TBS 2026: Key Prehospital Emergency Medicine papers

It’s fantastic to be back in Zermatt for the TBS (The Big Sick) conference. I was lucky enough to start the conference together with Iain Beardsell and Brian Burns to review interesting literature from the last year or so. TBS focuses on the first few hours and the cutting edge of resuscitation and that’s what we have tried to reflect in the choices below.

Prehospital emergency medicine continues to mature as a research discipline, with increasing methodological sophistication and a welcome move away from simple feasibility studies towards work that meaningfully challenges our assumptions. This year’s selection spans airway management, oxygen therapy, extracorporeal resuscitation, decision-making in traumatic cardiac arrest, and vascular access – all core components of contemporary PHEM practice.

Prehospital post-intubation hypotension and outcomes in severe TBI

This multicentre retrospective cohort study examined the association between post-intubation hypotension and 30-day mortality in patients with severe traumatic brain injury undergoing prehospital RSI in the East of England trauma network . Using HEMSbase data linked to TARN outcomes, the authors included over 500 patients intubated by physician-led HEMS teams over a seven-year period. Importantly, patients with pre-existing hypotension were excluded, allowing a more focused analysis of hypotension occurring as a consequence of induction and airway management.

We reviewed the paper here on the blog if you want a more in depth analysis.

Post-intubation hypotension — defined as a new systolic blood pressure below 90 mmHg within ten minutes — occurred in just under one in five patients. After adjustment for key confounders, this was associated with increased 30-day mortality in patients with polytrauma and severe TBI, and the effect size was strikingly larger in those with isolated TBI.

Key results

• Post-intubation hypotension occurred in 19% of patients.
• Thirty-day mortality was higher in hypotensive patients (43% vs 27%).
• Adjusted odds of death were increased in polytrauma (AOR ~1.7).
• In isolated TBI, post-intubation hypotension was associated with a very large increase in mortality risk.
• There seems to be an inflexion point at about 100mmHg. Go below that, and especially in isolated TBI, the mortality shoots up.

It’s a good paper, as there is high-quality physiological data capture, and thoughtful handling of confounding. The exclusion of pre-induction hypotension strengthens the data, though residual confounding remains inevitable in observational work. As with all retrospective studies, we cannot determine whether hypotension is a marker of severity, a mediator of harm, or both. Nevertheless, this paper adds weight to the argument that post-RSI physiology matters enormously, and that meticulous haemodynamic control during prehospital anaesthesia is not optional, particularly in isolated head injury.

I’ve changed my practice around BP management, especially in head injury. I always aim to get an arterial line in before induction, and then titrate opiates (fentanyl) carefully watching the BP before full induction. Any signs of dropping BP with the fentanyl means they get no more at that point.

Restrictive versus liberal oxygen in trauma: the TRAUMOX2 trial

TRAUMOX2 is a large, pragmatic, multicentre randomised controlled trial comparing early restrictive and liberal oxygen strategies in adult trauma patients, with enrolment beginning prehospital or on arrival at the trauma centre . Patients triggering full trauma team activation were randomised to either an SpO₂ target of 94% or to high-flow oxygen (or FiO₂ 0.6–1.0 if intubated) for the first eight hours of care.

Over 1500 patients completed the trial, with a composite primary outcome of death or major respiratory complications at 30 days. Outcome assessors were blinded, and adherence was monitored using arterial blood gases.

Key results

• No difference in the primary composite outcome between groups.
• Mortality was similar in restrictive and liberal oxygen strategies.
• Major respiratory complications did not differ overall.
• Atelectasis was less frequent in the restrictive oxygen group.

This is a well-conducted trial addressing a long-standing dogma in trauma care. Its pragmatic design has reasonable external validity, particularly for systems delivering physician-led prehospital care. However, the population was heterogeneous, with relatively modest injury severity overall, and only a minority were intubated at enrolment. It remains possible that subgroups, particularly those with severe TBI or prolonged transport times, may respond differently. The neutral result should not be interpreted as proof that oxygen targets do not matter, but rather that indiscriminate hyperoxia offers no clear benefit in early trauma care. That said it is consistent with lots of other trials that hyperoxia is not that helpful.

Prehospital ECPR for refractory cardiac arrest: the PRECARE pilot study

The PRECARE study is a prospective, single-arm feasibility trial evaluating prehospital extracorporeal CPR delivered by trained prehospital physicians in Sydney . Eligible patients were under 70 years of age, had witnessed arrest with an initial shockable rhythm, and were within a defined geographical radius. The focus was feasibility rather than efficacy, with descriptive reporting of process and outcomes.

Over approximately 100 recruitment days, the team attended more than 120 cardiac arrests, with 12 patients receiving prehospital ECPR. All were successfully cannulated on scene, and low-flow times were substantially reduced compared with historical in-hospital ECPR pathways.

Key results

• Successful on-scene cannulation in all treated patients.
• Mean arrest-to-ECMO flow time of 39 minutes.
• One third were weaned from ECMO.
• One quarter survived to hospital discharge with good neurological outcome.

This study demonstrates that prehospital ECPR is technically feasible within a physician-led EMS system, even with clinicians who initially had limited ECMO experience. The small numbers and lack of comparator arm preclude any conclusions about effectiveness, and the resource intensity is substantial. Nonetheless, PRECARE moves the conversation beyond “can it be done?” towards “who should do this, and for whom?”, setting the stage for more definitive comparative trials. It’s worth looking at the patient flow data here though, there were a huge number of patients screened and attended to find those that get onto pump. From a health economics perspective there is now an associated paper that suggests that it just makes economic sense if you take into account patient outcomes and possibilities of transportation (and so long as it’s a multi capable team and not solely focused on ECPR). That does also imply that ECPR will only work economically if able to cover a large population area.

Decision-making for prehospital resuscitative thoracotomy

This data-informed perspective paper addresses one of the most cognitively demanding decisions in PHEM: when to perform prehospital resuscitative thoracotomy in traumatic cardiac arrest . Drawing on a large, prospectively maintained cohort, the authors explore simple clinical surrogates to guide decision-making when time, diagnostics, and certainty are all limited.

Rather than presenting new outcome data, the paper synthesises existing evidence to propose a pragmatic framework based on injury location as a surrogate for aetiology, and presenting ECG rhythm as a marker of physiological viability.

Key messages

• Injury location helps distinguish tamponade from exsanguination.
  • They showed that you can predict the likelihood of tamponade, exsanguination or both depending on the location of the wound. You can see that key graphic here.
• Organised rhythm suggests residual viability when timelines are unclear.
• Immediate RT is prioritised when tamponade is likely.
• Haemorrhage control and transfusion take precedence when tamponade is unlikely.
• There is a useful graphic table that explains how the decision making is now applied in practice. You can see that here.

The strength of this paper lies in its clinical realism. It acknowledges uncertainty rather than attempting to eliminate it, and provides a structured way to think rather than a rigid algorithm. As a perspective piece, it cannot validate outcomes prospectively, and local governance and training remain critical.

That said there is quite a lot of complexity here. In thoracotomy decisions most people use a time-based indicator associated with a penetrating injury to the chest. This additional data may lead to better decisions, but whether those who do this infrequently can hold all the info under extreme time pressure remains to be seen.

Prehospital central venous access for haemorrhagic shock

I’m a big advocate of central access in shocked patients. I started my career with subclavian lines blindly inserted without USS and with landmark technique. It now seems that it is coming back, which is great.

This retrospective cohort study from London’s Air Ambulance evaluated the feasibility, efficacy, and safety of prehospital insertion of large-bore trauma lines in patients with exsanguinating haemorrhage . Over a four-year period, trauma line insertion was attempted in a small but highly selected group of severely injured patients.

Success rates, transfusion volumes, survival to hospital, and complications were assessed by cross-referencing prehospital records with in-hospital data.

Key results

• Trauma line insertion was successful in 80% of attempts.
• Successful insertion enabled significantly greater prehospital transfusion.
• Survival to emergency department arrival was higher after successful placement.
• Procedural complications were uncommon and mostly minor.

This paper provides reassuring data for teams already performing prehospital central access in extremis. The association between successful line placement and survival must be interpreted cautiously, as confounding by indication is inevitable. However, the low complication rate within a robust governance framework suggests that, in experienced systems, prehospital central access can be both feasible and safe when peripheral access fails.

So., some really interesting papers at an amazing conference.

vb

S

References

Pallavicini P, Carenzo L, Adams R, Bird F, Davenport R, Greenhalgh R, et al. An observational study of pre-hospital central venous access for patients with haemorrhagic shock due to major trauma. Anaesthesia. 2026;81:83–91. doi:10.1111/anae.16778.

Price J, Lachowycz K, Major R, McLachlan S, Keeliher C, Finbow B, et al. Prehospital postintubation hypotension and survival in severe traumatic brain injury. JAMA Netw Open. 2025;8(11):e2544057. doi:10.1001/jamanetworkopen.2025.44057.

Arleth T, Baekgaard J, Siersma V, Creutzburg A, Dinesen F, Rosenkrantz O, et al. Early restrictive vs liberal oxygen for trauma patients: the TRAUMOX2 randomized clinical trial. JAMA. 2025;333(6):479–489. doi:10.1001/jama.2024.25786.

Kruit N, Burns B, Shearer N, Hui J, Coggins A, Buscher H, et al. Pre-hospital ECPR for refractory cardiac arrest – the PRECARE pilot feasibility study. Resuscitation. 2025;212:110631. doi:10.1016/j.resuscitation.2025.110631.

ter Avest E, Kocierz L, Alvarez C, Hurst T, Ballard D, Lockey DJ, et al. Improving decision-making for prehospital resuscitative thoracotomy in traumatic cardiac arrest: a data-driven approach. Crit Care. 2025;29:485. doi:10.1186/s13054-025-05705-z.