Extravasation Risk with Midline Catheters
Midline catheters carry significant extravasation risk when used for vesicant medications, and continuous infusion of vesicants, parenteral nutrition, and solutions with extreme pH or osmolarity should be avoided through these devices. 1
Understanding Midline Catheter Limitations
Midline catheters terminate in peripheral veins (typically the axillary vein), not central circulation, which fundamentally distinguishes them from central venous access devices (CVADs). 1 Despite their increasing popularity as alternatives to central lines, the evidence base for their safety with high-risk infusates remains insufficient after more than 30 years of clinical use. 1
The Infusion Nurses Society Vesicant Task Force specifically identified midline catheter use as a possible risk factor for extravasation and concluded that vesicant infusions through midlines lack adequate safety evidence. 1
Risk Minimization Strategies
Device Selection and Placement
Use flexible cannulae rather than steel needles for any infusion. 2 Winged steel infusion devices ("butterfly" needles) must never be used for vesicant drugs as they can easily be displaced or puncture the venous wall. 2
Select large veins in the forearm for peripheral administration when midlines are used. 2 Avoid these high-risk sites:
- Joints (cannulation over joints increases extravasation risk) 2
- Inner wrist and lower extremities 2
- Anticubital fossa or dorsum of the hand, particularly for vesicant drugs 2
- Areas with lymphedema 2
Procedural Safeguards
After cannulation, verify blood flow, flush with 10 mL normal saline, and check for signs of extravasation before administering any medication. 2 This initial verification is critical.
Obtain blood return (flashback) before drug administration and check regularly throughout the infusion. 2 The absence of blood return is a key warning sign of potential extravasation. 2
Flush with 10-20 mL saline between different drug infusions. 2
Continuously monitor the insertion site for swelling, pain, redness, or sluggish infusion rate during all drug infusions. 2 This vigilance is essential for early detection.
Patient Education and Monitoring
Instruct patients to immediately report any tingling, burning, discomfort, pain, or swelling at the injection site. 2 Early patient reporting enables prompt intervention before significant tissue damage occurs.
Common pitfall: Patients with sensory deficits, communication difficulties, or young children cannot reliably report early symptoms, substantially increasing extravasation risk. 2 Consider alternative vascular access in these populations.
High-Risk Medications Requiring Central Access
For vesicant drugs requiring prolonged infusion (12-24 hours or longer), central venous access is highly recommended rather than midline catheters. 2 This includes:
- Continuous vesicant infusions 1
- All parenteral nutrition formulas 1
- Infusates with extreme pH or osmolarity 1
The evidence shows that while short-term vasopressor infusions through midlines may have lower extravasation rates in some studies 3, the INS guidelines emphasize that continuous vesicant infusions should be avoided due to insufficient safety evidence. 1
Risk Factors Requiring Heightened Vigilance
Patient-related factors that increase extravasation risk with midlines include: 2
- Small, fragile, hard, or sclerosed veins from prior chemotherapy
- Prominent but mobile veins (elderly patients)
- Impaired circulation (Raynaud syndrome, advanced diabetes, severe peripheral vascular disease)
- Obesity (difficult peripheral access)
- Coagulation abnormalities
Procedure-related factors: 2
- Untrained or inexperienced staff
- Multiple cannulation attempts
- Inadequate catheter fixation
- High flow pressure or bolus injections
When Extravasation Occurs
If extravasation is suspected, leave the cannula in place and attempt to aspirate extravasated solution. 2 Never remove the cannula immediately. 2
Apply dry cold compresses for 20 minutes several times daily for 1-2 days. 2 Avoid alcohol compresses.
Elevate the limb and administer analgesia as necessary. 2
Common pitfall: Manual pressure over the extravasated area should be avoided as it can worsen tissue damage. 2
Bottom Line on Midline Safety
The fundamental issue is that variations in catheter terminology, tip locations, and absence of consensus on appropriate indications make evidence-based decision-making difficult for midline catheters. 1 Given patient safety concerns and inadequate clinical outcome data, the conservative approach is to reserve midlines for non-vesicant, isotonic infusions of limited duration and use CVADs when vesicant medications or high-risk infusates are required.