Martin‐Trapero 2013.

Methods	2‐arm RCT undertaken in Spain
Participants	People diagnosed with cholelithiasis undergoing elective laparoscopic cholecystectomy Exclusion criteria: > 70 years of age; diabetes; having a fever; and current treatment with immunosuppressants
Interventions	Group A (n = 101): non‐occlusive dressing (gauze) Group B (n = 96): 0.2% polyhexamethylene biguanide (PHMB) dressing The disinfection of the skin prior to surgery was performed 2 times with a solution of povidone iodine. A single dose of prophylaxis antibiotics was given at anaesthetic induction. Metal staples were used to close the surgical wound. Once incisions closed the wound was cleaned with povidone‐iodine 0.01% and the gauze or PHMB dressing was applied.
Outcomes	Primary review outcome: SSI (CDC definition) Secondary review outcomes: none (based on translation)
Notes	Trial outcome data: see Table 12 Information extracted from English abstract and limited translation of methods and results Follow‐up: 30 days
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Based on translation "....were assigned by an automatic method after the preparation of a spreadsheet (MS Excel) using the function ‐random tool where the researcher did not know the allocation of the next patient to be included in the study (concealment of random allocation)"
Allocation concealment (selection bias)	Low risk	Based on translation "....were assigned by an automatic method after the preparation of a spreadsheet (MS Excel) using the function ‐random tool where the researcher did not know the allocation of the next patient to be included in the study (concealment of random allocation)"
Blinding (performance bias and detection bias) All outcomes	Unclear risk	Not able to assess
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Not able to assess
Selective reporting (reporting bias)	Unclear risk	Not able to assess
Other bias	Unclear risk	Not able to assess