A femoral line is a type of central venous catheter inserted into the large vein in the upper thigh, used to deliver medications, fluids, and treatments that can’t safely go through a standard IV. It’s one of three main sites for central venous access, alongside the neck (internal jugular) and the area below the collarbone (subclavian). Femoral lines are especially common in emergencies and critical care settings where fast, reliable access to the bloodstream is essential.
Why a Femoral Line Instead of a Regular IV
Standard IVs placed in the hand or arm work well for simple fluids and many medications, but they have limits. Some treatments are too concentrated or caustic for small peripheral veins. Medications like vasopressors (which raise dangerously low blood pressure), chemotherapy drugs, high-concentration nutrition solutions, and certain electrolyte mixtures can damage or collapse smaller veins. A femoral line delivers these directly into a large, high-flow vein where they’re rapidly diluted by blood volume.
Femoral lines also allow clinicians to run multiple medications simultaneously through separate channels, or “lumens,” within a single catheter. This matters when a critically ill patient needs several drips that can’t be mixed together. In some cases, a femoral line is also used to monitor central venous pressure, which helps guide fluid resuscitation and assess heart function.
Common Clinical Uses
The most frequent reasons for placing a femoral line include:
- Emergency vascular access: When peripheral IVs fail or can’t be placed quickly enough, such as during cardiac arrest or severe trauma, the femoral vein offers a large, accessible target in the groin that doesn’t interfere with chest compressions or airway management.
- Emergency dialysis: Patients with sudden kidney failure who need dialysis right away often receive a temporary femoral catheter. This is particularly common when the operator is less experienced or ultrasound isn’t immediately available, since the femoral site has a high success rate with fewer insertion complications.
- Continuous renal replacement therapy (CRRT): ICU patients too unstable for standard dialysis may receive a slower, continuous form of blood filtration through a femoral catheter.
- Delivering irritating medications: Vasopressors, parenteral nutrition, and chemotherapy agents that would damage smaller veins are routed through a femoral line.
- Volume resuscitation: Patients in shock or hemorrhage may need large volumes of fluid or blood products pushed rapidly, which the wide-bore femoral vein can accommodate.
- Hemodynamic monitoring: Measuring pressures inside the central veins helps guide treatment decisions in critically ill patients.
Why the Femoral Site Specifically
The femoral vein runs through the upper thigh and takes a relatively shallow course near the skin at the groin crease before passing under the inguinal ligament into the pelvis. This superficial positioning makes it easier to locate and access than deeper vessels.
The femoral site has distinct advantages in certain situations. During CPR, it’s far from the chest, so insertion doesn’t interrupt compressions. One study of catheterization during active cardiopulmonary resuscitation found that ultrasound-guided femoral access achieved a 90% success rate compared to 65% with the traditional landmark technique, with zero accidental arterial punctures versus 20% with the older method. It’s also the preferred site for patients who can’t lie flat, who have chest trauma, or who have devices like pacemakers occupying the neck or chest sites.
For dialysis specifically, the choice between femoral and neck access can depend on body size and mobility. Research from the Cathedia Study suggests that for critically ill, bed-bound patients with a BMI below 24, the femoral site is a reasonable first choice, while the internal jugular may be better for patients with a BMI above 28.
Risks and Tradeoffs
Femoral lines carry real tradeoffs, which is why they’re typically not the first choice when other sites are available.
The biggest concern has traditionally been infection. CDC guidelines recommend avoiding the femoral vein in adults when possible and favoring the subclavian site to minimize infection risk. However, recent data is more nuanced. A retrospective analysis covering 2014 through 2025 found no statistically significant difference in bloodstream infection rates between femoral, internal jugular, and subclavian catheters. This challenges the older assumption that femoral lines are inherently dirtier, though the groin area is still harder to keep clean, especially in patients who are incontinent or sweating heavily.
Blood clots are a more clearly documented risk. A randomized trial published in JAMA found that femoral catheterization was associated with overall thrombotic complications in 21.5% of patients, compared to 1.9% for subclavian catheters. Complete blockage of the femoral vein occurred in 6% of patients. This is a significant consideration, particularly for patients who will need the catheter for more than a few days or who already have risk factors for clotting.
When Femoral Lines Should Not Be Used
Active skin infection or soft tissue infection at the groin rules out femoral placement entirely. So does vascular injury near the insertion site, such as from pelvic or abdominal trauma. If a patient is expected to need the femoral vein later for a cardiac catheterization procedure, clinicians will typically choose a different site. Distorted anatomy from prior surgery, congenital differences, or existing hardware in the area also makes placement inadvisable.
What to Expect During Placement
The procedure is done at the bedside, usually in an emergency department or ICU. You’ll lie flat while the groin area is cleaned and draped. Current standard of care calls for ultrasound guidance, where a probe is placed on the skin so the clinician can see the vein in real time and guide the needle precisely. This has largely replaced the older technique of feeling for anatomical landmarks, since ultrasound significantly reduces complications.
Access can be gained with a standard introducer needle or a smaller “micropuncture” needle. Once the vein is entered, a guidewire is threaded through the needle, the needle is removed, and the catheter is advanced over the wire into position. The whole process typically takes only a few minutes in experienced hands. You may feel pressure at the groin but the area is numbed with local anesthetic beforehand.
How Long a Femoral Line Stays In
Femoral lines are meant to be temporary. There’s no fixed number of days mandated for routine replacement. CDC guidelines emphasize removing any intravascular catheter as soon as it’s no longer needed. If the line was placed during an emergency where sterile technique may have been compromised, guidelines recommend replacing it within 48 hours.
In practice, clinicians reassess daily whether the femoral line is still necessary. If central access is needed longer term, the catheter is often moved to the internal jugular or subclavian site, or a more permanent tunneled catheter is placed. The longer a femoral line remains, the greater the cumulative risk of clotting and infection, so the goal is always to transition to a safer option or remove it entirely as soon as the patient’s condition allows.