Understanding the Risks: Why Don't We Put IVs in Legs?

September 21, 2025 •

3 min read

Statistics show that peripheral IVs frequently fail, often due to complications. This is a major reason why don't we put IVs in legs, as lower-extremity access poses significantly higher risks for serious issues like blood clots and infections compared to arm placement.

Quick Summary

The practice of avoiding leg IVs in adults stems from an elevated risk of dangerous blood clots (DVT), vein inflammation, and infection due to slower blood flow, gravity, and limited mobility.

Key Points

Blood Clot Risk: Leg veins have slower blood flow due to gravity, significantly increasing the risk of forming dangerous blood clots (Deep Vein Thrombosis or DVT).
Pulmonary Embolism Threat: A blood clot from a leg IV can travel to the lungs, causing a potentially fatal pulmonary embolism.
Limited Mobility: An IV in the leg severely restricts patient movement, further increasing the risk of DVT and potentially leading to the line being dislodged.
Increased Infection: The lower extremities are more prone to contamination and infection, especially in patients with existing circulatory issues or those who are mobile.
Discomfort and Damage: The foot and ankle have many nerves, making leg IV insertion more painful and increasing the risk of nerve damage.
Exceptional Circumstances: Leg IVs are typically only used as a last resort in adults during emergencies or for non-ambulatory infants, where the risk profile is different.

The Primary Risk: Deep Vein Thrombosis (DVT)

One of the main reasons healthcare providers avoid placing IVs in the lower extremities is the heightened risk of deep vein thrombosis (DVT), a blood clot in a deep vein. Legs are already susceptible to DVT due to slower venous return, exacerbated by gravity. An IV catheter can further disrupt blood flow and increase the risk of clot formation. If a piece of the clot breaks off, it can travel to the lungs and cause a life-threatening pulmonary embolism (PE).

Virchow's Triad and Leg IVs

This increased risk aligns with Virchow's Triad, which identifies endothelial injury, venous stasis, and hypercoagulability as factors for thrombosis. A leg IV contributes to endothelial injury (from the needle) and venous stasis (due to gravity), increasing the risk of adverse outcomes.

Increased Risk of Inflammation and Infection

IVs in the legs are also associated with a greater chance of inflammation and infection.

Phlebitis and Thrombophlebitis: Inflammation of a vein (phlebitis) is more common in the legs and can lead to thrombophlebitis, involving inflammation and a blood clot.
Poor Circulation: Conditions affecting circulation, like diabetes, can impair healing and increase infection susceptibility in the legs.
Contamination: The location makes leg IV sites more vulnerable to contamination.

Practical Challenges and Patient Comfort

Practical considerations also influence IV site selection.

Limited Mobility: Leg IVs restrict movement, which can further increase the risk of DVT.
Increased Dislodgement Risk: Moving patients are more likely to dislodge a leg IV.
Pain and Nerve Damage: The foot and ankle have many nerves, making insertion more painful and increasing the risk of nerve damage.

Comparing Arm vs. Leg IV Placement


Factor	Upper Extremity (Arm)	Lower Extremity (Leg)
Risk of DVT/PE	Significantly lower due to gravity and better venous return.	Significantly higher due to venous stasis and gravity.
Vein Access	Easier to access and more superficial for visualization.	Less preferred; deep veins increase complication risk.
Patient Mobility	Interferes less with mobility and daily activities.	Significantly restricts mobility, increasing DVT risk.
Patient Comfort	Generally more comfortable for the patient.	Often more painful and irritating, especially at flexion points.
Infection Risk	Lower risk of contamination due to location.	Higher risk of contamination from proximity to floor and feet.

Are Leg IVs Ever Used? (The Exceptions)

Leg IVs are typically avoided in adults but may be used in specific situations:

Emergencies: If upper extremity veins are inaccessible in a critical situation.
Non-Ambulatory Infants: Foot veins are an option for infants who are not walking.
Severe Trauma: When upper body access is not possible due to trauma.

Alternative Vascular Access Options

When arm veins are unsuitable, safer alternatives than leg IVs in adults include:

Central Lines: Catheters in large central veins for long-term or high-volume needs, such as PICC lines.
Intraosseous (IO) Access: An emergency procedure delivering fluids and medications into the bone marrow.
Ultrasound-Guided IVs: Using ultrasound to locate deeper arm veins.

Conclusion

Avoiding leg IVs in adults is a standard practice for patient safety due to the high risk of blood clots (DVT) and pulmonary embolisms (PE). Increased discomfort, limited mobility, and higher infection rates further support prioritizing arm veins. While there are rare exceptions in emergencies or for pediatric patients, the decision for vascular access is based on individual patient needs and risks to minimize complications. For more information on vascular access guidelines, consult the Infusion Therapy Standards of Practice.

Frequently Asked Questions

Yes, in very rare circumstances, such as a dire emergency where upper extremity access isn't possible, or for non-ambulatory infants, it may be used as a last resort.

While not directly, a blood clot (DVT) from a leg IV can travel to the lungs, causing a pulmonary embolism, which can be life-threatening. The clot does not typically go to the brain to cause a stroke.

In non-ambulatory infants, the risk of mobility-related complications and DVT is much lower, making the foot a viable option when other sites are inaccessible.

Phlebitis is inflammation of a vein. It is a known complication of all IVs but occurs more frequently and with higher risk in the lower extremities due to factors like slower blood flow.

The veins of the upper extremities (arms and hands) are the preferred site for peripheral IV access because they offer better patient mobility and lower risk of serious complications.

An infiltrated IV means fluid leaks into surrounding tissue. In the legs, this can be more serious due to compromised circulation, potentially leading to tissue damage, swelling, or necrosis.

If arm veins are inaccessible, alternatives include central venous access (like a PICC line) or, in emergencies, intraosseous access, where the needle goes directly into the bone.

Maintaining a patient's mobility is important for comfort and to prevent complications. Prolonged immobility can contribute to venous stasis and increase the risk of blood clots, especially in the legs.