Posted by Matthew Mac Partlin on Friday, November 16, 2012

OK, so we all love ultrasound; who doesn't? I remember a time when ultrasound was a diagnostic utility that gave medical school physics lecturers something to talk about and later on, a modality that lived somewhere at the back of a dark corner of the radiology department, crooned over by pale-faced, moon-eyed individuals. In the past couple of years, it is a modality that has arisen phoenix-like and has become almost the next Seldinger technique, with a multitude of applications ... vascular access, intracranial pressure assessment, detection of pneumothoraces and free intraperitoneal fluid. And now with devices like the Sonosite M-turbo and GE's V-scan which mean U/S is no longer tethered to a hospital wall and has gained popularity in the pre-hospital field, with both diagnostic and interventional uses.

Here's another use that I've been aware of, but haven't looked at properly until recently: Confirmation of endotracheal tube placement in the trachea and ETT tip position.

Is there anything that ultrasound cannot do? (Well, yes there is, but let's not dwell on that too much for now).

Sure, you could use an EtCO2 monitor (Actually, you SHOULD be using one. It's the standard of care and not using one was identified by the NAP4 audit as a major contributing factor to poor airway outcomes), but there's always that nervous period when you are wondering if the colourimeter is out of date or if the waveform is ever going to appear and be sustained for more than 5 breaths. With ultrasound, you could find out in real time whether the ETT is in the trachea or the oeophagus and if it has gone too far into the right, or less often the left, main bronchus. But you'll still connect the EtCO2 monitor to confirm what you now already know.

So how do I do this and what's the evidence to back me up? Thankfully, I haven't had to work too hard, because Matt Dawson and Mike Mallin, who run the Ultrasound Podcast website, have put up a podcast that goes through the how to and numbers for using ultrasound to confirm ETT placement in the trachea and making sure that the tip lies lower than the vocal cords and higher than the carina. Check it out and then go and watch some of their other podcasts.