Intravenous Cannulation Procedure Guide

Intravenous cannulation (IV) is a fundamental clinical skill, frequently assessed in Objective Structured Clinical Examinations (OSCEs) for medical and nursing students. This Intravenous Cannulation Procedure Guide provides a clear, step-by-step approach to safely performing IV cannulation, from preparation to completion, ensuring you understand the best practices.

Mastering the Intravenous Cannulation Procedure

Successful IV cannulation requires meticulous preparation and a precise technique. This guide breaks down the process into manageable steps, focusing on patient safety and comfort, and is designed to help students confidently perform the procedure.

Introduction and Patient Communication

Before beginning, it's crucial to establish rapport and ensure patient understanding and consent.

• Wash hands thoroughly using alcohol gel or soap and water.
• Introduce yourself clearly to the patient.
• Confirm patient details (name, date of birth) and check for any allergies.
• Explain the procedure: "I need to insert a small plastic tube into your vein using a needle. This will allow us to give you fluids and medications intravenously. It will be a little uncomfortable, but it hopefully won't be painful."
• Check for understanding: "Does everything I've said make sense? Do you have any questions? Are you okay for me to go ahead with the procedure?"

Essential Equipment for IV Cannulation

Gathering all necessary equipment beforehand ensures a smooth and efficient procedure. Place items within safe and easy reach on a clean tray.

• Clean procedure tray
• Non-sterile gloves
• Disposable apron (optional)
• Tourniquet
• Cannula (appropriate size for the indication)
• Sterile dressing pack (to create a sterile field)
• Cannula dressing
• Luer lock cannula cap or extension set
• Gauze swabs
• Normal saline (0.9%) – 10ml
• Syringe – 10ml
• Alcohol swab (2% chlorhexidine gluconate in 70% isopropyl alcohol)
• Sharps container

Preparing for Cannulation: Setting Up Your Workstation

Careful preparation minimizes risks and optimizes the procedure. Remember to maintain aseptic non-touch technique throughout.

1. Don gloves before preparing your saline flush.
2. Open the sterile dressing pack and place the cannula, cannula dressing, and other sterile items onto the field.
3. Prepare the normal saline flush: Draw 10ml of 0.9% normal saline into your syringe. If using a pre-filled flush, you can skip this step.
4. Prime the extension set (if applicable): Attach the extension set to the flush and prime the line, expelling any air.
5. Position the patient's arm: Place a pillow under the arm to be cannulated for patient and operator comfort.
6. Place a field below the arm to prevent any blood spillage onto the patient or furniture.

Identifying a Suitable Vein for Cannulation

Selecting the right vein is crucial for successful cannulation and patient comfort. Consider location, visibility, and feel.

1. Position the arm: Ensure the patient's arm is comfortably extended, providing adequate exposure of the planned cannulation area.
2. Inspect for suitable veins: Ideally, a suitable vein should be visible without a tourniquet. For IV fluids or antibiotics, choose a site least restrictive for the patient, preferably distally on the arms. Always ask the patient if they have a preference for which arm to use.
3. Apply the tourniquet: Place it approximately 4-5 finger widths above the intended puncture site.
4. Palpate the vein: Look for a vein that feels "springy" and is relatively straight to accommodate the cannula. Tapping the vein or asking the patient to repeatedly clench their fist can improve visualization and palpation. Prefer the non-dominant arm and avoid areas near elbow and wrist joints to reduce dislodgement.
5. Areas to avoid: Avoid areas where two veins join (due to valves), limbs with pre-existing medical conditions (e.g., arterio-venous fistula, lymphoedema, previous mastectomy), and sites with broken, bruised, or infected skin (e.g., cellulitis).
6. Clean the site: Once a vein is identified, clean the site with an alcohol swab for 30 seconds. Start from the center and work outwards to cover an area of 5cm or more. DO NOT touch the cleaned site afterwards; if touched, repeat the cleaning procedure.

Step-by-Step Intravenous Cannula Insertion

This is the core of the intravenous cannulation procedure. Follow these steps carefully, maintaining aseptic technique.

1. Wash hands again before donning non-sterile gloves.
2. Don non-sterile gloves (maintaining aseptic non-touch technique).
3. Remove the cannula sheath.
4. Prepare the cannula:

• Open the cannula wings.
• Slightly withdraw and then replace the needle; this ensures it glides smoothly.
• If the cannula is ported, unscrew the cap at the back and place it upright in the tray.

5. Secure the vein: With your non-dominant hand, gently pull the skin distal to the insertion site to stabilize the vein.
6. Warn the patient: Inform them of a "sharp scratch."
7. Insert the cannula: Position the cannula directly above the vein, bevel facing upwards. Insert it through the skin at an angle of 10-30°.
8. Observe for flashback: Watch for blood appearing in the cannula chamber.
9. Advance after flashback: Decrease the angle between the needle and skin, then advance the needle a further 2mm to ensure the tip is securely within the vein's lumen.
10. Partially withdraw the introducer needle: Ensure the needle end remains within the plastic tubing of the cannula.
11. Advance the cannula: Carefully advance the plastic cannula fully into the vein.
12. Release the tourniquet.
13. Place sterile gauze directly underneath the cannula hub.
14. Apply pressure: Gently apply pressure to the proximal vein, close to the tip of the cannula, to minimize bleeding.
15. Remove the introducer needle: While holding the cannula in position, gently pull the introducer needle backwards until it is completely removed.
16. Connect cap/extension set: Immediately connect a luer lock cap or a primed extension set to the cannula hub.
17. Dispose of the needle: Immediately place the introducer needle into a sharps container.
18. Secure the cannula: Apply adhesive strips to secure the cannula wings to the skin. Do not obscure the insertion site, as this needs to remain visible for early detection of phlebitis.

Flushing and Securing the Cannula

Confirming patency and securing the cannula properly are vital steps after insertion.

1. Inject the saline flush: Slowly inject the saline into the cannula using the prepared flush.

• It should flow smoothly with little resistance.
• Watch for signs of swelling around the site; stop immediately if observed.
• If the patient complains of pain, stop immediately.

2. Close the cannula port (if ported).
3. Apply a dressing: Secure the cannula with a sterile dressing, ensuring it is functioning appropriately.
4. Label the dressing: Clearly label the dressing with the insertion date.

Completing the Intravenous Cannulation Procedure

Proper documentation and disposal are essential for patient safety and record-keeping.

• Dispose of clinical waste into appropriate bins.
• Wash hands.
• Thank the patient.
• Document the procedure on a visual infusion phlebitis (VIP) chart, including:
• Patient details (name, DOB, hospital number)
• Date and time of cannulation
• Reason for cannulation
• Type of cannula used (e.g., 20 gauge)
• Site of the cannula (e.g., dorsum of the left hand)
• Date the cannula should be removed or replaced
• Your name, grade, and contact details

It is important to note that recommended cannulation methods can vary. Always consult your local medical school or hospital guidelines for specific protocols.

Frequently Asked Questions about IV Cannulation

What is flashback in IV cannulation and why is it important?

Flashback refers to the appearance of blood in the cannula chamber, indicating that the needle tip has successfully entered the vein's lumen. Observing flashback is a critical visual cue to proceed with advancing the cannula, ensuring proper placement within the vein.

Why should I advance the needle a further 2mm after seeing flashback?

Advancing the needle an additional 2mm after initial flashback ensures that not just the tip, but a small portion of the cannula's plastic sheath, is also within the vein. This helps prevent the cannula from slipping out when you fully advance it and withdraw the introducer needle.

What should I avoid when selecting a vein for cannulation?

Avoid veins near joints (elbow, wrist) to prevent dislodgement, areas where two veins join (due to valves), and limbs affected by medical conditions like lymphoedema or an arterio-venous fistula. Also, never cannulate through broken, bruised, or infected skin.

How do I properly secure an IV cannula after insertion?

After inserting and flushing the cannula, secure its wings to the skin using adhesive strips. It's crucial not to obscure the insertion site with these strips, as the site needs to remain clearly visible to allow early detection of complications such as phlebitis.

What are the key steps for safe disposal after IV cannulation?

Immediate and safe disposal of the introducer needle into a sharps container is paramount to prevent needle-stick injuries. All other clinical waste should be disposed of in appropriate bins, and hands must be washed thoroughly after the procedure is complete.