Dear Readers: Infection prevention is currently included among standardized hospital, home care, and ambulatory outpatient clinic quality measures.¹ Thus far, only 2 actions are required of hospitals to meet quality standards—administration of prophylactic antibiotics within 1 hour prior to the surgical incision and discontinuance within 24 hours after the end of surgery.² Other decisions significantly affect wound infection rates. For example, in hospitalized burn patients, limiting invasive device use and strictly adhering to aseptic technique reduce nosocomial infection rates.^3,4 This Evidence Corner will summarize 2 systematic reviews that explore the evidence base for some cherished beliefs about preventing surgical site infection (SSI). I. Kelman Cohen, in his acceptance speech for the Fifth Annual John Boswick Memorial Award and Lectureship, quoted Charlie Chan, noting that the mind is like a parachute, working best when open. These systematic reviews have the potential to open our minds to the evidence on how to prevent SSI and challenge some long held assumptions.

Preoperative Hair Removal Effects on SSI

Reference: Tanner J, Woodings D, Moncaster K. Preoperative hair removal to reduce surgical site infection. Cochrane Database Syst Rev. 2006 Apr 19;(2):CD004122.
Rationale: It is believed that preoperative surgical site hair removal reduces infection rates, but some methods of surgical site hair removal have been found to increase the likelihood of SSI.
Objective: The objective of this systematic review of randomized, controlled trials (RCTs) was to determine whether routine preoperative hair removal reduced the likelihood of SSI and which techniques were most effective in doing so.
Methods: The authors conducted a systematic review of RCTs in the Cochrane Wounds Group Specialised Register, Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, CINAHL, and the ZETOC database of conference proceedings. The authors also contacted hair removal product manufacturers to find studies comparing hair removal techniques and their effects on SSI. Each author independently assessed quality of all identified RCTs; an author extracted the data; and another author crosschecked the data.
Results: Of the 11 RCTs included in the review, 3 studies with a total of 625 patients found no significant effect of preoperative hair removal using depilatory cream or razors on SSI as compared to no hair removal. None of the trials compared clipping with no preoperative hair removal on SSI incidence. Three trials with a total of 3,193 patients found twice the risk of a SSI when patients were shaved rather than clipped (P < 0.05). Seven trials that compared shaving with depilatory cream on a total of 1,420 patients found no difference in SSI risk between the 2 techniques. Risk of SSI was not affected by either shaving (1 study) or clipping (a different study) on the day of surgery as compared to the day before surgery.
Conclusion: It is unknown whether clipping hair at the surgical site reduces the likelihood of a SSI as compared to no hair removal, but if hair must be removed, clipping is likely to result in fewer SSIs than shaving. Evidence is insufficient to support any other conclusion about the effect of preoperative hair removal on SSI incidence.

Do Preoperative Skin Antimicrobial Agents Reduce SSI?

Reference: Webster J, Osborne S. Preoperative bathing or showering with skin antiseptics to prevent surgical site infection. Cochrane Database Syst Rev. 2006 Apr 19;(2):CD004985.
Rationale: It is not clear whether preoperative patient bathing with antimicrobial agents reduces the likelihood of SSI, even though this practice is known to lower the bacterial burden of the skin.
Objective: The authors’ objective was to review evidence regarding efficacy of preoperative bathing or showering with antimicrobial agents in preventing hospital-acquired SSI.
Methods: This was a systematic review of RCTs comparing effects of preoperative full-body patient bathing or showering using antimicrobial agents on the incidence of SSI. The literature searches were conducted using the Cochrane Wounds Group Specialised Register, Cochrane Central Register of Controlled Trials, and MEDLINE databases. Searches were expanded to include reference lists from all articles found. Study authors were queried (when needed) to qualify a study for inclusion. Both Cochrane reviewers independently assessed study quality and extracted data from the studies.
Results: Six controlled studies with a total of 10,007 participants qualified for inclusion in the systematic review. Three studies with a total of 7,691 patients compared antimicrobial use when bathing (4% chlorhexidine) with placebo and found no statistically significant reduction in SSI incidence. Three studies that compared preoperative wash with bar soap versus 4% chlorhexidine on 1,443 patients also found no significant reduction in SSI risk with use of an antimicrobial agent. Two trials consisting of 1,092 patients found no difference in SSI rate following preoperative bathing with 4% chlorhexidine compared to no preoperative washing of the surgical site. No qualifying controlled studies were found on any other antimicrobial bathing agent.
Conclusions: The evidence is sufficient to support the conclusion that preoperative bathing with 4% chlorhexidine solution has no statistically significant effect on postoperative SSI as compared with either no bathing or bathing using placebo or soaps. No controlled studies were found on other surgical site-cleansing agents.

Clinical Perspective

       Without evidence, it is difficult to determine if we are following Hippocrates’ admonition to “Do no harm.” These reviews question the value of 2 practices currently carried out in many hospitals. Shaving surgical sites preoperatively increases the likelihood of SSI compared to clipping. According to current evidence, the value of preoperative hair removal is a decision to be based on clinical need rather than the assumption that it prevents SSI. The tradition of preoperative skin preparation with a 4% chlorhexidine scrub has been conclusively proved ineffective in preventing SSI. Please note that this conclusion refers only to cleansing the patient preoperatively and only to 4% chlorhexidine preparations, the sole agent with controlled study evidence. The same surgical scrub reduced the likelihood of surgeons’ hand contamination prior to surgery, as compared to alcohol gel, though the effect on subsequent SSI was not measured.⁵ Following clinical hand-washing protocols is still a “must.” These results suggest that medical professionals may have been focusing on cleaning the patient’s skin, when it is really cleaning the clinician’s skin that reduces the likelihood of nosocomial infections.⁶
       Reviews like these show us a current snapshot of what is genuinely known. Opportunities remain for research to answer questions about whether clipping hair preoperatively reduces SSI risk or whether it is reduced by other skin cleansers. Could other variables, such as timing or patient comorbidities, have obscured more subtle effects of hair removal techniques or surgical site cleansing? What are the effects of reducing patients’ normal microflora? These reviews serve to make us wonder what other routine clinical behaviors would stand the test of research.