Surgical site infection (SSI) is the third most common nosocomial infection; it occurs in 5% to 16% of hospitalized patients1,2 and is more common when patients undergo colon/rectal surgery.3 This is a major problem due to associated higher morbidity and mortality rates (2- to 11-fold risk of death)4 as well as increased cost and prolonged hospital stay for patients.2,5-7
Prospective, randomized, double-blinded studies have found that in most SSI, the source of pathogens is endogenous, originating from the natural flora of the skin, mucous membranes, or hollow viscera of the patient; epidemiologic studies8-12 report the pathogen most frequently isolated is Staphylococcus aureus, followed by coagulase-negative staphylococci, Enterococcus spp, Escherichia coli, and Pseudomonas aeruginosa. However, the National Healthcare Safety Network9 epidemiologic review, stratified by type of surgery, reported abdominal surgery-related SSIs have a more frequent incidence of E coli (18.6%), followed by S aureus (12.7%), E faecalis (7.8%), coagulase-negative staphylococci (6.4%), and P aeruginosa (6.1%).
Several reviews13,14 on SSI based on randomized trials and epidemiologic studies have described the influence of different patient, surgical, and environmental variables such as patient age, nutritional status, laboratory values, comorbidities, antiseptic techniques and solutions used, type of surgery performed, region and system of the body involved, duration of surgery, operating room ventilation, and adequate sterilization of instruments; these factors may increase the risk for SSI.2,3,15-20 Due to changes and developments in medicine aimed at performing more outpatient surgeries and enabling shorter hospital stays, SSI surveillance and monitoring has become more complex. In reviews and forums,21,22 experts agree that because most hospitals do not have the resources to monitor the evolution of all surgical patients, and the level of surveillance is different depending on the risk of procedures, SSI rates may be underreported.
Degree of surgical site (SS) contamination classifications were initially developed by the American College of Surgeons and then adapted by the Centers for Disease Control and Prevention (CDC) in 1985; currently, a globally accepted consensus classifies SS as Grade I (clean), Grade II (clean-contaminated), Grade III (contaminated), and Grade IV (dirty/infected). Guidelines and evidence-based recommendations have directly correlated the grade of contamination or wound classification with the subsequent probability of infection.15-18 [Editor’s note: As of January 2017, the CDC is using “classes” in lieu of “groups.” This article was researched and written before the change.]
Various techniques and solutions have been implemented for irrigation purposes to prevent and avoid the formation of abscesses and infection of tissues and cavities in contaminated SSs (eg, grades II to IV).23 A nosocomial infection rate of 9.0% among almost 8000 patients was reported in a 1-year prospective surveillance study conducted in a general hospital (Durango, Mexico) by Tinoco et al.24 Vilar-Compte et al25 performed an 18-month prospective study involving 3372 surgeries performed in their hospital (Mexico City, Mexico) and reported a general SSI incidence of up to 9.28% for grades I through IV (7.35%, 10.5%, 17.3%, and 21.5%, respectively). Of these, 27.16% were diagnosed during the hospital stay and 72.84% after hospital discharge, underscoring the need for extended monitoring of patients.19,24,25
Although experimental studies26,27 have demonstrated the antimicrobial and fungicidal activity of local anesthetics and the molecular and cellular mechanisms involved, the effectiveness of products in preventing SSI is not without controversy. Animal models27 have shown an excessive inflammatory response and a decrease in the incidence of SSI when antimicrobials are provided. In their randomized clinical trial in 2011 comparing wound irrigation with 2% lidocaine versus saline solution among 22 patients from a rural clinic, Noriega-Salas et al23 noted a decrease in the frequency of SSI in grade II and grade III wounds. The authors reported a SSI incidence of 27% (3 patients) in the saline group versus none in the lidocaine group. Although a statistical difference was observed, the sample size was limited.
Currently, Mexico does not have a national data repository. Some institutions report their prevalence independently through research. The General Hospital of Durango reported a SSI incidence rate of 4.9% in the surgery department; E coli (36%) and P aeruginosa (18%) were the most common pathogens.24 The Instituto Nacional de Cancerología25 reported E coli as the most common pathogen, followed by coagulase-negative staphylococci. This study characterized SSI incidence according to the procedure performed and the most frequently isolated pathogens and emphasized the need for surveillance up to postoperative (postop) day 30. Internationally, S aureus seems to be the most common microorganism isolated.2 A general hospital in Mexico City recently reported a SSI incidence of 67.8%, with S aureus (70%), coagulase-negative staphylococci (15.3%), and E coli (9.4%) the most common strains.19 This along with other epidemiologic studies19,25,28 noted the importance of establishing monitoring programs after patient discharge.
Hospitals and institutions in Mexico need to improve SSI surveillance and data reports. The General Hospital of Ciudad Victoria, “Dr. Norberto Treviño Zapata,” does not have a well-established SSI surveillance or statistical data system. The objectives of this study were to: 1) assess the incidence of SSI in the general surgery department, and 2) compare the 30-day postoperative infection outcomes of saline irrigation to saline irrigation followed by 2% lidocaine application.