Cannulation

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Procedure

  1. Find the patient. Check they are the right patient, and then tell them what you are going to do. i.e. ‘we would like to put a needle in you arm so we can give you drugs. The needle will stay in for several days, this is so we don’t have to use lots of needles every time we give you drugs. ‘ or the same for a drip etc etc.
  2. Wash your hands with soap and water.
  3. Clean tray – inside and out with alcohol swab. Allow 30seconds to dry.
  4. Alcohol gel your hands and then put on gloves.
  5. Collect your equipment – you will need a tourniquet, cannula, an IV link, syringe x2, saline, liquid wipes, and a clean sticky label. You should always use the smallest cannula possible for your intended purpose. Normally, the smallest are pink or blue and the largest is brown.Open all your packets, and check the date on all the equipment. Usually blue or pink are fine, but brown or green may be used in emergency situations where the pateint may need a lot of fluid.
  6. Fill up the syringe with 5ml saline solution, and dispose of the needle in the sharps bin. Then fill the IV connector with the solution, making sure there are no air bubbles.
  7. Visit the patient –Put on the tourniquet. Palpate for a good vein. Ideally, you want one on the top of the hand / wrist / forearm. You should go upstream of bends and splits – you want the straightest bit you can find. The requirements of a vein for cannulation are different from those for venipuncture. For Cannulation you want a vein that is far from joints so that the cannula itself will be subject to little movement in relation to the body. preferably, you should chose a vein on the non-dominant hand. Once you are happy you have found one, clean it with the cleany thing.
  8. Wash hands again! – after you have found a good site, then wash your hands and put on new gloves. Then swab the area for 3 seconds and leave to dry (usually take about 15 seconds)
  9. Insert the cannula – do this at a small angle (about 20’). When you see flashback, you should still push it a bit further in. Push it all the way into the vein, but make sure you don’t puncture the far side of the vein! A little tip would be that when you are in the vein, retract the needle slightly, but then push the cannula tube in a little further. You need to withdraw the needle from the plastic part a little bit to check for flashback.  Take the tourniquet off BEFORE removing the needle from the cannula!
Insertion of an IV cannula
Insertion of an IV cannula. This file is taken from wikimedia commons and is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license.

10. Blocking off the cannula – you should take off the tourniquet, then remove the needle slowly. If the cannula begins to fill with blood as you are removing the needle, then you know you have got it in the right place. You can stick the cannula even further in at this stage. You can now remove the tourniquet. Withdraw the rest of the needle and the very quickly, stick on the IV connector and make sure you dispose of the needle quickly in the sharps bin. You will probably spill a little bit of blood. Use your syringe filled with saline to flush out any blood from the cannula. If you are spilling a lot of blood, then it is possible to press on the vein upstream of the cannula site to prevent as much blood spilling everywhere.

11. Stick it down – Clean away the blood, then stick down the wings of the cannula first with tape. Then stick the big sticky thing down over the cannula. Date the date sticker and stick this down. If you don’t get flashback, then withdraw the needle as far as you can without taking it out of the skin. It is less painful to poke around in the subcutaneous tissue (and saves you the time of getting a new cannula!) than sticking it back in the skin again.

IV cannula
An example of a very neatly stuck down cannula! This file is taken from wikimedia commons and is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license.

Finishing off

Mark in the notes:
  • Date
  • Location (i.e. which arm etc)
  • That ANTT was used

Complications

  • Infection
  • Haematoma
  • Nerve damage

References

Read more about our sources

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Dr Tom Leach

Dr Tom Leach MBChB DCH EMCert(ACEM) FRACGP currently works as a GP and an Emergency Department CMO in Australia. He is also a Clinical Associate Lecturer at the Australian National University, and is studying for a Masters of Sports Medicine at the University of Queensland. After graduating from his medical degree at the University of Manchester in 2011, Tom completed his Foundation Training at Bolton Royal Hospital, before moving to Australia in 2013. He started almostadoctor whilst a third year medical student in 2009. Read full bio

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