Vascular Access Techniques

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Vascular Access Techniques: Prep & Prudence - Ground Zero

  • Indications: Diagnostic (angiography), Therapeutic (embolization, stenting).
  • Contraindications:
    • Absolute: Active infection at site, severe uncorrectable coagulopathy.
    • Relative: Moderate coagulopathy, patient refusal.
  • Pre-procedural Workup:
    • History: Allergies, renal function, anticoagulants/antiplatelets.
    • Exam: Pulses, Allen's test (radial).
    • Labs: CBC, PT/INR (< 1.5-1.8), aPTT, Creatinine, Platelets (> 50,000/μL).
  • Informed Consent: 📌 PRBA (Procedure, Risks, Benefits, Alternatives).

⭐ Allen's test is crucial before radial artery cannulation to ensure ulnar artery collateral circulation.

Vascular Access Techniques: Site Seeing - Entry Points

Arterial Access:

  • Common Femoral Artery (CFA): Most common. Landmark: Inguinal ligament, femoral pulse. 📌 NAVEL (Lateral to Medial: Nerve, Artery, Vein, Empty space, Lymphatics).
    • Pros: Large vessel, easy access.
    • Cons: Retroperitoneal bleed risk, infection.
  • Radial Artery (RA): ↑Patient comfort, ↓complications. Landmark: Styloid process of radius, radial pulse.
    • Pros: ↓Bleeding, early ambulation.
    • Cons: Smaller vessel, spasm risk.
  • Brachial Artery (BA): Landmark: Medial to biceps tendon, brachial pulse.
    • Pros: Alternative if CFA/RA unsuitable.
    • Cons: ↑Nerve injury risk (median nerve).

Venous Access:

  • Internal Jugular Vein (IJV): Preferred for central lines. Landmark: Triangle b/w sternal & clavicular heads of Sternocleidomastoid (SCM) muscle, carotid pulse (medial).
    • Pros: ↓DVT/pneumothorax vs subclavian.
    • Cons: Carotid puncture risk.
  • Femoral Vein (FV): Medial to CFA. Landmark: Inguinal ligament, femoral pulse.
    • Pros: Easy access in emergencies.
    • Cons: ↑DVT risk, infection.
  • Subclavian Vein (SCV): Landmark: Junction of medial 1/3 & lateral 2/3 of clavicle.
    • Pros: Patient comfort.
    • Cons: ↑Pneumothorax/hemothorax risk.
  • Peripheral Arm Veins: (Basilic, Cephalic) For PICCs.

Femoral artery access landmarks

⭐ The Seldinger technique is the cornerstone of percutaneous vascular access, involving needle puncture, guidewire insertion, sheath placement over wire, and finally catheter introduction through sheath.

Vascular Access Techniques: Needle Ninjutsu - Technique Toolkit

  • Seldinger Technique: Core method for vascular access.
  • Modified Seldinger (Micropuncture):
    • Initial access with smaller 21G needle & 0.018" wire.
    • System then upsized if needed.
    • Benefits: Reduced vessel trauma, safer for challenging or small vessels.
  • Ultrasound Guidance: Real-time needle and vessel visualization.
    • Views: Transverse (short-axis/out-of-plane) vs. Longitudinal (long-axis/in-plane).
    • Advantages: ↑ first-pass success, ↓ attempts, ↓ mechanical complications (e.g., hematoma, pneumothorax).
  • Fluoroscopic Guidance: X-ray imaging confirms final wire/catheter position, often using bony landmarks.
  • Aseptic Technique: Critical. Includes sterile field, skin prep (chlorhexidine preferred), sterile attire, draping.

Ultrasound guided vascular access techniques

⭐ The most common site for iatrogenic arterial injury during central line placement is the carotid artery when attempting internal jugular vein access on the same side.

Vascular Access Techniques: Gizmos & Gadgets - The IR Arsenal

  • Needles:
    • Types: Bevelled (sharp for initial puncture), trocar-tipped (blunt dissection).
    • Sizes: 18G (standard Seldinger), 21G (micropuncture).
  • Guidewires:
    • Diameters: 0.018" (micropuncture), 0.035" (standard workhorse).
    • Tips: J-tip (atraumatic navigation), angled, straight. Stiffness: floppy to stiff.
    • Coatings: Hydrophilic (↓friction), heparin (↓thrombogenicity).
  • Catheters: $Fr = \text{Outer Diameter (mm)} \times 3$.
    • Types: Diagnostic (e.g., pigtail, vertebral) vs. Guiding (support).
    • Material: Polyurethane, nylon, polyethylene.
  • Sheaths: Introducer with hemostatic valve & side port (flushing/infusion).

⭐ The 0.035" guidewire is the most versatile and commonly used size for a wide range of general angiography and interventions. 📌 Nice Green Cars Shine (Needles, Guidewires, Catheters, Sheaths). Vascular Access Toolsoka

Vascular Access Techniques: Code Red - Oops & Outcomes

  • Access Site Complications:
    ComplicationKey Sign(s)Mgmt Hint
    HematomaSwelling, pain (most common)Compression
    PseudoaneurysmPulsatile mass, to-and-fro DopplerUS-Thrombin Inj.
    AV FistulaThrill/bruit, continuous DopplerRepair
    DissectionIntimal flap, ↓flowStent/Surgery
    Thrombosis↓flow, ischemiaAnticoagulation
  • Systemic/Other: Contrast reaction, air embolism, infection, nerve injury (brachial/femoral).
  • ⚠️ Retroperitoneal hemorrhage: High femoral access (above inguinal lig.).
  • 📌 PAIN: Pseudoaneurysm, AV fistula, Infection, Nerve injury.
  • VCDs (Vascular Closure Devices): Active/Passive. Risks: failure, infection, stenosis.

⭐ Femoral puncture above the inguinal ligament (i.e., above inferior epigastric artery origin) significantly ↑ risk of retroperitoneal hemorrhage.

Femoral Artery Access & Complications

High‑Yield Points - ⚡ Biggest Takeaways

  • Seldinger technique is fundamental for percutaneous vascular access.
  • Common femoral artery: most common arterial access; Allen's test for radial artery patency.
  • Ultrasound guidance is standard for central venous access; improves safety for arterial access.
  • Micropuncture kits (e.g., 21G needle) reduce access site complications.
  • Key complications: hematoma, pseudoaneurysm, AV fistula, infection, retroperitoneal bleed.
  • Catheter sizes in French (Fr) (1 Fr = 0.33 mm); guidewires in inches.

Practice Questions: Vascular Access Techniques

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Which one of the following is not a wound closure technique?

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Flashcards: Vascular Access Techniques

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The _____ cyst is a contraindication for PAIR.*other contraindications?

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The _____ cyst is a contraindication for PAIR.*other contraindications?

calcified

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