RE: Lung ultrasound in cardiogenic pulmonary oedema

Roger Wilkinson — Mon, 20 Jun 2022 21:09:57 GMT

You are the gold standard Dave

Many thanks again

Agree with you on training. I've significantly changed what I try to teach people these days. Am working on a GP scan protocol (to cover heart, lungs, thorax, abdo) at the moment and thinking to abandon all cardiac measurements and focus instead on subjective assessment of chamber proportions, septal bowing, auricular shape, lung ultrasound.

I've seen several chihuahuas now with early DMVD and b lines apparently due to URT obstruction caused by laryngeal saccules.

...and perplexing cats with cardiomyopathy plus b lines apparently due to concurrent interstitial pneumonia.

Yeah, not easy!

RE: Lung ultrasound in cardiogenic pulmonary oedema

Dave Dickson — Wed, 15 Jun 2022 11:44:07 GMT

Hi Roger

It's an interesting question. Here are my few pennies...

1. I agree, CXR is poorly sensitive for pulmonary oedema. And many vets struggle to either get diagnostic views, or interpret them correctly.

2. CXR is the historical gold standard and, as ever, it takes a while for a new standard to appear. This happened in human medicine - I remember a lecture by a French imager who published 100+ papers and spend 20 years to convince the general medical community that LUS was useful, let alone better. I expect it will take us a similar amount of time to catch on.

3. From what I see in practice, LUS is used badly by a lot of people. I am inundated with over diagnosis of B-lines in CHF - I think this is probably a combination of wishful thinking by the vets (same reason they over diagnose PO on CXR) and bad training. I think if people are going to use LUS to rule CHF in or out, they need to combine it with at least a left atrial check. It seems to be the emergency practices who promote T-FAST and the like yet I don't think they are training people very well in it.

4. For me, big left atrium plus B-lines pretty much sells CHF. However, I see a lot of lung artefacts in non CHF cases - I'm comfortable with it, but I think many people struggle. I prefer E/IVRT but I accept that that isn't a tool for most people.

So in summary, I agree that LUS has a place, it probably deserves a bigger place in cardiology than we currently give it, but we need to focus on training vets in practice to use it more widely. Everyone always wants one cheap, easy test (proBNP is a good example) yet in medicine, things are never that easy and people need to remember that it usually requires a combination of findings (history, physical exam, diagnostics) to make a diagnosis of a complicated and very variable presentation like congestive heart failure.

[quote userid="16471" url="~/001/veterinary-clinical/small-animal/cardiology/f/expert-help/30326/lung-ultrasound-in-cardiogenic-pulmonary-oedema"] Is it because people are often not very good at separating B lines from other lines? Or it's because we don't have the right set of criteria to define what's positive Vs negative yet?[/quote]

For me, I think it's both. And more - diagnosing CHF is just plain hard, a lot of the time. People (who write books and articles) often make out like it is easy but I personally find it a challenge.

Dave