Maximum Dwelling Time for Midline Catheters
Midline catheters do not have a predetermined maximum dwelling 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
No Routine Replacement Required
- The CDC explicitly recommends against routine replacement of midline catheters to reduce infection risk (Category IB recommendation). 1, 2
- Midline catheters should be removed only when specific clinical indications arise, not based on arbitrary time limits. 2
Documented Safe Duration
- Midline catheters have been safely used for up to 49 days in prospective studies, with a median dwell time of 7 days. 2
- The infection risk does not increase with duration of catheterization. 2
- Bloodstream infection rates remain low at 0.8 per 1,000 catheter-days regardless of dwell time. 2
Optimal Use Window (6-14 Days)
While midlines have no maximum duration, guidelines define their optimal use window:
- For peripherally compatible infusates lasting 6-14 days, midline catheters are preferred over PICCs due to lower complication rates. 1, 3
- For durations ≥15 days, PICCs become preferred due to higher midline failure rates beyond 14 days. 3
- For durations ≤5 days, peripheral IV catheters are more appropriate. 1, 3
When to Remove Midline Catheters
Remove midlines only for these specific clinical indications 1, 2:
- Signs of phlebitis (warmth, tenderness, erythema, palpable venous cord)
- Evidence of infection at insertion site
- Catheter malfunction or occlusion
- Infiltration or extravasation
- Completion of IV therapy
Daily Monitoring Requirements
- Evaluate the insertion site daily by palpation through the dressing to detect tenderness. 1, 2
- Visually inspect if using transparent dressings. 1
- Remove opaque dressings only if clinical signs of infection develop. 1
- Periodically reassess whether the catheter is still needed. 2
Common Pitfalls to Avoid
- Do not apply arbitrary time limits (such as 14 or 28 days) for midline removal based solely on duration—this contradicts CDC guidelines. 1, 2
- Do not routinely apply prophylactic topical antimicrobials to the insertion site. 1, 2
- Do not use midlines for vesicants or irritants—these require central access via PICC regardless of duration. 3, 2
- Do not continue midlines beyond 14 days if alternative devices (PICCs) would be more appropriate for the clinical scenario. 3
Practical Considerations
Recent research shows that while midlines can remain in place safely for extended periods, complication rates increase after 15 days compared to PICCs. 4 A 2024 randomized trial found midlines had higher catheter-related complications (13.2% vs 7.2%) compared to PICCs overall, but this difference disappeared when catheters were used for less than 16 days. 4 This supports the guideline recommendation that midlines are optimal for the 6-14 day window, with PICCs preferred beyond 15 days. 1, 3