costs by preventing infections and catheter dysfunction.²³ The calculus is never just about the sticker price of the device; it is about the total cost of keeping it working safely for as long as it is needed.