A Cochrane review included 7 studies with a total of 10 157 subjects. Antiseptic preparations used for preoperative full-body washing or showering were compared with non-antiseptic preparations in patients undergoing surgery. The antiseptic used in all trials was 4 % chlorhexidine. Three trials involving 7 791 participants compared chlorhexidine with a placebo. Full-body washing with chlorhexidine compared with a placebo did not result in a statistically significant reduction in surgical site infections (SSIs); the RR of SSI was 0.91 (95 % CI 0.80 to 1.04). Three trials of 1 443 participants compared bar soap with chlorhexidine and found no difference in the risk of SSIs (RR 1.02, 95 % CI 0.57 to 1.84). One study (n=1 530) found a statistically significant difference in favour of full-body washing with chlorhexidine compared to partial localized washing (Incidence of SSIs 1.7 % vs. 4.2 %, RR 0.40, 95 % CI 0.19 to 0.85). The smaller studies found no difference between patients who washed with chlorhexidine and those who did not wash preoperatively.
Comment: The quality of evidence is downgraded by study limitations (lack of blinding).