Makindo Medical Notes

💡 Key Point: Ultrasound-guided (2D) insertion is now the standard of care for all central venous lines. It improves success rates, reduces the number of attempts, and significantly lowers the risk of pneumothorax and arterial injury. Always confirm venous flow on Doppler before needle insertion. 🩺

🧠 Overview

• Central venous access allows secure administration of irritant or hyperosmolar drugs, haemodynamic monitoring, and blood sampling.
• Common access sites: Internal Jugular (IJV), Subclavian, and Femoral veins.
• Technique: Seldinger method using sterile ultrasound guidance.

⚠️ Precautions

• 👩‍⚕️ Only experienced or supervised clinicians should perform CVC insertion.
• 🧴 Full aseptic technique — gown, gloves, mask, cap, sterile field.
• 📡 Use real-time ultrasound whenever available.

🎯 Indications

• Measurement of Central Venous Pressure (CVP).
• Frequent central venous blood sampling or ScvO₂ measurement.
• When peripheral access is impossible or inadequate.
• Infusion of irritant or hyperosmolar solutions — e.g. inotropes, chemotherapy, TPN.
• Procedures: haemodialysis, plasmapheresis, or temporary pacing.

🚫 Contraindications

• Uncooperative or agitated patient (cannot maintain sterility).
• Uncorrected coagulopathy, thrombocytopenia, or recent thrombolysis (relative).
• Local skin infection or burns at insertion site.
• Pneumothorax or single lung — avoid subclavian on the functional side.
• Most are relative — weigh risk-benefit and seek senior advice if urgent access is needed.

📍 Choice of Site

Site	Advantages	Disadvantages / Risks
Internal Jugular Vein (IJV)	Preferred site; ultrasound visible, compressible if bleeding.	Arterial puncture, pneumothorax (rare with US guidance).
Subclavian Vein	Comfortable for longer-term access, low infection risk.	Not compressible; ↑ bleeding risk, pneumothorax/haemothorax.
Femoral Vein	Compressible, safest in coagulopathy, quick in emergencies.	Higher infection & thrombosis risk with prolonged use.

🧭 Surface Anatomy Tips

• 🩸 IJV: At apex of the triangle between SCM heads and clavicle; use Trendelenburg unless contraindicated.
• 🦴 Subclavian: Beneath midclavicle; insert just below clavicle, aim toward sternal notch.
• 🦵 Femoral: Medial to femoral artery — “NAVY” mnemonic (Nerve → Artery → Vein → Y-fronts).

🧰 Equipment Checklist

• Central venous catheter (typically 20 cm triple-lumen for IJV/subclavian; 15 cm for femoral).
• Sterile gown, gloves, mask, drapes.
• Ultrasound machine with sterile probe cover.
• 1–2 % Lidocaine for local anaesthesia.
• Seldinger kit: needle, syringe, guidewire, dilator, scalpel.
• Transparent dressing, suture material.
• Flushes and sterile 0.9 % saline.

🪡 Step-by-Step: Seldinger Technique

1. 🗣️ Consent & Position: Explain procedure. Trendelenburg (10–15°) for IJV/subclavian to distend veins; supine for femoral.
2. 🧴 Asepsis: Disinfect skin and apply sterile drapes.
3. 💉 Local Anaesthetic: Infiltrate lidocaine at puncture site.
4. 📡 Ultrasound Guidance: Identify vein; avoid arteries. Insert needle at 45° angle under live US view.
5. 🩸 Confirm Venous Entry: Dark, non-pulsatile blood return.
6. 🧵 Guidewire: Advance gently; never force. Remove needle while maintaining wire position.
7. ✂️ Skin Nick: Use scalpel to enlarge entry for dilator.
8. 🔧 Dilation: Advance dilator briefly to enlarge tract.
9. 📍 Catheter Insertion: Thread catheter over guidewire to correct depth (tip at SVC–RA junction).
10. 💧 Flush & Secure: Withdraw wire, flush lumens, suture in place, apply transparent dressing.
11. 📸 Post-procedure: Chest X-ray (or US) to confirm position and exclude pneumothorax (not needed for femoral lines).

⚠️ Complications

• 🩸 Arterial puncture or haematoma.
• 💨 Pneumothorax / Haemothorax.
• ↩️ Catheter malposition or embolism.
• 🌬️ Air embolism: Always keep patient head-down during insertion/removal.
• ❤️ Arrhythmias: If guidewire advanced too far into heart.
• 🦠 Infection / Line sepsis.
• 💔 Cardiac tamponade: Rare; due to vessel or cardiac perforation.

📈 Central Venous Pressure (CVP) Monitoring

• Measured in cm H₂O relative to right atrium (normal: 0–8 cm H₂O).
• Serial trends are more informative than isolated readings.
• Fluid challenge (250 mL colloid): A rise <5 cm H₂O or transient only → suggests hypovolaemia.
• Consider artefacts: tricuspid regurgitation, mechanical ventilation, and intra-thoracic pressure changes.

📚 References

• NICE NG137: Sepsis and IV access recommendations
• BJA Education: Central Venous Access Techniques
• RCS / BTS / ICS Joint Safety Guidelines (2023)

🧩 Teaching Pearl: Always confirm vein patency + depth + angle on ultrasound before needle insertion — the most common cause of complication is *anatomical guesswork*. When in doubt: Stop. Scan. Start again. ⚕️