Summary of findings 3. Chlorhexadine 4% compared with no wash.

Chlorhexadine 4% compared to no wash for surgical patients
Patient or population: surgical patients Settings: Hospital Intervention: Chlorhexadine 4% Comparison: no wash
Outcomes	Illustrative comparative risks* (95% CI)		Relative effect (95% CI)	No of Participants (studies)	Quality of the evidence (GRADE)	Comments
	Assumed risk	Corresponding risk
	no wash	Chlorhexadine 4%
Surgical site infection Follow‐up: 1 ‐ 3 weeks1	Study population		RR 0.82 (0.26 to 2.62)	1142 (3 studies)	⊕⊝⊝⊝ very low2,3,4
	56 per 1000	46 per 1000 (15 to 147)
	Medium risk population
	46 per 1000	38 per 1000 (12 to 121)
*The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). CI: Confidence interval; RR: Risk ratio;
GRADE Working Group grades of evidence High quality: Further research is very unlikely to change our confidence in the estimate of effect. Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate. Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate. Very low quality: We are very uncertain about the estimate.

¹ Some studies followed patients only until hospital discharge; as the studies were over 20 years old, we have assumed this to be one week.
 ² A number of potential biases existed including inadequate allocation concealment and blinding.
 ³ Hetrogeneity between studies was evident; this was most likely due to different types of surgeries, differences in length of follow‐up, varying sample sizes and ways of defining infection.
 ⁴ Wide confidence intervals, low event rate.