# Is home-based self-swabbing feasible for postoperative wound culture after cardiac surgery? A multicentre mixed-methods feasibility study in the UK

## TL;DR

This study explores whether patients can successfully collect wound swabs at home after heart surgery to improve infection diagnosis and antibiotic use.

## Contribution

The study introduces and evaluates a novel home-based self-swabbing method for postoperative wound monitoring in cardiac surgery patients.

## Key findings

- The feasibility of home-based self-swabbing will be assessed by the proportion of patients who successfully submit usable samples.
- Patient and staff feedback will inform the acceptability and usability of the self-swabbing process.
- A health economic model will compare current and proposed pathways for antibiotic use and cost-effectiveness.

## Abstract

Poor 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.

TREASURE is a multicentre, mixed-methods feasibility study. A total of 40 patient participants and 10 staff stakeholders will be included. 40 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 coproduced 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 with samples received at the laboratory within 24 hours and deemed suitable for processing. 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. A 30-day follow-up will capture wound complications, antibiotic prescribing and healthcare utilisation via patient questionnaires, case note review, general practitioner confirmation and patient interviews. 10 staff stakeholders will be interviewed to inform pathway development.

Quantitative data will be analysed descriptively, with proportions reported alongside 95% CIs. 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.

West 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, patient and public involvement-led activities and engagement with National Health Service (NHS) stakeholders.

NCT07200401, ISRCTN28466609.