Duration of Midline Catheter Use
Midline catheters should be used for short to intermediate-term intravenous therapy lasting between 6-14 days, while longer durations (≥15 days) warrant consideration of PICC lines or other central venous access devices. 1, 2
Appropriate Duration Based on Guidelines
Midline catheters are peripheral venous access devices that are typically 8-25 cm in length and are inserted into upper arm veins such as the brachial or cephalic, with the distal tip ending below the level of the axillary line 3. The duration of use is guided by evidence-based recommendations:
- Short-term use (≤5 days): Peripheral IV catheters are more appropriate than midlines 1
- Intermediate-term use (6-14 days): Midline catheters are recommended 1, 2
- Long-term use (≥15 days): PICC lines, tunneled catheters, or implanted ports are preferred 1, 2
Clinical Considerations for Midline Use
Appropriate Indications
- Frequent phlebotomy needs
- Intermediate-duration IV therapy with peripherally compatible infusates
- Patients with difficult venous access who need 6-14 days of therapy 2
Solution Compatibility
- Midlines are appropriate for solutions with pH between 5-9
- Osmolarity should be less than 500 mOsm/L 1, 3
- Not suitable for vesicant medications or solutions requiring central venous administration 1
Advantages Over Other Devices
- Lower risk of bloodstream infection compared to PICCs 2, 4
- Lower rates of catheter occlusion compared to PICCs (2.1% vs 7.0%) 4
- No need for chest X-ray confirmation of placement 3
- Higher patient comfort and acceptance 5
Special Populations
Patients with Chronic Kidney Disease
- For patients with CKD stage 3b or greater (eGFR <45 mL/min), tunneled small-bore central catheters are recommended instead of midline catheters to preserve peripheral veins 2
Patients Requiring Lifelong Access
- For patients who may require lifelong access but are infrequently hospitalized (≤5 hospitalizations per year):
- Midlines are preferred over PICCs for durations of 6-14 days
- PICCs become appropriate when duration exceeds 15 days 1
Skilled Nursing Facility Residents
- Midlines are appropriate for infusion of non-irritant, non-vesicant treatments when duration exceeds 15 days
- For durations of 6-14 days, midlines are still appropriate 1
Monitoring and Maintenance
- Daily evaluation of the insertion site for signs of phlebitis (warmth, tenderness, erythema, palpable venous cord) 2
- Midlines should not be routinely replaced to reduce infection risk 2
- Remove when no longer clinically necessary or when complications develop 2
Complications to Monitor
- Phlebitis (less common with midlines compared to short peripheral IVs) 3
- Deep vein thrombosis (conflicting evidence on risk compared to PICCs) 4
- Infiltration/extravasation
- Catheter occlusion
- Dislodgement (higher rate compared to PICCs) 6
Key Takeaway
While midlines can technically remain in place for up to 6 weeks in some cases 3, the strongest and most recent evidence supports their use primarily for intermediate-term therapy (6-14 days). For therapy expected to last 15 days or longer, transitioning to a more appropriate device like a PICC line or tunneled catheter is recommended to minimize complications and optimize patient outcomes.