Maki 1991.

Methods	Single‐centre RCT (USA) Study period: 1986‐1987. Setting: surgical ICU
Participants	All adult patients over 18 years old Number of participants:176 Number of catheters;176 Age: mean age ranged from 51 to 53 years (SD of 19 in all three groups) Sex: not reported.
Interventions	Skin antisepsis prior to CVC insertion and every 48 h thereafter using 1 of 3 antiseptic solutions. Intervention A: 10% povidone‐iodine. Intervention B: 70% isopropyl alcohol. Intervention C: 2% chlorhexidine gluconate.
Outcomes	"Catheter‐related infections" (catheter colonisation) "Catheter‐related bacteraemia" (catheter‐related BSI) Outcomes assessed at various points during in‐patient stay.
Notes	Although not clearly stated, it appeared that each patient had only 1 catheter included in the study, as Table 1 in the article suggested. Authors studied both venous and arterial catheters and reported outcome data separately. Funding source: partly funded by Stuart Corporation (ICI, Ltd) of Wilmington, Delaware.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	'Materials and methods', 'Procedures for insertion and care of catheters': "At the time of insertion, each catheter was randomised to one of three antiseptic solutions . . ." There was no description of random sequence generation
Allocation concealment (selection bias)	Unclear risk	Not reported
Blinding of participants and personnel (performance bias) All outcomes	High risk	'Materials and methods', 'Source of clinical data': "Although it was not possible for the users or the research nurses to be blinded to the antiseptic agent used . . ."
Blinding of outcome assessment (detection bias) All outcomes	Low risk	'Materials and methods', 'Source of clinical data': "[T]he research microbiologist who processed all cultures had no knowledge of the antiseptic group to which the catheter had been assigned"
Incomplete outcome data (attrition bias) All outcomes	Low risk	It appeared that there were no withdrawals, as the number of catheters analysed matched the number of catheters enrolled initially. The authors appeared to follow the intention‐to‐treat principle by analysing the catheters in the originally assigned groups.
Selective reporting (reporting bias)	Low risk	Authors reported both major outcomes of catheter colonisation and catheter‐related BSI as stated in the 'Methods' in sufficient detail in the 'Results'. An additional outcome of adverse event was reported, although this was reported as an overall percentage without separating venous from arterial catheters.
Other bias	Low risk	None identified