Yes, a hemodialysis catheter is a central line. The CDC defines these catheters as central venous catheters (CVCs), and they are tracked, managed, and monitored using the same infection surveillance standards applied to all central lines. The distinction matters mostly because hemodialysis catheters are a specialized, larger-bore version designed to handle the high blood flow rates that dialysis demands.
What Makes It a Central Line
A central line is any catheter whose tip terminates near the heart or in one of the great vessels (the large veins leading to and from the heart). Hemodialysis catheters meet this definition. Tunneled versions are threaded under the skin before entering a vein and sit with their tip in the upper to mid-right atrium of the heart. Non-tunneled versions travel directly from the skin entry point into a vein and terminate in or near the superior vena cava, just above the heart. Both qualify as central venous catheters by placement and function.
This classification has real consequences. Because hemodialysis catheters are central lines, they fall under the CDC’s National Healthcare Safety Network surveillance for bloodstream infections. Hospitals and dialysis centers track infection events tied to these catheters using the same framework they use for any other central line, monitoring for antimicrobial starts, positive blood cultures, and signs of infection at the access site.
How Dialysis Catheters Differ From Standard Central Lines
While all hemodialysis catheters are central lines, they are not identical to the central lines used for IV medications or nutrition. The key difference is size. A standard single-lumen central line used for infusions measures about 5 to 8 French (roughly 1.7 to 2.7 mm in outer diameter). A tunneled hemodialysis catheter ranges from 14.5 to 16 French (4.8 to 5.3 mm), making it roughly twice the diameter. That extra width is necessary because dialysis requires pulling blood out of the body, running it through a filter, and returning it at flow rates of 300 to 400 mL per minute. A standard IV central line could never sustain that kind of flow.
Hemodialysis catheters also have two lumens (channels) side by side: one draws blood out and the other returns it. Standard central lines may have one, two, or three lumens, but they are designed for slow infusions rather than rapid, high-volume blood exchange.
Tunneled vs. Non-Tunneled Types
Hemodialysis catheters come in two forms, and both are central lines.
Non-tunneled catheters are placed directly into a large vein, most often the internal jugular vein in the neck. They are intended for short-term use. Clinical guidelines recommend removing them within about two weeks because infection risk climbs sharply after that point. One study found infection rates of 8.16% for non-tunneled catheters, with risk diverging significantly from tunneled catheters around day 10.
Tunneled catheters are designed for longer use. During placement, the catheter is routed through a short tunnel under the skin before entering the vein. This tunnel creates a physical barrier that makes it harder for bacteria to travel from the skin surface into the bloodstream. A fabric cuff sits within the tunnel and promotes tissue growth around it, anchoring the catheter in place. Infection rates for tunneled catheters run around 3.15%, less than half the rate seen with non-tunneled versions. Tunneled catheters also achieve higher blood flow rates, partly because they are available in larger sizes and partly because their tips are positioned deeper, in the upper to mid-right atrium rather than just the superior vena cava.
Where They Are Inserted
The most common insertion site is the internal jugular vein in the neck. The subclavian vein, which runs beneath the collarbone, is another option. Both feed into the large central veins that lead to the heart, which is what makes the catheter “central” regardless of where it enters the body.
Choosing between these sites involves tradeoffs. The subclavian approach tends to be more comfortable for patients and has lower overall complication rates in some studies, but it carries a higher risk of central vein stenosis, a narrowing of the vein that can compromise future access options. This is a serious concern for dialysis patients, who may eventually need an arteriovenous fistula or graft in the arm. Stenosis in the subclavian vein can make those permanent access types fail. The internal jugular site has a lower rate of catheter kinking (about 3% compared to 13% for subclavian), though it comes with its own risk of stenosis at around 26% in some studies.
Why Catheters Are Not the Preferred Long-Term Option
Even though hemodialysis catheters work as reliable central line access, they sit at the top of the infection risk hierarchy for dialysis. The CDC ranks vascular access types in order of increasing infection risk: arteriovenous fistulas (created from a patient’s own blood vessels) carry the lowest risk, followed by arteriovenous grafts (made from synthetic materials), then tunneled central lines, and finally non-tunneled central lines at the highest risk.
Current clinical practice guidelines from KDOQI (the Kidney Disease Outcomes Quality Initiative) emphasize a patient-centered “Life-Plan” approach. This means thinking ahead about the full trajectory of vascular access a patient will need over their lifetime, not just what works today. Catheters often serve as a bridge, providing immediate access while a fistula or graft matures and becomes usable, or while a patient transitions between access types. The goal is to minimize the total time spent relying on a catheter.
Central vein stenosis is one reason for this caution. A study of 106 hemodialysis patients found that 28.3% had central vein stenosis, and the risk increases with longer catheter use, stiffer catheter materials, and repeated catheter placements over time. Each episode of stenosis narrows the options for future vascular access.
How Dialysis Catheters Are Maintained
After each dialysis session, the catheter lumens are filled with a locking solution to prevent blood clots from forming inside. Heparin, an anticoagulant, is the most commonly used lock in U.S. dialysis units. Concentrations have historically ranged from 1,000 to 10,000 units per milliliter, but current recommendations favor a lower concentration of 1,000 units/mL. Studies comparing 1,000 to 5,000 units/mL found no meaningful difference in how well the catheter stayed open over time, making the lower dose preferable since it reduces the risk of heparin leaking into the bloodstream.
The connection point where the catheter meets the dialysis tubing, sometimes called the hub, is also a critical infection control site. The CDC maintains specific protocols for disinfecting this hub before and after each use, treating it with the same rigor applied to any central line access point.