Key Facts

Pre-hospital care in the UK is delivered by ambulance services (10 NHS trusts in England), supplemented by HEMS/air ambulance services and community first responders. The integration of pre-hospital and in-hospital care through major trauma networks has significantly improved outcomes.

Epidemiology

UK ambulance services respond to approximately 10 million 999 calls per year. There are approximately 30,000 out-of-hospital cardiac arrests per year. Major trauma affects approximately 20,000 patients per year in England. HEMS services attend approximately 20,000-30,000 missions per year.

Aetiology

Pre-hospital emergencies include cardiac arrest, major trauma, acute medical emergencies (MI, stroke, sepsis), obstetric emergencies, and paediatric emergencies. The scope of pre-hospital care has expanded significantly with critical care paramedics and HEMS physicians.

Pathophysiology

The concept of the 'golden hour' in trauma reflects the time-critical nature of definitive intervention. In cardiac arrest, brain injury begins within 3-5 minutes of normothermic arrest. For STEMI and stroke, 'time is muscle' and 'time is brain' respectively. Pre-hospital interventions aim to bridge the gap between injury/illness onset and definitive hospital care.

Pre-Hospital Assessment

• ABCDE approach: Standard for all pre-hospital emergencies
• cABCDE in trauma: c = catastrophic haemorrhage control first (tourniquet, packing)
• Scene safety: Before patient contact — personal safety, traffic, hazardous materials, violence
• Mechanism of injury: Guides clinical suspicion and decision-making

Major Incident Declaration (METHANE)

• M: Major incident declared
• E: Exact location
• T: Type of incident
• H: Hazards present
• A: Access routes
• N: Number of casualties
• E: Emergency services required

Red Flags (Pre-Hospital)

• Cardiac arrest — immediate CPR and defibrillation
• Catastrophic haemorrhage — tourniquet/pressure
• Airway obstruction — airway manoeuvres, consider RSI
• Tension pneumothorax — needle decompression
• Time-critical transfer needed — do not delay on scene

Pre-Hospital

• 12-lead ECG: For chest pain — pre-hospital STEMI activation direct to PCI centre
• Blood glucose: Capillary — for all altered consciousness
• SpO2: Continuous monitoring
• ETCO2: Waveform capnography for intubated patients and cardiac arrest quality monitoring
• Point-of-care lactate: Some HEMS services carry portable analysers

Communication

• Pre-alert: To receiving hospital for time-critical patients (major trauma, STEMI, stroke, sepsis)
• SBAR handover: Situation, Background, Assessment, Recommendation
• ATMIST handover (pre-hospital to hospital): Age, Time, Mechanism, Injuries, Signs, Treatment given

Non-pharmacological

• Scene safety: First priority — personal safety, then patient
• Catastrophic haemorrhage control: Tourniquets, haemostatic dressings, direct pressure
• Airway management: Head tilt/chin lift, jaw thrust, OPA/NPA, SGA, ETT (RSI by trained personnel)
• C-spine immobilisation: Head blocks, scoop stretcher (collars increasingly optional)
• Pelvic binder: For suspected pelvic fracture
• Splintage: Traction splint for femoral shaft fracture

Pharmacological

• Adrenaline 1mg IV/IO: Cardiac arrest — as per ALS guidelines
• Amiodarone 300mg IV: Refractory VF/pVT
• Morphine 0.1-0.2mg/kg IV or ketamine 0.25-0.5mg/kg IV: Analgesia
• Tranexamic acid 1g IV: Major trauma within 3 hours
• Aspirin 300mg PO: Suspected ACS
• Salbutamol 5mg nebulised: Acute asthma
• Pre-hospital blood products: O-negative pRBC and FDP (freeze-dried plasma) for haemorrhagic shock (HEMS)

Pre-Hospital RSI (Rapid Sequence Induction)

• Indication: GCS ≤8, airway compromise, anticipated deterioration
• Drugs: Ketamine 1-2mg/kg + rocuronium 1.2mg/kg (typically)
• Personnel: Doctor or critical care paramedic with specific training
• Equipment: Videolaryngoscope, bougie, surgical airway kit

Referral/Transport Decisions

• Major trauma (mechanism/injury-based criteria): Bypass local ED to MTC
• STEMI: Direct to primary PCI centre (bypass non-PCI hospitals)
• Stroke: Direct to HASU
• Paediatrics: Consider nearest ED with paediatric capability
• HEMS activation: For critical patients requiring interventions beyond paramedic scope

• OHCA survival to discharge: ~8-10% overall; ~30% if bystander CPR + early defibrillation
• Public access defibrillation: Increases VF survival from ~10% to ~50-70%
• Major trauma network: 20-25% mortality reduction since MTC implementation (TARN data)
• HEMS intervention: Associated with improved survival in the most severely injured patients
• Pre-hospital STEMI recognition: Reduces door-to-balloon time and improves survival
• Response time targets: Category 1 mean 7 min; faster response improves cardiac arrest outcomes

UK Ambulance Response Categories (ARP)

Triage Sieve (Primary Triage — UK)

ATMIST Pre-Hospital Handover