A mixed-methods feasibility and external pilot study to inform a large pragmatic randomised controlled trial of the effects of surgical wound dressing strategies on surgical site infections (Bluebelle Phase B): study protocol for a randomised controlled trial

Background: Surgical site infections are common, occurring in up to 25% of >4 million operations performed in England each year. Previous trials of the effect of wound dressings on the risk of developing a surgical site infection are of poor quality and underpowered.Methods and design: This study is a feasibility and pilot trial to examine the feasibility of a full trial that will compare simple dressings, no dressing and tissue-glue as a dressing. It is examining the overall acceptability of trial participation, identify opportunities for refinement, test the feasibility of and validate new outcome tools to assess SSI, wound management issues and patients' wound symptom experiences. It is also exploring methods for avoiding performance bias and blinding outcome assessors by testing the feasibility of collecting wound photographs taken in theatre immediately after wound closure and, at 4-8 weeks after surgery, taken by participants themselves or their carers. Finally, it is identifying the main cost drivers for an economic evaluation of dressing types. Integrated qualitative research is exploring acceptability and reasons for non-adherence to allocation. Adults undergoing primary elective or unplanned abdominal general surgery or caesarean section are eligible. The main exclusion criteria are abdominal or other major surgery less than three months before the index operation or contraindication to dressing allocation. The trial is scheduled to recruit for nine months. The findings will be used to inform the design of a main trial.Discussion: This pilot trial is the first pragmatic study to randomize participants to no dressing or tissue-glue as a dressing versus a simple dressing. Early evidence from the on-going pilot shows that recruitment is proceeding well and that the interventions are acceptable to participants. Combined with the qualitative findings, the findings will inform whether a main, large trial is feasible and, if so, how it should be designed.