Surgical site infection (SSI) is the most common complication in surgical patients. Significant advances have occurred over the last few decades resulting in better understanding of the relevant risk factors for SSI, and high-level evidence has identified specific preventive strategies that help reduce the incidence of SSI. With the introduction of asepsis and antisepsis, prophylactic antibiotics have had the most significant impact reducing the incidence of SSI. However, in order to achieve the benefits derived from their use and minimize potential undesired effects, practice of this strategy needs to follow specific basic principles.
This chapter reviews the epidemiology and clinical impact of SSI, describes the role of prophylactic antibiotics as a preventive strategy, and expands on the specific principles that guide their appropriate use. We will also summarize specific recommendations for different procedures while highlighting important aspects of different antibiotic regimens. Lastly, we will identify specific barriers to this practice and identify some health service interventions proven to improve past and current practice patterns when using antibiotic prophylaxis.
Surgical Site Infection Epidemiology and Risk Factors
It is estimated that over 40 million surgical procedures are performed every year in the United States. SSIs complicate approximately 2–5% of these procedures, representing 38% of nosocomial infections occurring in surgical patients. Risk factors for SSI can be classified as patient-related factors and local/surgical factors, and can be stratified into modifiable or potentially modifiable, and nonmodifiable risk factors. Modifiable risk factors include elective operations in the presence of associated infections, prolonged preoperative hospital stays, seromas, dead space, foreign bodies, routine drain use, among others, and can be modified with the use of good surgical practice and specific preventive strategies. Nonmodifiable risk factors are most commonly patient related and have an important effect on the incidence of SSI for each individual patient. The wound class (Appendix 1) is a relatively good predictor of SSI and has traditionally been used to estimate the risk of SSI and as a benchmark for interinstitutional comparisons. However, with the more recent understanding of SSI and its multifactorial risk factors, different predictive scores, such as the National Nosocomial Infection Surveillance (NNIS) score, have been developed to better estimate the risk of SSI for each individual patient after considering the interaction between different risk factors (Table 50-1). Specific preventive measures have been identified and are used to decrease the risk of SSI. These include minimizing the presence of microorganisms (eg, prophylactic antibiotics), and optimizing the patient's ability to fight those still present at the surgical site, during the perioperative period.
Table 50-1 National Nosocomial Infection Surveillance (NNIS) System Classification for Determining the Risk of Surgical Site Infection ||Download (.pdf)
Table 50-1 National Nosocomial Infection Surveillance (NNIS) System Classification for Determining the Risk of Surgical Site Infection
|Procedure duration ≥ 75th percentile of duration for that specific operation||1|
|Contaminated or dirty wound...|