I spent some time this week with the interns shoring up their technique for using ultrasound in vascular access. Specifically, I’m referring to an out-of-plane approach – which I recommend in most cases as it lets you see the needle in relation to any large arteries or nerves that may be around.

I think if I had one point to reinforce, it would be the fact that this a dynamic process for BOTH HANDS.

Without a doubt, the rookie mistake here is holding the ultrasound probe in a fixed position while gouging with the needle and not realizing that the dot on the screen is not the tip of the needle. Remember, in cross section, every part of the needle will look like a white dot on the screen. There is no way to know what part of the needle you are looking at. The only defining feature of the tip of the needle is the fact that if the probe is positioned just ahead of it, it will ‘come into the picture’ as it is advanced. Once the needle is on the screen, there is no way to differentiate the tip from the shaft. So, the technique here is to keep moving the probe just in front of the needle so that you are constantly seeing it ‘come into the picture.’ That makes it clear that you are seeing the tip of the needle. Otherwise, the tip could be anywhere – the lung or carotid artery, for example.

Ultrasound guided vascular access using an out-of-plane technique requires two active hands. There is frequent, albeit subtle, movement of the probe to keep it just in front of the needle tip (left hand in my case) as well as advancement of the needle (right hand).

This is not a difficult to task to master, but it does not come naturally. It takes time and repetition. From my end, it is very clear when learners master this step. Practice on a gel phantom or a chunk of tofu actually works nicely as well. Once this is easy, you can progress to an in plane approach where the opposite is true: the probe is held static.