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Prehospital critical care for out-of-hospital cardiac arrest: a complex intervention in a complex environment

Von Vopelius-Feldt, Johannes



Prehospital critical care has the potential to improve the currently low survival rates following out-of-hospital cardiac arrest (OHCA). In some areas of the United Kingdom, prehospital critical care teams are dispatched to OHCA, while in others the standard of care of Advanced Life Support (ALS) is seen as sufficient. This thesis examines prehospital critical care for OHCA from different perspectives and aims to provide stakeholders in prehospital care with the information required to guide the funding and configuration of prehospital critical care for OHCA.

1. Qualitative analysis of stakeholders’ views on research and funding of prehospital critical care. Data from focus groups and interviews of five stakeholder groups were analysed using the framework approach.
2. Economic analysis of ALS and prehospital critical care for OHCA. A decision analysis model of costs and effects of ALS for OHCA was created, using secondary data as well as data provided from relevant prehospital organisations. A range of possible effects of prehospital critical care for OHCA were simulated. A probabilistic sensitivity analysis was chosen to reflect the uncertainty of the underlying data.
3. Prospective multicentre observational analysis, comparing survival to hospital discharge in patients with OHCA who received prehospital critical care or ALS. Propensity score matching was used to adjust for confounding and bias, subgroup analysis in patients with witnessed OHCA with shockable rhythm and two sensitivity analyses (primary dispatch and multiple imputation datasets) were used.
4. Descriptive analysis of prehospital critical care interventions during and after OHCA. Frequencies of critical care interventions were analysed according to patient groups; a propensity score matching analysis examined the effect of treatment at a cardiac arrest centre in patients transferred to hospital.

Stakeholders expressed strong and often opposing views on a variety of topics discussed in regards to prehospital research, prehospital critical care and funding strategies.
The current standard of care, Advanced Life Support (ALS) delivered by paramedics, was cost-effective at less than £20,000 per quality-adjusted life year (QALY) gained.
After propensity score matching to account for an imbalance in prognostic factors, survival to hospital discharge did not differ between patients with OHCA receiving prehospital critical care or ALS care. These results were stable throughout the subgroup and sensitivity analyses. In addition, prehospital critical care for OHCA is considerable more expensive than ALS and therefore highly unlikely to be cost-effective.
The reasons for this lack of clinical effectiveness of prehospital critical care can be likely found in the low frequency of interventions delivered and the relatively late arrival of critical care teams at the scene of an OHCA.
Stakeholders’ considerations in regards to further funding of the complex intervention of prehospital critical care for OHCA will likely include additional factors such as social acceptability, available resources and the potential for indirect benefits.

This research provided a multi-faceted analysis of the complex intervention prehospital critical care for OHCA. The results can aid decision making in regards to future funding but also consider uncertainty in data analysis and the complex environment in which prehospital critical care is being delivered.


Von Vopelius-Feldt, J. Prehospital critical care for out-of-hospital cardiac arrest: a complex intervention in a complex environment. (Thesis). University of the West of England. Retrieved from

Thesis Type Thesis
Deposit Date Aug 13, 2019
Publicly Available Date Aug 14, 2019
Keywords Cardiac arrest, Emergency Medical Services
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