How to Cannulate in the Back of an Ambulance

Like everything else you do as a Paramedic, you have to ask yourself if this procedure is necessary. Do I need to cannulate this patient? Sometimes they need a drug to be administered intravenously, sometimes they are at a high risk of deteriorating and need a cannula for precaution. Whatever the case, ensure that you do not spend excessive time at the scene attempting to cannulate at the detriment of the patient.

Once you’ve decided to cannulate the patient there are a number of steps you may take to make the procedure much easier for yourself. You should determine if you need the cannula before you can move the patient, or wether you can wait and cannulate him or her in the controlled environment of the back of your Ambulance. Ultimately, you must follow your own Ambulance Service’s procedures, but these are the steps that I  follow as a paramedic to make the process easier:

Reassure the patient and explain what I’m going to do and why I’m going to do it. One of the most important aspects to cannulating a patient is getting the patient’s consent and trust. The patient isn’t going to consent to a paramedic putting a cannula in because he or she needs the practice. So tell them why you need to insert it: for example, “I’m going to put a small needle in the back of your hand so that I can give you morphine and take away your pain.”

Make sure the environment is exactly as you want it – unlike a Doctor in a hospital, as a paramedic your environment is rarely controlled, so you have to modify it to make it easier for you to cannulate. If you can turn on extra lights in the room, or get someone to hold a torch on the side of the road that may help. I put a tourniquet on both arms, and get comfortable so that I’m not in an awkward position while I’m cannulating. Canulation involves some fine motor skills, and the easiest way to do this is to make yourself comfortable.

I continue chatting to the patient (or taking more of a history) while I get everything out of the drug kit and ready for use. This includes cannula, cannula reflux valve (bung), something to tape it in with, and of course ensure that the sharps container is open and easily accessible. If you’re going to cannulate in someone’s nice clean house it’s a good idea to put down a bit of cloth (bluey) or something to ensure that you don’t accidentally spill any blood on the floor, bed, or anything else (if this occurs, you will not only look un-proffesional or incompetent, but also they will remember the mess you made of their carpet and the cost, irrespective of the benefit you gave their family member). It is important to keep the patient focussed on something other than the fact that you’re about to put a needle into their arm, hand or leg. Also, it makes you look more comfortable with what you’re doing, and relieves the patient of the fear that this is the first time you’ve ever done this before (even if it is).

Okay, now I start to actually determine where I’m going to insert the cannula. The right arm is my preference if possible (only because this is closest to the paramedic seat and I get to avoid reaching over the patient). I then look for the back of the hand (this generally seems to hurt the least), followed by the forearm, which I like because it is a long straight part of the arm, that makes it less likely the patient will accidentally knock it out once I’ve put it in. Lastly, I’ll take the large veins of the cubital-fossa. I look for straight veins, wide veins, veins without bifurcations (separations into two veins), which often have venous reflux valves that cause nothing but trouble. If I’m really having trouble finding a vein that I like I will get the patient to leave their arms drooped as low as possible causing the venous blood to fill the veins. Personally, I have found that lightly slapping the back of the hand will help irritate the veins, causing a very mild inflammatory reseponse which releases chemical mediators which cause vasodilation and makes for easier cannulation (however, there is evidence to suggest that this ultimately makes it harder to insert the cannula; but in my experience this is a tried and true method of bringing a vein up). If I find a small vein that I don’t quite feel comfortable cannulating, I will follow it up and “milk” the blood into the vein so that I have a nice easy wide vein to cannulate. You will find some good paramedics who “never miss a cannula” -are so good because they always make sure that the vein is clear, striaght and has been prepared perfectly so that any paramedic can insert a cannula there.

Use the right cannula – it always amazes me that a paramedic will try to shove a large bore cannula in a little vein when they are planning on using it only to administer a medication that is very small. For example, giving morphine for pain relief.

Okay, so you are now ready to cannulate – generally speaking, if the road is relatively smooth, there is no difference in cannulating in the back of a moving Ambulance or cannulating in a hospital bay (although new paramedics may perceive the need to stop the Ambulance before cannulating. If the road is rough, I will set everything up, pick a vein, alcohol wipe it, and then, get the Driving Officer to pull over just before I actually insert the cannula – this should only take 10-15 seconds. And then you should be able to continue driving towards the hospital.

Depending on type of cannula and how you are comfortable holding it, hold the cannula by the insertion pads with the thumb and fingers to insert needle into skin. Vissually inspect the cannula needle to ensure needle bevel is pointed upwards (this means that the sharpest point is going to pierce the skin and hopefully the vein).

Anchor the vein with gentle skin traction. This can be achieved through a variety of methods depending on the site chosen for venepuncture. For the hand, I traction the skin by gently holding the hand into a fist, which naturatally brings the veins to the surface and anchors them; for the forearm, I will apply gentle lateral traction of the skin by holding the arm from underneath; for the cubital fossa, I still often use the non-dominant hand’s thumb to pull on the skin. These are my methods, but whatever works for you is good too.

Insert needle at a 15-30 degree angle and wait for flashback of blood (don’t forget this may take longer if the patient is peripherally shut down).

Once blood flashback occurs, advance the needle a small amount to ensure the entire needle bevel is in the lumen of the vein.

Then lower the angle of the cannula to 10-15 degrees and slowly advance the catheter.

Remove the tourniquet, and apply pressure to the vein just proximal (above) the cannula site to ensure that the blood doesn’t pour out the vein. If you do this properly, you can generally save yourself having to clean up the spilt blood that pours out the cannula.

Remove cannula needle and place it immediately in a sharps container.

Attach cannula reflux valve.

Tie cannula in according to specific Ambulance Service Paramedic policy – remember, the sign of a good paramedic is his or her ability to keep a cannula insitu, not just insert it. There’s no point going through all the trouble to insert a cannula only to have it pulled out or fall out a couple minutes later because the patient (naturally) moves their arms or rolls over suddenly. 

Write the time and date of insertion on the cannula cover – don’t forget that this may be the only cannula used in the patient while he or she is in hospital. As a general rule, cannulas shouldn’t stay in-situ for greater than 3 days in order to reduce the risk of infection.  Most Nursing and Medical staff in Australia will remove a cannula if there is no date of insertion on the cannula to identify how long the cannula has been in-situ.

Flush the cannula with saline to ensure that it is correctly positioned and patent.