What are the indications for using a midline catheter versus a peripherally inserted central catheter (PICC)?

Indications for Midline Catheters vs Peripherally Inserted Central Catheters (PICCs)

Midline catheters should be used for peripheral-compatible infusates lasting 6-30 days, while PICCs are indicated for central-only infusates (vesicants, high-osmolarity solutions) or peripheral-compatible therapies exceeding 14-30 days.

Duration-Based Selection for Peripheral-Compatible Infusates

Short Duration (≤5 days)

• Standard peripheral IV catheters or ultrasound-guided peripheral IVs are preferred over both midlines and PICCs 1
• Midlines and PICCs are generally inappropriate for this brief duration unless difficult venous access exists 1

Intermediate Duration (6-14 days)

• Midline catheters are the preferred device for this timeframe 1
• Ultrasound-guided peripheral IVs are also acceptable alternatives to PICCs 1
• PICCs are rated as appropriate but not preferred, given lower complication rates with midlines for short-term use 1, 2
• Midlines demonstrate significantly lower rates of catheter-related bloodstream infection (CRBSI) and occlusion compared to PICCs in this duration 2

Extended Duration (15-30 days)

• PICCs become preferred over midlines due to higher midline failure rates beyond 14 days 1
• Midlines remain acceptable up to 4 weeks but carry increased risk of complications after 14 days 1, 3
• For parenteral nutrition in this timeframe, both PICCs and non-tunneled CVCs are suitable 1

Long Duration (≥31 days)

• Tunneled catheters or implanted ports are indicated for therapy exceeding 3 months 1
• PICCs remain appropriate for medium-term therapy (up to 3 months) 1
• For home parenteral nutrition requiring daily access, tunneled catheters are preferable to PICCs 1

Infusate-Based Selection

Peripheral-Compatible Solutions (pH 5-9, osmolarity <850 mOsm/L)

• Midlines are appropriate for solutions meeting these parameters 1, 3
• Examples include most antibiotics, crystalloid fluids, and low-osmolarity formulations 3
• Midlines should be considered early rather than serial short peripheral IVs 3

Non-Peripheral-Compatible Infusates

• PICCs are mandatory for vesicants, irritants, chemotherapy, and high-osmolarity parenteral nutrition (>850 mOsm/L) 1
• Midlines are rated inappropriate for these infusates at all durations 1
• Catheter tip must be positioned in the lower third of the superior vena cava or upper right atrium for high-osmolarity solutions 1
• Non-tunneled CVCs are appropriate alternatives if skilled operators are available and duration is ≤14 days 1

Indication-Specific Recommendations

Difficult Venous Access

• For expected duration 6-14 days: ultrasound-guided peripheral IVs or midlines are preferred over PICCs 1
• For expected duration ≥15 days: PICCs are appropriate 1
• Ultrasound guidance allows midline placement in deep arm veins (basilic, brachial) even when superficial veins are absent 1
• Tunneled catheters are only appropriate if duration ≥31 days is expected 1

Frequent Blood Sampling (≥3 phlebotomies/day)

• For duration ≤5 days: appropriateness is uncertain; decision should involve patient discussion of risks/benefits 1
• For duration ≥6 days: PICCs are appropriate 1
• Midlines can accommodate repeated blood sampling for up to 14 days 4
• Implanted ports are inappropriate for frequent blood draws at all durations 1

Parenteral Nutrition

• Peripheral PN through midlines requires osmolarity ≤850 mOsm/L and limited duration 1
• Central access (PICC or CVC) is mandatory for high-osmolarity PN 1
• For short-term inpatient PN: both PICCs and non-tunneled CVCs are suitable 1
• For medium-term or home PN: PICCs are appropriate, though they may limit self-care by disabling one arm 1
• For home PN >3 months: tunneled catheters are preferable to PICCs for patients requiring daily access 1

Chemotherapy

• Central venous access via PICC is required for vesicant chemotherapy 1
• Midlines are inappropriate for chemotherapy administration 1
• For long-term oncology patients: implanted ports have lowest CRBSI rates 1
• Ports are appropriate only if therapy duration ≥31 days is expected 1

Complication Profile Comparison

Infection Risk

• Midlines demonstrate significantly lower CRBSI rates compared to PICCs when evaluated per patient (OR 0.24,95% CI 0.15-0.38) 5, 2
• In short-term use (≤30 days), midlines show 0.4% vs 1.6% bloodstream infection rate compared to PICCs 2
• Both devices require strict aseptic technique during placement and maintenance 1

Thrombosis Risk

• Midlines carry higher risk of superficial vein thrombosis compared to PICCs (OR 2.30,95% CI 1.48-3.57) 5
• PICCs have lower risk of symptomatic deep vein thrombosis in time-to-event analyses 2
• No significant difference in pulmonary embolism risk between devices 5
• Thrombosis prevention requires smallest catheter gauge compatible with therapy (ideally catheter diameter ≤1/3 vein diameter) 1

Occlusion Risk

• Midlines demonstrate significantly lower occlusion rates: 2.1% vs 7.0% for PICCs 2
• Proper flushing protocols are essential for both devices 1

Critical Technical Considerations

Midline Specifications

• Length: 8-25 cm (3-10 inches), terminating below the axillary line 3, 4
• Placement sites: brachial, basilic, or cephalic veins of upper arm 3
• No chest X-ray required for placement verification 3
• Can remain in place up to 6 weeks, though optimal duration is ≤14 days 3, 4

PICC Specifications

• Length: 50-60 cm, with tip positioned at cavoatrial junction 1
• Placement via basilic or brachial vein using ultrasound guidance and micro-introducer technique 1
• Post-insertion chest X-ray mandatory if tip position not confirmed during procedure 1
• Suitable for therapy up to 3 months 1

Common Pitfalls to Avoid

• Do not use midlines for solutions with osmolarity >850 mOsm/L or pH outside 5-9 range 1, 3
• Avoid femoral vein access for parenteral nutrition due to high contamination and thrombosis risk 1
• Do not place PICCs in patients with stage 3-5 chronic kidney disease who may require future hemodialysis access 1
• Avoid high internal jugular approaches (anterior/posterior to sternocleidomastoid) due to difficult exit site care and infection risk 1
• Do not use short peripheral cannulas for home parenteral nutrition due to high dislocation risk 1
• Avoid subclavian vein access in patients with advanced chronic kidney disease to preserve future dialysis access options 1