Cannulation Tips and Tricks

The thing above is a cannula, which is used to give IV fluids and medications.  As a Junior Doctor, often my sole purpose as a human being is to put this bastard thing in some drug users shit veins or an obese idiot with an ultra low pain threshold.  Now, luckily I'm pretty good at getting these things in and I'm usually the go to guy if someone else can't get one of these in.  Here are the order of events and some tips and tricks I've come up with which never let me down!

1) Primary survery: 

Have a GOOD look on both arms of the patient.  Sometimes you'll miss an easy massive vein just because you haven't taken the time to look around and palpate both arms.  Don't be a lazy douche - put on the tourniquet in several different places and feel and look!  The other day I had to put a cannula in a Hep C positive drug user.  No one had been able to put a cannula in all day for his medications so it got handed over to me (I was the house officer on nights).  He had shit veins everywhere but he had a bulging vein on his bicep - which I got straight away.  So always LOOK!!!!!!

2) Put tourniquet on:

Yep even this is possible to fuck up.  Always put the tourniquet on ULTRA tight.  Look, even if you've put it on as tight as you can it's not going to harm the patient.  It's not going to cause myonecrosis in the five minutes it takes you to have a look and put in a cannula.  So put it on TIGHT!!!! REALLY TIGHT!!! And don't place the tourniquet too proximally.  It should be a few inches above the cannula insertion site.

3) Clean the area with a swipe (let it dry).

Yeah, most people can manage this bit.  Often cleaning the skin makes the area shiner and often pronounces the appearance of the vein.  Also, rubbing the vein makes them stand out due to mast cells releasing histamine and the endothelium releasing crap like leukotrienes.  Also don't be afraid to really tap the vein hard before putting in a cannula.  It really works and you get to hit patients.  I mean really tap them hard.  I don't care what others say - it makes a massive difference and it's less painful than repeated failed attempts.

4) Put in cannula 

Ok, this is the make or break time.  ALWAYS make sure the vein is REALLY taught when going into a vein.  Do this by anchoring the vein distally to the entry site.  I'm right handed so I pull the skin taught with my left hand.  I make sure my left hand isn't too proximal to the entry site so that it's in the way (which would mean that I'd have to go into the vein at too much of an acute angle with the cannula), or too distal (which would mean I'm not able to pull the skin taught enough).

Always enter the vein at a NARROW angle!! As narrow as you go!!  People often go in at too much of an acute angle = fail already.


5) Get flashback 

Some people say go in a couple of mm because if you have flashback then the tip of the needle is in but not necessarily the catheter itself.  The fact of the matter is that this isn't always true.  I VERY rarely advance the needle any further once I get flashback.  Instead I hold the needle very very still in place and push in the plastic catheter - the needle simply guides in the cannula.  This is make or break time and loads of people fuck up here.  If you follow my advice then it should be ok.

6) Retract needle and get second flash back within the plastic catheter and advance catheter in vein 

You have to do all of this with ONE hand.  Your non dominant hand should always be keeping the skin taught.  Until you can insert the cannula and pull of the needle with one hand you'll never get good at them and will continue to mess things up.

7) Remove tourniquet, flush with normal saline, put on tegaderm sticker

Tegaderms are shit.  I always mummify my inserted cannulas with tape to make sure they don't move and that nurses don't pull them out by accident. Also alot of patients are stupid and will pull them out accidently when they go to wipe their ass or something.

EXTRA TIPS!  Finding a suitable vein is often the hardest part - esepecially in long term patients who have been stabbed constantly for the previous three years or whatever.  When finding a vein always pull the skin taught to see if the veins are malleable and able to straighten up.  Often a vein will seem like it's too short or has too many angles, but they can be straightened up.

Also, remember that if you can see it you can get a cannula in.  Often in fat people you can't feel a vein but you can see them.  There's no reason you can't get a cannula in.

Veins which are literally a green tiny thin veins - you can get blues into them.  Anything bigger is a pink at least.

Don't be afraid to go in the anterior surface of patients forearms. For some reason people tend to overlook them, but a lot of the time there are some awesome veins there.  On the anterior surface of the wrist is also often a gold mine.  It's quite sensitive and painful for the patient but there are good veins there!!

Anyways I hope this has helped someone.  This is all the shit I wish someone had told me before I started work as a ward monkey.