# AIRCHILL Cardiac-Arrest Pivotal Trial: Budget & RTW Deployment Plan

> Source-backed planning model for the ~2,300-patient AIRCHILL cardiac-arrest pivotal trial: 24-month recruitment, total study budget and the number of RTWs/devices required under different deployment strategies.

- Canonical: https://www.medicalcooling.com/airchill-cardiac-arrest-trial-budget-rtw-deployment/
- Markdown: https://www.medicalcooling.com/airchill-cardiac-arrest-trial-budget-rtw-deployment/index.md
- Language: en-US
- Last modified: 2026-09-11T23:05:34+00:00

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.

Patients
≈2,300
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.

Normal fleet coverage
≈1,000–1,500 devices
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.

Targeted dispatch
≈600–800 devices
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.

Budget
€68.38m base
Harmonised bottom-up P50 planning case for ~2,300 patients before contingency. The same detailed model gives €78.64m including a 15% contingency. The lean case is €41.45m including reserve; the high commercial-CRO case is €159.36m including reserve.

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 →](https://www.reanimationsregister.de/themen/jahresberichte.html)

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 →](https://pubmed.ncbi.nlm.nih.gov/38417773/)

Fleet-model inputValueStatus

German EMS resuscitation incidence71.6 / 100,000 / year (2025)SOURCED · German Resuscitation Registry 2025

Shockable-rhythm fraction22% planning anchorTRANSFERRED ANCHOR · EuReCa reported 22.2%; final German/site-specific value must come from feasibility data

ROSC within candidate shockable cohort55%AIRCHILL ASSUMPTION

Still unconscious / ventilated and otherwise eligible85%AIRCHILL ASSUMPTION

Operational capture / randomisation75%AIRCHILL ASSUMPTION

Resulting enrolment yield≈5.5 randomised patients / 100,000 population / yearDERIVED from the inputs above

Population coverage required for 1,150/year≈20.8 million inhabitantsDERIVED

Interpretation. The 20.8-million-population requirement is not a forecast of the final trial. It is a transparent stress test. A higher shockable-ROSC yield, broader eligibility or intra-arrest enrolment reduces the required catchment; stricter eligibility or poorer capture increases it.

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 →](https://doi.org/10.1007/s10049-024-01408-0)

Deployment casePopulation basisRTW densityActive equipped RTWs+12% spare / service pool

Urban / efficient base≈20.8m inhabitants4.60 / 100k≈958≈1,073 devices

Mixed national fleet≈20.8m inhabitants6.36 / 100k≈1,324≈1,483 devices

Rural-heavy deployment≈20.8m inhabitants7.32 / 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.

24 months recruitment vs. 24 months total study calendar. The ≈1,000–1,500-device base range assumes approximately 24 months of active recruitment. If the entire programme from first enrolment to last 90-day primary endpoint must finish within 24 calendar months, active recruitment must be shorter. With ~18 months of active recruitment, the urban/base fleet requirement scales from ~1,073 to about 1,430 devices including the spare pool; with only ~15 months of active recruitment it rises to about 1,720 devices. Start-up activities would therefore need to be completed before the formal two-year study clock wherever possible.

Best operational strategy for a two-year target. Do not distribute 600 devices randomly. Select high-volume EMS systems, link suspected-OHCA dispatch codes to equipped vehicles, monitor screen-to-randomise yield weekly, and add or move devices only where marginal enrolment per device is high. A 100-device pilot deployment can establish actual randomisations/device/year before committing to the full fleet.

Budget model

## €68.38 million is the harmonised base case before contingency.

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 →](https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2796179)

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 →](https://pmc.ncbi.nlm.nih.gov/articles/PMC6861404/)

ScenarioCore assumptionsApprox. subtotal+15% contingency

Lean / investigator-ledHarmonised 21-line detailed model; requires strong academic infrastructure, lower site payments and substantial in-kind support.€36.04m€41.45m

Base / multinational EUHarmonised 21-line detailed P50 planning model for ~2,300 patients, including device fleet, sites/EMS, central operations, regulatory work, follow-up and close-out.€68.38m€78.64m

High / commercial CROHarmonised 21-line high-cost case with expensive CRO/site pricing, larger fleet, slower recruitment and more commercial execution.€132.80m€159.36m

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.

### Harmonised base-case cost stack

Source of truth: the detailed line-item model now governs the budget: €68.38m before contingency and €78.64m including a 15% reserve. This deployment page no longer maintains a second, competing cost stack. See [Detailed cost model & benchmark studies →](https://www.medicalcooling.com/airchill-pivotal-trial-detailed-cost-model-benchmarks/) for the full 21-line budget.

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 →](https://pubmed.ncbi.nlm.nih.gov/41680915/)

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](https://www.reanimationsregister.de/themen/jahresberichte.html).

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](https://doi.org/10.1007/s10049-024-01408-0).

Trial-design benchmark: PRINCESS2 plans 1,022 shockable-rhythm OHCA patients, on-scene randomisation and cooling, across 20–25 European/US sites. [Source](https://pubmed.ncbi.nlm.nih.gov/38417773/).

Complex-device cost benchmark: pivotal-study per-patient cost US$54,332 in 2018 dollars in a published US complex-device development model. [Source](https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2796179).

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 →](https://www.medicalcooling.com/airchill-pivotal-trial-detailed-cost-model-benchmarks/) · [AIRCHILL-CA protocol synopsis →](https://www.medicalcooling.com/protocol-airchill-cardiac-arrest/) · [Full cardiac-arrest CIP →](https://www.medicalcooling.com/cip-airchill-cardiac-arrest/) · [Clinical Investigation Package →](https://www.medicalcooling.com/airchill-clinical-investigation-package/)