Infection risk in sterile operative procedures: a systematic review and meta-analysis

The most important goal of modern hospital hygiene and infection control is to give patients the best possible protection against avoidable hospital-acquired infections. The occurrence of these infections can be reduced by infection control measures (1– 3). Table 1 gives an overview of the incidence of postoperative wound infections after sterile surgical procedures. Values shown are mean rates of postoperative wound infection observed using various surveillance systems. Table 1 Healthcare-associated infection rates for sterile operative procedures. Values are mean wound infection rates (%) per 100 procedures The results of the SENIC study (Study on the Efficacy of Nosocomial Infection Control, aimed at the reduction of healthcare-associated infections [HAI]), have been available for many years (4). The study investigated the effect of infection control programs on the reduction of HAI over the course of 5 years in more than 300 US hospitals. It found that hospitals that employed hygiene personnel in a targeted way (one full-time person per 250 beds) and instituted suitable monitoring and feedback systems were able to reduce their HAI rates by 32%. In contrast, hospitals that did not implement this measure saw infection rates rise by 18% during the same period. On the basis of these findings, it was concluded that at least one-third of HAI can be avoided by maintaining standards of infection control measures (4). However [so entspricht es dem deutschen Original], the potential for reducing HAI varies greatly, being strongly dependent on the hospital baseline situation. There is evidence, though, that significant reduction of HAI can be achieved by various interventions (5– 7). Postoperative wound infections are a problem in all surgical disciplines, although the infection risk is not the same for different kinds of surgical procedure. It depends on multiple factors such as local wound conditions, the patient’s immune status, and others. As an example, the differences between wound infection rates for cesarean sections (Table 1) in Germany and the European Union can be partly explained by the fact that in Germany even pregnant women with no risk factors may undergo cesarean sections. Differences in wound infection rates are particularly due, however, to differences in the degree of contamination of the surgical site. Health authorities in the United States, for example, have set national reduction targets between 25% and 70% in their “Roadmap to Elimination” action plan (Table 2). Thus, the targets of the US action plan are seen not as zero values, but as percent reduction rates—an approach also followed by the German regional medical associations (Landesarztekammern) with their quality control data. These too monitor not outcome parameters alone, but also process parameters. Table 2 United States national action plan for the prevention of health care–associated infections with targets up to the year 2020 In Germany we are now seeing demands for zero infection rates in sterile operative procedures: “A national campaign for the creation of a culture of targeting zero health care-associated infections and zero tolerance for unsafe practices is long overdue” (8). There is agreement that postoperative wound infections in general can and must be reduced. However, the reality is that an infection rate of zero in sterile operative procedures is not achievable. This article shows the extent to which the demand for “zero infections in sterile operations” is not evidence-based. It is based on a systematic literature review and meta-analysis of existing studies. The analysis is limited to the past 10 years, since the hypothesis that a zero infection rate is possible was first put forward in 2006.