Tuesday 27 April 2021

Outpatient Treatment of Low-Risk Pulmonary Embolism in the Era of DOACs: A Systematic Review

Is it safe to send someone home with a low-risk PE on a rivaroxaban or apixaban?

This systematic review identified 12 studies (four RCT’s and 8 prospective cohort studies) that might provide us the answer. Of course, the foundation author is Jeff Kline.

Patients were mostly categorized as “low risk” by using the HESTIA, PESI, or sPESI scores. (I personally like the HESTIA score as it has face validity and seems to send a lot of patients home.)

1,814 patients were included in this systematic review and they pretty much all did fine. Rates of mortality, recurrent VTE, and major bleeding was all below 1%.

“There was a single instance of PE related mortality within 90 days among the 1,814 outpatients in high quality studies.”

The authors state they have three main findings.

First, there are few controlled studies. But to answer the question, I don’t think we need a control arm. A well conducted cohort study should be fine.

Second, there were low rates of major adverse outcomes.

Third, there was no difference in patient outcomes with warfarin or with DOACs. For what it’s worth, 97% of the DOACs chosen were rivaroxaban.

It appears that the preponderance of evidence shows that sending low-risk patients home with oral rivaroxaban is safe.

However, there is a currently a large study by Jeff Kline enrolling patients in 33 hospitals in the USA to look at a protocol for outpatient management of VTE. So of course, our thoughts could all change.



Maughan B, Frueh L, McDonagh MS, et al. Outpatient Treatment of Low-risk Pulmonary Embolism in the Era of Direct Oral Anticoagulants: A Systematic Review. Acad Emerg Med 2021;28:226-239. [Link to article]

Monday 26 April 2021

Apnoeic oxygenation was associated with decreased desaturation rates during RSI in multiple Australian and New Zealand ED’s

The Australian New Zealand ED airway registry (ANZEDAR) includes 43 ED’s that prospectively submit data on patients they intubate. It has provided a wealth of information on how we manage airways.

This study looked at patients who got apnoeic oxygenation (ApOx) during RSI vs. those that did not. (ApOx was defined as patients getting up to 15L of oxygen via a nasal cannula.) They excluded patients intubated during cardiac arrest and those that got BVM or NIV during the apnoeic period.

The primary outcome was rates of desaturation to <93%.


1669 (66%) patients got ApOx and 850 (33%) did not. Desaturation occurred in 10% of the ApOx group vs. 13% in the other group.

ApOx rules!!!

Maybe… maybe not…

This was not a randomized trial. As such, there could have been confounding factors or that led to the differences observed. (But to be fair, I would imagine that doctor would have been more likely to provide ApOx in those patients that they were worried might desaturate. Therefore, making the ApOx group look potentially worse. But perhaps I’m wrong…)

This was a study of registry data. Unfortunately, this data is often of poor quality. It’s possible we may have a “garbage in, garbage out” phenomenon. Intubation is often an anxiety provoking procedure where doctors get task focused. They may have not really been aware of how low the saturations dropped. Ideally, one would get the data from a research assistant who is tasked to collect accurate data at the time.

Desaturation is not really a patient-oriented outcome. Transient hypoxemia probably causes no harm in most patients. Ideally, we would look at more important outcomes involving real patient morbidity and mortality. But good luck powering such a study!

If ApOx doesn’t really change any important patient outcomes than arguably it may be one extra step that distracts us from getting the job done. In times of high stress, we need to keep our processes as simple as possible.

The debate continues…



Perera A, Alkhouri H, Fogg T, et al. Apnoeic oxygenation was associated with decreased desaturation rates during rapid sequence intubation in multiple Australian and New Zealand emergency departments. Emerg Med J 2021;38:118-124. [Link to article]

Sunday 25 April 2021

The Use of Tranexamic Acid to Reduce the Need for Nasal Packing in Epistaxis (NoPAC): RCT

We all know tranexamic acid (TXA) is good for everything. It’s great for trauma, all kinds of bleeding and heck, tastes great on Weet Bix. But a lot of this enthusiasm is now being challenged by hard science.

These researchers from the UK randomized 496 patients with epistaxis (after failure of nasal compression and topical vasoconstrictor) to topical tranexamic acid or placebo.

Trial treatment was with cotton wool dental roll either soaked in 200mg tranexamic acid or sterile water. The dental roll was left in for 10 minutes and could be repeated a second time if the bleeding continued.

The primary outcome was the need for anterior nasal packing.


The mean age was about 70 and two thirds were on anticoagulants.

In the end, the rates of anterior nasal packing were about the same in both groups at 40%.

The authors conclude the that tranexamic acid is no better than placebo.

But I’m not so sure this is going to change practice to those who are tranexamic acid afficionados.

The inclusion of mostly elderly patients on anticoagulants could have diluted the results to the null hypothesis. These are a hard group to treat and, in my experience, often get nasal packing. And remember, the patients enrolled in this study had already failed compression and vasoconstrictors.

So, perhaps TXA will work better in a different population.

Many would argue that TXA is cheap and very unlikely to cause harm. But so are bedside anti-epistaxis incantations. Either one of them is possibly a waste of time and distracting from performing other measures.

Perhaps save TXA for the Weet Bix? Hmmmm….



Reuben A, Appelboam A, Stevens K, et al. The Use of Tranexamic Acid to Reduce the Need for Nasal Pcking in Epistaxis (NoPAC): Randomized Controlled Trial. Ann Emerg Med. 2021 Feb 18;S0196-0644(20)31461-X [Link to article]




Diagnostic Accuracy of the HINTS Exam in an Emergency Department: A Retrospective Chart Review

The HINTS exam for evaluation of patients with acute vestibular syndrome (AVS) has been all the rage over the past decade. Originally described in 2009, it reported phenomenal accuracy at differentiating peripheral from central causes of vertigo. However, the performance of the test has mostly been validated by neurologists and otolaryngologist.

To qualify for a HINTS exam, patients must have AVS characterized by continuous dizziness and ongoing in the ED, nystagmus, and gait unsteadiness.

This retrospective chart review looked at how often a HINTS exam was appropriately performed and the sensitivity & specificity of the test at this single ED in Ontario. The authors point out that doctors did not get any specific training on the HINTS exam prior to this review.

A total of 2,309 patients presented with a primary complaint of vertigo or dizziness. Almost 20% got a HINTS exam! However almost all (96.9%) of them were performed inappropriately as it was not clinically indicated. In addition, many patients got both a Dix-Hallpike test and a HINTS exam… which should never happen as they are “intended in mutually exclusive patient populations.” 

In the end, the sensitivity & specificity of the test as performed was terrible.

What are we to conclude?

At this single ED, the HINTS exam performed poorly in untrained doctors who did the exam on the wrong patients.

They conclude that “additional training of emergency physicians may be required.” This is quite an understatement.

Of course, this study is far from perfect, but it serves as a cautionary tale.

This is not the only study suggesting a problem. A systematic review and metanalysis in 2020 concluded that “the HINTS exam, when used in isolation by emergency physicians has not been shown to be sufficiently accurate to rule out a stroke in those presenting with AVS.”

I do not think the HINTS exam is overly simple. Nor did I believe there are enough cases of vestibular stroke for an average emergency physician to develop and maintain proficiency with the exam. But perhaps I’m wrong… there are some very clever doctors who disagree with me.

Until such time we get further evidence, we should not be giddy over the HINTS exam.

 (** Addendum 28/4/2021: Please see comment section for feedback on my summary from Dr Peter Johns. He is a Canadian Emergency physician and vertigo guru. He wrote the book on vertigo... literally wrote the chapter in Tintinalli)


Dmitriew C, Regis A, Bodunde O, et al. Diagnostic Accuracy of the HINTS Exam in an Emergency Department: A Retrospective Chart Review. Acad Emerg Med 2021;28:387-393. [link to free full text]