Tick killing in situ before removal to prevent allergic and anaphylactic reactions in humans: a cross-sectional study

The Australasian Society of Clinical Immunology and Allergy (ASCIA) recommends killing ticks in situ with an ether-containing spray and allowing them to drop off. The rationale is that this helps prevent allergy or anaphylaxis, since removal by other means might squeeze intra-abdominal contents and introduce more allergens.

One would think such a recommendation is based on high-quality evidence. It turns out this paper is probably the best evidence we have to inform practice. Oh great! Let’s have a look.

Just a word of warning, this ride is about to get bumpy.

Let’s start with the paper’s conclusion. It states, “[Our] results support killing ticks in situ before careful removal by mouthparts to reduce allergic/anaphylactic reactions…”

This wording suggests the researchers prospectively compared freezing with other methods of removal. But they didn’t. I am not joking.

The authors report their experience essentially using one method of tick removal and conclude it worked well. Once again, they did not properly compare it with anything else.

They do mention that anaphylaxis still occurred in some patients after ticks were frozen. Is it possible that the brief act of freezing a tick causes it to regurgitate more allergenic contents compared with careful removal using fine tipped forceps? The honest answer is that we simply do not know. There is clear clinical equipoise here and a proper comparative trial would be entirely ethical.

Unfortunately, there has now been a considerable amount of confidently expressed advice from ASCIA and others telling people that ticks must be killed before removal and that you should “freeze it and don’t squeeze it.” The certainty of these recommendations is not justified based on the evidence available.

One might ask, what is the harm in freezing before removal? Well, putting aside the possibility that we do not actually know whether freezing could worsen allergic reactions, the sprays themselves come with some cost. I checked my local pharmacy and they were about $25. The recommendation may also encourage people to present to busy emergency departments and wait hours before removal. Even worse, some people may become reluctant to remove ticks at all, despite prolonged attachment being associated with tick paralysis and tick-borne infections.

Oh, and not to be pedantic, but the title of the paper describes it as a cross-sectional study. It isn’t. It’s a prospective case series, or at best a prospective cohort study without a comparator group.

This is not a rant. It is simply pointing out the obvious. There is currently no good quality evidence supporting the recommendation to kill ticks in situ before removal. For all we know, it may even make things worse.

The emperor has no clothes!

 

Covering:

Taylor BWP, Ratchford A, Nunen S, et al. Tick killing in situ before removal to prevent allergic and anaphylactic reactions in humans: a cross-sectional study (although it’s not). Asia Pac Allergy. 2019;9(2):e15. [Link to full text of paper]

 

Evolution of secondary findings in acute cholecystitis: A temporal analysis from POCUS to subsequent imaging

Sonographic signs of cholecystitis tend to progress from the primary findings of cholelithiasis and a positive sonographic Murphy’s sign to the secondary findings of gallbladder wall changes, namely wall thickening and pericholecystic oedema. The presence of these secondary signs increases the specificity for diagnosing cholecystitis and surgeons often rely on them to guide admission and treatment decisions.

How quickly these changes develop has not really been established… until now.

These authors from the USA performed a dual site retrospective cohort study with good methodology. They included adult patients who underwent POCUS in the ED and later had a formal radiology ultrasound after admission.

The gold standard for diagnosing cholecystitis was primarily positive histology following cholecystectomy.

A total of 352 patients were included, with a 50% prevalence of cholecystitis.

Among the 252 patients without initial gallbladder wall changes on ED POCUS, around 20% developed wall changes on subsequent imaging, with a median time of 4 hours. Gallstones and a positive sonographic Murphy’s sign predicted the later development of wall changes.

The authors conclude that the evolution of cholecystitis is a dynamic process. This makes intuitive sense, as inflammatory conditions evolve over time, so there are no major surprises here.

There was another important finding. Acute cholecystitis can occur without gallbladder wall changes. In this study, most patients with cholecystitis did not have wall changes in the ED and never developed them prior to cholecystectomy. Importantly, these patients had positive histology following surgery, so this was unlikely to represent false positive diagnoses.

Interestingly, there was no mention of stones impacted in the gallbladder neck. This is the most common cause of cholecystitis. In my experience, it is also a fairly specific finding that strongly suggests developing cholecystitis.

So what is the take home message?

Yes, cholecystitis is a dynamic process. It takes time, with a median of 4 hours in this study, for gallbladder wall changes to appear on ultrasound if they are going to develop at all. This raises the possibility of repeat imaging in early presenters or in patients observed in a short stay unit when there is reasonable clinical suspicion for cholecystitis. 

Covering:

D. Ivanov, D. Cannata, K. A. Chin et al. Evolution of Secondary Findings in Acute Cholecystitis: A Temporal Analysis from Point of Care to Subsequent Imaging. J Emerg Med 2025;78:266-274. [link to article]

Duration of resuscitation interruption using point-of-care ultrasound versus traditional manual pulse check: A systematic review and meta-analysis

We know manual pulse checks during CPR are unreliable and often slow. “Do you feel a pulse…? I’m not sure… is that my pulse?”

So, is a POCUS pulse check faster and more accurate? Hmmm…

But first: what is a POCUS pulse check?

No, it’s not just looking at the heart during a rhythm check. It means using a linear probe to assess the carotid artery for compressibility and pulsatility, or using pulse-wave Doppler at the femoral artery to assess flow velocity.

So, is this actually better than our old-school manual checks?

The authors reviewed seven studies involving 496 participants. Overall, ultrasound was associated with a shorter pulse-check duration—by about 1.39 seconds.

Yes, that is not exactly a clinically earth-shattering difference.

(For what it’s worth, I’m a little skeptical of the overall data. Pulse checks in both groups were remarkably quick—around 3 to 10 seconds. This is quite different from earlier studies reporting much longer interruptions.)

But the more interesting difference is accuracy. Who cares how fast it is if it gets the answer wrong?

Three studies reported accuracy data. Manual pulse checks had a pooled sensitivity of 62% and specificity of 91%. POCUS pulse checks performed much better, at 99% and 96%, respectively.

Thoughts? Should we abandon manual pulse checks?

To be fair, major guideline groups (ILCOR, ACC/AHA, etc.) have recognised this problem and have been moving away from manual pulse checks for years. For lay rescuers, they now recommend looking for signs of life instead. Even so, health professionals are still checking pulses.

The authors do add some caution: the overall certainty of evidence is low. They also highlight the need for standard protocols, operator training, and high-quality prospective studies before practice changes too much.

For what it’s worth, I usually have a quick peek at the heart during rhythm and pulse checks. If it’s not moving, there's no point hunting for a pulse. (If you want to see this in action, check out Vijay’s paper in Emergency Medicine Australasia.)

Oh, and a strong word of caution: do not waste time checking for a pulse when a shockable rhythm is present!

If you want the best paper using a femoral artery catheter as the gold standard, look at Cohen’s study below. They used femoral pulse-wave Doppler to calculate peak systolic velocity and correlated it with blood pressure. It sounds complicated, but it's not. To me, this looks like the most promising technique.

What’s the takeaway?

POCUS pulse checks may catch on. Keep your eyes peeled and your finger on the pulse… or maybe not.

Covering:

Neto ES, Scapin M, Lazaro-Paulina F, et al. Duration of resuscitation interruption using point-of-care ultrasound versus traditional manual pulse check: A systematic review and meta-analysis. Amer J Emerg Med. 2025;98:145-152. [Link to article]

Cohen AL, Li T, Becker LB, et al. Femoral artery Doppler ultrasound is more accurate than manual palpation for pulse detection in cardiac arrest. Resuscitation. 2022;173:156-65. [Link to article]

Haematoma block is the most efficient technique for closed forearm fracture reduction: a retrospective cohort study

The answer to some research questions are so glaringly obvious that they really don’t need to be studied.

Anyone who has done a haematoma block for a wrist fracture knows that they are a lot quicker and less resource intensive than a Bier’s block or procedural sedation. This is the major advantage of choosing a haematoma block over the other techniques.

Nevertheless, these researchers from Australia put the answer in black and white with this retrospective cohort study. Looking at the metric of ED length of stay (LOS), they proved that haematoma block was faster in their two ED’s. The mean ED LOS was 187 minutes for haematoma block, 227 minutes for Bier’s, and 239 minutes for procedural sedation.

I suspect that other ED’s might have more impressive differences if they have trouble accessing crowded resuscitation rooms and qualified staff that are busy with other tasks.

On the flip side, procedural sedation had a higher rate of successful first attempt reduction at 94% vs. 76% for haematoma block. But groups were not randomised and reductions under procedural sedation were twice as likely to have senior staff present and an orthopaedic registrar.

They also mention the cost of consumables and opportunity cost were less with haematoma block. No surprise here.

More patients had complications with procedural sedation 18%, Bier’s 14% and 13% with haematoma block. All but one of the complications of haematoma block were due to “block failure.” I don’t believe this to be a complication but rather an expected outcome. Sometimes haematoma blocks simply don’t work and one needs to proceed to plan B. No big deal.

In their conclusion, the authors state haematoma block “should be the default anaesthetic technique” for closed reduction of closed forearm fracture reductions. Obviously, the choice is multifactorial and comes down to patient and local institutional factors. But generally speaking, I agree.

Covering:

Pitman GR, Soeyland T, Popovic G, Thomson D. Haematoma block is the most efficient technique for closed forearm fracture reduction: a retrospective cohort study. Emerg Med J. 2024 Sep 25;41(10):595-601. doi: 10.1136/emermed-2023-213591. PMID: 39019579. [link to article]

Predictive value of indirect ultrasound signs for low risk of acute appendicitis in paediatric patients without visualisation of the appendix on ultrasound

Have you ever ordered an ultrasound on a patient and had the report come back stating “appendix not visualised”? This seems to be a common and frustrating occurrence. We have historically considered this to be a result that doesn’t change our thought process, and we throw the report in the bin.

But what about the indirect signs of appendicitis that may be seen on ultrasound? If the appendix is inflamed, often so are the surrounding structures. Can the presence or absence of indirect signs change how we think about the post-test probability of disease?

Researchers from a single centre in beautiful Valladolid, Spain conducted a retrospective study of paediatric patients aged 3-13 who were thought possibly to have appendicitis and had a diagnostic workup.

There were 1,756 patient encounters. They used the Alvarado score to risk stratify the kids into low, intermediate or high risk. The positive appendicitis rate was ultimately found to be 18%.

A total of 60% of children had an ultrasound performed. About half the time the appendix was not visualised. In this cohort of patients, they went further to look at the ultrasound report for possible indirect signs of appendicitis.

Indirect ultrasound findings independently associated with appendicitis were a small amount of free fluid (OR 5), abundant free fluid (OR 30), and inflammation of the periappendiceal fat (OR 7).

The authors conclude that the absence of these indirect signs ruled out appendicitis in patients with low or intermediate suspicion with a sensitivity of 85% and a negative predictive value of 99% even when the appendix was not visualised. The missed cases tended to be patients that presented early after onset of pain as they likely had less inflammation present.

Some might argue that 85% sensitivity is not good enough. But appendicitis is not aortic dissection. I think a lower sensitivity is acceptable so that we are not causing harm by over investigation and admission.  A short delay to diagnosis of appendicitis is not likely to be harmful especially in early presenters that don’t have ultrasound signs of inflammation. Obviously, we must give good discharge instructions and return precautions for those that we send home.  

To be complete, there were a lot of limitations to this retrospective study. But there are other studies out there with similar results and conclusions.

Next time you get an ultrasound report of “appendix not visualised” make sure you read further. Indirect signs might be your friend.

Covering:

Pernía J, Cancho T, Segovia I, de Ponga P, Granda E, Velasco R. Predictive values of indirect ultrasound signs for low risk of acute appendicitis in paediatric patients without visualisation of the appendix on ultrasound. Emerg Med J. 2024 Jul 22;41(8):475-480. doi: 10.1136/emermed-2023-213466. PMID: 38729752. [link to article]

 

The Oakland Score to identify low risk patients with lower GI bleed that can be safely discharged

The Oakland score was derived in 2015 but it somehow slipped my attention. The score is quite simple and mostly includes at a combination of age, vital signs and hemoglobin level to risk stratify patients [Oakland score MdCalc link]. 

This new external validation study was a multicenter effort that was conducted in 140 US hospitals. It identified 38,067 patients admitted to the hospital with a primary diagnosis of lower GI bleed by ICD-10 codes. They retrospectively applied the Oakland score to these inpatients to see if this decision instrument could identify a group that was safe for discharge. Test characteristics of the score were reported at several cut-offs (8,9, and 10 points)

The primary outcome to determine “safe discharge” was a composite of an absence of the following: in hospital rebleeding, RBC transfusion, therapeutic colonoscopy, mesenteric embolization, laparotomy, in hospital death and readmission with subsequent lower GI bleeding 28 days.

Results?

Average age was 70 years old and 68% of patients received a blood transfusion. Yikes! These were not low risk patients… probably why they were admitted in the first place.

Applying the rule to this inpatient cohort identified a measly 8.7% of patients considered safe for discharge at the 8-point threshold with a sensitivity of 98.4% and 16% specificity. If the threshold score was increased to 10, identified 17.8% with similar sensitivity but increased specificity to 32%.

Overall, it’s a pretty bad decision instrument in this population as it is not discriminatory. It pretty much calls everyone positive. 

However, I think there is a bigger issue with this study.

It was conducted on inpatients. The decision to admit was already made!

For overall utility, it should have been done in the ED. Nevertheless, the authors did state, “a prospective cohort study is needed, in which all patients presenting to the emergency department are included, regardless of their admission status.”

For what it is worth, I might see myself documenting a low-risk Oakland score to support my decision to send home a low-risk patient with lower GI bleed home. But in its current form, I fear the lack of specificity may result in more patients being admitted to hospital if we apply it without thinking.

Ultimately, yes, I would really like to see this study prospectively validated in an ED population and compared to gestalt. Anyone interested in a research project?

Covering:

Oakland K, Kothiwale S, Forehand T, Jackson E, Bucknall C, Sey MSL, Singh S, Jairath V, Perlin J. External Validation of the Oakland Score to Assess Safe Hospital Discharge Among Adult Patients With Acute Lower Gastrointestinal Bleeding in the US. JAMA Netw Open. 2020 Jul 1;3(7):e209630. doi: 10.1001/jamanetworkopen.2020.9630. PMID: 32633766; PMCID: PMC7341175. [link to full text article]

 

 

 

 

 

Subarachnoid haemorrhage in the ED… pushing the boundary of negative CT out to 24 hours?

On non-contrast head CT, a SAH is usually found by identifying the presence of bright white blood in the subarachnoid space. But over time, the blood becomes isodense and becomes more difficult to find. As such, we are generally happy to exclude SAH if we have a negative non-contrast head CT performed within 6 hours of headache onset. But what about a longer time window… is a CT adequately sensitive to exclude SAH up to 24 hours?

These authors from the UK sought to answer this question by conducting a prospective multicentre cohort study of consecutive patients presenting to the ED with acute headache.

Investigation, diagnosis and management were conducted using their standard practice. All patients were followed up for 28 days to see if they missed any haemorrhages.

3663 patients were enrolled. About 90% got a CT and one third got a lumbar puncture after negative CT. Prevalence of SAH was 6.5% (n=237).

What were the results?

A CT withing 6 hours of headache onset was 97% sensitive with a negative predictive value of 99%. CT within 24 hours had a sensitivity of 94% and a post-test probability of disease of less than 1%. The authors believe this data will inform clinicians and patients about the need (or not) for further investigation after a negative CT.

Although I would very much like to believe these conclusions, there is one major concern with the methodology.

Incorporation bias.

The head CT, the test that they are trying to determine was good or not, formed a crucial part of the gold standard. An alternative title to the paper could have been, “We did a head CT to excluded SAH, it was negative, and we believed it.”

To be fair to the authors, it would be unfeasible and not ethical to have performed angiograms and lumbar punctures on all patients to exclude SAH. And their 28 day follow up was probably a reasonable surrogate to find missed SAH’s.

What should we conclude?

This study provides some evidence that we might be able to push the time window of CT a bit further. But I doubt the quality of this study will be enough to change guidelines. Unfortunately, there still is no right answer, and we will continue to engage in shared decision-making discussions with our patients.

 

Covering:

Trainee Emergency Research Network (TERN). Subarachnoid haemorrhage in the emergency department (SHED): a prospective, observational, multicentre cohort study. Emerg Med J. 2024 Oct 4:emermed-2024-214068. doi: 10.1136/emermed-2024-214068. [Link to article]

 

ED consultant’s gestalt vs. screening tools for the prediction of sepsis in the critically ill

This study sought to compare ED doctor’s gestalt vs screening tools to identify sepsis. The tools included SIRS, qSOFA, SOFA, MEWS, and a machine learning one called LASSO.

We would intuitively believe that these screening tools are an improvement over gestalt. Why would we use them if they weren't better? Oddly enough, the screening tools have never been compared to gestalt. What if they are worse?

This study took place in a single well-functioning ED in the USA with over 100,000 patient visits per year. They included undifferentiated adults who were critically ill and went to the resuscitation area of their ED. They excluded trauma, obvious cause of illness, STEMI, strokes, and transfers.

At 15 and 60 minutes after presentation to the ED, a trained independent researcher asked the ED consultant a single question; “What is the likelihood that this patient has sepsis.” They rated their answer on an iPad displaying a slide bar from 0 (no infection) to 100 (infection).

The gold standard diagnosis of sepsis was determined by an ICD-10 code at hospital discharge. Gestalt and screening tools performance were appropriately compared by looking at using area under the curve (AUC).

Results?

2,484 patients met eligibility. 275 (11%) had sepsis.

Which was better? Gestalt or screening tools?

Gestalt was crazy good with an AUC of 0.9. This is really exceptional. Other tools performed worse. Machine learning AUC 0.84 (pretty good), MEWS 0.72 (good), and qSOFA, SIRS and SOFA about 0.67 (not great.) Don’t forget, an AUC of 0.5 is considered random… like flipping a coin.

Although I agree with the overall message of this paper, there are some important limitations. I’ll only mention a few.

They only included very sick patients that went to resuscitation. Sepsis should be more obvious in this cohort. I’m guessing this is why gestalt performed so well. What I am really interested in are the subtle cases that may still be in the waiting room. One could argue that they studied the wrong patient population.

This was a single centre that used the gestalt of a highly experienced consultant. In addition, they were very quick and efficient at getting diagnostic tests back including x-ray, bloods, vital signs, and POCUS.

The paper relied on a hospital discharge diagnosis of sepsis as the gold standard. It is very likely that patients with medical conditions who presented to the ED without sepsis subsequently developed the condition while in hospital. This would bias the results against gestalt.

What is my take home message?

Before we rely upon screening tools or clinical decision instruments, we must know that they are better than what we are currently doing. As demonstrated in this limited study, tools may perform worse!

 

Covering: Knack SK, Scott N, Driver B, et al. Early Physician Gestalt vs Usual Screening Tools for the Prediction of Sepsis in Critically Ill Emergency Patients. Ann Emerg Med;84:246-258. [Link to article]

 

 

 

Emergency department versus operating room intubation of patients undergoing immediate hemorrhage control surgery

There are theoretical reasons why endotracheal intubation can make trauma patients worse. Induction agents can cause hypotension. Positive pressure ventilation decreases venous return and can decrease cardiac output. This is not to mention the potential complications of the procedure itself. 

Of course, all of this must be balanced with the possible need for a definitive airway and to ensure oxygenation & ventilation.

So… for trauma patients requiring surgery, is it better to intubate in the ED or wait to go to the operating theatre?

This study looked at the National Trauma Data Bank (registry data… beware) and identified 9,667 patients at 253 trauma centers who underwent hemorrhage control surgery within 60 minutes of ED arrival. To attempt to minimize confounding, they excluded patients with GCS <8, dead on arrival, ED thoracotomy, or those “with clinical indications for intubation.”

The primary outcome was mortality when comparing ED intubation vs. in theatre.

The unadjusted mortality for those intubated in the ED was 17% vs. 7% in theatre. Absolute increase of 10% or a number needed to kill (NNK) of 10.

Intubating in the ED is lethal!?

Wait a minute…

Of course, the sicker patients are more likely to get intubated in the ED!

This study was no exception. ED patients had markedly higher injury severity scales. They had lower GCS, more chest, lung, heart, thoracic vascular and liver injury. They were more tachycardic and twice as likely to get a thoracotomy for hemorrhage control.  

The authors tried the usual fancy statistical adjustments that we often see with observational study design, but this is far from a perfect science. Studies like this invariably have some residual confounding which makes the interpretation difficult.

To be fair, the authors do a good job of mentioning the study limitations but unfortunately overstate their conclusion.

There is an association between ED intubation and worse outcomes. Yes, but is this a causal relationship? That is the big question which can only be answered with a randomized clinical trial.

 

Covering:

Dunton Z, Seamon MJ, Subramanian M, et al. Emergency department versus operating room intubation of patients undergoing immediate hemorrhage control surgery. J Trauma Acute Care Surg. 2023;95:69-77. [link to article]

 

 

“Diagnostic accuracy of clinical examination to identify life-and limb-threatening injuries in trauma patients”

How good is the physical examination for finding life threatening stuff in trauma patients?

This study sought to answer this question but the title is somewhat misleading. It should have been a bit longer as below:

Diagnostic accuracy of the single pre-hospital physical examination to identify life and limb threatening injuries performed by a doctor in the field around London, UK without using adjuncts who had no idea they were going to participate in a study and may or may not have collected or written down information as sought by the investigative team.

It’s clear that I was not involved in the peer review process of this paper.

Since the methods employed never really had a hope of answering the research question, I’m not going to go into much details of the paper. Nevertheless, I still think their conclusion is correct! “Clinical examination… has only a moderate ability to detect life and limb threatening injuries.”

Even a broken clock is correct twice a day.

Just to reiterate, this was a retrospective study of a single physical exam. It was performed pre-hospital, possibly in an austere environment with no ultrasound or other adjuncts. The doctor very likely had other significant priorities; i.e. scoop and run. It cannot speak to the utility of serial examinations or those performed a bit later as things evolve.

My fear is someone may pull this paper out of their pocket to suggest that we need to do away with physical exam and perform full body CT scans in all trauma patients. This could likely cause harm, especially in lower risk trauma patients or pediatrics.

 

Covering:

Wohlgermut JM, Marsden ME, Stoner RS, et al. Diagnostic accuracy of clinical examination to identify life- and limb-threatening injuries in trauma patients. Scand J Trauma Resusc Emerg Med. 2023;31:18 [link to free full text article]

 

 

Emergency Department REBOA in trauma patients with exsanguinating hemorrhage- Finally an RCT!

Resuscitative Endovascular Balloon Occlusion of the Aorta has had lots of exciting coverage over the past few years. But despite the hype, we don’t really know if it helps or harms patients.

Huh… Why don’t we know if it works?

Existing data has exclusively been observational. Researchers have passively sat back and looked to see if there are outcome differences between those who got REBOA and those who didn’t. The problem is these are two VERY different groups. Despite all the fancy statistical analysis, it is impossible to properly adjust for all the between group confounding.

What is the best way to get rid of confounding?

Randomization.

The process of randomization ensures that there are equal amounts of known and unknown confounders in each group. Problems solved… theoretically.

So here is the first randomized clinical trial of REBOA in trauma!

The UK-REBOA RCT was conducted in 16 major trauma centers in the UK. Patients with exsanguinating hemorrhage were enrolled over 4+ years.

The primary outcome was all-cause mortality at 90 days. There were lots of secondary outcomes.

Results?

90 patients were enrolled almost all (97%) with blunt trauma. As expected, they were super sick with a median injury severity score (ISS) of 41.

In the end, the trial was stopped for harm. Mortality was 54% with REBOA vs. 42% in the standard care arm. Number needed to kill (NNK) is 8. In addition, all the secondary outcomes and bleeding seemed to be worse with REBOA.

Does this signal the death of REBOA?

Probably not.

Unfortunately, this paper has lots of limitations. The biggest of which is only 19 out of 46 patients randomized to REBOA got the device inserted and balloon inflated. It is hard to demonstrate a treatment effect when most patients don’t get the treatment. But perhaps this shows the real-world difficulties of performing REBOA.

Critics of this paper will highlight many other issues: training of providers, time delays, specific device used, small numbers, stopped early, baseline differences favored the control arm, no penetrating trauma, etc.

Despite all the issues, I think there is a big take home point.

REBOA is very hard to study.

These authors went to great efforts. They included 16 centers over 4+ years and still they had major issues. In the end, I doubt we will see much better evidence anytime soon. Nevertheless, I think we will see a shift away from REBOA... don't believe the hype. 

Covering:

Jansen, JO, Hudson J, Cochran C, et al. Emergency Department Resuscitative Endovascular Balloon Occlusion of the Aorta in Trauma Patients with Exsanguinating Hemorrhage: The UK-REBOA Randomized Clinical Trail. JAMA. 2023;330(19):1862-1871. [Link to article]

 

 

 

Aspirin vs Enoxaparin for thromboprophylaxis after a fracture

You are sending home a patient from the ED with a broken ankle after you carefully crafted a new plaster. Hmmmm… do you need to worry about DVT prophylaxis?

Guidelines and local practice vary. When you see this variation, it invariably means there is not conclusive evidence to inform practice.

Perhaps this RCT from the New England Journal of Medicine might help?

These researchers from the USA conducted a pragmatic, multicentre, randomized non-inferiority trial. They included patients who had a fracture of an extremity (hip to midfoot or shoulder to wrist) that were treated operatively or who had pelvic or acetabular fracture.

Patients were randomized to aspirin 81mg BD vs. enoxaparin 30mg BD while in hospital but could get whatever after discharge “according to the clinical protocols of each hospital.” (For what it’s worth, BD aspirin is not a typo…)

Primary outcome was death from any cause and secondary outcomes looked at PE’s, DVT’s and bleeding complications.

Results?

12,211 patients were included! Mean age 44 years old and 87% had lower extremity fractures. Median BMI was 27. On average, patients received about 9 in-hospital doses of thromboprophylaxis and were prescribed a 21-day supply of whatever upon discharge.

Primary outcome… no difference at 0.7% mortality in both groups. There was statistically more DVT’s in the aspirin group by a whopping 0.8% margin (NNT 125). PE’s were no different and nor were complications.

What should we conclude in the ED?

Yes, this is the tricky. The patients included in this study were not patients discharged from the ED. Extrapolating the findings from this RCT to our population is problematic. Bummer…

In addition, I’m disappointed they did not standardize the take home thromboprophylaxis. This likely made it much more difficult to find differences between the groups as patients were likely to cross-over.

Further, this trial did not restrict enrollment to high-risk patients. These are precisely the patients I want to target… another bummer. It is very possible that enrolling all-comers diluted down the benefits & differences of therapy. Who knows… but it’s common sense.

In the end, I don’t think this should substantially change how we think about ED patients that we send home with fractures. Nevertheless, I anticipate this study will influence the guidelines… we might see some more aspirin being recommended. But I'm not sure if this is for the better or worse.

 

Covering:

METRC Consortium, Aspirin or Low-Molecular-Weight Heparin for Thromboprophylaxis after a Fracture. N Engl J Med 2023;338:203-13. [Link to article]

 

 

 

Intra-articular Hematoma Block Compared to Procedural Sedation for Closed Reduction of Ankle Fractures

I must have missed this paper originally published in 2018 in Foot and Ankle International… perhaps my subscription has lapsed.

Either way, I’m intrigued.

These researchers sought to compare intra-articular hematoma blocks (IAHB) vs. procedural sedation to aid in the reduction of displaced ankle fractures (fracture subluxations or dislocations).

This was a retrospective chart review without great methods… but what the hell.

They identified 221 patients that underwent IAHB vs. 114 who got PS over 11 years in their single ED in Minnesota. The primary outcome was rate of successful reduction. But they also looked at reduction attempts, time to successful reduction, length of stay in the ED and some adverse events. However, they did not report on adequacy of pain reduction or patient satisfaction.

A hematoma block was performed using 10 to 12ml of 1% lignocaine without adrenalin that was injected into the tibiotalar joint. Ultrasound guidance was not used (but in my opinion can be helpful).

Results?

Patients were not randomised and as such, there were some substantial differences between the groups. As you can discern from the numbers, they liked their hematoma blocks twice as much as procedural sedation. However, more patients with complete dislocations got sedation.

The rate of successful reduction was about the same in both groups. About 70% were reduced with one attempt and 25% more by the second. Overall, there was a 90% success rate.

As for safety, one patient in the procedural sedation group got intubated… yikes!

This study has many limitations and is not high-quality evidence. Nevertheless, it is yet another paper demonstrating the utility and uptake of hematoma blocks for displaced ankle fractures. Even the New England Journal of Medicine has jumped on board with these blocks for ankles.

The beauty of a haematoma block is no need for a resuscitation room and lots of resources. It can quickly be performed by a single provider. In addition, a further reduction attempts can easily take place as the block will last for a while.

 

Covering:

MacCormick LM, Baynard T, Williams B, et al. Intra-articular Hematoma Block Compared to Procedural Sedation for Closed Reduction of Ankle Fractures. Foot & Ankle Int. 2018;39:1162-8. [Link to article]

Have you heard about the HEAR score?

We’ve all heart about the HEART score for risk stratification of patients with chest pain in the ED. Take away the troponin and you’ve got the HEAR score!

Yes, the HEAR score tries to identify patients at very low risk of ACS that don’t even need a troponin. The thought is this will decrease resource utilisation and improve patient flow.

The original “derivation” of the HEAR score was in 2020 by Smith LM, et al. These subsequent researchers from Calgary (go stampede!) sought to externally validate this strategy.

They conducted a secondary analysis of a prospective cohort study of patients with chest pain that got a troponin to exclude MI in their single ED.

They enrolled 1150 patients. Of those, 8% had index MI and 11% with MACE by 30 days. HEAR score <1 identified 202 (17.6%) of patients at very low risk of adverse events with a 99% sensitivity (95% CI 95.6-99.9%). Only one patient out of 202 was missed. 

As with most screening tools that are highly sensitive, it often means they are terribly non-specific. The HEAR score is no exception. As such, it should only be used as a one-way decision instrument. 

The authors of this study appropriately conclude that this very low risk cohort of HEAR <1 is unlikely to benefit from troponin testing and will lead to significant resource savings.

This is not exactly ground-breaking. A young patient with a low-risk story, a normal ECG, and no risk factors is very unlikely to have a problem.

Sure, it’s probably fine to skip the troponin. I think a lot of us have been doing this over the years via gestalt. But at least this study quantifies the risk and provides support for those clinicians who want to avoid troponin testing in very low risk patients.

Perhaps the greatest use of HEAR score is to allow you sleep at night… perhaps a bit of medico-legal defense when you document the score and send that low risk patient home without blood tests.

Covering:

O'Rielly CM, Andruchow JE, McRae AD. External validation of a low HEAR score to identify emergency department patients at very low risk of major adverse cardiac events without troponin testing. CJEM. 2022;24:68-74. [link to article]

Not so FAST? How a study on lung ultrasound got it wrong…

This study out of UC San Diego set out to determine the accuracy of lung ultrasound vs. supine portable chest x-ray for the detection of traumatic pneumothorax.

Yes, I also thought this research questions had been suitably answered.

In 2020, a CochraneReview included 13 prospective paired comparative accuracy studies and concluded that ultrasound was about 90% sensitive vs. 50% for a chest x-ray. Both are highly specific.

Regardless of the consistent evidence, let’s consider face validity. Anyone who is competent in lung ultrasound knows that ultrasound is much better at finding pneumothorax. There is no planet in the solar system where a supine portable chest x-ray is going to be more sensitive than ultrasound.

But this study concludes the opposite… chest x-ray was better!

Huh? How could this be?

This was a retrospective registry review. Retrospective data is often poor quality. Registry data is even worse. Garbage in... garbage out. Ironically, this study would never have been included in the Cochrane review.

What is the probability that this single study with worse quality evidence is correct and all the consistent higher quality studies are wrong?

Yes, the probability is close to zero.

But where did this study really go wrong?

I think the authors answered the question themselves, “… in a non-study environment, such as ours, the pleural views were not universally performed with the same rigor as in a prospective study designed specifically to detect pneumothorax.”

I think this is probably the answer.

There are many other problems with this study, but I’m limited by word count. So briefly, the  methods for assessment of diagnostic accuracy of a test were performed backwards. They used the wrong probes for lung ultrasound. They used the wrong clinicians to perform and interpret the ultrasound. That was only to name a few...

As expected, there were many concerned letters to the editor. Even one from Dr Giovanni Volpicelli who is the world leader and pioneer of lung ultrasound. But the authors stuck with the strategy of “never admit you are wrong” and doubled-down in their conclusions.

A bit sad really...

Covering:

Santorelli JE, Chau H, Godat L, et al. Not so FAST- Chest ultrasound underdiagnoses traumatic pneumothorax. J Trauma Acute Care Surg.2022;92:44-8.[link to article]

 

 

Nonoperative or Surgical Treatment of Acute Achilles’ Tendon Rupture

Why do emergency clinicians need to know about this paper? Afterall, we will not be making treatment decisions about to operate or not…

Two reasons.

First, we need to know the “next step” and be able to inform our patients of what the treatment options are likely to be.

Second, this was an RCT published in the New England Journal of Medicine. This is the highest impact medical journal on the planet. Papers published here set the guidelines about how we practice medicine.

These authors from Norway randomized 554 patients with acute Achilles tendon rupture to one of three treatment arms: conservative, open repair, or minimally invasive surgery.

The primary outcome was the change in the Achilles tendon Total Rupture Score at 12 months. They also looked at incidence of tendon re-rupture.

They standardized the aftercare & rehabilitation in all groups. They required casts and weight bearing as tolerated using an ankle-food orthosis with heel wedges for 6-8 weeks. They did not report on earlier return to functional status between groups.

Results?

At 12 months, there was no difference in the rupture score. As expected, there were more re-ruptures in the conservative vs. surgical arms (6.2% vs. 0.6%). And there were more nerve injuries in the surgical groups.

All studies have limitations and this one is no exception. An RCT is only as good as the measuring tool of its primary outcome. I’m not sure what to make of the rupture score and self-reporting may have led to bias.

What are we to make of this?

In the long term, there probably is no big difference between conservative vs. surgical management.  

Nevertheless, there is probably enough wiggle room with the interpretation of this study for orthopedists to continue doing whatever they like. Conservative seems fine in the long run, but there are higher rates of re-rupture. Surgical treatment is about the same but comes with the potential for nerve injury and infection.

Seems like we are right back where we started!

 

Covering:

Myhrvold S, Brouwer E, Andresen T, et al. Nonoperative or Surgical Treatment of Acute Achilles’ Tendon Rupture. N Engl J Med 2022;386:1409-20. [link to article]

Risk of delayed intracranial hemorrhage after an initial negative CT in patients on DOACs with mild traumatic brain injury

To identify delayed hemorrhage, some clinicians will repeat a head CT in patients on NOAC’s with mild traumatic brian injury (TBI) after the initial head CT is negative.

How common is delayed hemorrhage with DOAC’s?

Hmmm….

These authors from Italy performed a retrospective multicentre observational study. They found 1426 patients taking NOAC’s who were evaluated in the ED for mild TBI (GCS 14-15). Of these 916 (68%) underwent 24 hours of observation and a repeat CT after the initial one was negative.

In the end, only 14 (1.5%) patients had delayed hemorrhage found on repeat CT. None of these patients had neurosurgery or died (but I presume they had their DOAC’s withheld).

Another interesting aspect… no delayed hemorrhages were found in patients who had the initial head CT greater than 8 hours after injury.

The findings of this study are similar with others looking at warfarin. Consistency in the literature is comforting.

So, we have a pretty simple message. Routine delayed head CT is not necessary. But 1.5% is not zero… so we still need to be a little careful.

And another question… is it DOAC’s or NOAC’s?

 

Covering

Turcato G, Cipriano A, Zaboli A, et al. Risk of delayed intracranial haemorrhage after an initial negative CT in patients on DOACs with mild traumatic brain injury. Am J Emerg Med. 2022;53:185-189. [link to article]

Single dose phenobarbital for the outpatient treatment of alcohol withdrawal... interesting

Phenobarbital has some ideal properties for the treatment of alcohol withdrawal. In particular, it has a long half life (about 100 hours) allowing for a single dose without the requirement for prescriptions.

However, there are some genuine safety concerns especially if they are mixed with other drugs or alcohol. And there is little high-quality evidence to support it’s use in patients being sent home from the ED.

This is a retrospective chart review of patients discharged from a single ED in California over a three-year period with a discharge diagnosis of alcohol withdrawal. Patients were stratified into three categories; those who got benzo’s, benzo’s plus phenobarbital or just phenobarbital alone.

The primary outcome was return ED encounter within 3 days of the index visit. (Yes, this is an odd primary outcome, but it was chosen for pragmatic purposes as below...)

470 patients were included. 235 got benzo’s, 133 got phenobarbital, and 102 got the combination special.

Results?

Treatment with phenobarbital (alone or in combination) was associated with a decreased odds ratio of a return ED visit within 3 days. (AOR 0.45 95% CI 0.23, 0.88  and AOR 0.33 95% CI 0.15,0.74 respectively).

The cynic in me wonders if this is because phenobarb patients died… (But this was probably not the case as the author were eventually able to account for most patients)

It is interesting to note that patients who received phenobarbital got much more GABA agonist medication than those that simply got benzodiazepines. Four times as much was given if you adjust for drug equivalence. Perhaps this is why they were less likely to return?

Unfortunately, this paper does not address the big question of safety. It would take a much larger study with more robust methodology (that avoids loss to follow-up) to answer this. And such a study would be very difficult to undertake as this cohort of patients are unreliable and not likely to be compliant with study protocols etc.

What’s the take home message?

Phenobarbital for the outpatient treatment of alcohol withdrawal is tempting, but there is arguably not enough evidence to support its routine use.

 

Covering:

Lebin A, Mudan A, Murphy CE, et al. Return Encounters in Emergency Department Patients Treated with Phenobarbital Versus Benzodiazepines for Alcohol Withdrawal. J Med Tox. 2022;18:4-10.  [link to full text of article]

 

Risk for recurrent VTE in patients with subsegmental PE managed without anticoagulation- A prospective study

Modern imaging technologies have put a virtual microscope into the human body and can find smaller and less significant disease. Our treatment of these conditions often falls under old recommendations meant for more substantial illness. Can treatment of mild disease result in more harm than benefit?

This question is particularly true when it comes to subsegmental PE. Does it require anticoagulation?

These researchers found 266 patients with low-risk subsegmental PE and referred them to a thrombosis clinic for management. The patients underwent lower extremity ultrasound to exclude DVT at the time of diagnosis and one week later. Patients without DVT had anticoagulation withheld and they were followed up for 90 days looking for evidence of recurrent VTE.

In the end, 8  (3% 95% CI, 1.6%-6.1%) out of the 266 patients developed VTE. The authors report higher rates in some subgroups but this analysis is not really justified given the low number of recurrences. 

There are some important limitations to remember. These patients were low risk. They did not have cancer nor prior VTE. They all had repeated leg ultrasound to exclude DVT. Long term rates beyond 90 days were not assessed. In addition, false positive CTPA's may have skewed the results towards lower rates of recurrent disease. 

What are we to conclude?

Recurrent VTE in low-risk patients with subsegmental PE is pretty low. This may be a good time for shared decision making.

 

Covering:

Le Gal G, Kovacs M, Bertoletti L, et al. Risk for Recurrent Venous Thromboembolism in Patients With Subsegmental Pulmonary Embolism Managed Without Anticoagulation. Ann Intern Med. 2022;175:29-35 [link to article]

Cannabinoid hyperemesis syndrome: A 6-year audit of adult presentations to a single ED in Melbourne

I'll preface everything by stating this paper is not high science.

Sorry…

These authors performed a retrospective chart review on adult patients who they thought had cannabinoid hyperemesis syndrome (CHS) in their single ED in northern Melbourne.

Obviously, the diagnosis of CHS is based on clinical findings. There is no blood test for CHS and no agreed formal diagnostic criteria. So, who knows if they identified all patients with CHS or if the ones they diagnosed truly had it?

Nevertheless, there might be a few useful pieces of information… so let’s continue on our magic carpet ride.

142 patients were included. 77 were unique presentations and the rest were frequent visitors.

I’m not going to report their clinical features as this formed part of how they identified patients in the first place… kind of an incorporation bias. (Suffice to say, they were vomiting a lot.) Plus, the retrospective nature of the data means a lot of things were probably not recorded (i.e. relief from hot shower was only written down 11% of the time).

More objectively, I was interested to see that most had elevated white blood cell counts and lactates. Median WBC was 14 (IQR 11.2-16.8) and lactate was 1.95 (IQR 1.4-2.9)

These doctors also liked droperidol and the authors go on to state, “Response to droperidol (or haloperidol) as previously reported may also guide clinicians in their determination as to whether CHS should be considered.”

Arguably the best part of the paper is their proposed CHUNDER score to aid in the diagnosis of CHS. This mnemonic stands for, “Cyclical vomiting, History of regular cannabis, Under fifty years old, Normal lipase, Diagnosis of exclusion, Elevation of CRP<50, and Reduction in symptoms after droperidol.

I’m chunder struck…

 

Covering:

Rotella J, Ferretti O, Raisi E, et al. Cannabinoid hyperemesis syndrome: A-year audit of adult presentations to an urban district hospital. 2022 Feb 23. doi: 10.1111/1742-6723.13944 [link to article]