Effectiveness of intensive care for patients undergoing major lower limb revascularisation or amputation in the United Kingdom

Research question Which patients benefit most from admission to intensive care after lower limb bypass or major lower limb amputation? Background Lower limb surgical bypass and major lower limb amputation are performed on over 9000 people per year in the UK with significant associated mortality and morbidity, with a 30-day mortality of 6.4% to 8.3%. Appropriate selection of patients for intensive care beds is essential to improve clinical outcomes, reduce delays and cancellations, and improve allocation of limited resources. However, the evidence base and clinical guidelines for intensive care triage is limited, and it is unclear which patients stand to benefit most from intensive care versus ward-based care after lower limb surgery. Aims and objectives The aim of the study is to evaluate utilisation and impact of intensive care after lower limb bypass or major lower limb amputation, and to identify patients most likely to benefit from intensive care admission. The specific objectives are to: Describe contemporary intensive care use after lower limb bypass and major lower limb amputation, identify variations in practice, and explore patient-level and hospital-level characteristics associated with intensive care admission. Evaluate the clinical effectiveness of intensive care versus ward-based care after lower limb bypass or major lower limb amputation, and in specific patient subgroups. Provide recommendations and improved triage tools to identify patient subgroups most likely to benefit from intensive care after surgery for lower limb bypass or major lower limb amputation. Methods and timelines Linked data from the National Vascular Registry, Intensive Care National Audit and Research Centre, Hospital Episode Statistics, and Office of National Statistics databases will be used to address the study objectives. Objective 1 - Retrospective quantitative analysis of observational data to describe contemporary intensive care utilisation after lower limb bypass and major lower limb amputation, identify inter-hospital variation, and define characteristics associated with intensive care admission. (months 1-9) Objective 2 - An emulated target trial will compare intensive care versus ward-based care in patients undergoing lower limb bypass and major lower limb amputation, with precise definitions, outcomes, and minimally clinically important difference to be refined by a clinical and PPI panel. Preliminary PPI input recommended outcomes include mortality and quality of life indicators. An instrumental variable (IV) design will provide accurate estimates of relative effectiveness and minimise the risk of unmeasured confounders between groups. The IVs considered will be intensive care bed capacity and each vascular centre's tendency for intensive care admission. Subgroup analysis will be performed based on mode of admission and diagnostic subcategories. (months 10-21) Objective 3 - Translation workshops will be held with stakeholders and patients and the public to make recommendations about which patient subgroups are most likely to benefit from intensive care after surgery for lower limb bypass and major lower limb amputation. (months 22-25) Anticipated impact and dissemination Results will be disseminated amongst patient and clinical groups, presented at conferences and published in peer-reviewed journals. Clinical co-applicants and advisory panel will ensure translation to key clinical organisations and guidelines.