Abstract
Abstract
Surgical site infections remain an important topic of concern for surgeons in all specialties and are currently the focus of global health agencies for prevention. Because patients have numerous co-morbidities that increase the risks of surgical site infections, and because of the emergence of more resistant pathogens, it is necessary to revise and update guidelines to assist surgeons in the prevention of these infections. This article will summarize the most recent WHO Global Guidelines for the prevention of Surgical Site Infection that will have applicability for surgeons in all countries.
S
New guidelines aimed at defining best practices for minimizing SSI have recently come forward from the Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO); the CDC document is intended for use by a range of healthcare professionals in the United States, and the WHO document is intended to serve as a globally applicable document for low-, middle-, and high-income countries.
Grading of Recommendations Assessment, Development, and Evaluation (GRADE) versus Other Mechanisms for Transparency in Guideline Production
Guidelines serve to translate new research findings into clinical practice when they are, in some way, certified as accurate. The relatively recent emergence of guidelines and other similar evidence-based documents marks a shift away from expert opinion-based practices toward more transparent, data-based recommendations. Historically, senior physicians or surgeons were viewed as the certification element because of the absence of robust clinical trial strategies. As publication of observational and randomized prospective clinical trials became more common, “experts” were re-defined as persons who had both extensive clinical experience and a wide grasp of the appropriate literature.
This approach did not, however, solve the important problem of bias. A strong-willed expert could quite easily generate a compelling case for some intervention not based on a complete review of available information and driven by his/her opinions and biases. One example of a failure of expert opinion was the use of extensive surgery for the treatment of cancer, which was based on the presumption of nodal spread; breast cancer was managed into the 1960s with standard radical mastectomies and skin grafts [7], and colon cancer was managed with aortocaval node dissection [8].
The current standard for evaluating clinical evidence involves a systematic review, meta-analysis of the results, and use of GRADE. The GRADE working group was formed in 2000 as a collaborative attempt to address the shortcomings of grading systems in healthcare [9]. This group has developed a practical and transparent approach to grading the quality and certainty of evidence and the strength of recommendations. The GRADE system incorporates input from many international organizations, and this approach is now considered the standard in guideline development.
Methodology of Systematic Reviews
Evidence-based guidelines and recommendations are built on systematic reviews of the proposed recommendation area. A systematic review requires a protocol that describes the search strategy used to identify all relevant published and unpublished studies; the eligibility criteria for the selection of studies; how studies will be critically appraised for quality; and, if feasible, a quantitative synthesis of the results of studies to estimate the overall effect of intervention (meta‐analysis). Systematic reviews, if conducted properly, reduce the risk of selective citation and improve the reliability and accuracy of decisions. These processes are also used by several governmental and quasi-governmental agencies, including the Institute of Medicine (IOM) [10], the Council on Medical Specialty Societies, and the American Health Association.
The systematic review process begins with the formulation of a search strategy to identify all published studies around the main concepts being examined in a review. The inclusion and exclusion criteria assist further in selecting the appropriate subject headings (terms used to index the articles) and text words for the search strategy. The controlled vocabulary for PubMed (MeSH) and EMBASE (Emtree) is not identical nor are databases indexed to the same depth. PubMed and EMBASE both search MEDLINE content, but an EMBASE search using essentially the same search terms may retrieve a greater number of results than PubMed. Therefore, search strategies need to be customized for each database. In addition, available index terms may not necessarily be as effective in retrieving relevant results as text word search terms. The search strategies for this systematic review were revised for each database. Also essential to a comprehensive search strategy is the inclusion of synonyms, related terms, and variations in spelling with the help of truncation and wildcards. Again, these features may vary across databases. In some databases fewer search terms yield more relevant results.
Developing a search strategy is a process of modifying the terms used based on what has been retrieved already. This process continues until a balance is found between more relevant versus less relevant search results. Including the search terms and strategies for each database used in a systematic review provides the opportunity to assess the comprehensiveness and completeness of the search and to replicate it.
Quality of Evidence: Definitions and Implications
Studies captured in systematic reviews may vary in quality. An important part of the GRADE system is the assessment of the quality of evidence based on pre-determined criteria. For systematic reviews, the quality of evidence reflects the extent of confidence that an estimate of effect is correct. Factors that go into the assessment of quality are study design, study limitations, inconsistent results, indirectness or incomparability of evidence, imprecision, and publication bias [11].
The levels of quality of evidence and the associated definition and implications as specified by GRADE are as follows:
High quality
• The guideline development group (GDG) is very confident that the true effect lies close to that of the estimate of the effect and further research is very unlikely to change confidence in the estimate of effect.
Moderate quality
• The GDG is moderately confident in the effect estimate. The true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different. Further research is likely to have an important impact on confidence in the estimate of effect and may change the estimate.
Low quality
• Confidence in the effect estimate is limited; the true effect may be substantially different from the estimate of the true effect. Further research is very likely to have an important impact on confidence in the estimate of effect and is likely to change the estimate.
Very low quality
• The group has very little confidence in the effect estimate; the true effect is likely to be substantially different from the estimate of the effect. Any estimate of effect is very uncertain.
The strength of the recommendation
The strength of a recommendation communicates the importance of adherence to the recommendation [12].
Strong recommendations
• With strong recommendations, the guideline communicates the message that the desirable effects of adherence to the recommendation outweigh the undesirable effects. This means that in most situations, the recommendation can be adopted as policy.
Conditional recommendations
• These are made when there is greater uncertainty about the four factors above or if local adaptation has to account for a greater variety in values and preferences, or when resource use makes the intervention suitable for some, but not for other locations. This means that there is a need for substantial debate and involvement of stakeholders before this recommendation can be adopted as policy. The WHO GDG included consumers from low- and middle-income countries (LMICs).
No recommendation
• When there is lack of evidence on the effectiveness of an intervention, it may be appropriate not to make a recommendation. In these cases, the lack of evidence can be highlighted by stating: “No recommendation can be made because of insufficient evidence.” Instead of providing a recommendation, the findings of the systematic review or an overview of interventions may be published. By doing so, a range of optional interventions can be presented without indicating a preference for one over the other. In other situations, guidance from WHO might be needed, despite there being little or no evidence. In these instances, the absence of evidence should be highlighted, and the basis of the options presented, such as case reports, national experience, or opinion, should be indicated clearly.
Formulation of the Recommendation Areas in the WHO Guideline
Earlier guidelines represent the cornerstone of this SSI guideline update. Within the framework of existing guidelines, specific topics were researched in various databases, including: PubMed, EMBASE, CINAHL, Cochrane Central Register of Controlled Trials (CENTRAL), WHO regional medical databases, African Index Medicus, and Cochrane. Specifically, literature was sought addressing knowledge gaps in previously published guidelines. This literature was summarized by a team organized by one GDG member for specific recommendation areas defined by the GDG. The narrative summary was then discussed at meetings of the GDG. Additional studies were added according to feedback from these experts.
Narrative summaries were then revised according to the evidence provided by this literature. These were reviewed by both an internal expert panel and by outside content experts to reach consensus agreement on the final guideline recommendations presented here. The recommendation areas considered are described in Table 1. These have been published previously.
SSI = surgical site infection; CHG = chlorhexidine gluconate; SAP = surgical antibiotic prophylaxis.
Implementation of Guidelines
The technical work of the guideline development process is followed by the adaptive work of guideline dissemination and implementation, which requires the support of the international healthcare community to be successful. Much of the implementation work done to date has focused on the creation of sustainable and facility specific changes in patient safety culture. Programs that have shown success in the reduction of SSI include the Comprehensive Unit-Based Safety Program (CUSP) and Surgical Unit-Based Safety Program (SUSP), protocols created at Johns Hopkins University to improve safety culture. Designed to make facility-specific mistakes more transparent and facilitate the discussion needed to design practical and effective interventions, CUSP and SUSP revolve around the formation of interdisciplinary teams that include surgeons, nurses, operating room technicians, and anesthesiologists. Implementation of the CUSP approach during a 2011 pilot program resulted in a 33.3% reduction in SSI rates after 12 months [13].
The WHO approach to successful guideline implementation incorporates tenets of safety culture such as CUSP with an added focus on adapting proven practices in high-income settings to low- and middle-income settings. Proposed strategies will be based on evidence review, implementation science, expert input, current gaps in implementation tool availability, and an emphasis on reaching those most in need of implementation support. A systematic review of implementation strategies for SSI prevention identified 116 relevant studies, 19 of which were performed in LMICs. Results from this systematic review, proven WHO multi-modal improvement strategies, and lessons from many regions were synthesized to map out common, critical elements for success: Engage, educate, execute, and evaluate [14].
When should guidelines be updated?
The process of creating guidelines does not stop at publication; maintaining the relevance and applicability of guidelines in a constantly shifting research landscape is an important component of the work. Considerations for whether a guideline should be updated include whether the review addresses a relevant and current topic, whether the review uses valid methods, and whether there are new methods, new studies, or new information on existing included studies that must be incorporated. The decision on whether to update a systematic review or guideline must be made for individual reviews. Frameworks for when and how to update systematic reviews have been published by Cochrane [15,16] and an independent panel [17].
Footnotes
Author Disclosure Statement
No competing financial interests exist.