Imaging for Suspected Infiltrated Midline Catheter
No imaging scan is routinely required to diagnose an infiltrated midline catheter—clinical assessment through visual inspection and palpation is the primary diagnostic method. 1, 2
Clinical Diagnosis Without Imaging
The diagnosis of midline catheter infiltration is fundamentally a bedside clinical diagnosis that does not require radiographic imaging:
- Daily visual inspection of the insertion site through transparent dressings should be performed to identify signs of infiltration including swelling, induration, and edema 1, 2
- Palpation through the dressing to detect tenderness, firmness, or tissue changes is recommended as standard practice 1, 2, 3
- Clinical signs of infiltration include presence of hematoma with associated induration and edema at or around the catheter site 1
When Ultrasound May Be Considered
While not standard for simple infiltration diagnosis, ultrasound imaging may have a role in specific clinical scenarios:
- Ultrasound can be used to assess the extent of tissue involvement if there is concern for deeper tissue damage or compartment syndrome 1, 3
- Doppler ultrasound may help evaluate for associated complications such as catheter-related thrombosis, which occurs in approximately 4% of midline catheters 4
- Ultrasound guidance is valuable for assessing vein patency and planning alternative access sites after infiltration has occurred 1, 3
Important Clinical Context
Infiltration/extravasation is a common complication affecting approximately 10% of midline catheters and represents one of the most frequent causes of midline catheter failure (accounting for 27 of 48 failures in one study) 4:
- The complication occurs more frequently than catheter-related infection (0.3%) or phlebitis (0.3%) 4
- Immediate catheter removal is indicated when infiltration is identified clinically 1, 3
- The catheter should be rested until swelling resolves before considering replacement in the same area 1
Common Pitfalls to Avoid
- Do not delay catheter removal while waiting for imaging confirmation when clinical signs of infiltration are present 1, 3
- Do not rely on imaging as a substitute for proper daily clinical assessment of the insertion site 1, 2
- Avoid removing opaque dressings for routine inspection unless clinical signs of complications develop 1
Advanced Imaging Considerations
If there is concern for rare complications such as fibroblastic sleeve embolization (documented in case reports after catheter removal), cardiac ultrasound or other advanced imaging may be warranted, but this is not part of routine infiltration assessment 5.
CT or MRI imaging has no role in the diagnosis of simple midline catheter infiltration and should not be ordered for this indication 1.