Bluebelle study (phase A): a mixed-methods feasibility study to inform an RCT of surgical wound dressing strategies

OBJECTIVES Dressing primary surgical wounds is common, but the implications for surgical site infection (SSI) remain unknown. The Bluebelle study aimed to determine the feasibility of a randomised controlled trial (RCT) comparing 'simple', 'complex' or 'no' dressings on abdominal wounds, as prespecified in a funder's research brief. Bluebelle includes exploratory work (phase A) to inform a pilot version of the proposed RCT (phase B). Phase A aimed to investigate current dressing practices and perspectives on the proposed RCT, with a view to refining the forthcoming pilot. DESIGN Mixed methods, including semi-structured interviews and document analysis. SETTING 6 UK hospitals. PARTICIPANTS 51 patients and 92 clinical professionals from abdominal surgical specialities. RESULTS Professionals had variable interpretations of what constitutes a 'dressing', particularly with respect to 'glue'-a product listed under 'wound-closure products' in the British National Formulary, which some surgeons reportedly applied as a 'wound covering'. Areas of ambiguity arising from interviews informed development of pragmatic definitions, including specification of conditions under which glue constituted a 'dressing'. Professionals reported that 'simple' dressings were routinely used in practice, whereas 'complex' dressings were not. This raised questions about the relevance of comparison groups, prompting the design of a survey to determine the types/frequency of dressing use in abdominal surgery (reported elsewhere). This confirmed that complex dressings were rarely used, while 'glue as a dressing' was used relatively frequently. 'Complex dressings' were therefore substituted for 'glue as a dressing' (following an updated Cochrane review, which found insufficient evidence to determine the effectiveness of 'glue as a dressing'). Patients and professionals acknowledged uncertainty around dressing use and SSI prevention, but felt dressings may serve practical and/or psychological benefits. This steered development of additional outcome measures for the pilot. CONCLUSIONS Pre-trial qualitative research can highlight areas of ambiguity and inform new lines of enquiry in relation to prespecified research briefs, enabling adjustments to RCT design that enhance relevance to practice.