Zworth Reading
EMMax’s EM Weekly Update
Highlight of the Week
Safety of outpatient management of pulmonary embolism diagnosed in the emergency department
CJEM · Retrospective cohort (LOE 4)
Single-centre retrospective review of 243 patients with confirmed PE at two EDs of a Canadian tertiary hospital. ED physicians discharged 101 (42%) low-risk patients directly, typically without consultation, with follow-up in a thrombosis clinic within 48 hours. Of those discharged, 9 (8.9%) returned within 5 days, 5 for PE-related symptoms, 4 for other reasons. Critically, none of the 101 discharged patients experienced clinical deterioration requiring escalation of care, and none were admitted for PE complications.
This is a retrospective chart review at a single academic centre with an established thrombosis clinic infrastructure. Generalizability to community EDs without rapid outpatient follow-up is limited. The 5-day return window is short; longer-term outcomes would strengthen confidence. Selection criteria for discharge were at physician discretion rather than a validated protocol, introducing unmeasured confounding. The 95% CI for the return rate (4.8-16.1%) is wide given the sample size. That said, the zero-deterioration finding among discharged patients is reassuring and aligns with prior literature supporting outpatient PE management in appropriately selected patients. This doesn't change practice (it confirms what many academic EDs already do) but it provides Canadian data supporting the safety of ED-initiated outpatient PE pathways when robust follow-up exists.
Bottom line: Outpatient PE management by ED physicians is safe when patients are appropriately selected and have rapid thrombosis clinic follow-up. This confirms existing practice rather than changing it, but provides useful Canadian data.
Important EM Papers
CJEM
Adults with substance-related nausea at music festivals randomized to inhaled 70% isopropyl alcohol vs saline placebo.
Small double-blind RCT (n=57). Isopropyl alcohol reduced nausea scores by 30% vs 16% for placebo (p=0.024), and halved rescue antiemetic requests (35% vs 70%, NNT 3). No adverse events.
Small sample, festival setting rather than ED, but the antiemetic-sparing signal is real. I will say this is not exactly a patient-centred outcome. Consistent with prior ED literature.
Bottom line: Isopropyl alcohol pads remain a cheap, fast, and safe option for nausea. Not practice-changing but a useful confirmation.
Diagnostic accuracy of point-of-care high-sensitivity troponin algorithms for ED rule-out and rule-in of acute myocardial infarction: a systematic review and meta-analysisLOE 1 (Systematic review / meta-analysis)
Emergency Medicine Journal
In adults with suspected AMI, how do serial high-sensitivity point-of-care (hs-POC) troponin algorithms (0h/1h or 0h/2h) perform for rule-out and rule-in compared to central lab testing?
8 studies, 19 datasets, 9,384 patients, 1,157 AMI cases across 4 different hs-POC platforms. Pooled rule-out sensitivity 98.0% (95% CI 96.0-99.0), NPV 99.9% at 10% prevalence, no additional missed AMIs on follow-up. Rule-in specificity 96.0% (94.0-97.0), PPV 68.5%. Turnaround 8-17 minutes. 0h/1h protocols performed similarly to 0h/2h.
Promising, but the enthusiasm needs tempering. The biggest interpretive challenge is that the meta-analysis pools 4 different platforms and 2 different algorithm types (complex multiparametric vs simple cut-off) across 2 different timing strategies. That's a lot of moving parts. So the pooled numbers are useful as a big-picture answer but each individual ED's mileage will depend on which specific platform and algorithm they end up implementing. Also worth noting only 14 of 19 datasets were low risk of bias on QUADAS-2, and there were modest small-study effects.
Bottom line: Genuinely promising and probably where we are heading, but likely a few years away from routine implementation. The technology works analytically, but real-world benefit depends on the specific platform your department picks and, more importantly, on workflow integration and stopping the reflex to send confirmatory lab troponins. File under 'things we will likely see down the road.'
FOAM Radar
PERC-Peds Rule Could Change How Children Are Evaluated for Pulmonary Embolism: A PECARN StudyKnowledge translation / clinical education
ALiEM · LOE 3 (prospective diagnostic accuracy study, PECARN)
ALiEM reviews the PECARN PERC-Peds derivation and validation study, in which a pediatric-specific 8-item bedside rule safely excluded PE in low-risk children across >4,000 patients with 99.6% sensitivity — meaning no D-dimer or imaging required in rule-out patients.
Bottom line: Pediatric PE is rare but easy to under-investigate or over-investigate. If PERC-Peds validates further and gets adopted, it gives us a validated way to safely defer imaging in low-risk kids — the pediatric analogue of what PERC has done for adults. Worth reading and watching.
EM@3AM: Retrobulbar HematomaClinical education / case-based review
emDocs · LOE 5 (expert opinion, case-based)
Classic presentation of traumatic retrobulbar hematoma with orbital compartment syndrome — proptosis, APD, ophthalmoplegia. Reviews lateral canthotomy and cantholysis as a vision-saving procedure.
Bottom line: High-stakes, low-frequency procedure that every EP should know. Good refresher on recognition and technique. The key teaching point: don't wait for ophthalmology if IOP is elevated and vision is threatened.
Guidelines Update
ACS Committee on Trauma / Society of Interventional Radiology
- IR should be integrated into trauma team activation protocols with defined response time expectations
- Trauma centres should have 24/7 IR availability with clear escalation pathways
- Hybrid OR or IR-capable resuscitation spaces should be considered for Level I centres
- Coordination protocols between trauma surgery and IR should be established prospectively, not ad hoc
Consensus/expert opinion (LOE 5). This is a position statement, not a systematic guideline. Recommendations are process-focused rather than clinical intervention-focused.
Conflicts with existing guidance: No direct conflicts. Reinforces existing ACS verification standards while clarifying IR-specific expectations.
Bottom line: Administrative rather than clinical guidance. The key message for EPs: if your trauma centre doesn't have a clear IR activation pathway with defined response times, this document gives you leverage to push for one. No new clinical recommendations.
Adjacent Specialties
Aggressive Versus Conservative Blood Pressure Reduction in Acute Intracerebral Hemorrhage: A Systematic Review and Meta-Analysis of Randomized Controlled TrialsLOE 1 (Systematic review of RCTs)
Critical Care Medicine · Neurocritical Care / Stroke
In adults with acute intracerebral haemorrhage (ICH), does aggressive BP lowering (SBP <150) versus conservative (SBP <220) improve functional outcomes, mortality, and hematoma expansion?
8 RCTs, 12,669 patients. Primary efficacy outcome (mRS 0-1 at 90 days): no significant difference (RR 1.07, 95% CI 0.99-1.16, p=0.08). Secondary functional outcome (mRS 0-2 at 90 days): no significant difference (RR 1.09, 95% CI 0.99-1.20, p=0.07). 90-day mortality: no difference (RR 0.90, 95% CI 0.77-1.05). Hematoma growth: no difference (RR 0.85, 95% CI 0.66-1.10). One statistically significant finding: 24-hour adverse events were lower with aggressive lowering (RR 0.87, 95% CI 0.76-0.99, p=0.03). Sensitivity analyses: the functional outcome benefit only emerged when the CHASE trial was excluded, or when INTERACT-4 was excluded (for mRS 0-2).
The primary and secondary outcomes in this meta-analysis are unambiguously negative — no difference in favourable functional outcome, mortality, or hematoma growth. The one positive finding is a reduction in 24-hour 'adverse events' in the aggressive arm, but it's worth unpacking what those adverse events actually include: pneumonia, sepsis, fractures, 'other non-vascular events' — outcomes we don't lower BP after ICH in order to prevent. The authors' conclusion — that 'aggressive BP reduction appears to be superior, reducing short-term adverse events and improving the likelihood of favorable functional outcomes at 90 days in selected patients' — is stronger than the data support.
Bottom line: The primary and secondary functional and mortality outcomes are negative. Aim for SBP 140-180 in the ED and don't stress about chasing a specific number below that. The 'aggressive is better' framing from the authors doesn't hold up when you look at what actually drives the composite adverse-event finding and how fragile the functional-outcome signal is to sensitivity analysis. Practically: this doesn't change practice.