How Long Can You Keep a Midline In? A Comprehensive Guide

September 28, 2025 •

5 min read

A midline catheter is designed for intermediate-term intravenous therapy, with a typical dwell time of 1 to 4 weeks, often exceeding the lifespan of a standard peripheral IV. Understanding how long can you keep a midline in is crucial for patients, as the exact duration depends on several key factors and proper care.

Quick Summary

Midline catheters offer a reliable venous access solution for therapies lasting between one and four weeks, providing a safer alternative to repeated standard IV insertions. The precise duration depends on the patient's treatment plan and vigilant care to prevent complications like infection or occlusion.

Key Points

Typical Duration: A midline catheter can typically remain in place for up to 28-30 days, or about 1 to 4 weeks, providing access for moderate-term therapies.
Proper Care is Key: Maximizing the catheter's lifespan requires careful management, including weekly dressing changes, regular flushing, and keeping the site dry.
Watch for Complications: Infection, occlusion (blockage), and thrombosis (blood clots) are key risks. Watch for signs like redness, swelling, fever, or difficulty flushing and contact a healthcare provider immediately.
Midline vs. PICC: Midlines are for moderate-term use and peripherally compatible fluids, while PICC lines are for longer use and certain irritating medications, as midlines do not reach central veins.
Patient-Specific: The ultimate duration is determined by the patient's treatment needs and clinical assessment, with removal indicated if complications arise before the four-week mark.
Avoid Water Immersion: The insertion site must be kept dry at all times to prevent infection; this means avoiding swimming, hot tubs, and baths.

What Exactly is a Midline Catheter?

Unlike a standard peripheral intravenous (IV) catheter, which is placed in a small vein for very short-term use, a midline catheter is a longer, more durable device. It is inserted into a larger peripheral vein in the upper arm, most commonly the basilic, cephalic, or brachial vein. From there, the catheter is advanced until its tip rests in the axilla (armpit) or below, but it does not reach the central circulatory system like a PICC line does.

This placement in a larger vessel allows for better blood flow and hemodilution of infused substances, reducing the risk of vein irritation and complications such as phlebitis. Midlines are a preferred option for therapies lasting longer than six days but shorter than a few months, bridging the gap between short IVs and long-term central lines.

The Standard Midline Dwell Time

For most patients, a midline catheter can remain in place for up to 28 to 30 days. The typical range cited by manufacturers and clinical guidelines is 1 to 4 weeks. The Michigan Appropriateness Guide for Intravenous Catheters (MAGIC), a widely respected resource, rates midlines as appropriate for up to 14 days, though they can often stay in longer if clinically indicated and complications are avoided.

Studies on midline catheter performance have shown varying average dwell times, highlighting the importance of individual patient factors. For instance, one study found a median dwell time of 11 days, while another noted a median of 16.7 days. It's important to remember that these are averages; some midlines may be removed earlier, while others may stay in for the full four weeks if no issues arise.

Factors That Influence Midline Duration

Several variables can affect how long a midline catheter can safely remain in place:

Patient Condition: Overall health, immune status, and any existing medical conditions (like a history of blood clots) play a significant role.
Type of Therapy: Midlines are used for specific, peripherally compatible infusions. They should not be used for administering vesicants (highly irritating medications), total parenteral nutrition (TPN), or solutions with extreme pH or high osmolarity, as these require central access.
Catheter Site and Care: Proper insertion, securement, and meticulous daily care are critical for maximizing dwell time. Catheters are more likely to fail prematurely if care protocols are not followed.
Complications: The emergence of complications such as infection, thrombosis, or occlusion necessitates immediate removal of the catheter.

Midline vs. PICC Line: A Comparison

It is helpful to compare midlines to Peripherally Inserted Central Catheters (PICC lines), another common IV device, to understand their respective roles and typical durations.


Feature	Midline Catheter	PICC Line (Peripherally Inserted Central Catheter)
Catheter Tip Location	Peripheral veins of the upper arm, ending near the axilla. Does not enter central circulation.	Larger central veins, with the tip resting near the heart (in the superior vena cava).
Typical Dwell Time	Up to 28-30 days.	Weeks to months, as long as clinically necessary.
Risk of Infection	Lower risk of catheter-related bloodstream infections (CRBSI) compared to PICCs, as it is not a central line.	Higher risk of CRBSI due to its central tip location.
Risk of Thrombosis	Risk exists, but generally lower compared to PICC lines, though studies show variations.	Higher risk of catheter-related thrombosis.
Suitable for...	Peripherally compatible infusions (e.g., certain antibiotics, IV fluids).	Vesicant medications, TPN, chemotherapy, and long-term infusions.
Placement Method	Inserted by trained vascular access specialists, often with ultrasound guidance.	Requires specialized placement and confirmation of tip location via imaging (e.g., chest X-ray).

Essential Care to Maximize Catheter Lifespan

Proper care is paramount for ensuring a midline lasts as long as needed for therapy and minimizing the risk of complications. Healthcare providers will provide detailed instructions, but the following are general best practices:

Strict Hygiene: Practice meticulous hand hygiene with soap and water or an alcohol-based hand sanitizer before and after touching any part of the catheter. Anyone assisting with care should do the same.
Regular Dressing Changes: The sterile, transparent dressing covering the insertion site should be changed at least weekly, or immediately if it becomes loose, soiled, or wet.
Keep it Dry: The catheter and dressing must stay dry. Avoid submerging the arm in water (no swimming, hot tubs, or baths). Special waterproof covers can be used for showering.
Routine Flushing: The catheter needs to be flushed regularly with a saline or heparin solution to prevent it from becoming blocked. Always follow the specific schedule given by your healthcare provider.
Protect the Catheter: Avoid tight clothing, sharp objects, and activities that could pull, bend, or damage the line. Limit strenuous activity and heavy lifting with the affected arm.
Site Monitoring: Regularly inspect the insertion site for any signs of infection or other issues, such as redness, swelling, tenderness, pain, or drainage.

For more specific guidance on preventing intravascular catheter-related infections, healthcare providers often follow recommendations from the Centers for Disease Control and Prevention.

What to Watch For: Complications and Removal

If complications arise, the midline will need to be removed or replaced before its expected duration. It is vital to contact your healthcare provider immediately if you notice any of the following:

Signs of Infection: Fever, chills, or visible signs of infection at the insertion site like redness, swelling, pain, warmth, or pus.
Catheter Occlusion: Inability to infuse fluids or draw blood, which may indicate a blockage.
Thrombosis: Swelling, pain, or tenderness in the arm, shoulder, or neck, which could signal a blood clot in the vein.
Catheter Dislodgement or Damage: If the catheter moves, leaks, or is accidentally pulled out.
Pain or Swelling: Persistent pain, tingling, or swelling in the arm.

Conclusion

In summary, a midline catheter provides a valuable option for venous access for a moderate duration, typically up to four weeks. Its lifespan is not fixed but rather depends on a combination of clinical guidelines, the patient's individual needs, and diligent care. By understanding the distinction between a midline and a PICC line, following proper care instructions, and recognizing the signs of potential complications, patients can maximize the lifespan and safety of their catheter, allowing for uninterrupted therapy.

Frequently Asked Questions

A midline catheter is typically designed to stay in for up to 28-30 days, or about 4 weeks. However, its actual lifespan depends on the patient's condition, the therapy, and the absence of complications like infection or blockage.

You can shower with a midline, but it is essential to keep the catheter and its dressing completely dry. You should avoid baths, swimming, or hot tubs. Waterproof covers, like a shower sleeve, or securely taped plastic wrap should be used.

Signs that your midline may need removal include fever or chills, redness, swelling, or drainage at the insertion site (signs of infection), pain or swelling in the arm, or if the catheter becomes blocked and cannot be flushed.

A midline catheter is for intermediate-term use (up to 4 weeks), whereas a PICC line is a central venous catheter intended for much longer-term therapy, potentially for months. PICCs are also used for medications that are too irritating for a midline.

If a midline is accidentally pulled out, you should immediately apply firm pressure to the insertion site with clean gauze or a towel to control any bleeding. Do not attempt to reinsert it. Contact your healthcare provider or go to the emergency room right away.

Flushing a midline with saline or heparin solution is crucial for preventing the catheter from becoming blocked by blood clots or medication residue. Following the specified flushing schedule helps ensure the line remains functional.

While some blood draws may be performed from a midline, it is not recommended for routine or frequent blood draws. Midline catheters may have a partial occlusion or inability to draw blood more often than PICC lines. Your healthcare team will determine if it's appropriate for your situation.