iPhoneIcon_BigA study in AJEM compares ultrasound visualisation of the subclavian vein using the supraclavicular and infraclavicular approaches.  With the increasing dominance of procedural ultrasound in central vein cannulation, perhaps there will be a shift towards supraclavicular cannulation at the expense of the classical infraclavicular approach.

Screen Shot 2014-09-16 at 16.34.05It’s interesting to see how our junior registrars embraced procedural ultrasound when placing central lines.

When working independently they always use ultrasound and most of them go for the IJV as it is easier to visualise on US.

A lot of our registrars, despite having been with us for some years, even refuse to blindly cannulate the IJV, SCV or femoral line without supervision.

I don’t like it. While ultrasound for CVL is the current standard of care, I’m not sure that’s an excuse for not knowing the blind techniques.

Another observation is how the IJV line placements, with the increasing use of ultrasound, are steadily creeping in the caudal and lateral directions. With US the registrars seem confident to cannulate not only further down the neck but they also tend to place them much more laterally/posteriorly. In extreme cases registrars, without knowing it, have cannulated the subclavian vein from the top of the shoulder using the, in my part of the world anyway, largely forgotten supraclavicular approach for cannulating the SCV.

The study
98 volunteer ED patients were ultrasounded in order to determine which approach, supraclavicular (SC) or infraclavicular (IC), allowed for the best visualisation of the subclavian vein. Both left and right approaches were assessed. Visualisation was scored on a Likert scale.

1 – SCV not located and cannulation impossible.
2 – SCV located but cannulation difficult
3 – SCV located but the physician would prefer another cannulation site.
4 – SCV located and the physician would be comfortable cannulating
5 – Excellent view of the SCV and cannulation anticipated to be easy.

Mean Likert scores for the four approaches were
Right  SC 4,08
Right  IC  3,07
Left     SC 3,82
Left     IC 3,12

Physicians were also asked which view provided the best view for cannulation. Overall the SC view was preferred over IC in 77% of patients.

Take-home message
According to the authors this study demonstrates that the ultrasound guided SC approach is superior to the IC approach for visualisation of the SCV. Optimal visualisation should result in easier and safer cannulation. So, it might be time to include the supraclavicular approach in your quiver.

Study lives here:
Am J Emerg Med. 2014 Aug;32(8):905-8. doi: 10.1016/j.ajem.2014.05.001. Epub 2014 May 10. A comparison of the supraclavicular and infraclavicular views for imaging the subclavian vein with ultrasound. Stachura MR1, Socransky SJ2, Wiss R3, Betz M4.

How to do it
Read our earlier post for an overview on the supraclavicular central line. And another video here:

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