January 2024

Authors

• Andy Neill

• Dave McCreary

Clinical question

• What does undifferentiated aortic dissection look like when it presents to the ED Authors - McLatchie 2023 EMJ Title - Diagnosis of Acute Aortic Syndrome in the Emergency Department (DAShED) study: an observational cohort study of people attending the emergency department with symptoms consistent with acute aortic syndrome

Background

• Authors open with "AAS could be considered a wold in sheep's clothing". No one could argue with that. We know we miss this, we know it's a very hard diagnosis to make. - we have a list of symptoms considered potentially associated with AAS. What do these patients look and do any of the existing cinical decision rules help?

Methods

• 27 EDs throughout the UK, some of you may have been involved in recruiting onto this. Data all from 2022. - inclusion criteria were kept broad with chest, back and abdo pain all considered. Syncope or theoretically any malperfusion symptoms could be enrolled. This is deliberately very broad and you can imagine it's a very wide net. But i emphasise that it has to be because AAS can present in all kinds of odd ways. - there was a mix of prospective and retrospective data collection. Which i think is a little concerning. If i'm collecting data prospectively for an AAS study i'm probably more likely to think more about it and maybe test more and certainly if i'm entering data prospectively by definition i'm considering the diagnosis. Whereas when it's done retrospectively we have no real way of knowing if the clinician considered it and as such their assessment may be very different - longer term outcomes (eg death or a delayed diagnosis of AAS) were looked for on the electronic health record. This is not an especially robust method, as patients may present somewhere else or die in the community and you would miss them. - their power calculation of >5000 pts allows for 125 CTA orderd and picking up 6 confirmed AAS. In other words they knew the rule in rate would be low

Results

• 5500 pts included, ~40% prospectivey about 45% retospectively and unclear in 15% - interestingly this represented ~7% of all majors type presentations in the study period. That's a huge proportion where we think AAS is within the differential. And despte CT being the definitive test we probably can't do CT scans in 7%. This emphasises again as the authors point out that this should remain a research priority. - found 12 AAS on CT with common alternate diagnoses being PE, pneumonia etc...

• Almost all confirmed AAS had the diagnosis in the differential which is somewhat ecnourarging

• None of the decision tools were any good in terms of sens/spec, of note they all had amazing nepgative predictive value which merely reflects the fact the denominator was so huge and the actual diagnosed AAS was so small.

Thoughts

• There is lots of great things here. I love the emphasis on a diagnosis that we struggle with and that really matters.

• It does tell us a lot 1) it tells us that none of the decision rules seem to work in this cohort, and 2) tells us that a whopping 7% of our majors presentations are considered to have symptoms we thing are potentially from aortic issues.

• Unfortunately it does not really tell us quite well how to pick it up.

• As i have mentioned before I have definitely missed at least 1 aortic dissection in my career and given how long i trained for i likely missed several others. But i have seen a change where the threshdol to CT for dissection has come way down due to various publicity and change in guidelines. Interestingly with my ICU hat on, i look after lots of dissection patients post theatre and there is a recurring theme of patients presenting to ED and a bedside echo shows something that prompts a CT. This is of course complete anecdote but we need to use all the tools we have to make the diagnosis.

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Authors

• Andy Neill

• Dave McCreary

Clincial question

• Does everyone with a low GCS need a tube Authors - Freund et al , JAMA 2023

Title

• Effect of Noninvasive Airway Management of Comatose Patients With Acute Poisoning

Background

• There is an old adage, GCS<8 intubate. Like most such pithy lines you can imagine that it's largely arbitrary. Indeed the GCS is a prognositc scoring system that predicts outcomes in TBI and is not designed to do things like predict if an airway is "protected" in inverted commas.

• As such those of us who work in EM have realised over many years that many people with a low GCS score do just fine if you position them nicely and keep an eye on them. In particular these are people for whom you have confidence that the diagnosis is intoxication with short acting benign agents like alcohol or maybe benzodiazepines. A regular night shift may involve observation of multiple such patients for a few hours enabling them to "metabolise to freedom" and a morninh discharge following regaining consciosness and tea and toast.

• This is a study to back up that little narrative

Methods

• This was a multicentre RCT of 20 EDs in France. It was as you might expect unblinded

• If you had a GCS <9 and the suspicion was acute poisoning you could be included. You would be excluded if the clinician looking after you felt yo should be tubed for some good reason including poisoing with nasty agents that have a less than benign clinical course.

• You were randomised to witholding intubation (unless a sensible list of things happened) or in the control group, intubation if the doctor wanted to.

• This period of radnomised observation only lasted 4 hrs. i suspect if you were still unconscious after the period most would have got tubed

• Primary outcome of death, ICU stay, hospital stay.

Results

• 220 pts randomised

• 60% male, 67% alcohol intoxication (though there were benzos and GHB too)

• 16% vs 57% intubation rates

• No deaths either group

• Shortened ICU and hospital length of stay.

Thoughts

• I think this is a great deal. it validates what i think many of us have done our whole careers. It takes experience and you do need to pay attention but many of these patients are best managed in the ED wihout a tube. I think the key is experience and if you have doubt then get the CT head or put the tube in. No one should be upset with you for doing more to keep the patient safe but this study shows that for many patient you can safely withhold intubation.

• I have seen some sceptical opininons on this trial online, in particular from folk who don't happen to work in the ED, they found the idea of randomising people to no intubation to be unethical.

• This trial importantly does have a sensiible list of reasons as to when to intubate someone with a GCS <9 but it suggests that GCS<9 on its own means very little.

Aortic-dissection

Blood Transfusion Part 1

Blood Transfusion Part 2