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Mrs Jones has been diagnosed with small bowel obstruction. She requires cannulation so that IV fluids can be administered. Please obtain consent for this and then, on the mannequin provided, demonstrate how to insert an IV cannula.

• To learn correct technique for cannula insertion
General Advice
• Obtain valid consent
• Ask the patient if they have an arm preference
• Consider if there are any pre-disposing medical or surgical
conditions that would not allow using a specific arm/blood
vessel, such as a renal fistula, cellulitis, mastectomy
• Check if the patient has any allergies such as to chlorhexidine

Equipment Checklist
(remember to check expiry dates on all equipment) (Fig 3.33)
a) Skin cleansing solution (e.g. ChloraPrep®)
b) 21-gauge needle (though for drawing up medications, IN ALL
cases a blunt draw up needle is preferred if available)
c) 10 mL syringe and syringe cap (or second needle if syringe
cap not available)
d) 10 mL 0.9% saline ampoule for flush
e) Sterile adhesive dressing
f) Cannula
g) Disposable tourniquet
h) Cotton wool
i) 2 pairs of non-sterile gloves
j) Tape (if you fail to site the cannula you will need to tape
some cotton wool over the puncture site)
k) Tray (as with phlebotomy)
l) Sharps bin: the sharps bin should always be taken to the point
of care
m) Single use disposable apron

Note: Skin-cleansing methods and methods of capping will vary depending on local policy. In addition, local policy may use alternative methods to cap. Any tubing that is attached, such as a bioconnector or a line, needs to be flushed first with 0.9% saline to avoid injecting air and risking an air embolus

Explaining Cannulation to the Patient
1. A cannula is a small plastic tube that remains in your vein
allowing you to receive fluid and medication
2. It is inserted using a needle, a bit like having a blood test. You
will feel a sharp scratch but the needle is removed once the
plastic tube is in place
3. It is held in place with a sticky dressing
4. The cannula will be changed every three days if you need it for
a longer period of time
5. It may take a few attempts to ensure the plastic tube is in the
correct place

Performing the Procedure
Preparing the Flush
1. Clean hands and put on non sterile gloves
2. Attach the 21-gauge needle to the 10 mL syringe (leave the
sheath on for now) (Fig 3.34)
3. Double check that you have selected 0.9% saline, that it is
in date, and that the packaging is clean and intact – many IV
medications appear in near-identical ampoules
4. Remove the top from the 0.9% saline and draw 10 mL up into
your syringe using a 21-gauge needle (Fig 3.35)
5. Expel any air from the syringe by tapping it/advancing the
plunger (Fig 3.36)
6. Discard the needle in the sharps bin and attach the syringe to
the second needle for storage (or if available, a sterilised cap
for the syringe tip)
7. Place the flush into the equipment tray alongside the other
cannulation equipmen

Insert the Cannula
1. Remove the cannula from its packaging and open the sterile
dressing pack
2. Position the patient’s arm comfortably
3. Place the tourniquet approximately 7-10cm proximal to the site
of insertion (Fig 3.37)
4. Select vein, then loosen tourniquet
5. Wash hands, put on new non sterile gloves and apron
6. Clean the site using the skin cleansing solution – clean for 30
seconds and leave to air dry (Fig 3.38)
7. Retighten tourniquet
8. Tether the vein that you have selected beneath the insertion
site and insert the cannula at approximately 15⁰ using NTT,
while warning the patient of a ‘sharp scratch’ (Fig 3.39)
9. Advance the cannula until flashback is obtained. Do not
repalpate the aseptic area of the skin at any time during
the procedure
10. Once flashback has been seen, advance the cannula slightly
further (1-2mm). This ensures the cannula tubing is within the
vein before you advance it forward, over and off the needle

11. Hold the needle still and advance the cannula over it, all the
way into the vein. No part of the cannula tubing must be seen
at the point of entry (Fig 3.40)
12. Release the tourniquet
13. Occlude the vein and cannula with firm pressure (Fig 3.41) and
then gently remove the needle
14. Dispose of the needle straight into the sharps bin (Fig 3.42)
15. Depending on Trust policy, attach a cap, bung or IV extension
set (which requires separate preparation) on the end of
the cannula
16. Wipe away any blood that may have leaked around the cannula
with cotton wool
17. Apply sterile adhesive dressing (Fig 3.43)
18. Write the date and time on the cannula dressing label

Flush the Cannula
1. Flip open the coloured cap of the cannula (note however that
if an IV extension set is applied, you would flush the cannula
through this, not the coloured cap)
2. Remove the needle or sterilised cap from the saline flush
syringe and attach the flush to the cannula
3. Slowly flush the cannula (1 ml at a time) with 5-10 mL of 0.9%
saline, checking that the fluid doesn’t leak into the surrounding
tissues, causing swelling (Fig 3.44)
4. Explain to the patient that they might feel coldness running up
their arm as you are flushing the cannula
5. When finished, remove the syringe and re-cap the cannula
6. Dispose of the syringe in a sharps bin
Finishing Off
1. Decontaminate tray as per local policy
2. Dispose of equipment in a clinical waste bin
3. Remove gloves
4. Wash hands
5. Complete a cannula insertion record, and place in notes
6. Explain to the patient that if they have any pain or redness at
or around the cannula site, or if they have any other concerns,
they should speak to a member of staff


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