Infection
Reduce Mortality: Prevent Surgical Site Infections
Oct
Case Presentation
George is a 54-year-old man with a history of diabetes and cigarette smoking (1 pack per day for 20 years). He fractures his right ankle and undergoes open reduction and internal fixation. Two weeks later he presents to his orthopedist for follow up with complaints of constant pain in his ankle even when taking his pain medication as directed. He also reports night sweats for the past week. After the physician removes the splint and dressing, he examines the incision site, observing erythema around the incision and purulent drainage seeping around the sutures.
The physician feels that the symptoms can be managed with wound care, ice, and elevation. He advises George to take an anti-inflammatory drug along with his pain medication and follow up in 1 week. The incision is cleaned thoroughly, a new dressing is applied, and George is put into another splint and sent home.
A few days later the physician receives a call that George has been admitted to the hospital and has been diagnosed with sepsis. George declines rapidly over the next week and passes away.
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Discussion
A surgical site infection (SSI) is a postoperative complication that manifests in a surgical wound after a patient has undergone a surgical procedure. SSIs are health care-associated infections (HAIs) and are estimated to cause up to 20% of all HAIs.1 An infection must have specific characteristics to be diagnosed as an SSI: (1) it must occur within 30 days after the surgery or within 1 year if the surgery involved an implant and an organ or space infection occurs; (2) the wound must only involve skin, subcutaneous tissues, deep tissue, or distant organs; (3) and the wound must display purulent drainage from the site or isolated organisms.2 An abscess that forms around a stitch may seem alarming, but it is not classified as an SSI.1,2
Etiology
Surgical site infections are caused by contamination of the wound by a microorganism that may be introduced to the site preoperatively, intraoperatively, or postoperatively. These bacterial microorganisms organisms can vary but are usually endogenous to the human body and include Staphylococcus aureus, Escherichia coli, and coagulase-negative staphylococci.2-6 Endogenous microorganisms reside on the patient’s skin and in mucous membranes and hollow organs; as soon as a skin incision is made, risk that an endogenous microorganism will contaminate the wound increases. Exogenous organisms also include the microbes that exist on surgical instruments, the surgical team, and any other materials in the operating room (OR).2 Maintaining sterility during a procedure and keeping ORs clean is essential to reduce the number of exogenous organisms that could potentially contaminate the surgical wound.
Risk Factors
Numerous patient- and procedure-related factors can increase an individual’s risk for developing an SSI (Table 1). Patient factors include sex, comorbidities, weight, and age. For example, a retrospective cohort study recently found that men had a higher risk than women.7 Procedural risk factors include the type of operation, duration, skin preparation, and perioperative length of stay. A study from a hospital in Greece showed that SSIs are more common in procedures that take longer than 90 minutes to complete (P <0.0001).4
Surgical operations and wounds are categorized as 4 types based on risk for a postoperative wound infection: clean, clean-contaminated, contaminated, and dirty-infected (Table 2).2
Table 1. Risk Factors for Surgical Site Infection4-8
| Category | Risk Factors |
| Patient-related | Male sexCoronary heart diseaseDiabetesIncreased body mass indexMalnutritionAdvanced ageSmoking |
| Procedure-related | Dirty or contaminated procedure typesProlonged operation timePoor skin preparationProlonged perioperative hospital stay |
Table 2. Categories of Procedures Based on Risk for Surgical Site Infection2
| Category | Description |
| Clean | Lowest risk Involve no inflammation during the procedureMaintain sterilityDo not enter the GI, urogenital, or pulmonary tracts |
| Clean-contaminated | Enter the GI, urogenital, or pulmonary tracts under controlled conditions with no contamination |
| Contaminated | Involve an incision through inflamed tissue or break in sterile techniqueTraumatic wounds older than 24 hRelease from the GI urogenital, or pulmonary tracts |
| Dirty-infected | Highest risk for infection Involve a perforated hollow organ or incision through inflamed tissueTraumatic wounds older than 24 h with necrosis Injury sustained via a dirty mechanism |
| GI, gastrointestinal. |
Presentation and Diagnosis of SSIs
The Centers for Disease Control and Prevention recognizes 3 categories of SSIs: superficial incisional infections, deep incisional infections, and organ/space infections.2 Superficial infections involve only the skin and subcutaneous tissue and account for 50% of SSIs, whereas deep infections involve muscles and fascia.2 An organ or space infection can involve any organ, but it must be related to the surgery and have purulent drainage from the organ or an isolated organism from the infected tissue.2
Signs and symptoms of SSIs typically appear a few days after the procedure and must appear within 30 days after the surgery for the infection to be classified as an SSI.2 SSIs can exhibit common systemic signs and symptoms of infection, such as fever, chills, altered mental status, and increased heart rate; as well as occurrences at the surgical wound, such as pain, erythema, swelling, and the presence of pus.2 These symptoms mimic the findings of inflammation, but differ in the presence of purulent drainage, persistent fever, and separation at the wound edges (wound dehiscence).2 Clinicians should be vigilant for wound dehiscence, as it could be an indication of infection.1,9 Wound dehiscence typically occurs 5 to 10 days after surgery.1 Staff should look for any collection of fluid, such as hematoma or seroma, because these could be early signs of wound dehiscence.1 Erythema, or redness, is very commonly seen with an SSI and should be examined further; however it does not always mean an infection is present.10
Source: National Library of Medicine/Mohan Rangaswamy, MBBS
If a wound is clinically suspicious for infection and involves discharge, a microbiology sample should be taken. The sample will be tested to confirm the presence of infection, identify the organism, and aid in determining treatment options based on the antibiotic resistance or sensitivity of the organism.2 Before a sample is taken, the wound should be prepared with sterile gauze and sterile normal saline.12 Wound samples are collected aseptically using sterile cotton swabs, which are placed into a sterile test tube and mixed with sterile normal saline.12 The samples are immediately taken to a microbiology lab and should be processed within 30 minutes.12 In the case of a processing delay, the handler should refrigerate the sample to store it until it is ready to be processed.1 In cases of suspected a deep infection, further evaluation with ultrasound, computed tomography, or magnetic resonance imaging may be helpful.2
Management
For systemic symptoms (eg, fever) or an infection that is starting to progress, an antibiotic should be prescribed based on the most likely organism, the patient’s allergies, and the local antibiotic resistance profile.1 If the antibiotic does not reduce local symptoms of a superficial SSI, it may be necessary to open up part of the wound under sterile conditions to let it heal by secondary intention.1 For a deep SSI, the incision should be reopened and infected tissue debrided.2 During such a procedure, the incision is typically made over the original incision scar and all pus and devitalized and necrotic tissue is debrided and suctioned out of the wound.13 If an implant is present, any biofilm that has formed should also be debrided and removed.13 In order to prescribe the most effective antibiotic for the treatment of the infection, it is necessary to take bacterial samples from the necrotic tissue and perform cultures and antibiotic sensitivity testing.13 Once the wound is adequately debrided and irrigated, it can be closed using primary intention, and specific antibiotics should be prescribed once the cultures come back.13
Prevention
Extensive measures are taken to prevent SSIs at all costs. These include the use of prophylactic antibiotics, which are typically given 30 to 60 minutes before a surgery to allow the medication to reach therapeutic levels in the tissue by the time of the first incision.2 Recommended agents for prophylaxis are narrow-spectrum and cover the microorganisms expected to be encountered for the type of operation being performed.2 Clean and clean-contaminated procedures require coverage for Staphylococci, typically with cephazolin or vancomycin with metronidazole, cefoxitin, or ertapenem.2 Contaminated and dirty-infected procedures don’t require prophylactic antibiotics as patients undergoing these types or procedures are typically already on antibiotics.2
Before a procedure, standard practice involves cleaning the incision site with an antiseptic, which thought to be more effective when mixed with alcohol.14 Alcohol is bactericidal and when combined with a preparatory agent, produces rapid and persistent antisepsis.15 Types of antiseptic solutions include chlorhexidine–alcohol and iodine–alcohol mixtures; comparative efficacy research is ongoing.14 Preoperative antiseptic showers are sometimes recommended, but evidence that this practice reduces the risk for SSIs is scarce.14 Surgeons and surgical scrub technicians also use a scrub solution with an antiseptic agent on their hands and forearms before the operation, scrubbing for 2 to 5 minutes depending on the type of surgery.15
During a procedure, the surgical team practices sterile techniques to prevent SSIs. The cleanliness and air temperature of the OR are constantly monitored, surfaces are disinfected, and instruments and drapes are sterilized before being brought in.15 When the surgical team uses gloves, double-gloving with 2 pairs can help reduce the risk for SSIs.15 Maintaining sterility throughout the procedure is crucial to avoid introducing any microbes into the surgical wound. In cases of glove contamination or perforation, the affected team member must immediately change gloves and potentially repeat the surgical scrub.15
Patient education is extremely important for providers to emphasize in all areas of practice. When recommending patients for surgery, it is imperative to consider risk factors that may increase their chances of developing an SSI—especially modifiable risk factors, such as weight, diabetes, and smoking status.2 As a preoperative prevention measure, the patient with a high BMI may be advised to lose weight, or the patient who smokes cigarettes may be advised to quit in order to decrease their risk for developing an SSI (as well as many other health issues). Before a patient with diabetes is scheduled for surgery, they may be encouraged to control their diabetes and hemoglobin A1c via medications or lifestyle change. These prevention methods should be practiced regularly in elective surgeries, as they can make a drastic difference in the patient’s infection risk.
Patients and caregivers should also be educated about how to care for the surgical site incision. The postoperative wound dressings should be left on the incision for at least 48 hours after surgery, during which time, patients should be advised to avoid getting the dressing and wound site wet.9 If a dressing begins to fall off or becomes saturated with blood or exudate, the patient or caregiver should remove the dressing and apply a new, clean dressing using an aseptic technique and avoid touching the incision.9 Patients or caregivers with concerns about an SSI developing should be advised to take precautions and call their providers or immediately report to the emergency department.
Importantly, at the time of discharge, patients are often weaning off sedative medications and may not remember the instructions given to them. Thus, providers should be sure to engage caretakers in the discharge conversation. This will also help the caretaker assist the patient with wound care if necessary.
Prognosis
More than one-third of postoperative deaths are attributed to SSIs.12,14 These serious infections often have poor prognosis and can also lead to a variety of complications affecting different organ systems or the entire body. Local complications include delayed healing, cellulitis, abscess, and osteomyelitis; systemic complications include bacteremia and sepsis.2 SSIs are associated with longer hospitalization stays, increased care requirements, higher costs for the patient, and higher rates of morbidity and mortality.12,14 The medium length of stay for a patient with an SSI is 11 days, which can cause a significant financial and physical burden.16 The implementation of preventative measures to avoid SSIs is critical, as these infections continue to challenge patients and health care facilities.
Conclusion
Despite the extensive measures currently in place to prevent SSIs, the mortality rate associated with these infections is 3%, and 75% of those deaths are directly attributable to the SSI.17 It is fundamental for health care workers to understand the extent of the consequences of SSIs, increase their knowledge and motivation to implement precautions, and take prevention recommendations very seriously. Early recognition is also of extreme importance to quickly manage SSIs before they progress to serious complications.
References
1. Sinha S. Management of post-surgical wounds in general practice. Aust J Gen Pract. 2019;48(9):596-599. doi:10.31128/AJGP-04-19-4921
2. Zabaglo M, Sharman T. Postoperative wound infection. In: StatPearls [Internet]. Treasure Island, FL: StatPearls Publishing; 2023.
3. Kolasiński W. Surgical site infections – review of current knowledge, methods of prevention. Pol Przegl Chir. 2018;91(4):41-47. doi:10.5604/01.3001.0012.7253
4. Papadopoulos A, Machairas N, Tsourouflis G, et al. Risk factors for surgical site infections in patients undergoing emergency surgery: A single-centre experience. In Vivo. 2021;35(6):3569-3574. doi:10.21873/invivo.12660
5. Magill SS, O’Leary E, Janelle SJ, et al. Changes in prevalence of health care-associated infections in U.S. hospitals. N Engl J Med. 2018;379(18):1732-1744. doi:10.1056/NEJMoa1801550
6. Isik O, Kaya E, Dundar HZ, Sarkut P. Surgical site infection: Re-assessment of the risk factors. Chirurgia (Bucur). 2015;110(5):457-61.
7. Cohen B, Choi YJ, Hyman S, Furuya EY, Neidell M, Larson E. Gender differences in risk of bloodstream and surgical site infections. J Gen Intern Med. 2013;28(10):1318-25. doi:10.1007/s11606-013-2421-5
8. Cheng H, Chen BP, Soleas IM, Ferko NC, Cameron CG, Hinoul P. Prolonged operative duration increases risk of surgical site infections: A systematic review. Surg Infect (Larchmt). 2017;18(6):722-735. doi:10.1089/sur.2017.089
9. Yao K, Bae L, Yew WP. Post-operative wound management. Aust Fam Physician. 2013;42(12):867-870.
10. Jiang Z, Ardywibowo R, Samereh A, et al. A roadmap for automatic surgical site infection detection and evaluation using user-generated incision images. Surg Infect (Larchmt). 2019;20(7):555-565. doi:10.1089/sur.2019.154
11. Rangaswamy M. Minimising complications in abdominoplasty: An approach based on the root cause analysis and focused preventive steps. Indian J Plast Surg. 2013;46(2):365-376. doi:10.4103/0970-0358.118615
12. Misha G, Chelkeba L, Melaku T. Bacterial profile and antimicrobial susceptibility patterns of isolates among patients diagnosed with surgical site infection at a tertiary teaching hospital in Ethiopia: a prospective cohort study. Ann Clin Microbiol Antimicrob. 2021;20(1):33. doi:10.1186/s12941-021-00440-z
13. Yin D, Liu B, Chang Y, Gu H, Zheng X. Management of late-onset deep surgical site infection after instrumented spinal surgery. BMC Surg. 2018;18(1):121. doi:10.1186/s12893-018-0458-4
14. Leaper D, Ousey K. Evidence update on prevention of surgical site infection. Curr Opin Infect Dis. 2015;28(2):158-63. doi:10.1097/qco.0000000000000144
15. Anderson DJ, Podgorny K, Berríos-Torres SI, et al. Strategies to prevent surgical site infections in acute care hospitals: 2014 update. Infect Control Hosp Epidemiol. 2014;35(6):605-27. doi:10.1086/676022
16. Taherpour N, Mehrabi Y, Seifi A, Eshrati B, Hashemi Nazari SS. Epidemiologic characteristics of orthopedic surgical site infections and under-reporting estimation of registries using capture-recapture analysis. BMC Infect Dis. 2021;21(1):3. doi: 10.1186/s12879-020-05687-z
17. Awad SS. Adherence to surgical care improvement project measures and post-operative surgical site infections. Surg Infect (Larchmt). 2012;13(4):234-7. doi:10.1089/sur.2012.131
