Background:

Surgical site infection (SSI) affects up to 20% of people with a primary closed wound after surgery. Wound dressings may reduce SSI.

Objective:

To assess the feasibility of a multicentre randomised controlled trial (RCT) to evaluate the effectiveness and cost-effectiveness of dressing types or no dressing to reduce SSI in primary surgical wounds.

Design:

Phase A – semistructured interviews, outcome measure development, practice survey, literature reviews and value-of-information analysis. Phase B – pilot RCT with qualitative research and questionnaire validation. Patients and the public were involved.

Setting:

Usual NHS care.

Participants:

Patients undergoing elective/non-elective abdominal surgery, including caesarean section.

Interventions:

Phase A – none. Phase B – simple dressing, glue-as-a-dressing (tissue adhesive) or ‘no dressing’.

Main outcome measures:

Phase A – pilot RCT design; SSI, patient experience and wound management questionnaires; dressing practices; and value-of-information of a RCT. Phase B – participants screened, proportions consented/randomised; acceptability of interventions; adherence; retention; validity and reliability of SSI measure; and cost drivers.

Data sources:

Phase A – interviews with patients and health-care professionals (HCPs), narrative data from published RCTs and data about dressing practices. Phase B – participants and HCPs in five hospitals.

Results:

Phase A – we interviewed 102 participants. HCPs interpreted ‘dressing’ variably and reported using available products. HCPs suggested practical/clinical reasons for dressing use, acknowledged the weak evidence base and felt that a RCT including a ‘no dressing’ group was acceptable. A survey showed that 68% of 1769 wounds (727 participants) had simple dressings and 27% had glue-as-a-dressing. Dressings were used similarly in elective and non-elective surgery. The SSI questionnaire was developed from a content analysis of existing SSI tools and interviews, yielding 19 domains and 16 items. A main RCT would be valuable to the NHS at a willingness to pay of £20,000 per quality-adjusted life-year. Phase B – from 4 March 2016 to 30 November 2016, we approached 862 patients for the pilot RCT; 81.1% were eligible, 59.4% consented and 394 were randomised (simple, n = 133; glue, n = 129; no dressing, n = 132); non-adherence was 3 out of 133, 8 out of 129 and 20 out of 132, respectively. SSI occurred in 51 out of 281 participants. We interviewed 55 participants. All dressing strategies were acceptable to stakeholders, with no indication that adherence was problematic. Adherence aids and patients’ understanding of their allocated dressing appeared to be key. The SSI questionnaire response rate overall was 67.2%. Items in the SSI questionnaire fitted a single scale, which had good reliability (test–retest and Cronbach’s alpha of > 0.7) and diagnostic accuracy (c-statistic = 0.906). The key cost drivers were hospital appointments, dressings and redressings, use of new medicines and primary care appointments.

Limitations:

Multiple activities, often in parallel, were challenging to co-ordinate. An amendment took 4 months, restricting recruitment to the pilot RCT. Only 67% of participants completed the SSI questionnaire. We could not implement photography in theatres.

Conclusions:

A main RCT of dressing strategies is feasible and would be valuable to the NHS. The SSI questionnaire is sufficiently accurate to be used as the primary outcome. A main trial with three groups (as in the pilot) would be valuable to the NHS, using a primary outcome of SSI at discharge and patient-reported SSI symptoms at 4–8 weeks.

Trial registration:

Phase A – Current Controlled Trials ISRCTN06792113; Phase B – Current Controlled Trials ISRCTN49328913.

Funding:

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 23, No. 39. See the NIHR Journals Library website for further project information. Funding was also provided by the Medical Research Council ConDuCT-II Hub (reference number MR/K025643/1).

Article history

The research reported in this issue of the journal was funded by the HTA programme as project number 12/200/04. The contractual start date was in June 2014. The final report began editorial review in January 2018 and was accepted for publication in July 2018. The authors have been wholly responsible for all data collection, analysis and interpretation, and for writing up their work. The EME editors and production house have tried to ensure the accuracy of the authors’ report and would like to thank the reviewers for their constructive comments on the final report document. However, they do not accept liability for damages or losses arising from material published in this report.

Declared competing interests of authors

Chris A Rogers reports grants from the British Heart Foundation to April 2017, outside the submitted work. Chris A Rogers is a member of Clinical Trials Units funded by the National Institute for Health Research (NIHR) and the Health Technology Assessment (HTA) Commissioning Board. Melanie J Calvert reports personal fees from Ferring Pharmaceuticals (Saint-Prex, Switzerland), outside the submitted work. Rhiannon C Macefield has a patent Wound Healing Questionnaire pending to the University of Bristol. Stephen O’Brien reports grants from Saving Lives at Birth Partners, outside the submitted work. Tim Draycott reports personal fees from Ferring Pharmaceuticals, outside the submitted work. Barnaby C Reeves reports membership of the HTA Commissioning Board (up to 31 March 2016), the Systematic Reviews Programme Advisory Group (up to 5 July 2017) and Interventional Procedures Panel Methods Group, the HTA Efficient Study Designs Board, SRP – Cochrane Programme Grant Funding Meeting and Systematic Reviews NIHR Cochrane Incentive Awards (all current).