Specialist surgical care systems and their relevance to patient outcome and experience: learning from an improvement study in the care of chronic subdural haematoma (IMPROVE-CSDH).

Background Patients requiring unplanned, 'specialist' surgery (such as neurosurgery), are frequently admitted to non-specialist centres, requiring referral and transfer to the hospital where surgery is performed. For conditions such as chronic subdural haematoma (cSDH) (a bleed between the skull and brain), up-to 90% of referrals occur in this 'indirect' manner. Chronic subdurals cause weakness, speech deficits, and confusion. Patients have multiple comorbidities and are frail. Operative workload is predicted to rise by >50% over the next 20 years. Delays and resource constraints impact patient experience and perioperative morbidity is high. Pilot data suggests morbidity may be higher in those needing inter-hospital transfer but verification using routine data is hindered by inaccurate coding. We believe the challenges in cSDH may affect other patients requiring expedited, but not time-critical, specialist surgery. We hypothesise that indirect admission via non-specialist centres may be harmful and a source of inequity by disproportionately impacting those from rural populations. Impetus A multidisciplinary group, co-led by the applicant, has developed, through co-design, a complex intervention comprising the first guideline for cSDH care and new care pathways. The intervention is being prepared for adoption in the east of England (EoE) in late 2024, offering a time-limited opportunity to evaluate efficacy, implementation fidelity, and relevance to other conditions. Research questions Does adoption of the cSDH intervention improve patient and system outcomes? What influences implementation of the cSDH complex intervention? Do pathways for other conditions requiring expedited specialist surgery exhibit similar challenges to those seen in cSDH? Are cSDH strategies relevant to these pathways? Does admission route affect patient outcome/experience after specialist surgery? Methods Programme evaluation for cSDH The impact of introducing the cSDH intervention will be assessed using a multi-method programme evaluation. A theory-of-change and logic model for the intervention will be formalised. Data relevant to process and outcomes will be subject to quasi-experimental (interrupted time series) analysis, including: time-to-surgery, elective cancellations, and patient satisfaction. A process evaluation will investigate influences on implementation, including fidelity, using interviews, focus groups, and surveys. Supported by the Royal College of Anaesthetists Centre for Research & Improvement, we will create and pilot a database capturing cross-institutional cSDH outcomes in 8 regions. This will permit a national examination of outcome by admission route while capturing variation in care processes. This will permit updating of our intervention logic model in readiness for future national implementation. Beyond cSDH We will use hospital episode statistics, UK biobank, and electronic records from our centre to identify other specialist surgery pathways at risk of similar challenges via the calculation of indirect admission rates and patient journey times as surrogates. At-risk pathways will be explored using narrative interviewing and process mapping, before cross-referencing these against logic models for cSDH interventions. We will use causal inference to evaluate whether 'indirect' admission is itself harmful as well as visualising baseline differences in socioeconomic/demographic factors. Anticipated impact Improved cSDH outcomes and neurosurgical services are expected within five years. Impact is amplified by development of national improvement infrastructure and assessing relevance to other surgical conditions.