Make sure your patient doesn’t have a fistula or other contraindication to an IV on the side you’re targeting. Sometimes, patient’s will have a “no BP cuff/IV on this arm” warning. Do a quick look/feel for a fistula in addition to checking for any signage in the room or asking the nurse.
Find a target vein.
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Your ideal vein should be about 0.4-1.2 cm deep, and at least 0.4 cm in diameter (source), but you aren’t always this lucky.
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Your vein should collapse with light probe pressure, and it should not be pulsatile when compressed.
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Your vein should have a dark (”anechoic”) lumen. Sometimes, peripheral veins have been accessed a lot and have a thrombus in them. You should avoid cannulating these or cannulate proximal to the clot.
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Choose the most distal site you can. It’s best to start on the forearm and work your way up. If an IV blows proximally, the vein distal to that can be compromised.
- Forearm IVs are less likely to be dislodged (the patient is moving less, and the biceps muscle isn’t there to pull the IV out) and tend to be more superficial (meaning more of the catheter is in the vein).
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Use more superficial sites when you can. There are a couple of benefits to this:
- More of the catheter is in the vein, meaning it’s less likely to be dislodged.
- Insertion is more comfortable for the patient, because you’re going through less muscle/fascia.
- The deep brachial vein is often used for PICC lines, and you want to avoid sticking these when you can to not complicate further access.
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Try to target veins away from arteries (pulsatile, non-compressible) or nerve bundles (honeycomb appearance).
- You can cannulate next to an artery, but especially if you’re just starting out, veins further away from arteries are better choices. If you’re targeting a vein next to the artery, slow down and make sure you can truly see the needle tip as you go.
Set up your IV supplies, including connecting the IV extension tubing to a flush.
Turn on the “Needle Finder” or other centerline marker on the ultrasound machine.
- This helps make sure that your vein is mid-line, and that you’re targeting midline. If your machine has it, also turn on the “Procedure Mode” that stops the screen from timing out.
Place the machine across from you, in line with the target vein.
- You can have the machine anywhere, but having it directly across from you helps for comfort and with spatial awareness with the needle (when I move the needle left, it moves left in front of me on the machine).
If using a probe cover, apply a layer of gel between the cover and the probe.
- This improves visibility. Note that ACEP recommends covers.
Chloroprep the entire arm.
- This lets you scan around for potential sites after cleaning. Use alcohol if the patient has a chloroprep allergy (rare).
Tourniquet the arm.
- Apply it proximal to your target site. I’ve found that placing it in the mid-upper arm can plumpen veins far distal and allow you a broad area to scan and potentially target. Consider using two tourniquets (right next to each other) if you expect access to be difficult.
Find your target vein, make sure it compresses, and scan proximally and distally to make sure it follows a straight path.
- Check compressibility to ensure you’re in a vein. Make sure no obvious blood clot (echogenic/white material) in the vein you’re targeting.
Puncture the skin with the needle at ~45 degrees, holding it from above.
- Make sure your needle is at the center of your probe, and that the centerline on the screen is centered on the vessel. Generally, if the target vessel is deeper, you want to puncture at a steeper angle so more of your catheter is in the vein.
- Some people puncture the skin right at the edge of the probe, others a few mm or a cm away from it. I have had success puncturing right at the edge.
- You can sometimes see the skin tenting/wiggling on ultrasound right before puncturing, and this can help make sure you’re in line with the vessel.
Right after puncturing the skin, try to find the needle tip.
- If you see a “shadow,” but no needle tip, then you’re probably over the body of the needle, not the tip. You need to move your probe proximally.
- Note that only the tip of the needle regularly shows up bright white on the ultrasound.
- Fan your probe (change its angle) if you can’t find the tip. You might have to have the probe at ~30 degrees so it’s perpendicular to the needle, not perpendicular to the skin.
