Maximum Duration for Midline Catheters
Midline catheters do not have a predetermined maximum dwell time and should not be routinely replaced based on duration alone—they should remain in place until therapy is complete or a complication occurs. 1, 2
Evidence-Based Duration Guidelines
The CDC explicitly states that midline catheters should not be routinely replaced to reduce the risk for infection (Category IB recommendation). 1, 2 This is a critical distinction from peripheral IV catheters, which require replacement every 72-96 hours in adults. 1
Practical Dwell Time Data
- Median dwell time: 7 days in clinical practice 2
- Documented safe use: Up to 49 days in prospective studies 2
- Routine use range: 2-6 weeks is commonly reported 3
- Extended use: Some evidence supports use for months when appropriately monitored 3
The infection risk with midline catheters does not increase with duration of catheterization, with a bloodstream infection rate of only 0.8 per 1,000 catheter-days. 2
When to Remove a Midline Catheter
Remove the catheter only when specific clinical indications occur: 1, 2
- Signs of phlebitis: warmth, tenderness, erythema, or palpable venous cord 1, 4
- Evidence of infection: local or systemic signs 2
- Catheter malfunction: occlusion, inability to flush or aspirate 2
- Infiltration or extravasation 2
- Therapy completion: when IV access is no longer needed 2
Daily Monitoring Requirements
The CDC recommends evaluating the catheter insertion site daily by: 1, 2
- Palpation through the dressing to detect tenderness
- Visual inspection if using a transparent dressing
- Removing opaque dressings only if clinical signs of infection develop (do not routinely remove to inspect) 1
Critical Pitfalls to Avoid
Do not apply arbitrary time limits for midline removal based solely on duration—this practice is not supported by evidence and unnecessarily increases catheter replacements, patient discomfort, and costs. 2 The key distinction is that while peripheral IV catheters require scheduled replacement every 72-96 hours, midlines are managed based on clinical need, not calendar days. 1
Do not routinely apply prophylactic topical antimicrobials to the insertion site, as this does not reduce infection risk. 1, 2
Selection Context
Midline catheters should be considered when IV therapy duration will likely exceed 6 days, making them appropriate for intermediate-term access (typically less than 3 months). 1 For durations of 6-14 days with peripherally compatible infusates, midlines are preferred over PICCs due to lower complication rates. 1, 5
The 80.9% therapy completion rate and low major complication rate (0.9% for DVT, minimal CRBSI risk) support the safety of duration-based use rather than scheduled replacement. 6, 7