Midline Catheters

What is a midline?

• Peripheral catheter placed in upper arm veins

• Tip terminates proximal to axilla (not central)

• Dwell time: 2–4 weeks

Indications:

• DIVA

• Need for IV therapy > 5–7 days

• Frequent blood draws

• Non-vesicant medications

Contraindications:

• Vesicants (usually continuous, short courses or single doses may be tolerable but weigh risks/benefits).

• TPN

• Need for central access (e.g., multiple pressors, hyperosmolar infusions)

• Local infection / upper extremity DVT

Risks:

• Extravasation

• Thrombosis (↑ brachial vein)

• Nerve Injury

• Arterial Cannulation

Placement:

• Mid-arm, avoid close to antecubital fossa → can cause elbow triangle ecchymosis

• Basilic vein preferred. Cephalic vein tapers distally, may not be ideal placement.

  • Brachial vein — high risk of thrombosis.

• Triangle Elbow Ecchymosis:

  • Distal placement near the antecubital fossa is associated with increased mechanical complications, often seen clinically as bruising, bleeding, and early line failure.

  • High motion zone (flexion/extension)

  • Leads to:

    • Line kinking

    • Dislodgement

    • Bleeding

    • Dressing failure

    • Extravasation

Single Lumen

• Most common

• Lower thrombosis risk

• May be less stable (softer catheter)

Double Lumen

• Allows simultaneous infusions

• Higher thrombosis risk (more catheter bulk → ↓ vein-to-catheter ratio)

• Requires:

  • Larger insertion tract

  • Often dilation

  • More procedural time

Rapid Infusion Catheters (RICs)

What is a RIC?

• Large-bore peripheral catheter (~7–8.5 Fr, ~5–6 cm)

• Placed using Seldinger technique (often over existing PIV, can be done after micropuncture)

• Designed for rapid, high-volume infusion

Indications

• Trauma / hemorrhage

• Massive transfusion

• Septic shock

• Any high-flow need

• DIVA when PIV placement fails

Pros

• Very high flow rates (superior to standard PIVs)

• Faster than placing central line in emergent settings

• Fully peripheral → avoids central line complications

• Can be placed rapidly in experienced hands

Cons

• Short-term use only (resuscitation device)

• Requires procedural skill (wire + dilation)

• Not suitable for:

  • Vesicants

  • Long-term therapy

Placement

• Upper arm veins preferred (basilic > cephalic > brachial)

• Large, straight vein segment

• Avoid:

  • Small distal veins

  • Areas crossing joints

Complications

• Mechanical

  • Vessel injury during dilation

  • Hematoma

  • Failed upsizing

  • Leaving dilator in place — do not forget to remove dilator

• Infusion-related

  • Extravasation

  • Compartment syndrome (rare but serious)

  • Tissue ischemia / necrosis (high-pressure infusions)

  • Risk increases with:

    • High flow rates

    • Poor vein selection

    • Catheter malposition

• Other

  • Thrombosis

  • Infection (lower than central lines but still possible)

Micropuncture Kit

What is a micropuncture kit?

• Small-caliber access system:

• 21G needle

• 0.018″ wire

• 4–5 Fr sheath

• Uses Seldinger technique for stepwise access

Indications

• DIVA

• Deep or small veins

• Failed standard PIV attempts

• Need for:

  • RIC placement

  • Midline placement

  • Can realistically be used for any Seldinger procedure (eg, pericardiocentesis)

Why It Works

• Smaller needle → less vessel trauma

• Wire access → confirms intravascular placement

• Stepwise dilation → controlled upsizing

Placement

• Target:

  • Vein diameter ≥ ~4 mm

  • Straight segment of vein

• Prefer upper arm veins for upsizing

• Avoid placement near joints

Complications

• Inadvertent arterial puncture during venous access

• Hematoma

• Wire misplacement

• Vessel injury (rare)