Abstract and Introduction
Healthcare-associated infection has emerged as the most frequent complication of modern surgery, led by surgical site infection, which alone is second only to transfusion among outcomes measured by the National Surgical Quality Improvement Program (Figure 1). As a result, surgical site infections have become the leading cause of postoperative readmission and carry the greatest economic cost of all healthcare-associated infections.[1,2] At the patient level, surgical site infection increases mortality and postoperative pain and decreases quality of life, mental health, and satisfaction with medical treatment.[3–5]
Relative frequency of adverse perioperative events reported in most recent National Surgical Quality Improvement Program registry data. Healthcare-associated infection (green) is the most common overall class of postoperative complication measured by the American College of Surgeons National Surgical Quality Improvement Program, driven largely by surgical site infection, which is second only to bleeding as the most common single adverse event type reported. American College of Surgeons National Surgical Quality Improvement Program 2019 Participant Use File, https://www.facs.org/quality-programs/acs-nsqip/participant-use, accessed September 2, 2021. Detailed data descriptions available in "2019 PUF User Guide" accessible at this site.
While rates of other adverse hospital-acquired conditions monitored by the Agency for Healthcare Research and Quality (Rockville, Maryland; e.g., falls, medication errors, postoperative thromboembolism, and other classes of healthcare-associated infection) have gradually improved over time, surgical site infection has seen little progress in recent years and by some measures even worsened. The limitations of traditional infection prevention measures in achieving significant further improvement have led to a fundamental reexamination of the causes of surgical site infection, yielding new conceptual models of pathogenesis with important clinical implications. Two emerging paradigms at the center of this development are (1) the role of the patient microbiome and (2) the spread of antimicrobial resistance into the general population. The relationship of these factors to surgical site infection is influenced by a range of microbiologic, metabolic, immune, and socioecological factors (Figure 2) that introduce new layers of biologic complexity to the traditional view of "hospital-acquired infection," but provide novel avenues for prevention and quality improvement.
Conceptual model of the human microbiome and layered factors influencing health and disease. The human microbiome can be conceptualized as having nested layers spanning epidemiologic to microscopic levels of organization, each of which can influence health and clinical outcomes such as infection. Community, diet, and medical treatments are among the most significant extrinsic factors (A) impacting the composition and function of the microbiome. Acute and chronic medical conditions as well as sociodemographic differences produce additional diversity in the microbiomes of individual patients (B). Within an individual, the distribution of microbes varies at anatomic and tissue levels (C), adding a spatial context to the dynamics of infection for surgeries performed on various body regions. The function and regulation of these communities are further affected by interactions between microbes (D) and with the host (E). At the level of an individual organism (F), differences in gene content, antimicrobial resistance, and virulence factor expression are clinically important determinants of infection that can be characterized and targeted.
Other important aspects of perioperative infection prevention have been covered in recent ANESTHESIOLOGY reviews and expert guidance documents, including cleanliness of the anesthesia workspace, hand hygiene, prevention of healthcare-associated infection in critical care environments, and controversies in surgical antimicrobial prophylaxis. This review focuses specifically on the prevention of surgical site infection,[1,2] covering new scientific evidence on pathogenesis and changing clinical approaches to prevention.
Anesthesiology. 2022;137(2):252-262. © 2022 American Society of Anesthesiologists | Lippincott Williams & Wilkins