Reviewing guidelines for SSI prevention

In the UK, surgical site infections (SSIs) are among the most serious and costly hospital infections.1 Infected patients are twice as likely to die following surgery,2 stay at least twice as long in hospital3 and cost almost three times more to treat than uninfected patients.4 More than 460,000 surgical procedures are estimated to result in wound infection, each year,5 with MRSA (Methicillin-resistant Staphylococcus aureus) accounting for a particularly high proportion. SSIs can occur when microorganisms naturally found on the skin of a patient enter the body when the skin’s protective barrier is compromised during the surgical procedure. There are many guidelines that suggest critical steps healthcare facilities can take to reduce the risk of surgical site infection, yet despite these recommendations SSIs continue to represent a significant and costly problem for the healthcare system. Since the publication of the NICE guidelines on prevention and treatment of surgical site infection, in October 2008, new data has also come to the fore which suggests that best practice needs to be reviewed.

Skin preparation – new evidence

Specifically, experts are calling for a reevaluation of the way patients are prepped for surgery, following the results of a trial comparing the efficacy of skin antiseptics in reducing the risk of SSIs. A prospective, randomised, multicentre clinical trial, conducted by Rabih Darouiche MD and colleagues, demonstrated that the use of 2% chlorhexidine gluconate and 70% isopropyl alcohol pre-operative skin preparation (ChloraPrep) reduced total surgical site infections (SSIs) by 41%, compared to use of povidone-iodine solution – the most commonly used pre-operative skin preparation.6 “In 2002, the US Centres for Disease Control and Prevention (CDC) issued recommendations indicating that 2% chlorhexidine gluconate and 70% isopropyl alcohol should be used instead of povidone-iodine preparations, or alcohol alone, to cleanse the skin at the site of insertion of vascular catheters. Although the recommendations became the standard of care in catheter insertion, the CDC did not issue these recommendations for skin preparation prior to surgery,” Rabih Darouiche explained. “Due to a lack of guidance on skin antiseptics in the US, three-quarters of the 30 million surgeries performed each year continued to use povidone-iodine,” he continued. “We wanted to establish whether 2% chlorhexidine gluconate and 70% isopropyl alcohol would be superior in preventing SSIs in line with the recommendations for catheter care, therefore.” Rabih Darouiche explained that there has been considerable interest in this issue. It is estimated that between 300,000 to 500,000 cases of SSI occur each year in the US alone. Although SSI is one of the most common infections and one of the most serious, optimal prevention has not yet been achieved. “Non-antimicrobial interventions (such as maintaining normothermia and ensuring adequate oxygenation), as well as antimicrobial interventions (such as antibiotic prophylaxis and the use of antimicrobial sealant), were some of the examples of approaches that collectively helped to reduce the rate of infection,” he commented. “However, in our view, this was not enough. We wanted to identify a preventative solution that was not only effective and safe, but also practical. Studies on the use of mupirocin have been well designed and produced promising results. However, testing for nasal carriage of Staphylococcus aureus and administering a course of mupirocin pre-operatively, involves a greater level of complexity, time and expertise, compared to skin preparation. The latter can be performed in a single application without advanced technical skills and, unlike molecular-based testing, everyone can use this approach.” Rabih Darouiche and his colleagues started work on the design of the study in 2002, which covered six centres and included 849 patients in the analysis. Patients in the two groups were similar with respect to multiple factors, including demographics, medical conditions, individual risk for infection, and both the length and type of surgery. The results of the study were finally published earlier this year in the New England Medical Journal.6 The researchers reported that the overall rate of surgical-site infection was significantly lower in the chlorhexidinealcohol group than in the povidone-iodine group (9.5% vs 16.1%; P=0.004; relative risk, 0.59; 95% confidence interval, 0.41 to 0.85).6 Chlorhexidine-alcohol was significantly more protective than povidone-iodine against both superficial incisional infections (4.2% vs 8.6%, P=0.008) and deep incisional infections (1% vs 3%, P=0.05) but not against organ-space infections (4.4% vs 4.5%).6 Rabih Darouiche pointed out that only 17 patients needed to receive the 2% chlorhexidine gluconate and 70% isopropyl alcohol skin antisepsis, instead of povidone-iodine, in order to prevent one case of surgical site infection. To put this into perspective, between 33 and 100 patients have to receive the chlorhexidine-based skin preparation, instead of povidone-iodine, to prevent one case of catheter-related bloodstream infection. The potential impact on patient outcomes is even greater therefore. According to the supplier of ChloraPrep, CareFusion, one of the key advantages of 2% chlorhexidine gluconate and 70% isopropyl alcohol is that it keeps fighting bacterial growth for at least 48 hours after application. Povidone-iodine, on the other hand, is neutralised by blood and other organic matter, reducing its effectiveness to two hours. This residual effect allows for added protection for patients against infections after surgery and not just during the procedure. “Our research has been received with considerable enthusiasm in the US and there are a number of organisations focusing on the quality of healthcare that have already made plans to include the approach as a new standard of care,” revealed Rabih Darouiche. “This includes not just regulatory agencies, but also professional and clinical associations.” He hopes that the UK and other nations will now embrace the evidence with the same enthusiasm: “If a UK study had resulted in such clear and powerful conclusions, we would have a responsibility in the US to learn from this and apply the recommendations. The UK now has this opportunity. Moreover, there is now enough evidence to mandate the use of this approach for pre-op preparation in my view.” Commenting on the study findings, Professor David Leaper, emeritus professor, University of Newcastle upon Tyne, and visiting professor of surgery at the wound healing research unit, Cardiff University, said: “In the UK, SSI represents approximately 20% of healthcareassociated infections (HCAIs) and one in twenty people having surgery develop an SSI. It is a largely preventable complication of surgery and is the subject of many ‘care bundles’ including the Safe Surgery Saves Lives campaign endorsed by the World Health Organisation. “Skin preparation prior to surgery has received scant attention for several decades. This new piece of research6 has shown convincingly that ChloraPrep can significantly reduce SSIs after cleancontaminated surgery and is clearly superior to widely accepted and ritualistic skin preparation using povidone-iodine. There is an added reduction in both postoperative morbidity and mortality related to SSI and significant potential to reduce a major financial burden to the NHS.”