Protocol: Is home-based self-swabbing feasible for postoperative wound culture after cardiac surgery? A multi-centre mixed-methods feasibility study in the United Kingdom

IntroductionPoor access to surgical wound swabbing in the community often results in delayed or inappropriate antibiotic prescribing for surgical site infections. This delay can contribute to prolonged wound healing and poor antimicrobial stewardship. Patient self-swabbing at home could improve access to diagnostic testing but its feasibility and acceptability remain unexplored.Methods and analysisTREASURE is a multi-centre, mixed-methods feasibility study. A total of 40 patient participants and 10 staff stakeholders will be included. Forty adult patients undergoing cardiac surgery via median sternotomy will be recruited from Harefield Hospital (n=25) and the Royal Sussex County Hospital (n=15). Eligible participants will receive a co-produced self-swabbing set of instructions and kit at discharge and perform wound swabbing at home within 1–21 days, observed remotely by a researcher via Microsoft Teams. Swabs will be couriered to a central laboratory for bacterial culture with antimicrobial susceptibility testing for pathogens.The primary feasibility outcome is the proportion of patients successfully completing self-swabbing at home to obtain usable culture swabs. Secondary safety and acceptability outcomes include usability of the kit and instructions; patient satisfaction; viability of samples for laboratory analysis; and recruitment and retention rates. Thirty-day follow-up will capture wound complications, antibiotic prescribing and healthcare utilisation via patient questionnaires, case note review, GP confirmation, and patient interviews. Ten staff stakeholders will be interviewed to inform pathway development. Quantitative data will be analysed descriptively, with proportions reported alongside 95% confidence intervals. Qualitative data from patients will undergo thematic analysis, and stakeholder interviews will be coded using Normalisation Process Theory. An early health economic model will be developed to explore resource use, costs and proportions of appropriate and timely antibiotic use between current pathways and a proposed pathway, including self-swabbing.Ethics and disseminationWest of Scotland Research Ethics Service has reviewed and approved the study (REC reference: 25/WS/0079). Findings will be disseminated through the study website, a webinar, peer-reviewed publications, conference presentations, PPI-led activities and engagement with NHS stakeholders.