Intravenous Cannulation (IV)

Insertion of an IV cannula involves putting a “tube” into a patient’s vein so that infusions can be inserted directly into the patient’s bloodstream.  Cannula’s (aka venflons) come in various colours, which correspond to the size of the “tube”. The size needed depends on what it to be infused e.g. colloid, crystalloid, blood products or medications; or at the rate the infusion is to run.  The other factor which could determine which size to use is the patients veins e.g. you may only get a small blue cannula into an elderly patient who has spindly veins!

This is a core clinical skill to know and is frequently examined upon.

Subject steps

  1. Position the arm so that it is comfortable for the patient and identify a vein.

  2. Stretch the skin distally and tell the patient to expect a sharp scratch.

  3. Carefully dispose of the needle into the sharps box.

  4. Check that the use-by date on the saline has not passed. If the date is ok, fill the syringe with saline and flush it through the cannula to check for patency. If there is any resistance, if it causes any pain, or you notice any localised tissue swelling; immediately stop flushing, remove the cannula and start again.

  5. Dispose of your gloves and equipment in the clinical waste bin, ensure the patient is comfortable and thank them

    Note that as an extension to procedure, you may be asked to set up an IV drip.