The Recipe For Success: Step 1 - Gather Your Ingredients
Doing it "the old way" will result in failure
You will need a longer IV than standard nursing IV kits contain. If you grab the convenient 1" catheters, you may get into the vessel but the IV will blow very quickly. That's because it's required to have >50% of the catheter in the vessel to be viable long-term, and the veins you're using with ultrasound are deeper than the very superficial veins used for blind cannulation. So! Grabbing 1.75" or longer catheters are Step 1.
The right tools are important
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An 18g long IV catheter will be the best place to start in most adults. You will also want to make sure you have a tourniquet, sterile gel, a sterile probe cover or sticker, and something to wipe up the gel afterwards (gel or skin prep wipe)
Want more proof?
Catheter length residing in the vein after cannulation is important. And you will burn more catheter getting to the vessel than you think. Check out this study that determined that "100% of IVs failed when <30% of the catheter was in the vein; 32.4% of IVs failed when 30%-64% of the catheter was in the vein; no IVs failed when ≥65% of the catheter was in the vein (p<0.0002)." Ultrasound-guided intravenous catheter survival impacted by amount of catheter residing in the vein - PubMed
Step 2 - How To Choose The Best Target
Arm Anatomy Varies - So Prescan!
"Start distal and move proximal" is an appropriate old adage here. Forearm veins are a great choice, but remember to not press too hard with your probe while scanning. You may be collapsing the very vein you're looking for! So float over the arm on a cushion of gel
Recognize Danger
Important note: you may be tempted to choose a large juicy vein located central in the upper arm as your target. Be cautious - the brachial vein (which you will see is touching the brachial artery) is a deep vein, under a layer of brachial fascia, which means it's a dangerous target. If the catheter dislodges, you will not know right away and could potentially cause harm.
Step 3 - The Secret Sauce
If you remember this, you'll be unstoppable
The most difficult part of ultrasound guided peripheral IV's is identifying the needle tip. It looks the same as every other part of the needle. For example, in the ultrasound image to the left we see a white circle (needle) in the vein. This could be the needle in Position A and be great, or it could just as easily be seen with the needle in Position B ... and your needle tip may actually be somewhere dangerous!
So how can you tell it's the needle tip?
Here's the secret: you can't. Unless you carefully advance your ultrasound probe until you just barely get past the needle. Then stop! Now advance the needle a tiny amount - 1mm - until you see it again. Then stop!
If you remember this, you'll be unstoppable
By repeating this 5-10 times or so, you will be able to carefully guide the tip of the needle precisely where it needs to go. This might sound backwards but it's true: "do not advance the needle if you can see it". Why? Because once you see it you don't know if its the tip anymore or not. So to know you're guiding it properly, you should be advancing your ultrasound probe into fresh territory (a tiny amount and stop), then catch up with your needle (a tiny amount and stop). When you master this, you'll be unstoppable.
By Andrew Butki, DO / WSU AEMUS Fellowship
