Process Evaluation of an Ambulance-Delivered Early Intensive Blood Pressure-Lowering Stroke Trial: Design, Rationale, and Reflection
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<b>
<i>Introduction:</i>
</b> The fourth INTEnsive ambulance-delivered blood pressure Reduction in hyper-ACute
stroke Trial (INTERACT4) is a large-scale, multicenter, prospective, randomized, open-label,
blinded endpoint assessment trial, initiated in an ambulance in China, aiming at evaluating
the effectiveness and safety of prehospital blood pressure (BP) lowering in patients
with suspected acute stroke and elevated BP. A prespecified process evaluation is
intended to explore the implementation of the trial intervention, provide support
to interpret the trial outcomes and put forward suggestions to scale up the intervention
in broader settings in the future.
<b>
<i>Methods:</i>
</b> This process evaluation is a mixed-methods design, and follows the Normalization
Process Theory (NPT) and the UK Medical Research Council (UK MRC) guidance. Fidelity,
reach, acceptability, appropriateness, adoption, sustainability, and relevant contextual
factors and mechanisms affecting the implementation of prehospital early intensive
BP-lowering treatment will be analyzed. Semi-structured interviews with ambulance
staff, ward and emergency department clinicians, and nurses are undertaken to explore
perceptions of the intervention, contextual factors, and potential suggestions for
future implementation in practice. Data from observational records, surveys, conventional
monitoring data, on-site records, and case report forms will be analyzed to understand
background care and context.
<b>
<i>Conclusion:</i>
</b> The process evaluation of INTERACT4 will provide insights for the implementation
of prehospital early intensive BP-lowering intervention in different health systems
and help better explain the trial results for further scale up.
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