
Overview
This module describes how to cannulate a peripheral vein. The terms ‘cannula’ and ‘catheter’ are sometimes used interchangeably; however, for the purpose of this application, ‘cannula’ refers to the needle/stylet and plastic sheath combined and ‘catheter’ refers to the sheath only.
Indications
Intravenous fluids for maintenance, resuscitation or rehydration
Intravenous medications such as antibiotics
Pre-emptive, such as prior to anaesthesia
Contraindications
Site challenges such as damaged skin, localised swelling, sclerosed veins, haematomas, or infection
Fistula or IV line already on the same limb
After previous lymph node resection or radiation of axilla on same side
Patient information & consent
Always verify your patient’s identity and obtain informed consent before proceeding.
How do I explain this procedure?
“I need to put up a drip, which is a small plastic tube in your vein. We use it to give you fluids or medicine.”
What can my patient expect?
“You may feel a sharp sting when I insert the needle, but it should stop hurting after that.”
“The plastic tube may stay in your arm for a few days, but the metal needle will be removed immediately.”
What is my patient’s role?
“Keep as still as possible while I insert the drip. Let me know if you have any allergies or a bleeding tendency, or use blood thinners. Fearing blood or needles is normal, but tell me if you have fainted from it. If the area around the drip gets tender, swollen or red or it starts bleeding, call a doctor or nurse immediately.”
Preparation
Prepare a trolley with equipment.

Documentation
Patient notes
Equipment
Non-sterile gloves
Alcohol-based hand rub
Alcohol swab
Tourniquet
- IV cannulaIV cannula
- Connector or “J-loop” (short extension)Connector or “J-loop” (short extension)
If the lock or port has tubing, use a 2 ml syringe to flush saline through the tubing.
Transparent dressing (Tegaderm or Opsite)
Cotton balls
- Sharps containerSharps container
If a sharps container is not within arm's length, use a kidney dish or other hard container to temporarily hold used sharps and to carry them to the sharps container for disposal.
Site & Positioning

Straight, visible veins on forearms of the non-dominant limbs are preferred. Other sites include veins on the wrist, the backs of the hands and, the antecubital fossa, feet, and the jugular vein as a last resort. Avoid insertion over a joint. Ensure good lighting. Do not cannulate arteries with this technique.
Procedure
Follow medical asepsis with non-sterile gloves.
Perform hand hygiene and don gloves.
Open equipment packages on a clean tray/surface.
Find a straight, visible, large vein and apply a tourniquet above it.
Clean the site with an alcohol swab and allow it to dry. Do not touch this area again.
Anchor the vein by placing the thumb of your non-dominant hand below the puncture site and stretching the skin.
Insert the IV cannula at a less than 30° angle with the bevel up. Advance until you enter the vein; you should see blood in the chamber (flashback); then advance 1 mm more.
Hold the catheter in place while you pull back the metal stylet until you can see blood entering the catheter, indicating it is in the
veinvein.
Release the tourniquet.
Holding the metal stylet steady, push the catheter all the way into the vein.
With your non-dominant hand, press on the skin above the insertion site to occlude the catheter tip and prevent bleeding while the stylet is completely removed.
Dispose of the metal stylet in sharps bin.
Attach the connector or short extension to the catheter.
Clean up blood spills with the cotton ball. Secure the catheter using the strip of the dressing and stick the dressing over the site, with the lock or port exposed.
Flush the cannula to see if it’s working. Using a 2-5 ml syringe, inject saline into the port or lock. It should run in easily with no swelling of the area.
Dispose of medical waste safely.
Record date of the procedure in patient notes. Catheters in the upper limb must be removed after 5 days and in the lower limb or neck after 4 days.
Troubleshooting
I can’t find a vein.
Check each hand. Apply heat to the skin and tap on the site to help raise the vein. Ask the patient to make a fist. Inflate the cuff of a sphygmomanometer between systolic and diastolic to create pressure in the veins. If not successful, try the antecubital fossa and other sites. Consider asking for help.
I’ve achieved flashback but the catheter won’t advance.
This usually means you’re not fully in the vein. Gently advance the stylet another millimeter and look again for flashback. Try advancing the catheter again. Try twice and if still unsuccessful, choose another site.
The site is swelling or bruising immediately.
This usually happens when you’ve gone right through the vein (“blowing” it). Get a fresh cannula and try a different site.
The vein is moving under the skin.
Make sure you anchor the skin firmly and ‘stab’ the vein before it can escape.
I am definitely in the vein, but now the catheter feels stuck.
You may have hit a valve in the vein. Try flushing the catheter with saline while advancing. The flush might open the valve so you can push through. Otherwise, if the catheter flushes well, secure it right there. Be aware that these half-inserted catheters often dislodge and don’t flow as well as when fully advanced.
I am unsuccessful after 3 attempts.
Ask help from a colleague or senior healthcare professional.
Risks
Extravasation of fluids or medication at the site
Minor bleeding/pain/haematoma at puncture site
Infection of the site
Sharps injury to healthcare personnel
Vasovagal response (fainting)
Catheter tip
embolisationembolisationWith repeated attempts to reinsert the stylet, the tip of the plastic catheter may shear off into the vein.
References
Harty E. Inserting peripheral intravenous cannulae – tips and tricks. Update in Anaesthesia; 2011.
Moureau N, & Chopra V. Indications for peripheral, midline and central catheters: summary of the MAGIC recommendations. British journal of nursing. 2016:25(8):S15–S24. Available from: https://doi.org/10.12968/bjon.2016.25.8.S15
Joubert A. Intravenous fluid therapy. In: Mulder M, Joubert A, Olivier N, eds. Practical Guide for General Nursing Sciences. 2nd ed. Pearson; 2020.