This Week in Emergency Medicine — Sep 1, 2026

Welcome to This Week in Emergency Medicine. This week we're covering 10 notable papers spanning chest pain and syncope pathways, resuscitation science, and prehospital trauma and department flow. Let's dive in.

We start with three large trials that ask whether doing more, or doing it faster, actually helps the patient in front of us. In The Lancet, Boeddinghaus and colleagues report PRESC1SE-MI, a pragmatic stepped-wedge cluster-randomised trial across 19 hospitals in ten countries, enrolling nearly 68,000 consecutive emergency department presentations with suspected myocardial infarction. Hospitals still using a zero and three hour high-sensitivity troponin pathway were randomised to switch to the guideline-recommended zero and one hour pathway either at six or twelve months. On safety, the newer pathway was non-inferior — death or new type 1 infarction at 30 days occurred in around one percent of presentations in each arm. But on efficacy, the result was flatly negative. Median emergency department length of stay was 309 minutes in both groups. Identical. The authors are blunt about the implication: adopting the zero-one-hour pathway on its own should not be expected to improve throughput, because the rate-limiting step in a crowded department is rarely the second blood draw. If your institution is planning a switch, plan the downstream disposition process alongside it, or you will buy safety without buying time.

The second chest pain paper, in the New England Journal of Medicine, tackles what to do after infarction has been ruled out. Lee and colleagues randomised 3,170 patients across 14 United Kingdom hospitals with a maximum high-sensitivity troponin above 5 nanograms per litre — an intermediate-risk group — to outpatient computed tomographic coronary angiography-guided care or standard care. After a median of three years, the composite of myocardial infarction or cardiac death occurred in about seven percent of patients in each arm, with no significant difference. Routine targeted CT coronary angiography in the ruled-out population did not reduce hard events. That sits alongside a similarly negative trial in the same journal from Reed and colleagues, the ASPIRED trial, which randomised 2,234 adults with syncope that remained unexplained after emergency department evaluation to 14 days of ambulatory electrocardiographic monitoring or standard care. The primary outcome was patient-reported syncope episodes at one year, and there was no significant difference — roughly one and a half episodes per patient in each arm. Notably, adverse events were more frequent in the monitored group, 49 versus 8, mostly minor. Taken together, these two trials push back hard on the reflex to add another test to the low-to-intermediate-risk patient after a reassuring emergency department workup. More imaging and more monitoring generated more findings but not better outcomes.

Moving to resuscitation, two papers look at the physiology and the mechanics of doing CPR well. In Resuscitation, Kano and colleagues studied cerebral tissue oxygen saturation measured by near-infrared spectroscopy during ongoing CPR in out-of-hospital cardiac arrest patients receiving in-hospital defibrillation for a shockable rhythm. Among the first monitored shock for each patient, median cerebral saturation was just under 49 percent in those who achieved return of spontaneous circulation versus about 38 percent in those who did not, and each one percent rise in saturation was associated with roughly a fifty percent increase in the odds of return of circulation. Discrimination was high, with an exploratory cut-off around 44 and a half percent. This is a selected single population and the authors are appropriately cautious: it needs external validation, and it must never delay guideline-directed defibrillation. But it points toward a real-time physiological marker of shock readiness. Complementing that, Prehospital Emergency Care published a randomised crossover simulation trial from Mickiewicz and colleagues in which 60 paramedics performed compressions on a standard manikin, an obesity-simulation manikin, and the obesity manikin while standing on a ten centimetre platform. The findings are stark. Compression depth fell by roughly 18 millimetres in the obesity conditions, and the proportion of compressions reaching adequate depth dropped from essentially universal on the standard manikin to zero. Perceived exertion and applied force both rose. And the ergonomic fix — elevating the rescuer — made no difference whatsoever. This is a manikin study, not patients, but it should prompt teams to think seriously about mechanical compression devices, earlier rescuer rotation, and bed height for patients with obesity rather than assuming a step stool solves the problem.

Our third theme covers prehospital trauma and emergency department process, where the message is about restraint and about what we fail to document. The Emergency Medicine Journal published a Faculty of Pre-Hospital Care consensus statement from Wood and colleagues on early management of crush injury and crush syndrome. The notable shift from previous guidance is a de-emphasis on aggressive fluid administration and on pre-emptive treatment for hyperkalaemia, reflecting the reality of short prehospital transport times in developed healthcare systems rather than prolonged entrapment in disaster settings. Alongside that theme of caution, Prehospital Emergency Care carries a case report from Gerstner and colleagues on the Abdominal Aortic and Junctional Tourniquet-Stabilized. A young man with multiple gunshot wounds to the pelvis and lower extremities arrived at a level one trauma centre with the device in place; removal in the trauma bay was followed by cardiac arrest, then metabolic acidosis, compartment syndrome, rhabdomyolysis, renal and liver infarcts, pulmonary emboli and stroke. Evidence for this device has been largely cadaveric and porcine, and this case is a reminder to anticipate profound reperfusion physiology and to have a plan before the device comes off. Also on the theme of caution, a short cut review in the Emergency Medicine Journal from Jaconelli and Crane examined intranasal epinephrine for anaphylaxis. Of 113 papers screened, eight were directly relevant, and almost all were case series, six of them conference abstracts only. The bottom line is that there is insufficient evidence to say intranasal epinephrine matches intramuscular, which remains the standard of care regardless of what device marketing suggests. Finally, two papers on flow and equity. In The Lancet, Sigera and colleagues report RESHAP-ED, a pragmatic randomised trial across five emergency departments in New South Wales in which 1,475 adults with uncomplicated musculoskeletal presentations were assigned to physiotherapist-led care or usual physician or nurse practitioner-led care. Mean length of stay fell by a full hour, from 3.4 to 2.4 hours, with no difference in adverse events and lower costs. That is a rare, genuinely positive flow intervention, and it contrasts pointedly with the null throughput result from the troponin pathway trial — the bottleneck is staffing and process, not laboratory timing. And in the American Journal of Emergency Medicine, Hahn and colleagues retrospectively examined nearly 6,000 adult trauma registry encounters at a level one trauma centre and found that when a triage pain score was simply missing, patients were substantially less likely to receive any analgesia — about 37 percent versus 63 percent of those with a documented score — and roughly half as likely to receive opioids. It's observational and cannot establish causation, but a blank pain field is not neutral missing data; it flags a patient at risk of going untreated.

If you only have time for one paper this week, make it the physiotherapist-led care trial in The Lancet [4]. It is one of the few rigorously randomised interventions to actually shorten emergency department length of stay while remaining safe and cost-saving, and it is directly actionable for anyone designing a department staffing model.

Here are the key takeaways from this week in Emergency Medicine. First, the zero-one-hour troponin pathway is safe but will not, by itself, decompress your department [1]. Second, after myocardial infarction has been ruled out, neither routine CT coronary angiography nor 14-day ambulatory monitoring for unexplained syncope improved hard outcomes [2,3]. Third, chest compression quality collapses in simulated obesity and raising the rescuer does not fix it — think mechanical devices and rotation instead [6]. Fourth, prehospital crush injury guidance now de-emphasises aggressive fluids, junctional tourniquet removal can precipitate catastrophic reperfusion, and intramuscular epinephrine remains the standard for anaphylaxis [7,9,8]. And fifth, a physiotherapist-led model cut length of stay by an hour, while a missing triage pain score should be read as a warning sign rather than a blank [4,10].

That's your roundup for This Week in Emergency Medicine. The full transcript and references are available on the episode page in your AudioScholar library. This is an AI-curated summary — for clinical decisions, always consult primary sources and current guidelines. See you next week.

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This is an automated summary generated by artificial intelligence, which can make mistakes. Always review the original source materials.