The patient is stabilized. You've done your part. Now they need to go elsewhere: a HUB center, an interventional cardiology unit, a neurosurgery department 180 km away.
And now comes the part that many underestimate: secondary transport is a phase of care, not a pause from care.
Ambulance, helicopter, or airplane. The choice is not trivial. And making a mistake (or not knowing how to justify it) can be costly.
Before choosing the vehicle: the rarely asked question
Is it worth transferring this patient?
This isn't rhetoric. SIAARTI guidelines explicitly state: transport always carries a risk. Every secondary transfer temporarily suspends continuous monitoring, disconnects the patient from a controlled environment, and introduces variables (kinetic, environmental, logistical) that no monitor can fully compensate for.
If the transfer is not strictly necessary to ensure definitive therapy or continuity of care, it should be reconsidered.
That said: when transport is indicated, the choice of vehicle is a clinical decision—not organizational, not economic, not based on service availability.
Ehrenwerth Scale: stratifying risk before choosing the vehicle
Before discussing vehicles, we need a common language to define patient criticality. The Ehrenwerth scale (adopted by SIAARTI criteria for critical patient transport) classifies risk into five classes and directly guides team composition and vehicle choice.
Class | Clinical Profile | Minimum Required Team |
|---|---|---|
I | Stable, non-critical patient | Driver + rescuer |
II | Stable with potential for deterioration | Driver + nurse |
III | Unstable but controlled | Physician + nurse |
IV | Unstable, high risk of acute deterioration | Intensivist + critical care nurse |
V | Unstable, in active resuscitation | Intensivist + nurse + complete equipment |
The class is not static: a patient can progress from III to IV during transport preparation. Reassessing before loading is part of the clinical decision, not a formality.
Classes IV and V require a mobile ICU or equivalent ICU configuration, regardless of the chosen vehicle. Sending an Ehrenwerth IV patient on an inadequate vehicle is not a shortcut: it's an error.
Ambulance: the underestimated vehicle
The ambulance, especially the mobile ICU (Centro Mobile di Rianimazione), is often the most solid choice for transports up to 200 km, and in many cases remains the only viable option.
What it can do:
- Transport patients of any Ehrenwerth risk class (I–V), with the appropriate team
- Accommodate ventilator, defibrillator, multiparameter monitor, infusion pumps
- Operate at night, in any weather, on any accessible road
- Allow direct access to the hospital unit, without intermediate transfers
- Allow the presence of a family member, which in certain contexts has real clinical weight
What it cannot do well:
- Distances over 300–400 km: times become clinically unacceptable for time-dependent conditions
- Guarantee atraumatic transport: vibrations over long stretches impact unstable spinal injuries, head trauma, drained pneumothorax
- Overcome road traffic during critical hours: that delay may not be recoverable
The often-ignored limitation: the quality of ambulance transport depends almost entirely on the quality of the onboard team. An experienced intensivist on a well-equipped mobile ICU is a mobile intensive care unit. An undersized crew on an ordinary vehicle is not.
Helicopter: powerful, conditional, often misunderstood
The air ambulance is the vehicle of choice for urgent interhospital transports over distances between 50 and 300 km, when time is the critical factor and operational conditions allow.
What it can do:
- Drastically reduce transfer times compared to ambulance
- Offer generally more atraumatic transport (fewer lateral stresses compared to road curves)
- Reach hospital helipads directly, eliminating a ground transfer
- Manage critical patients with onboard ICU configuration: anesthesiologist-intensivist + critical care nurse
- Be the reference choice for polytrauma, hemorrhagic stroke, STEMI with distant primary angioplasty
Contraindications every operator should know:
Condition | Rationale |
|---|---|
Adverse weather (wind, fog, snow) | Pilot's decision: non-negotiable |
Darkness (without NVG certification) | Operational limitation of the service |
Uncontrolled psychomotor agitation | Risk to team and vehicle integrity |
Non-stabilizable patient | No takeoff without minimum vital stability |
Imminent delivery | Not manageable in flight |
High infectivity without adequate containment | No HEPA filters on a standard helicopter |
Dimensional incompatibility | Patient or devices too bulky for the cabin |
The real problem: the helicopter is often requested as the default "because it's faster." But on short routes (<50 km), the time for activation, takeoff, and ground transfer upon arrival can make the ambulance overall faster. And in nighttime or marginal weather conditions, availability is not guaranteed.
Medical airplane: long-range, stable patient, complex organization
The air ambulance is a specific tool for a specific category of transports: continental or intercontinental distances, medical repatriations, evacuations from resource-limited contexts.
What it can do:
- Cover distances over 800–1000 km where ambulance and helicopter are impractical
- Cruising speed up to 800–900 km/h, on international routes
- Accommodate multiple patients simultaneously (in specific configurations)
- Offer controlled microclimate: pressurization, temperature, lighting
- Transport neonates with certified thermal incubators (Babypod II for weight <8 kg)
Structural limitations:
- Not for unstable patients. This is the fundamental difference from the helicopter with onboard ICU: the medical airplane requires adequate prior stabilization
- Activation times are long: authorizations, airport coordination, team transfer, from 2 to 24 hours
- Requires double ground transport (hospital → departure airport, arrival airport → destination hospital)
- For commercial flights with medical escort, visas, airline authorizations, and onboard personnel limitations are added
The table you should have in mind
Ambulance | Helicopter | Airplane | |
|---|---|---|---|
Optimal distance | <200 km | 50–300 km | >800 km |
Activation | Immediate | 30–60 min | 2–24 hours |
Unstable patient | ✓ (with mobile ICU + physician) | ✓ (with onboard ICU) | ✗ |
Weather independence | High | Low | Medium |
Night operations | Yes | Limited | Yes (with airport) |
Spinal injuries | ⚠ Stress | ✓ Atraumatic | ✓ Atraumatic |
Family members onboard | Yes (1–2) | Rarely | Yes (if space) |
Relative cost | € | €€€ | €€€€ |
How the decision is made: 5 variables that matter
- Clinical stability. A non-stabilizable patient does not board any aircraft. First stabilize, then transport.
- Distance and time to definitive therapy. Not GPS distance: the clinically acceptable time based on the pathology.
- Time-dependent pathology. STEMI, hemorrhagic stroke, major trauma: every minute has a different weight compared to an elective transfer.
- Actual vehicle availability. Not theoretical. Weather conditions, time of day, operating base, service saturation.
- Competence of the available team. The best vehicle with the wrong team is worse than the worst vehicle with the right team.
The final note that changes everything
Secondary transport is a continuum of care, not an interruption. Clinical responsibility does not transfer to the pilot or driver: it remains with the medical team onboard.
This means one concrete thing: the physician who decides the transfer must be able to manage any clinical deterioration during transport. If they cannot, or if the vehicle does not allow that management, the decision to transport must be reassessed.
This is not a bureaucratic matter. It is the heart of prehospital emergency medicine.
References
Italian guidelines and institutional documents
- SIAARTI, in collaboration with ANIARTI, ARES 118, HEMS, SIIET, SIEMS, SIMEU. Guidelines for helicopter emergency medical service management of critical patients. Approved by CNEC – v.1, September 26, 2023. Published on ISS.it. [https://www.iss.it/-/gestione-in-elisoccorso-paziente-critico]
- SIAARTI. Recommendations for Inter- and Intra-Hospital Transfers. Document approved by the SIAARTI Board of Directors – Naples, October 24, 2012. Prot. n. 562/b. [Full text (SIMLA)]
- Ministry of Health – Quality Department. Recommendations for the prevention of adverse events during medical transport. Rome: Ministry of Health. [https://www.salute.gov.it/imgs/C_17_pubblicazioni_1162_allegato.pdf]
- HEMS Association. Indications for secondary helicopter transport. [https://www.hems-association.com/assets/indicazioni/Trasporti-secondari.pdf]
International scientific literature
- Ehrenwerth J, Sorbo S, Hackel A. Transport of critically ill adults. Critical Care Medicine. 1986;14(6):543–547. doi:[10.1097/00003246-198606000-00005](https://doi.org/10.1097/00003246-198606000-00005). The original study from which the risk classification for transport is derived.
- Warren J, Fromm RE Jr, Orr RA, Rotello LC, Horst HM; American College of Critical Care Medicine. Guidelines for the inter- and intrahospital transport of critically ill patients. Critical Care Medicine. 2004;32(1):256–262. doi:[10.1097/01.CCM.0000104917.39204.0A](https://doi.org/10.1097/01.CCM.0000104917.39204.0A)
- Markakis C, et al. Evaluation of a risk score for interhospital transport of critically ill patients. Emergency Medicine Journal. 2006;23:313–317. doi:[10.1136/emj.2005.026435](https://doi.org/10.1136/emj.2005.026435). Validation of the RSTP (Risk Score for Transport Patients), integrated into the SIAARTI 2012 classification.
- Maccari C. Urgent interhospital transports. Published on ResearchGate, March 2016. [https://www.researchgate.net/publication/302989772]
Article intended for EMS professionals. For specific protocols in your region, consult local organizational procedures and updated SIAARTI guidelines.
