AIRCHILL Cardiac-Arrest Pivotal Trial: Budget & RTW Deployment Plan
Pivotal trial operations · sourced planning model
What would the cardiac-arrest trial cost — and how many RTWs need AIRCHILL?
This planning model translates the current AIRCHILL-CA pivotal concept — approximately 2,300 randomised patients — into a 24-month recruitment target, an EMS fleet requirement and a bottom-up budget. It distinguishes sourced epidemiology and external cost benchmarks from AIRCHILL planning assumptions. Final numbers must be replaced by quotations, site feasibility data and Phase-II screening yields before sponsor approval.
Executive answer
For a two-year pivotal recruitment period, think in hundreds to more than a thousand equipped RTWs.
Working Phase-III sample for the current +7-percentage-point planning case. Two active recruitment years require about 1,150 randomisations per year or about 96 per month.
Best current planning range if AIRCHILL is carried on the ordinary RTW fleet across high-volume study catchments and the trial remains post-ROSC / narrowly phenotyped. This includes roughly 10–15% operational spare capacity.
Potentially achievable if equipped RTWs are deliberately concentrated in high-incidence urban networks and dispatch algorithms preferentially send them to suspected cardiac arrest. This is an AIRCHILL operational assumption that must be validated prospectively.
Detailed bottom-up P50 planning case for ~2,300 patients, including RTW device fleet, site/EMS payments, central operations and 15% contingency. A lean investigator-led model is ~€41m; a highly outsourced/commercial model can reach ~€120–160m.
Why the fleet becomes large
The limiting factor is not Germany’s total OHCA volume — it is capturing the right patient on an equipped vehicle.
Germany has enough cardiac-arrest cases for the study. The 2025 German Resuscitation Registry reports 71.6 EMS resuscitations per 100,000 inhabitants per year, corresponding to at least about 59,800 EMS-treated OHCA patients nationally. The report includes 26,438 cases from 208 EMS systems and a reference group of 12,116 patients from 56 EMS systems. German Resuscitation Registry annual reports →
However, the pivotal AIRCHILL-CA programme is not intended to enrol every OHCA. It currently favours a more homogeneous phenotype, potentially an initial shockable rhythm, sustained ROSC, persistent unconsciousness and invasive ventilation. PRINCESS2 similarly narrows its confirmatory population to initial shockable rhythm and plans 1,022 patients across roughly 20–25 European and US sites. PRINCESS2 design paper →
| Fleet-model input | Value | Status |
|---|---|---|
| German EMS resuscitation incidence | 71.6 / 100,000 / year (2025) | SOURCED · German Resuscitation Registry 2025 |
| Shockable-rhythm fraction | 22% planning anchor | TRANSFERRED ANCHOR · EuReCa reported 22.2%; final German/site-specific value must come from feasibility data |
| ROSC within candidate shockable cohort | 55% | AIRCHILL ASSUMPTION |
| Still unconscious / ventilated and otherwise eligible | 85% | AIRCHILL ASSUMPTION |
| Operational capture / randomisation | 75% | AIRCHILL ASSUMPTION |
| Resulting enrolment yield | ≈5.5 randomised patients / 100,000 population / year | DERIVED from the inputs above |
| Population coverage required for 1,150/year | ≈20.8 million inhabitants | DERIVED |
RTW calculation
German RTW density converts catchment size into the device fleet.
A recent nationwide structural analysis reports daytime RTW availability of approximately 4.60 RTWs per 100,000 inhabitants in large cities, 7.32 in rural districts, and 6.36 overall. Structural parameters of German EMS →
| Deployment case | Population basis | RTW density | Active equipped RTWs | +12% spare / service pool |
|---|---|---|---|---|
| Urban / efficient base | ≈20.8m inhabitants | 4.60 / 100k | ≈958 | ≈1,073 devices |
| Mixed national fleet | ≈20.8m inhabitants | 6.36 / 100k | ≈1,324 | ≈1,483 devices |
| Rural-heavy deployment | ≈20.8m inhabitants | 7.32 / 100k | ≈1,524 | ≈1,707 devices |
Calculation: required covered population × published RTW density. The spare/service pool covers device failure, maintenance, calibration, vehicle swaps and training units. It is a planning assumption, not a published standard.
High-performance network sensitivity
If Phase-II feasibility identifies high-incidence networks with a higher screening yield — for example 80.1 CPR/100,000/year, 25% shockable rhythm, 60% ROSC, 90% remaining eligible and 80% operational capture — the model needs only about 13.3 million inhabitants. At urban RTW density this is about 612 active RTWs or ~685 devices including 12% spare capacity. This is why the operational recommendation is 600–800 devices only after a run-in demonstrates that high-volume dispatch and eligibility assumptions are real.
Budget model
€50–80 million is the current realistic planning envelope.
External literature shows why a large device trial can become expensive. A JAMA Network Open model of complex therapeutic medical-device development used an estimated US$54,332 per pivotal-study patient in 2018 dollars. Applied literally to 2,300 patients, that alone exceeds US$124 million before inflation. This is not an AIRCHILL quotation; it is an external upper-cost anchor. Complex-device development cost study →
A separate study of industry-sponsored medical-device trials found mean costs of Can$18,243 per experimental-arm enrollee and Can$13,827 per control enrollee, illustrating how strongly device type and delivery model change trial economics. Medical-device trial cost study →
| Scenario | Core assumptions | Approx. subtotal | +15% contingency |
|---|---|---|---|
| Lean EU investigator-led | €8k/patient clinical research cost; 50 networks × €75k start-up/training; ~1,000 devices at €7.5k internal unit cost; lean central operations | ≈€43.1m | ≈€49.6m |
| Base EU / multinational | €12k/patient; 60 networks × €100k; ~1,100 devices at €10k; central CRO/data/statistics €10m; service/logistics €4m; regulatory/quality €4m | ≈€64.3m | ≈€73.9m |
| CRO / US-heavy | €20k/patient; 70 networks × €150k; ~1,200 devices at €15k; larger CRO/data, regulatory and service package | ≈€108.5m | ≈€124.8m |
AIRCHILL unit costs, consumables and service costs are planning assumptions because the certifiable production configuration is not yet frozen. The table therefore separates external evidence from internal scenario assumptions.
Base-case cost stack (~€74m including contingency)
| Cost block | Planning value | What it covers |
|---|---|---|
| Patient-level research operations | €27.6m | 2,300 × €12k: screening/enrolment effort, hospital data, 90-day follow-up, site research workload |
| EMS / site activation and training | €6.0m | 60 networks × €100k |
| AIRCHILL fleet manufacture | €11.0m | 1,100 devices × €10k assumed internal study-unit cost |
| Central CRO / EDC / monitoring / statistics / DSMB | €10.0m | Central study operations |
| Service, calibration, logistics and replacements | €4.0m | 24-month field operation across ambulance fleets |
| Intervention consumables | €1.7m | Illustrative disposable/gas-path cost for treatment arm |
| Regulatory, quality, insurance, submissions | €4.0m | MDR/ethics and possible FDA/IDE-related programme work |
| Subtotal | €64.3m | Before contingency |
| 15% contingency | €9.6m | Recruitment, inflation, replacement and scope uncertainty |
| Total base case | ≈€73.9m | Planning estimate, not a supplier quotation |
How to reduce the number of devices and the budget
Use Phase II to optimise recruitment per device before buying the pivotal fleet.
The strongest cost lever is not cutting statistical quality; it is increasing eligible randomisations per deployed device. The pivotal programme should therefore start with a deployment run-in that measures OHCA dispatches per equipped RTW, shockable-rhythm frequency, ROSC, final eligibility, treatment-start success and randomisations per device-month. If equipped RTWs can be preferentially dispatched without delaying care, the required fleet may fall from roughly 1,000–1,500 devices toward the 600–800 range. If this cannot be demonstrated, the budget should assume near-fleet-wide coverage in selected catchments rather than under-equipping the study.
PRINCESS2 demonstrates that very early on-scene cooling can be run in a multicentre EMS trial and reports 92% protocol adherence in its first 100-patient pilot, supporting the value of a prespecified operational pilot before pivotal completion. PRINCESS2 pilot →
Source register
Sources and evidence status.
German OHCA incidence: Deutsches Reanimationsregister, public annual report 2025 (published August 2026): 71.6 EMS resuscitations/100,000/year and at least ~59,800 nationally. Source.
RTW availability: nationwide German EMS structural survey: 4.60 RTW/100,000 in large cities, 7.32 in rural districts, 6.36 overall in daytime availability. Source.
Trial-design benchmark: PRINCESS2 plans 1,022 shockable-rhythm OHCA patients, on-scene randomisation and cooling, across 20–25 European/US sites. Source.
Complex-device cost benchmark: pivotal-study per-patient cost US$54,332 in 2018 dollars in a published US complex-device development model. Source.
AIRCHILL assumptions: shockable/ROSC/eligibility/capture fractions, device-unit cost, consumables, site payments, CRO budget, spare percentage and targeted-dispatch efficiency are planning assumptions and must be replaced by Phase-II observations and supplier/site quotations before financial approval.
Detailed cost model & benchmark studies → · AIRCHILL-CA protocol synopsis → · Full cardiac-arrest CIP → · Clinical Investigation Package →