Three papers today. Paper one — smart first-responder alerting beat a small alert radius for getting rescuers to a cardiac arrest before the ambulance, but a simple big radius did just as well. Paper two — ventilation with PEEP during CPR was linked with better odds of getting a pulse back. Paper three — portable brain ultrasound added to stroke scales could sharpen prehospital triage for large vessel occlusion.

Paper one — the Journal of the American Heart Association. A randomised three-arm trial from Germany, eight hundred and twenty-three cardiac arrest activations, fourteen hundred and eighty-two community first responders dispatched. The question: does smartphone alerting, which estimates travel times for each responder, get a first responder to the scene before the ambulance, compared with a simple fixed alert radius? First responders arrived before the ambulance in fifty-eight per cent of missions with smart alerting, fifty-seven per cent with a two-and-a-half-kilometre radius, and thirty-one per cent with a six-hundred-metre radius. So smart alerting clearly beat the small radius — a difference of nearly twenty-seven percentage points. But against simply widening the alert radius, there was nothing in it, a difference of about one per cent. And smart alerting came with its own cost — nearly a third of responders who accepted the alert were excluded because their predicted arrival was later than the ambulance's. The caveat here: no patient outcomes were measured, so we don't know if any of this changes survival. Community first-responder schemes already run in parts of Australia, so the radius-versus-estimated-travel-time question transfers directly.

Paper two — The American Journal of Emergency Medicine. A single-centre observational cohort, three hundred and sixty-two intubated adults with out-of-hospital cardiac arrest, managed by a physician-staffed prehospital team. Some patients were ventilated mechanically with PEEP during CPR, the rest by hand without it. Intratracheal pressure was monitored continuously, so the PEEP was verified, not guessed. After adjustment, mechanical ventilation with PEEP was associated with higher odds of return of spontaneous circulation — an odds ratio of one point five eight. The unadjusted odds ratio for survival to hospital discharge was two point two two. Now the caveats: it's observational, single-centre, and the survival-to-discharge figure wasn't adjusted for confounders at all. The physician-staffed crewing model isn't what runs in Australia, but mechanical ventilation with PEEP is an intensive care paramedic capability in most Australian services, so the ventilation question itself is squarely relevant. Worth watching for randomised data before anyone changes practice.

Paper three — Frontiers in Neurology. An exploratory reanalysis of the twenty-patient SONAS trial. A portable, non-imaging brain perfusion ultrasound device was combined with prehospital stroke scales to detect large vessel occlusion. On their own, the best stroke scales performed about the same as the ultrasound — and still misdiagnosed some patients. Combined, though, the two methods sorted suspected stroke into three groups: highly probable large vessel occlusion, highly probable non-occlusion, and not assessable — and every patient misclassified by one method alone landed in that not assessable group. Sensitivity and negative predictive value both shifted higher. There was a nice detail too: three patients flagged by a prehospital bleeding-stroke score as haemorrhage false positives all showed severe perfusion deficits suggesting large vessel occlusion. The caveats are obvious — twenty patients, retrospective, and the authors themselves call validation critical. Portable ultrasound is carried by a handful of Australian services, most don't, so this informs the debate rather than changing practice.

Quick recap. One — smart first-responder alerting beat a small alert radius, but a simple big radius did just as well. Two — PEEP during CPR was linked with better odds of return of spontaneous circulation. Three — brain perfusion ultrasound plus stroke scales may sharpen large vessel occlusion triage.

That's the roundup for Monday the ninth of November. Papers on the dashboard. Back tomorrow.