FFinalistSouthampton · 2027
All procedures
GMC #18/Therapeutic procedures taught Y3

Intravenous cannulation

Insert a cannula into a patient's vein and apply an appropriate dressing.

Target · Perform under supervision0% ready

Do it on a patient with a supervisor observing you (GMC “direct supervision”).

Overview

IV access for fluids, drugs and blood. Choose the right gauge for the job, confirm patency by flushing, and secure well.

Key numbers

  • Approx. flow rates: grey 16G ~200 mL/min · green 18G ~90 · pink 20G ~60 · blue 22G ~36 (bigger gauge number = smaller bore)Manufacturer (ISO 10555)
  • Grey/green for rapid fluids, blood and resuscitation; pink/blue for routine accessRCN / local policy

Indications

  • IV fluids, medications, blood products, contrast

Contraindications & cautions

  • Avoid the same-side arm after mastectomy (lymphoedema), an AV fistula, or infected/injured skin

Equipment

Cannula (appropriate gauge)Tourniquet, antiseptic, ANTT dressing, saline flushSharps bin, tape/securement

Step by step

Prepare
  1. 1Confirm identity, consent, allergies; wash hands, gloves
  2. 2Apply the tourniquet; select a suitable vein (back of hand/forearm; avoid joints and the dominant hand where possible)
  3. 3Clean the skin and let it dry
Cannulate
  1. 1Anchor the skin; insert bevel-up at ~15–30° until flashback
  2. 2Advance slightly, then slide the cannula off the needle into the vein
  3. 3Release the tourniquet; withdraw the needle into the sharps bin
  4. 4Cap, then flush with saline to confirm patency (no pain/swelling)
  5. 5Secure with a sterile dressing; label with the date
Aftercare
  1. 1Document; monitor the site (VIP score) for phlebitis/extravasation

Complications

  • Extravasation/infiltration, phlebitis, infection, haematoma, failed cannulation

OSCE tips

  • Match the gauge to the need: grey 16G/green 18G (rapid fluids/blood), pink 20G/blue 22G (routine).
  • Flush to confirm patency — a key safety step.
  • Release the tourniquet before removing the needle; date the dressing.

Read

IV cannulation — OSCE GuideGeeky Medics

Reference cards

Sources & credits

Authored to UK finals standard and verified against UK guidance (Manufacturer (ISO 10555) · RCN) and Geeky Medics OSCE guides . Southampton teaching materials © University of Southampton. Always follow current local policy.