As part of my fellowship I began a research project offering training in US guided peripheral IV insertion to our ED RNs.
This post is a collection of techniques to aid needle visualization that we as a group have found helpful, they are all initially described in regards to vascular access but the techniques can be extrapolated to aid other procedures requiring needle visualization with US.
Several excellent comprehensive reviews of the evidence and technique exist, here is a recent systematic review.1
My hope is that the addition of some visuals might help explain some of these techniques
… if not at least they are fun to make!
Think back to grade school geometry and that crazy greek guy in the hot-tub…
Ultrasound lets you reach deeper but be sure you leave enough catheter to lie securely in the vessel.
Keep in mind when cannulating upper arms surrounded by generous.. ahem.. ‘tissues’
that interstitial infusion may be initially occult, be vigilant and remember the geometry.
Our angiocaths max out at 3cm, remember you have to account for the depth and the runway.
Here is a table with recommended target depths in excellent review available from ACEP. 2
Your ultrasound will produce the crispest image when the beam is directly perpendicular to the target. 3
Since your needle and vessel have different axes, staying perpendicular to your needle
might not produce the best image of your needle.
Try heeling the probe slightly towards your needle to improve your needle visualization when using an in-plane approach.
Bounce lightly on the skin to ensure you are centred over the target.
Reposition as needed before advancing the needle.
Even better just slide the needle under the gel and save the patient the scout-pokes!
This is likely the most common error I have seen when first using US for peripheral IVs
Unlike the IJ, peripheral veins collapse with frustrating ease under just the weight of the probe.
They hide in fascial planes and are invisible in their collapsed state. Anchor your hand against
the patient’s arm to allow fine control. Use lots of gel and float the probe….
Early visualization of the needle tip is key, be sure to insert the needle
RIGHT against the probe to avoid having your needle tip show up too far down
(suggesting you went through the target).
Sweep back slightly with the probe to allow the needle to be introduced.
You can increase your angle once you are happy you have the tip in sight.
The ‘SKI LIFT’ technique was described in 2010 to allow better visualization when using a long axis approach.
Keeping a mm thick US beam in line with a mm thick needle can be tricky.
Try lifting the proximal end of the probe and laying your needle in perfect long axis beneath it to improve your starting view.
For a detailed description see the original paper.4