SURGICAL SITE INFECTIONS


was generally poorly reported. Efforts were made to blind outcome assessors, but patients and surgeons often were not blinded, compromising internal validity.”


They therefore concluded that:


“There is insufficient evidence to support one antiseptic over another.”7,38


Patient outcomes The problems with RCTs in respect to patient outcomes are obvious. It is impossible to isolate the one variable to be tested amongst the many variables that are known to cause SSIs. There are several reasons why academically the studies may be relevant, but in practice they can do no more than point the reader in the right direction for clinical practice. The most important factors to take into consideration when looking at infection control related outcome studies are the extraneous variables that involve the patient. A simple example of this would be to assess the individual patient’s immune system, as an indicator of their potential to fight off potential infections. If these variables are not isolated, when asked for ‘evidence’ in reference to patient outcome, infection control studies should therefore be considered, at best, weak. The clinical effectiveness of


pre-surgical antiseptic showers have been reported in three Randomised Controlled Trials (RCTs) and four cohort studies.10,16


The clinical effectiveness of antiseptic preparation versus non


The ‘observer effect’ or ‘Hawthorn effect’, where the act of measuring alters the outcome, is impossible to measure in studies looking at the link between skin disinfectant solutions and patient outcome.


medicated soap and alcohol or saline was reported in two RCTs published in 2001 and 2005.17,18


The effectiveness


of one antiseptic preparation versus another for reducing bacterial colonisation and SSIs has been reported in five RCTs and four non-randomised studies published between 2002 and 2011.19,27


reported by seven RCTs11,13,19,21,28


Skin colonisation levels were and


one observational study.16 Studies considered all bacterial species when determining colonisation. Two RCTs reported that pre surgical showering with PI12


or CHG11 resulted


in a statistically significant reduction in preoperative skin colonisation. One RCT13


showed no statistically


significant reduction in preoperative colony counts with CHG showering compared with control or placebo. In a cohort study, twice-daily, five-day topical 4% CHG scrubbing reduced preoperative perineal colonisation four-fold compared with usual hygiene in patients undergoing artificial urinary sphincter placement.16


One RCT19


showed a statistically significant reduction in pre surgical bacterial colonisation in patients prepared with


4% CHG in 70% isopropyl alcohol compared with patients prepared with PI. Until recently the effects over extended time periods, of ethyl alcohol on its own on skin bacterial counts have also been overlooked. Several “real time” audits of skin flora now show that alcohol, when used on its own, may actually be detrimental to bacterial levels on the skin. Two RCTs23,28 retrospective study29


and one published between


2002 and 2005 focused on the use of iodophor-impregnated incise drapes to prevent surgical wound infection. The evidence available, although inconclusive, suggests that preoperative showers with an antiseptic agent are effective at reducing bacterial colonisation of the skin and that could be used to reduce SSIs. CHG was primarily used as the ‘antiseptic’ with varying showering regimens and varying compliance rates in those trials. As the results do remain inconclusive, it is unusual then for section 8A.1. of the USCDC 2017 guidance on prevention of SSIs51


to state: “Advise patients to shower or bathe (full body) with soap (antimicrobial or non-antimicrobial) or an antiseptic agent on at least the night before the operative day.” This is given a “category 1B – strong recommendation” based on “accepted practice.” If there is no appropriate RCT evidence, then the authors must clearly be assuming that the antiseptic shower will reduce skin CFU counts, and therefore less bacteria - including skin commensals - at the time when surgical skin preparation is undertaken, will have a positive effect on potential outcome. This should not be a surprise when it is known that the skin commensal Staphylococcus Epidermidis (which is the most prolific skin bacterial species), has the capacity to evade the human immune system, as well as being resistant to Oxacillin.50


The dangers


associated with this bacterial species can therefore not be overestimated in a surgical wound.


As the USCDC takes the view that OPERATING THEATRE l JULY 2018 l 31


t


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