Delivering effective non-invasive ventilation in amyotrophic lateral sclerosis using intensive remote support (DENIM): protocol for an embedded process evaluation in a hybrid type 3 implementation-effectiveness trial

Background Non-invasive ventilation (NIV) is the only intervention that significantly improves survival and quality of life in motor neuron disease, extending life by 8-13 months. However, at least half of patients are unable to reach the recommended ≥ 4 h daily NIV use, and current NHS services provide insufficient follow-up for intensive optimisation. Delivering Effective Non-Invasive ventilation in Motor neuron disease using intensive remote support (DENIM) is a stepped-wedge cluster randomised trial. This protocol describes a process evaluation embedded within DENIM aiming to understand how and why the implementation strategy works (or does not work) across different contexts.Method The process evaluation employs a convergent mixed-methods multiple-case study design across twelve NHS ventilation services. We developed a programme theory informed by Normalization Process Theory (NPT), the Consolidated Framework for Implementation Research and Expert Recommendations for Implementing Change, which states how the DENIM implementation strategy is expected to achieve normalisation of evidence-based NIV practice. Data collection across twelve sites include: ethnographic observations of patient-staff interactions; semi-structured interviews with staff (n = 24-48) and patients/carers (n = 24) exploring implementation experiences; the NoMAD questionnaire measuring normalisation perceptions from healthcare professionals within the services and NIV adherence data from participants' ventilators. Barriers and facilitators to research participation for underserved populations including ethnic minorities, those with low digital literacy, and women over 80 with bulbar onset disease will also be identified. Qualitative data will be analysed using NPT-informed thematic analysis. Integration occurs at three levels (design, methods, interpretation) with joint display tables presenting quantitative and qualitative findings alongside meta-inferences.Discussion This process evaluation will generate explanatory insights into how implementation strategies can address the evidence-to-practice gap in complex, technology-supported care for progressive diseases, with implications for health equity and wider NHS digital transformation.Trial registration ISRCTN10105285. 16/04/2025.