Zworth Reading
EMMax’s EM Weekly Update
Highlight of the Week
Initial 12 mg Versus 6 mg Adenosine for Supraventricular Tachycardia in the Emergency Department
Academic Emergency Medicine · Prospective observational study with propensity score matching
Single-centre prospective observational study of 142 hemodynamically stable SVT patients comparing initial adenosine doses. After 1:1 propensity score matching (n=104), first-dose conversion was 82.7% with 12mg versus 53.8% with 6mg (adjusted OR 4.12, 95% CI 1.85-9.14). NNT of 3.8 to achieve one additional first-dose conversion. Adverse effects were similar between groups. SVT recurrence lower with 12mg (1.4% vs 9.9%).
This is LOE 3 — observational, not randomized. The propensity score matching helps but cannot eliminate unmeasured confounding. We don't know why physicians chose 12mg versus 6mg initially — sicker-appearing patients, larger body habitus, or prior failed cardioversions could all influence both dose selection and outcomes. The study is single-centre, limiting generalizability. That said, the effect size is large (NNT 3.8), the confidence interval doesn't approach 1, and the safety signal is reassuring. Adenosine's half-life is seconds, so a larger initial bolus makes sense. This doesn't definitively prove 12mg is better, but it challenges the reflexive 6mg-first approach many of us learned.
Bottom line: Strong signal that starting with 12mg adenosine for stable SVT improves first-dose conversion without increasing adverse effects. Not definitive (observational design), but the NNT of 3.8 and equivalent safety profile make this worth adopting. I'm switching to 12mg first for most adult SVT.
FOAM Radar
EMCrit 424 – 2026 Crashing PE UpdateKnowledge translation with opinion
EMCrit · Mixed — incorporates recent AHA guidelines (LOE varies by recommendation) plus newer primary literature
Weingart updates his approach to crashing PE, integrating recent AHA guideline changes (covered in a previous newsletter) and newer studies including STRATIFY and HI-PEITHO.
Bottom line: Worth the listen. Weingart is upfront about evidence quality. Still paywalled but an episode should be coming out on their FOAM Feed in the next couple weeks so stay tuned.
Journal Feed Weekly Wrap-UpLiterature summary/curation
Covers ipratropium in asthma (old question, new data), prolonged pediatric CPR outcomes in out of hospital cardiac arrest (<1% after 15 minutes without ROSC), and a simplified PE/D-dimer strategy using 1000 as a cutoff if PE is not your number one diagnosis. Useful as a quick scan of what others are reading this week.
Bottom line: Efficient way to stay aware of what's circulating. Additional data suggesting that using a D-Dimer cutoff of 1000 may be safe in patients where pretest probability for PE is low. Not yet ready for prime time but I'm eagerly awaiting more data on the "Adjust Unlikely" rule.
Adjacent Specialties
Diagnostic Delays in Pediatric Acute Ischemic Stroke: 24-Year Trends and Contributing Factors in SwitzerlandLOE 4 — Retrospective cross-sectional registry study
Stroke · Pediatric Neurology
In children with acute ischemic stroke, what factors are associated with diagnostic delay, and have delays improved over 24 years?
Median time to diagnosis was 26.9 hours. 77.5% of pediatric strokes are still diagnosed beyond the thrombolysis window. Younger age, posterior circulation symptoms, and nonspecific presentations predicted longer delays. Direct presentation to stroke centres shortened time to diagnosis.
This is a well-conducted registry study with a large sample over 24 years. The findings are sobering but not surprising — pediatric stroke is rare, mimics are common, and index of suspicion is low. The limitation is that this is Swiss data; Canadian systems may differ. Still, the message is clear and actionable.
Bottom line: We're still missing most pediatric strokes within treatment windows. Posterior circulation symptoms and younger children are at highest risk for delay. Keep stroke on your differential for children with unusual presentations and focal neurologic findings.
Major Journals Scan
Lancet Why it matters to EPs: GLP-1 agonists are everywhere, and patients with alcohol use disorder are common in the ED. This study is also relevant to the broader question of whether these drugs have CNS/behavioral effects beyond weight loss. Semaglutide 2.4mg weekly reduced heavy drinking days by 41 percentage points vs 26 for placebo (difference 13.7 percentage points, p=0.0015) over 26 weeks. 81% completed the trial. Adverse effects were typical GI symptoms, more common with semaglutide but generally tolerable. Well-designed single-center RCT with reasonable retention. The effect size is clinically meaningful. A 14 percentage point absolute reduction in heavy drinking days is substantial for this population. Limitations: single center, required comorbid obesity (so not generalizable to all AUD), and 26 weeks is relatively short for a chronic relapsing condition. The mechanism (GLP-1 effects on reward pathways) is biologically plausible. This won't change ED management of acute intoxication or withdrawal, but it's an important signal for a condition with limited pharmacotherapy options. Bottom line: Semaglutide shows promise for alcohol use disorder in patients with obesity. Not ED-actionable today, but important to know about. We will see more and more patients using these agents and so need to recognize side effects. |
Methodology Flag
Resuscitation
Finding that CFIO (Boussignac device) is associated with worse neurological outcomes than BVM will get attention and may influence airway management discussions
- Observational design with different EMS systems using different ventilation strategies — this is comparing systems, not just devices
- Unmeasured confounding is substantial: EMS systems that chose CFIO may differ in response times, training, protocols, patient populations, and hospital capabilities
- No information on quality of CFIO or BVM delivery — technique matters enormously for both
- Retrospective registry data with inherent limitations in data quality and completeness
What it does contribute: Raises a hypothesis that CFIO may not be equivalent to BVM and warrants proper RCT evaluation. Also highlights that some systems have adopted CFIO devices based on physiologic reasoning and surrogate outcomes without definitive patient-oriented outcome data.
Bottom line: Do not conclude from this study that CFIO causes worse outcomes. The comparison is confounded at the system level. However, it's a reminder that we shouldn't assume newer airway adjuncts are equivalent or superior without proper trials.