TERN’s Top Papers: March 2021

Authors: Raj Chatha, Pippa Evans, Ben Clarke, Jocelyne Velupillai, Jake Adams and Krishma Kataria / Codes: HAP29 / Published: 11/03/2021

Happy TERNSday! At TERN we recognize that trainees do not always have time to read the most recent papers. We want to help you all stay up to date by producing a monthly summary of important articles. The idea is that teams of trainees from each region (with the assistance of the TERN Education Leads) will produce a summary each month. This will be comprised of a selection of the most important articles to trainees based around that month’s theme published from the past year. This summary will be written by trainees for trainees. Participation will help EM trainees evidence the research specialty learning outcome (SLO10) and will help aspiring EM trainees demonstrate commitment to spe- cialty. If you are interested in getting involved email us at tern.education@rcem.ac.uk with your name, grade, and dean- ery.

This month’s theme was last month’s articles and was the turn of South East Scotland trainees and was led by one of the new Education Leads — Raj Chatha. Over a thousand articles were reviewed by the authors. They then settled on the final seven over beers via a Friday night Teams call. That’s about as good as it gets in Edinburgh during lockdown!

Prospective validation of Canadian TIA Score and comparison with ABCD2 and ABCD2i for subsequent stroke risk after transient ischaemic attack: multi-centre prospective cohort study. Perry et al.1

This study aimed to validate the Canadian TIA Score against ABCD2 and ABCD2i Scores. This was a prospective study, based across six emergency departments for five years, enrolling 7607 patients. The primary outcome was subsequent stroke or carotid endarterectomy /carotid stenting over next 7 days. The Canadian TIA Score stratified the risk of stroke, carotid endarterectomy/carotid artery stenting, or both within seven days as low (risk =0.5%; interval likelihood ratio 0.20, 95% confidence interval 0.09 – 0.44), medium (risk 2.3%; interval likelihood ratio 0.94, 0.85 – 1.04), and high (risk 5.9% interval likelihood ratio 2.56, 2.02 – 3.25) more accurately (area under the curve 0.70, 95% confidence interval 0.66 – 0.73) than the ABCD2 (0.60, 0.55 – 0.64) or ABCD2i (0.64, 0.59 – 0.68). Results were similar for subsequent stroke regard- less of carotid endarterectomy/carotid artery stenting within seven days.

Bottom Line:

This study validates the new Canadian TIA score for clinical use. In practice, this means greater confidence in deciding who can be discharged safely with outpatient follow-up, and who needs urgent discussion with Stroke teams or admission. The score is made up of very reasonable items that a normal ED work-up for TIA would cover (see table 1), and doesn’t rely on unattainable investigations. However, it is a long list of things to memorise, and FSPAHHHIDAIPG isn’t quite as catchy a mnemonic as ABCD2. However, as the authors state – who doesn’t use an app for scores these days?

 

This study aimed to determine whether topical tranexamic acid (TXA) is more effective than placebo in controlling bleed- ing after failed standard treatment in ED patients presenting with spontaneous epistaxis. The study, involving 496 pa- tients, was multi-centre, randomized, double blind, and placebo-controlled. Standard treatment referred to the use of measures such as nasal clips and topical vasoconstrictors. Rates of nasal packing and admission to hospital for further treatment of epistaxis were measured as primary and secondary outcomes respectively.

Contrary to findings from previous small unblinded studies3, the results showed that there was no significant difference

in the rates of nasal packing between the participants that received topical TXA versus the placebo group (43.7% in TXA group and 41.3% in placebo group; OR 1.11, 95% CI [0.77-1.59], p=0.59). There were also no significant differences in rates of hospital admission and recurrent epistaxis.

Interestingly, less than half of the patients who continued to bleed despite standard treatment received nasal packing. Since this is considerably less than the 95% patients predicted in the sample size calculation, the study is technically un- derpowered. The use of other methods such a silver nitrate cautery (reported in 25% of No-PAC patients) may partly explain this discrepancy. There were no serious adverse events related to the use of topical TXA.

Bottom Line:

The No-PAC trial is a high quality study which demonstrated no benefit in the use of topical TXA in spon- taneous epistaxis in which standard treatment had not achieved haemostasis. As such, although safe, it should not routinely be recommended.

This study looking at the ideal haemoglobin (Hb) target in patients with acute myocardial infarction. Uncertainty exists in this population as anaemia (even those with Hb 10-12g/dL) is associated with an increased rate of major adverse cardio- vascular events (MACE) but the ideal Hb target has not been identified. Previous studies have found that targeting a low- er Hb (termed a ‘restrictive strategy’) is non-inferior to targeting higher Hb levels (termed ‘liberal strategy’) in cardiac surgery, septic shock and acute upper gastrointestinal bleeding (TRICS-III, TRISS and TRICC).

The investigators performed a randomised controlled trial designed to assess for non-inferiority of a restrictive transfu- sion strategy (patients transfused if Hb <8g/dL) as compared to a liberal transfusion strategy (patients transfused if Hb <10g/dL) in patients aged >18yo with acute myocardial infarction (with or without ST elevation, symptoms in the last 48hrs and elevated biomarkers indicating myocardial injury).

They recruited 668 patients across 35 sites in France and Spain between March 2016 and September 2019. Their primary outcome was MACE, a composite measure used in numerous previous cardiovascular studies comprising of all-cause death, stroke, recurrent MI and emergency revascularisation prompted by ischaemia. The authors had set a margin for non-inferiority at a relative risk of 1.25, which resulted in positive result in this trial (relative risk 0.79 with 1-sided 97.5% CI 0—1.19) with a trend towards reduction of MACE at day 30 in the restrictive strategy group as compared to the liberal strategy group (absolute difference of -3% with 95% CI of -8.4% – 2.4%). Given that the CI for relative risk crossed 1 the restrictive strategy did not meet criteria for superiority in the planned subsequent analysis.

Bottom Line:

The results suggest that a restrictive strategy for blood transfusion in patients with AMI and anaemia is safe however this study population was not large enough to satisfactorily exclude the possibility of patient harm by using this strategy, as the CI for relative risk extended to 1.19. In order to definitively prove this strategy is superior or at least as safe as a liberal strategy a larger study is needed. Luckily, just such a study is currently underway in the form of the Myocardial Ischaemia and Transfusion (MINT) study, which aims to recruit 3500 patients by April 2021.

The cause of out-of-hospital cardiac arrest is not always clear and though available guidelines recommend a number of tests to evaluate for cause (including ECG, chest x-ray, echocardiogram and serologic evaluation) a probable cause is not identified in more than 10% of cases in which the patient is successfully resuscitated. This paper reports a prospective observational pilot study to see if CT imaging could aid in diagnosing the cause of cardiac arrest in this population.

Patients who presented to one of two US academic medical centres were eligible for recruitment if they had no obvious cause of cardiac arrest on arrival to the Emergency department, were sufficiently stable to undergo CT scan and received their CT within 6 hours of OHCA event. Exclusion criteria were acute STEMI, known non-revascularised CAD, known se- vere renal dysfunction (unless ordering physician believed CT was warranted regardless of creatinine), implantable defib- rillator, known contrast allergy or hospice care/terminal disease with life expectancy <3 months. The sudden death CT (SDCT) included non-contrast head CT, ECG-gated thorax CT and non-gated venous phase abdo/pelvis CT.

104 non-sequential patients were included in the study (out of 307 OHCA survivors assessed for eligibility), recruited between December 2015 and February 2018. The SDCT scans identified the eventual adjudicated cause of cardiac arrest in 39% (41/104) of patients and in 13% of cases (13/104) it was felt the cause would not have been identified by stand- ard of care without CT scanning. It also identified presumed resuscitation complications in 16% of patients (17/104) in- cluding liver/spleen lacerations, pneumothorax and pulmonary lacerations.

Bottom Line:

In centres where CT scans are becoming a readily available resource the significant diagnostic yield for idiopathic OCHA and post-CPR complications identified in this study makes for encouraging reading. This was an ob- servational study without a patient-orientated outcome so probably not ready for prime time yet as it does not show clear clinical benefit. However it does have face validity and therefore a prospective randomised trial certainly seems warranted.

This study out of Canberra aimed to determine the most effective first aid method of stopping uncontrolled lower limb bleeding, commonly the cause of death in shark attacks. In 34 volunteers, doppler ultrasound showed body weight com- pression in the inguinal region resulted in a mean reduction of popliteal artery peak systolic velocity (PSV) of 89.7% which was significantly higher than the mean reduction of 43.8% when using a rope tourniquet. Furthermore, with inguinal com- pression there was a complete reduction (100%) in PSV in 75% of cases, indicating cessation of blood loss, compared to 20.5% of cases using a rope tourniquet.

There are several interesting points to note about this study. All volunteers were minimally pre-morbid adults. Thigh cir- cumference had no meaningful impact on results using either method. Inguinal compression was performed after only a brief instruction, demonstrating the ease of the method. The surfboard rope tourniquet twice wrapped around the proxi- mal thigh and tied with a double hitch is likely to produce different results than a commercial high grade tourniquet found in our emergency departments or with prehospital practitioners.

Bottom Line:

We get rather less shark attacks here in the UK, but we do deal with catastrophic haemorrhage from lower limb trauma. The immediate thought after direct compression to an exsanguinating wound may be to apply a tourni- quet, however as shown by this study, proximal compression is far superior. Proximal artery compression does away with the potential complications of tourniquets, both local and systemic, whilst allowing a view of a wound unimpeded by haemorrhage for the consideration of arterial clamping or suture.

This study looks into prescription medication use by emergency department doctors to improve work and academic performance, and to manage stress and anxiety. A voluntary, anonymous, cross sectional survey was sent with no ex- clusion criteria to Australasian College of Emergency Medicine (ACEM) fellows and trainees. A literature search identi- fied medications that ED doctors take to aid their performance; respondents of the survey were asked if they had tak- en any of these medications in the previous 12 months and, if they had, for what purpose and whether it was within 4h of shift commencement. The survey showed one hundred and thirty-nine (46.5%) respondents used one or more of the medications, with a significantly greater proportion among trainees. Melatonin and benzodiazepine use were most common (used by 23.1% and 10.7% of respondents, respectively). Significantly greater proportions of trainees used these medications as well as zopiclone, another sedative. Thirty (10.0%) of 299 respondents used oral opioids and four used injectable opioids. Thirteen (4.3%) of 299 used modafinil, with a significantly greater proportion among trainees. Sleep aid use was most common, especially among trainees who work night shifts.

Bottom Line:

The use of medications for stress and anxiety is notable in this population. This study was not based in UK so may not be generalisable, but is worth thinking about the implications.

The objective of this study was to understand the association between ED elevated blood pressures and cardiovascular outcomes. This was a performed as a retrospective cohort study using electronic medical records for all adults treated and discharged from a high-volume ED in 2016. The primary outcome measure was a composite of stroke or transient ischemic attack, acute coronary syndrome, new heart failure, or death. Findings of 30,278 adults treated and released from the ED, 14,717 (48.6%) had elevated BP readings; 10,732 (72.9%) had no prior diagnosis of hypertension.

3,480 patients had a BP of 160/100 mm Hg with no prior diagnosis, 907 (26.1%) of these patients subsequently received a diagnosis of chronic hypertension or were prescribed antihypertensive therapy in other settings within 2 years . After ad- justing for age, sex, diabetes, atrial fibrillation, and prior cardiovascular disease, these patients did not have an elevated risk of adverse outcomes (adjusted hazard ratio 0.84; 95% confidence interval 0.71 to 1.004 during 2 years).

Bottom Line:

Elevated BP readings in the ED are common and are often the first time hypertension is detected; howev- er, they were not associated with adverse cardiovascular outcomes within 2 years of the visit. The next time you are asked whether we need to worry about an elevated BP for a patient being discharged from ED we can now with evi- dence base say.. No and recommend they see a GP for investigation!

References:

  1. Perry, Jeffrey J et al. “Prospective validation of Canadian TIA Score and comparison with ABCD2 and ABCD2i for subsequent stroke risk after transient ischaemic attack: multicentre prospective cohort study.” BMJ (Clinical research ed.) vol. 372 n49. 4 Feb. 2021, doi:10.1136/bmj.n49
  2. Reuben, Adam et al. “The Use of Tranexamic Acid to Reduce the Need for Nasal Packing in Epistaxis (NoPAC): Randomized Con- trolled Trial.” Annals of emergency medicine, S0196-0644(20)31461-X. 18 Feb. 2021, doi:10.1016/j.annemergmed.2020.12.013
  3. Joseph, Jonathan et al. “Tranexamic acid for patients with nasal haemorrhage (epistaxis).” The Cochrane database of systematic reviews vol. 12,12 CD004328. 31 Dec. 2018, doi:10.1002/14651858.CD004328.pub3
  4. Ducrocq, Gregory et al. “Effect of a Restrictive vs Liberal Blood Transfusion Strategy on Major Cardiovascular Events Among Patients With Acute Myocardial Infarction and Anemia: The REALITY Randomized Clinical Trial.” JAMA vol. 325,6 (2021): 552- 560. doi:10.1001/jama.2021.0135
  5. Branch, Kelley R H et al. “Early Head to Pelvis Computed Tomography in Out-of-Hospital Circulatory Arrest Without Obvious Etiology.” Academic emergency medicine : official journal of the Society for Academic Emergency Medicine, 10.1111/ acem.14228. 19 Feb. 2021, doi:10.1111/acem.14228
  6. Taylor, Nicholas B, and David W Lamond. “Stopping Haemorrhage by Application of Rope tourniquet or inguinal Compression (SHARC study).” Emergency medicine Australasia : EMA, 10.1111/1742-6723.13736. 7 Feb. 2021, doi:10.1111/1742-6723.13736
  7. Eggink, Karin M et al. “Prescription medication use by emergency department doctors to improve work and academic perfor- mance, and to manage stress and anxiety.” Emergency medicine Australasia : EMA, 10.1111/1742-6723.13733. 2 Feb. 2021, doi:10.1111/1742-6723.13733
  8. McAlister, Finlay A et al. “Elevated Blood Pressures Are Common in the Emergency Department but Are They Important? A Retrospective Cohort Study of 30,278 Adults.” Annals of emergency medicine, S0196-0644(20)31363-9. 9 Feb. 2021, doi:10.1016/j.annemergmed.2020.11.005

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