Bevel up or down for IJ central lines?

Lim T, Ryu H-G, Jung C-W, Jeon Y, Bahk J-H. Effect of the bevel direction of puncture needle on success rate and complications during internal jugular vein catheterization*. Critical Care Medicine. 2012 Feb.;40(2):491–494.  PMID 21983370

METHODS

• elective thoracic surgery pts
• US guided
• measurements by consultant, lines by a resident
• randomised bevel up or down
• end point was rate of post wall haematoma by US after the procedure- and this is the key point – there’s no definition of what a haematoma was. They give a picture as an example but I don’t know what it means

RESULTS

• n = 338
• 6 v 17 post wall haematomas favouring bevel down approach
• rates of success and everything else equal

THOUGHTS

So it seems bevel down is better. Though it worries me that there was no attempt to define what a haematoma is.

I suspect (though I honestly wouldn’t be sure) that I’m a bevel up person normally, but this would make me think of changing my mind.