The main objectives were achieved in both WP1 and WP2, but, as described in Content and changes during the programme, some changes were required in response to factors that were difficult to predict.
Work package 1
Objective 1
We did not find any previous published studies of enhanced paramedic roles in the context of time-critical care provision to address the main aim of the systematic review,29 but reports of simple innovations (e.g. a generic structure for handover formats) provided useful material for discussion with a wide range of stakeholders to develop the PASTA intervention. Service and public engagement at this stage was essential for the success of the trial.
Objective 2
As described in Content and changes during the programme, owing to slow uptake of the intervention training, the primary outcome was changed to the proportion of patients receiving thrombolysis, which required far fewer patients to show an important effect than a health outcome would have required. Future ambulance trials could plan timelines that reflect the challenge of pre-hospital research training and choose a primary outcome that will provide direct evidence of the intervention effect. In the trial process evaluation, we had not anticipated that patients within 7 days of stroke would be unable to provide views about the intervention, and future studies may have to consider whether or not another approach (e.g. video data) should be used to address this question. The use of ambulance audit data to show the impact of the PASTA intervention on response targets was a novel approach that could be used in other trials to guide future implantation decisions.
Objective 3
The PASTA trial generated an unexpected cost-effectiveness result, which has raised questions about the quality of standard care decisions for thrombolysis in sites with lower levels of specialist availability. However, as this outcome had not been anticipated and there were limited research delivery resources, we did not collect data from individual patient records to prove this hypothesis and masking of outcome assessors was not possible.
Work package 2
Objectives 1, 2 and 4
There was very productive engagement with collaborators outside the programme (notably the NIHR CLAHRC South West Peninsula) to co-ordinate development of a high-impact model of IAT cost-effectiveness. This used existing data sets and a DES model developed in our previous PGfAR study,87 but it was adapted to respond to the changing landscape of IAT evidence and service provision.
Objective 3
The incorporation of public views into the modelling was a novel approach, particularly the use of BWS. Although online data capture was the only realistic method and we hoped for a larger number of responses, these were consistent enough to provide confidence in the development of pathway configurations.
Objective 5
It was beyond the remit of the programme to formulate an IAT implementation plan across the NHS, but outputs fed directly into NHS Commissioning Guidance 20184 and The NHS Long Term Plan.96 However, the programme lead, WP2 lead and an external collaborator (Professor Martin James) developed and published online an implementation guide aimed at commissioners and stroke care providers.25 We have also developed an online tool aimed at health-care commissioners/providers (i.e. ITEMS) to facilitate commissioning decisions by providing readily adjustable inputs of key variables to suit the local context.