Introduction
- IV access is a key skill, essential in emergencies. Seek guidance as needed, especially if alternatives like palliative care might be more appropriate.
- In hypovolaemic patients, avoid struggling with large cannulas; start with two 18G (green) cannulas to initiate fluid resuscitation.
- Femoral vein access (most medial structure in femoral triangle) offers a robust route for large bore access. Maintain strict asepsis and check the site daily for signs of infection.
- Flow rate through a cannula depends on cannula radius and fluid reservoir height. Larger cannulas enable faster infusions, especially useful for blood products or rapid fluids.
- Consider ultrasound for difficult access cases, where applicable.
Central Lines
- Central lines are beneficial for irritant drugs or CVP measurement but are not ideal for rapid fluid resuscitation due to slower flow rates.
- Preferred sites: internal jugular vein (accessible and compressible), subclavian vein (non-compressible), and femoral vein (harder to keep clean).
- Ultrasound guidance can enhance accuracy during placement.
Procedure Introduction
- Verify patient ID, explain the procedure, and obtain verbal consent.
- Check for any AV fistulas and wash hands; ensure your name badge is visible.
- If the patient lacks capacity, consider the necessity in their best interests.
Equipment
- Sterile gloves, tourniquet, alcohol wipes
- Choose cannula size based on need (e.g., pink or green for general use; grey for large-volume infusions)
Choosing the Cannula
| Color | Size | Flow Rate | Common Uses |
|---|---|---|---|
| Yellow | 24 gauge | 13 ml/min | Paediatrics, Cytotoxic therapy |
| Blue | 22 gauge | 31 ml/min | Paediatrics, Small fragile veins |
| Pink | 20 gauge | 67 ml/min | Maintenance fluids, Antibiotics |
| Green | 18 gauge | 103 ml/min | Blood products, Large volume fluids |
| Grey | 16 gauge | 236 ml/min | Trauma, Major surgery, Blood transfusions |
| Orange | 14 gauge | 270 ml/min | Rapid high-volume fluids, Major trauma |
Technique
- Preparation: Wash hands, introduce yourself, explain the procedure, and gain consent.
- Place tourniquet around upper arm and identify an accessible vein (forearm, anatomical snuffbox, back of hand).
- Clean the skin with alcohol wipes and warn the patient about a sharp scratch.
- Insert the cannula at a shallow angle, advance until flashback is visible, then push plastic tubing over the needle into the vein.
- Secure with dressing (e.g., Tegaderm), flush with 10 ml sterile saline, and ensure no leaks.
General Advice
- Use upper limbs over lower limbs whenever possible.
- Start with distal veins before moving proximally.
- Avoid dominant arms and forearms where renal dialysis might be needed.
- Lower limb cannulas should be replaced with upper limb access at the earliest opportunity.
After Procedure
- Dispose of sharps safely and clean up.
- Address any patient questions and provide reassurance.
Complications
- Failure: Limit attempts to 2-3 before seeking assistance.
- Haematoma: Often occurs if needle is withdrawn before removing the tourniquet.
- Arterial puncture: Apply pressure and avoid reinsertion at that site.