PRE-HOSPITAL EMERGENCY MEDICINE · UK EDITION
PHEM Evidence Rundown
May 2026 | Monthly Issue
Jake Turner
Curated with the assistance of AI (Perplexity). All content editorially reviewed.
Standout item: JRCALC April 2026 Clinical Update — resuscitation extended to 45 minutes, paediatric defibrillation escalation to 8 J/kg, prehospital ROSC fluid targets now formalised. Effective now across all UK ambulance services. CHANGE items this issue: JRCALC resuscitation update (CHANGE TONIGHT) • Prehospital TXA meta-analysis — 28% reduction in 24 h mortality (CHANGE THIS MONTH) • AP pad positioning mechanistic data from DOSE-VF substudy (INFORMING PRACTICE) • PRINCESS2 pilot safety data (INFORMING PRACTICE)
- AAUK National Policy Position Statement 2026 (CHANGE WHEN GUIDELINE UPDATES) • HEMS outcomes EMJ (INFORMING PRACTICE) No new MHRA FSNs specific to prehospital drugs or equipment this month.
BOTTOM LINE UP FRONT — MAY 2026
ACT ON THIS NOW
TONIGHT JRCALC April 2026: Extend minimum resus to 45 min. Target SBP 100 mmHg post-ROSC (80 mmHg in traumatic TCA). Paediatric refractory VF: escalate to 8 J/kg after 5th shock.
TONIGHT Paediatric defibrillation escalation: 8 J/kg after 5th shock for refractory VF/pVT. Confirm your defibrillator can deliver this energy. Update cognitive aids now.
THIS MONTH Prehospital TXA: New meta-analysis (n=12,682) — 28% reduction in 24 h mortality (OR 0.72). Give within 3 h of injury. No increase in VTE. Reinforces JRCALC guidance.
GUIDELINE WATCH AAUK Policy 2026: Advocate for 24/7 helipad access at all MTCs. PRANA data linkage critical for air ambulance outcome tracking.
KNOW FOR NEXT TIME
INFORMING AP pad positioning: DOSE-VF substudy (n=342) — AP position independently associated with ROSC (aOR 2.01). Consider AP as default for VF/pVT OHCA at scene.
INFORMING PRINCESS2 pilot (n=100): On-scene trans-nasal brain cooling in VF arrest is safe and feasible (92% protocol adherence). Main trial ongoing — 1022 patients target.
INFORMING OnScene ECPR trial ended inclusion (July 2025, n≈220). Outcome data Q2–Q3 2026. HEMS-delivered ECPR paradigm about to be tested.
INFORMING PHTEE-OHCA RCT: Prehospital TOE in OHCA — feasible without impairing CPR metrics in physician-staffed EMS. Not yet routine; larger trial needed.
UK DATA Stroke routing: 1 in 10 suspected stroke patients transported to non–stroke-capable centre. LVO triage tools and bypass protocols reduce this gap — key paramedic lever.
INFORMING Ketamine vs morphine for prehospital analgesia: MA of 4 RCTs (n=757) — no pain-score advantage for ketamine; higher adverse events. Role in haemodynamic instability preserved.
May 2026 arrives with a landmark JRCALC update that restructures how UK prehospital teams approach resuscitation — extending the minimum effort window, formalising post-ROSC blood pressure targets, and overhauling paediatric defibrillation energy for refractory rhythms. Alongside this, a mechanistic substudy of the DOSE-VF trial clarifies why AP pad positioning works — pad position, not delivered current, is independently linked to ROSC, giving every HEMS team a concrete on-scene rationale to switch from AL to AP for shockable rhythms. A new TXA meta-analysis of 12,682 patients provides the clearest prehospital mortality signal yet, while PRINCESS2 reports that on-scene brain cooling is safe and protocol-adherent in VF arrest. The OnScene ECPR trial has concluded recruitment and outcomes data are expected Q2–Q3 2026 — watch this space.
CONTENTS
§1 Key PHEM Articles & Trials
1. DOSE-VF AP Pad Substudy — AP Position Independently Drives ROSC (aOR 2.01) 2. PRINCESS2 Pilot (n=100) — On-Scene Brain Cooling: Safe & Feasible in Shockable OHCA 3. Prehospital TXA Meta-Analysis — 28% Reduction in 24 h Mortality (n=12,682) 4. OnScene ECPR Trial — Inclusion Complete; Results Q2–Q3 2026 5. PHTEE-OHCA RCT — Prehospital TOE in Cardiac Arrest: Feasible Without CPR Compromise 6. KSSAA HEMS Outcomes — 5 Additional Survivors per 100 Major Trauma Patients (EMJ 2026) 7. Ketamine vs Morphine for Prehospital Analgesia — No Pain Advantage, More Adverse Events 8. Prehospital POCUS in Rural EMS — Feasible, Influences 18% of Transport Decisions 9. Protocolised Prehospital RSI — SR/MA: Improved First-Pass Success, Reduced Hypoxaemia 10. EMS Stroke Routing — 1 in 10 Transported to Non–Stroke-Capable Centre
§2 Guidelines & UK Updates
11. JRCALC April 2026 Clinical Update — Resuscitation, Paediatric Defibrillation, Post-ROSC Targets 12. AAUK National Policy Position Statement 2026 — Helipads, PRANA, EGNOS, Funding 13. Royal College of Paramedics — 25th Anniversary & Strategy 2026–2036 14. Sub30 London Prehospital ECPR — Comparable Survival to In-Hospital ECPR
§3 Paediatric PHEM
15. Paediatric Drowning — ETI vs BVM: No Outcome Difference (PMID 41819339) 16. JRCALC Paediatric Defibrillation Escalation — 8 J/kg After 5th Shock
§4 FOAMed & Critical Appraisal
17. St Emlyn's: Prehospital Z1 P-REBOA — LAA Cohort Analysis and Limitations 18. OnScene Trial Conclusion — The Most Important PHEM Trial of 2026? 19. PRINCESS2 in Context — Why Prehospital Brain Cooling Trials Have Failed Before
§5 Quick Hits · Core Revision · Action Points · Trials to Watch
TAGS:
OPERATIONAL | CHANGE TONIGHT
1 — KEY PHEM ARTICLES & TRIALS
RESUSCITATION · MARCH 2026 · PMID 41856454
AP Pad Position Independently Drives ROSC in Refractory VF — DOSE-VF Substudy
A mechanistic substudy of the landmark DOSE-VF trial (Resuscitation, March 2026; PMID 41856454) examined 342 patients with refractory VF, contributing 849 interventional shocks across anterolateral (AL), vector-change AP (VC-AP), and double-sequential external defibrillation (DSED) strategies. Mean transthoracic current was significantly higher for AP shocks in both VC (19.6 A) and DSED (19.2 A) configurations versus standard AL (16.6 A). However, in generalised estimating equation modelling, AP pad positioning was independently associated with ROSC (aOR 2.01; 95% CI 1.12–3.59), while delivered current was not. This finding separates the mechanism of benefit: the AP vector — not higher current — is what matters.
PHEM angle: HEMS and BASICS teams applying DSED or VC protocols must ensure the posterior pad is correctly placed (left of spine, below scapula at heart level) — not just anywhere on the back. Incorrect posterior pad placement (anterior drift) seen in ~80% of simulated AL placements in related studies. AP as default initial position for VF/pVT OHCA is now mechanistically justified. Review pad placement training at your service.
Critical appraisal: Substudy of an RCT; the randomisation was to defibrillation strategy, not to pad position per se. Observational analysis within the interventional arms. GRADE: Low (observational within RCT context). Does not yet justify a protocol change for initial placement but strengthens the case for upcoming RCTs.
- aOR 2.01 AP POSITION → ROSC
- n=342 REFRACTORY VF PATIENTS
- 19.6 A MEAN AP CURRENT (VS 16.6 AL)
- NS CURRENT NOT ASSOC. WITH ROSC
PMID 41856454 · Resuscitation 2026 · DOI 10.1016/j.resuscitation.2026.111061
CRITICAL CARE · FEBRUARY 2026 · PMC12930594
PRINCESS2 Pilot (n=100): On-Scene Trans-Nasal Brain Cooling — Safe, Feasible in Shockable OHCA
The PRINCESS2 trial (Critical Care, February 2026) published pre-specified pilot results from its first 100 patients (median age 64 years; 91% male) randomised to on-scene trans-nasal evaporative cooling (RhinoChill device) followed by systemic hypothermia at 33°C for 24 h, vs. normothermia. Protocol adherence was 92%. Survival to 72 h was identical: 64% (intervention) vs. 63% (control). Prehospital re-arrest rates were equivalent (22% vs. 23%). Minor adverse events: 4 cases of epistaxis, 2 nasal whitening in the intervention arm. No serious device-related events. The trial will continue to its full target of 1,022 patients.
Why it matters: This is the first European multicentre trial of prehospital trans-nasal brain cooling targeting VF arrest — the most treatable OHCA rhythm. The pilot confirms safety data that prehospital ambulance crews can operate this device without increasing on-scene time or re-arrest risk. The key question — whether early cooling improves complete neurological recovery — remains unanswered until the main trial reports, expected 2027.
Critical appraisal: Pilot phase — not powered for outcomes. 72 h survival is a surrogate. Neurological recovery (the primary endpoint) not yet reported. GRADE: Insufficient (pilot only). Watch for main trial results.
- 92% PROTOCOL ADHERENCE
- n=100 PILOT PHASE (1022 TARGET)
- 64% vs 63% 72 H SURVIVAL (NO DIFF)
- 22% vs 23% PREHOSPITAL RE-ARREST (NS)
PMC12930594 · Critical Care 2026 · DOI 10.1186/s13054-026-05851-y
FRONTIERS IN MEDICINE · MARCH 2025 · PMID 40160319
Prehospital TXA Reduces 24 h Mortality 28% — Meta-Analysis of 12,682 Patients
A systematic review and meta-analysis (Frontiers in Medicine, March 2025; PMID 40160319) included 12 studies (5 RCTs, 7 observational cohorts) covering 12,682 trauma patients. Prehospital TXA was associated with a significant 28% reduction in 24 h mortality (OR 0.72; 95% CI 0.54–0.94; p=0.02). No significant increase in VTE (OR 1.14; 95% CI 0.98–1.33; p=0.09). No significant differences in 28–30-day mortality, overall mortality, hospital length of stay, or incidence of multiple organ failure. This is the largest prehospital TXA meta-analysis to date and provides the clearest early-mortality signal yet.
PHEM angle: This reinforces existing JRCALC and FPHC guidance: give TXA to all major trauma patients with suspected haemorrhage as soon as possible, ideally within 1 h of injury (benefit maintained to 3 h). The 28% reduction in early mortality is a clinically meaningful effect. The VTE signal (trending but non-significant) warrants monitoring in registry data.
Critical appraisal: Heterogeneity in study populations, TXA doses, and comparators limits certainty. 28–30-day mortality not significantly changed — early survival benefit may not translate to long-term outcomes. GRADE: Moderate. The CRASH-2 and PATCH-Trauma data remain foundational; this MA strengthens the evidence base.
- OR 0.72 24 H MORTALITY REDUCTION
- NNT ≈12 NNT — 24 H MORTALITY
- n=12,682 12 STUDIES (5 RCTS)
- OR 1.14 VTE RISK (NS)
PMID 40160319 · Frontiers in Medicine 2025 · DOI 10.3389/fmed.2025.1552271
ONSCENE TRIAL · STATUS UPDATE JULY 2025
OnScene ECPR Trial — Inclusion Complete (n≈220); Results Expected Q2–Q3 2026
The OnScene trial — the first nationwide prehospital ECPR programme delivered via HEMS — closed inclusion on 1 July 2025 after recruiting approximately 220 patients over 3.5 years across the Netherlands. Follow-up (6 months) will complete and results are expected Q2–Q3 2026. The trial aims to answer whether helicopter-delivered ECPR in refractory OHCA improves neurologically intact survival vs. conventional ALS. Approximately half of enrolled patients received ECPR.
Why it matters for UK PHEM: If OnScene demonstrates outcome benefit, it will provide the strongest evidence base yet for a nationwide UK HEMS-delivered ECPR programme. The Sub30 London pilot demonstrated comparable survival rates to in-hospital ECPR in a metropolitan setting. UK HEMS services should be reviewing ECPR logistics and cannulation training now.
Tell your service: UK ambulance services and HEMS medical directors should monitor the OnScene trial results and consider readiness assessment for prehospital ECPR pathways in their regions.
onscenetrial.com · Status update July 2025
CRITICAL CARE · JANUARY 2026 · PMID 41484784
PHTEE-OHCA RCT: Prehospital TOE in Cardiac Arrest — Feasible Without CPR Compromise
The PHTEE-OHCA randomised controlled pilot trial (Critical Care, January 2026; PMID 41484784) evaluated prehospital transesophageal echocardiography (TEE) during OHCA in a physician-staffed European EMS. Probe insertion and image acquisition were possible in all intervention cases. Hands-off time and chest compression fraction (CCF) were comparable between groups. TEE provided clinically relevant diagnostic information (reversible causes, guide to cannulation for ECPR). Study limitations: unblinded, small n, significant collapse-to-arrival imbalance between groups, conducted in a high-resource physician-led system.
Critical appraisal: Feasibility confirmed in a highly resourced system — this cannot yet be generalised to standard UK paramedic EMS. TEE requires: secured airway, ≥3 on-scene personnel, experienced operator. Do not interpret as justification for routine prehospital TEE. GRADE: Very Low (pilot feasibility only).
PHEM angle: For physician-led HEMS services, this supports TEE as a conditional adjunct (e.g., when ECPR is being considered). The diagnostic value — identifying pseudo-PEA, guiding cannulation — is the key potential benefit, not CPR metric improvement.
PMID 41484784 · Critical Care 2026 · DOI 10.1186/s13054-025-05805-w
EMERGENCY MEDICINE JOURNAL · FEBRUARY 2026 · DOI 10.1136/EMERMED-2025-215451
KSSAA HEMS Outcomes — 5 Additional Survivors per 100 Major Trauma Patients (EMJ 2026)
A regional HEMS outcomes study (Emergency Medicine Journal, February 2026) analysed 3,225 trauma patients treated by Kent, Surrey and Sussex Air Ambulance (KSSAA) from 2013–2022. HEMS attendance was associated with favourable survival outcomes: approximately 5 additional people survived per 100 severely injured patients compared to predicted mortality from standard models. Younger patients and those more responsive at initial assessment benefited most. Among 1,316 traumatic cardiac arrest patients, 27% achieved ROSC during transport. Likelihood of achieving ROSC from traumatic cardiac arrest increased by 6% per year between 2013 and 2022, reflecting improving HEMS practice.
Why it matters: This is a 10-year regional UK dataset with improving outcomes over time — the improving traumatic CA survival rate is particularly striking and validates investment in HEMS resuscitation protocols (RSI, REBOA, ECPR, TXA). The 5/100 NNT for HEMS is consistent with prior KSSAA/LAA data.
Tell your service: Use this data in service-level planning and commissioning discussions. The PRANA data linkage requested in the AAUK Policy Statement 2026 would enable this type of analysis nationally — advocate for it.
EMJ February 2026 · DOI 10.1136/emermed-2025-215451
NEUROLOGY · APRIL 2025 · DOI 10.1212/WNL.0000000000210558
Ketamine vs Morphine for Prehospital Analgesia — MA of 757 Patients: No Pain Advantage, More Adverse Events
A meta-analysis of 4 RCTs (757 patients) found that sub-dissociative ketamine was not superior to morphine for prehospital traumatic pain (mean difference in pain scores: −0.90; 95% CI −2.19 to 0.40; p=0.17). Adverse event rate was significantly higher with ketamine (64.5% vs 35.5%). Ketamine was associated with a greater rise in systolic blood pressure (+6.27 mmHg; p=0.0002). No differences in heart rate or respiratory rate.
Critical appraisal: Only 4 trials included; high heterogeneity in doses (sub-dissociative 0.1–0.3 mg/kg IV vs. IM dosing). The adverse event definition varied — many events were mild dissociation/emergence. GRADE: Low. The haemodynamic advantage of ketamine (higher SBP) may be relevant in trauma with hypotension where morphine is relatively contraindicated.
PHEM angle: Ketamine remains the preferred analgesic agent in hypotensive trauma (morphine causes vasodilation/histamine release), for patients requiring RSI induction, and for isolated TBI where opioid-related respiratory depression is a risk. The "no advantage for pain scores" finding does not diminish ketamine’s role in PHEM — context determines agent choice.
Neurology 2025 · DOI 10.1212/WNL.0000000000210558 (n=757, 4 RCTs)
PREHOSPITAL EMERGENCY CARE · FEBRUARY 2026 · DOI 10.1080/10903127.2026.2625227
Prehospital POCUS in Rural and Wilderness EMS — Feasible, Influences 18% of Transport Decisions
A prospective quasi-experimental study (Prehospital Emergency Care, February 2026) assessed implementation of eFAST and limited cardiac ultrasound in rural and wilderness paramedics. Participants showed a 44% increase in knowledge scores post-training (p<0.0001) with good retention at 4 months. 22 scans were performed in routine patient care; 4 (18.2%) were deemed clinically meaningful by receiving physicians, influencing diagnosis and transport decisions. No adverse events attributable to POCUS use.
PHEM angle: UK wilderness BASICS doctors and rural HEMS teams working in prolonged transport environments (mountain rescue, rural BASICS) should consider eFAST training. 18% decision-change rate is consistent with prior urban HEMS POCUS data (36% change in transport decisions in the SJTREM HEMS POCUS study covered in Issue 2).
Prehospital Emergency Care 2026 · DOI 10.1080/10903127.2026.2625227
J CONTEMPORARY CLINICAL PRACTICE · NOVEMBER 2025
Protocolised Prehospital RSI — SR/MA Shows Improved First-Pass Success, Reduced Hypoxaemia
A systematic review and meta-analysis of 10 studies evaluated protocolised RSI (checklists, bundles, mandatory bougie) vs. usual care across ED and prehospital settings. Protocolisation was consistently associated with improved first-pass success (FPS) and approximately 20–30% relative reduction in peri-intubation hypoxaemia (pooled RR 0.77; 95% CI 0.65–0.91). Benefits were largest in physician-led interventions but positive in paramedic-led systems. UK HEMS data (Price et al.) showed 90.2% vs. 87.4% FPS comparing physician to critical care paramedic operators (NS difference).
PHEM angle: Structured RSI checklists are a patient safety intervention. The "7 Ps" pre-RSI checklist — Patient (position, monitoring), Pre-oxygenation, Physiological optimisation, Premedication, Paralysis & induction, Placement with proof, Post-intubation management — should be mandated in all HEMS and critical care paramedic services.
- RR 0.77 HYPOXAEMIA REDUCTION
- 10 studies PREHOSPITAL + ED
- ~30% RELATIVE HYPOXAEMIA REDUCTION
- Moderate EVIDENCE QUALITY
JOURNAL OF THE AMERICAN HEART ASSOCIATION · DECEMBER 2025 · PMC12826932
Prehospital Stroke Routing — 1 in 10 Patients Transported to Non–Stroke-Capable Centre
A cross-sectional analysis of 200,000+ EMS encounters for suspected stroke found that 10% of patients with suspected stroke were transported to facilities without verified stroke care capabilities. Substantial between-agency variation persisted even when multiple destination options were available. Rural location, higher community social vulnerability, and EMS agency characteristics were associated with lower odds of appropriate routing. This mirrors the 2026 AHA/ASA ischaemic stroke guidelines’ Class 1A recommendation for EMS triage to LVO-capable centres.
PHEM angle for UK: UK ambulance services operate under JRCALC and local stroke network protocols for LVO triage and bypass to hyper-acute stroke units (HASUs). G-FAST (≥2/3 positive for LVO) has been validated — the key paramedic action is confident HASU-bypass decision. The 2026 AHA/ASA guidelines now state bypass for >45–60 min extra transport is NOT beneficial (Class 3). UK paramedics: apply Face-Arm-Speech-Time-Eyes (FAST-E) or equivalent local LVO tool, and pre-notify the HASU regardless of bypass decision.
Tell your service: Review local stroke network bypass protocols. Ensure crew familiarity with LVO triage tools and pre-notification pathways. Record stroke scale scores consistently — this is the biggest determinant of hitting door-to-needle time targets.
PMC12826932 · J Am Heart Assoc 2025
2 — GUIDELINES & UK UPDATES
JRCALC · APRIL 2026 · EFFECTIVE IMMEDIATELY
JRCALC April 2026 Clinical Update — Resuscitation, Paediatric Defibrillation, Post-ROSC Targets
Released 18 April 2026 and effective immediately across all UK ambulance services via JRCALCPlus and ICPG apps. Key changes:
| Area | Previous | Updated (April 2026) |
|---|---|---|
| Minimum resuscitation duration | 30 minutes | 45 minutes (with favourable factors) |
| Paediatric defibrillation — refractory shockable rhythm | 4 J/kg throughout | Escalate to 8 J/kg after 5th shock (max 360 J; adult pads may be needed) |
| Post-ROSC SBP target — medical | Not formalised | Target SBP ≥100 mmHg |
| Post-ROSC SBP target — traumatic TCA | Not formalised | Target modified SBP 80 mmHg (100 mmHg if raised ICP suspected) |
| Pad position | AL or AP — no specific guidance on refractory failure | Clearer direction on pad position for refractory VF + recommended actions after 3 unsuccessful shocks |
| Handover | Local variation | AMIST template now recommended for handover |
| RCUK traumatic CA algorithm | Not included | New prehospital TCA algorithm — HOT principles by clinical priority, not sequentially |
Action required: All HEMS, BASICS, and critical care paramedic services should update cognitive aids and crew briefings now. Paediatric defibrillation dose escalation to 8 J/kg after 5th shock is a meaningful protocol change that requires clinical familiarity before use.
JRCALCPlus April 2026 Update · Class Professional Publishing · AACE explainer video (YouTube)
AIR AMBULANCES UK · MARCH 2026
AAUK National Policy Position Statement 2026 — Helipads, PRANA, EGNOS, Funding
Air Ambulances UK (AAUK), supported by the APPG for Air Ambulances, published the UK’s Air Ambulance Charities’ National Policy Position Statement 2026 (March 2026). Four national policy priorities:
1. 24/7 helipad access at all new and existing UK Major Trauma Centres and specialist hospitals. 2. PRANA data linkage — secure access to linked patient outcome data to enable air ambulance charities to track outcomes and integrate with NHS systems. 3. EGNOS restoration — temporary re-joining of the European Geostationary Navigation Overlay Service to improve flight safety and reduce weather-related mission delays post-Brexit. 4. Public understanding of the independent charitable funding model of the UK’s 21 air ambulance charities.
Operational note: PRANA data linkage is the most clinically important priority. Without it, air ambulance charities cannot track what happens to their patients in hospital — limiting quality improvement and commissioning evidence. Advocate for this with NHS regional teams.
AAUK Position Statement 2026 (PDF) · March 2026
ROYAL COLLEGE OF PARAMEDICS · 2026
Royal College of Paramedics — 25th Anniversary & Strategy 2026–2036
The College of Paramedics (granted Royal Charter by HM King Charles III in 2024) marks its 25th anniversary in 2026 with its annual national conference (21–22 May 2026, Newport, South Wales) and the launch of its Strategy 2026–2036. The conference will address disaster response, frailty, and the future of the paramedic profession. The strategy sets the direction for the Royal College of Paramedics over the next decade, including expanding scope of practice and advocating for prehospital research.
Tell your service: PHEM trainees and critical care paramedics should engage with the Royal College of Paramedics — membership, CPD opportunities, and advocacy for PHEM research funding. The Royal Charter status strengthens the profession’s voice in NHS commissioning.
RCoP Strategy 2026–2036 (PDF) · Annual Conference May 2026
ST EMLYN’S / LONDON’S AIR AMBULANCE
Sub30 London Prehospital ECPR — Comparable Survival to In-Hospital ECPR
The Sub30 feasibility study (Singer et al., London Ambulance Service / LAA) evaluated prehospital ECPR in refractory OHCA in London. The study did not meet its primary outcome of achieving full ECPR flow within 30 minutes of collapse, but demonstrated safe, timely, and effective delivery of ECPR with survival rates comparable to in-hospital ECPR programmes. The study has directly informed the OnScene trial model and reinforces the feasibility of a UK prehospital ECPR programme via HEMS.
St Emlyn’s: Sub30 Review · London’s Air Ambulance / LAA
3 — PAEDIATRIC PHEM
RESUSCITATION-RELATED JOURNAL · MARCH 2026 · PMID 41819339
Paediatric Drowning: Prehospital Airway Interventions — ETI vs BVM, No Outcome Difference
A registry study (PMID 41819339; March 2026) examined prehospital respiratory interventions in paediatric drowning OHCA and non-OHCA patients. Among OHCA patients, endotracheal intubation was not associated with significantly different odds of favourable neurological outcome or survival to discharge compared to BVM ventilation. In non-OHCA drowning patients, supplemental oxygen did not significantly differ in outcomes. The study reinforces that the priority in paediatric drowning is early, high-quality CPR and airway positioning rather than advanced airway device selection.
PHEM angle: This aligns with JRCALC and ERC 2025 guidance — for paediatric OHCA, SGA or BVM first-pass is preferred over ETI given lower first-pass success rates for ETI in children. The key prognostic factors in drowning remain: submersion time (<5 min most favourable), water temperature (cold water neuroprotection), witnessed arrest, and bystander CPR quality. Focus prehospital team effort on high-quality CPR and rapid transport to a paediatric major trauma / PICU centre.
Critical appraisal: Registry study with inherent selection bias — sicker children more likely to receive ETI. Cannot exclude confounding by severity. GRADE: Low. However consistent with prior paediatric airway evidence. Do not change to ETI as default based on this data.
PMID 41819339 · March 2026
JRCALC · APRIL 2026 · EFFECTIVE IMMEDIATELY
JRCALC Paediatric Defibrillation Escalation — 8 J/kg After 5th Shock in Refractory VF
The April 2026 JRCALC update introduces a critical paediatric defibrillation change: for children with refractory shockable rhythms, defibrillation energy should escalate to 8 J/kg (maximum 360 J) after the fifth shock, aligning with ERC 2025 paediatric ALS recommendations. Standard paediatric energy remains 4 J/kg for the first four shocks. Adult pads may be required to achieve the appropriate energy level when escalating to 8 J/kg (smaller paediatric pads may be unable to deliver sufficient energy at higher doses on some devices).
PHEM action: Check your defibrillator’s capacity to deliver 8 J/kg with paediatric pads — if maximum output is <8 J/kg for the child’s weight, switch to adult pads (ensuring no contact/overlap). Include this change in your next paediatric resuscitation training exercise. Ensure cognitive aids are updated.
Rationale: Refractory paediatric VF (rare but recognised in channelopathies, hypothermia, myocarditis) has extremely poor outcomes. Higher-energy defibrillation in adults has demonstrated improved termination of refractory VF (DOSE-VF). This extrapolation to paediatrics is physiologically plausible and supported by limited case series data.
JRCALC April 2026 Clinical Update — AACE YouTube
4 — FOAMED & CRITICAL APPRAISAL
ST EMLYN’S · BASED ON JAMA SURGERY 2024
St Emlyn’s: Prehospital Z1 P-REBOA — LAA Cohort Analysis and Limitations
St Emlyn’s published a full critical appraisal of the London’s Air Ambulance prehospital Zone 1 Partial REBOA (Z1 P-REBOA) cohort study (JAMA Surgery, 2024). Key findings: Z1 P-REBOA feasible in 8/11 patients where attempted; associated with improved proximal blood pressure and early mortality. Median time from injury to REBOA: 57 minutes (vs. 135 min for in-hospital UK-REBOA). However, 30-day survival was only 18% (2/11) with most late deaths from multi-organ dysfunction. The appraisal notes the critical contextual point: in-hospital UK-REBOA RCT showed REBOA may increase mortality when insertion delays definitive haemorrhage control. The prehospital model avoids this delay by bridging to surgery faster.
Critical appraisal: n=16 total (11 received Z1 REBOA). IDEAL 2A feasibility design — not powered for outcomes. The 30-day mortality remains high. Whether earlier REBOA (at scene vs. ED) changes outcomes requires an RCT. EAST REBOA PMG 2025 (carry-over) emphasises patient selection is critical — wrong patient, wrong zone = harm.
St Emlyn’s: Zone 1 P-REBOA · Based on JAMA Surgery 2024 (DOI 10.1001/jamasurgery.2024.1937)
ONSCENE TRIAL WEBSITE · JULY 2025
OnScene Trial Conclusion — The Most Important PHEM Trial of 2026?
The OnScene trial website confirmed that inclusion ended 1 July 2025. The trial enrolled approximately 220 patients across the Netherlands — the world’s first nationwide prehospital ECPR programme via HEMS. Data analysis is underway and results are expected Q2–Q3 2026. If positive, OnScene will provide the largest RCT evidence base for HEMS-delivered ECPR ever published and will directly inform UK commissioning decisions.
Context: The Sub30 London study showed comparable survival to in-hospital ECPR. The ARREST trial (Minneapolis) showed in-hospital ECPR superior to conventional ALS for refractory OHCA. OnScene is asking: can we bring this to the scene via helicopter? The scale (n=220) and RCT design make this the most consequential prehospital resuscitation trial since PARAMEDIC2.
EMCRIT / PRINCESS2 TRIAL CONTEXT · 2026
PRINCESS2 in Context — Why Prehospital Brain Cooling Trials Have Failed Before
A key concern with PRINCESS2 is historical: the TTM trial (2013, NEJM) showed no benefit of 33°C vs. 36°C targeted temperature management, and the HYPERION trial (2019) showed modest benefit only in non-shockable rhythms. Previous prehospital cooling trials (cold IV fluids) showed re-arrest signals. PRINCESS2 differs critically: (a) it uses trans-nasal evaporative cooling (volume-neutral — no cold fluid re-arrest risk), (b) it targets only shockable rhythms where subgroup analysis from PRINCESS showed benefit, and (c) it combines prehospital brain cooling with in-hospital systemic hypothermia at 33°C. The pilot safety data is reassuring.
Critical appraisal context: TTM2 (2021, NEJM) showed no benefit of 33°C vs. fever avoidance alone — this undermines the in-hospital cooling arm of PRINCESS2. If normothermia with fever control is now equivalent to hypothermia in-hospital, does the additional prehospital brain-cooling step add anything? The trial design assumes in-hospital hypothermia still has value in shockable OHCA — a contested premise.
5 — QUICK HITS
EMS WELLBEING
OPERATIONAL EMS Burnout & Moral Injury — Scoping Review (Frontiers in Health
Services, March 2026) A scoping review mapped burnout and moral injury across public safety personnel (PSP) including EMS. Personal burnout prevalence: 38.3% paramedics, 24.9% EMTs. Work-related burnout: 30.1% paramedics. Key organisational drivers: insufficient sleep from overnight shifts, perceived incompetence of colleagues, lack of safety culture, moral distress from resource constraints. Systems-level interventions (scheduling, peer support, leadership) are more effective than individual resilience training alone. PHEM relevance: HEMS clinicians face uniquely intense exposure — critical interventions, traumatic deaths, complex decisions. Peer support officers and structured post-event debriefs are evidence-based mitigation strategies. Review your service’s wellbeing provisions. [PMC13076284]
TRAUMA
DipIMC/FIMC EAST REBOA Practice Management Guideline 2025 — Carry-Over
The EAST PMG on REBOA provides clear selection criteria for REBOA use in haemorrhagic trauma: Zone 3 for suspected pelvic haemorrhage, Zone 1 for junctional/abdominal haemorrhage with TCA or imminent TCA. Key point: REBOA is a bridge to definitive haemorrhage control — if it delays surgery, it harms. Patient selection and team experience are paramount. Prehospital REBOA should only be performed by services with an established training, governance, and outcome tracking programme. Applicable to UK physician HEMS teams currently operating or planning REBOA programmes.
HAEMOSTASIS
DipIMC/FIMC TEG/ROTEM Portable VET — Maturing Prehospital Haemostasis
Assessment Carry-over from tracking list: portable viscoelastic testing (VET) is becoming viable for prehospital use in resource-replete HEMS systems (Am J Hematol Dec 2025). Point-of-care TEG/ROTEM can guide targeted blood product administration (FFP vs. platelets vs.
cryoprecipitate) in major haemorrhage rather than empirical 1:1:1 ratios. Currently limited to HEMS with a full blood product capability. The UK-ROTEM trial in the London MTC setting provides in-hospital context. Prehospital application remains early-phase.
NHS POLICY
UK DATA NHS England 2026/27 Ambulance Service Specification — Carry-Over The NHS England 2026/27 ambulance service specification sets HEMS performance
expectations and introduces enhanced response metrics. Critical care paramedic deployment thresholds and clinical intervention rates will be audited against national benchmarks. Services should review CCP deployment protocols and ensure outcome data reporting is aligned with NHS England requirements.
CORE REVISION — PREHOSPITAL TXA: MECHANISM, TIMING, AND PRACTICE (DIPIMC/FIMC)
Core Revision Topic: Tranexamic Acid in Prehospital Trauma — A Critical Summary for DipIMC/FIMC
| Domain | Key Points |
|---|---|
| Mechanism | Competitive inhibitor of plasminogen activation. Prevents fibrinolysis by blocking lysine binding sites on plasminogen → fibrin clot stabilisation. Not a procoagulant. Does not cause de-novo clot formation. |
| Trauma physiology | Major trauma → tissue factor release → fibrinolysis activation → hyperfibrinolysis in ~30% of major trauma patients. TXA prevents clot breakdown that would otherwise amplify haemorrhage and coagulopathy. |
| Timing | Most benefit within 1 h of injury. Statistically significant benefit maintained to 3 h. After 3 h: possible harm signal (increased death from bleeding paradoxically — ? due to fibrinolysis shutdown phase). CRASH-2 principle: give early or not at all. |
| JRCALC dose | 1 g IV/IO in 100 mL 0.9% NaCl over 10 min. Second dose (1 g) given in hospital over 8 h. Paediatric: 15 mg/kg (max 1 g) as per PROX trial evidence. |
| Indications | All major trauma patients with suspected significant haemorrhage who can receive treatment within 3 h of injury. Penetrating trauma, pelvic fracture, major limb injury, traumatic TCA. |
| Contraindications | Known allergy. Isolated TBI without haemorrhage (CRASH-3 showed no mortality benefit and possible increased disability). Established DIC (relative — clinical judgment required). |
| Safety | VTE: no significant increase in multiple meta-analyses (OR 1.14 in current MA). Seizures: dose-dependent at very high doses (>30 mg/kg) — not relevant at JRCALC doses. No myocardial injury signal (CRASH-2 subgroup). |
| Evidence base | CRASH-2 (20,211 patients, OR 0.91 overall mortality), MATTERS (military, 57% mortality reduction with early TXA), PATCH-Trauma (90 min window — Australian prehospital RCT), current meta-analysis (OR 0.72 for 24 h mortality, n=12,682). |
| DipIMC/FIMC exam point | Know the mechanism (anti-fibrinolytic, not procoagulant), the 3-hour window, the dose, and the TBI caveat (CRASH-3). Be able to discuss |
the CRASH-2 result critically (intention-to-treat, all-cause mortality vs. haemorrhagic mortality).
6 — ACTION POINTS
- Update cognitive aids and crew briefings now — JRCALC April 2026: extend minimum resus to 45 min, post-ROSC SBP targets (100 medical, 80 traumatic TCA), AMIST handover template. CHANGE TONIGHT.
- Review paediatric defibrillation protocol — 8 J/kg after 5th shock for refractory VF/pVT. Confirm your defibrillator can deliver this with available pads. Include in next paediatric simulation. CHANGE TONIGHT.
- TXA: give early in all major trauma — meta-analysis (n=12,682) confirms 28% reduction in 24 h mortality. No VTE increase. Give within 1 h ideally, <3 h absolutely. Do not delay for IV access — IO is acceptable.
- Consider AP as default pad position for VF/pVT — DOSE-VF substudy shows AP vector independently drives ROSC (aOR 2.01). Discuss with your medical director whether to formalise AP-first in your service SOP.
- Pre-notify for stroke — record stroke scale score every time — 10% of suspected stroke patients transported to non-stroke capable centres. LVO triage tool completion and pre-notification are the two strongest determinants of hitting DTN time targets.
- ECPR readiness review — OnScene trial results expected Q2–Q3 2026. If positive, UK HEMS services will need ECPR protocols, training, and governance structures. Start the conversation with your medical director now.
- AAUK Policy Statement 2026 — advocate for PRANA data linkage and 24/7 helipad access at MTCs with your regional NHS contacts and parliamentary representatives.
- Wellbeing audit — burnout prevalence 38.3% in paramedics. Review your service’s peer support structures, post-event debrief processes, and scheduling practices. Evidence supports systems-level intervention over individual resilience programmes.
TRIALS TO WATCH
EXPECTED WITHIN 3 MONTHS
OnScene ECPR RCT (Netherlands) — n≈220; nationwide HEMS-delivered ECPR vs. conventional ALS for refractory OHCA. Results Q2–Q3 2026. This is the most significant prehospital resuscitation trial of 2026.
JRCALC JRCALCPlus 2026 Full Update — expected later in 2026; further revisions anticipated following RCUK 2025 guideline implementation period.
EXPECTED 3–12 MONTHS
PRINCESS2 Main Trial Results — 1,022-patient European multicentre RCT; on-scene trans-nasal brain cooling in shockable OHCA → survival with complete neurological recovery. Expected 2027.
PHTEE-OHCA Full RCT — larger multicentre trial following feasibility pilot. Prehospital TEE-guided resuscitation in OHCA. Design phase.
EAST REBOA PMG Implementation Studies — outcome data from services implementing the 2025 EAST Practice Management Guideline for REBOA in trauma.
ONGOING TRIALS TO MONITOR
EMPIRIC (UK) — Empirical TXA in Prehospital TBI; examining TXA in isolated TBI following CRASH-3 null result. Patient recruitment ongoing.
PRANA National Data Infrastructure — not a trial, but a policy initiative. If approved, will enable the first national linked air ambulance outcomes dataset in the UK.
Prehospital Whole Blood RCTs — following SWiFT trial (covered Issue 2), further UK trials examining optimal blood component ratios and warm fresh whole blood feasibility in HEMS.
Jake Turner
Curated with the assistance of AI (Perplexity). All content editorially reviewed. PHEM Evidence Rundown — May 2026 — UK Edition Published by EM Evidence. For clinical use only. Feedback form · emevidence.org · emevidence999@gmail.com