Background Currently, most callers to 999 ambulance services are transported to the hospital emergency department (ED). However, ambulance services receive no further information on those patients, and commissioners do not have the full picture of patient care. The London Ambulance Service have worked with one acute trust to establish the feasibility of data linkage, but questions remain about transferability of the model, and how learning from linked data can bring about changes in patient care and outcomes.

Methods PHED Data is our two-year mixed-methods observational study which began in May 2015. We aim to establish the potential for routinely linking data from acute trusts and ambulance services, to allow diagnosis, health care intervention, and mortality outcomes to be tracked, with a range of potential benefits for patient care within ambulance services and across the healthcare economy.

We will work with six acute trusts from across London, selected to give a range of performance. The study has six work packages: WP1 examines the technical aspects of the linkage process; WP2-5 each analyse the data to develop one themed indicator set, with qualitative work examining their perceived relevance and viability; WP6 examines how the indicator sets might influence commissioning decisions and service improvements.

Results So far, we have engaged with six selected acute trusts; all have shown strong interest in collaborating. We are currently arranging the logistical aspects of data sharing. We aim to respond to trusts' particular interests in our analyses, in addition to developing our common indicator set.

Conclusions The proposed work has the potential to bring about quality improvements to current systems and support the development of new pathways and protocols for pre-hospital interventions. Benefits will be felt across the healthcare system. Our findings will be relevant to health service providers across the UK, who all face similar challenges in pre-hospital care.