Prevention and Control of Surgical Site Infections

Step One: Definition and Epidemiology
Surgical site infection (SSI) refers to an infection occurring at the surgical incision or in the organ/space involved in the surgery. It is one of the most common types of healthcare-associated infections following surgery. Based on the depth of involvement, SSIs are classified into: Superficial incisional SSI (involving only skin and subcutaneous tissue), Deep incisional SSI (involving deeper soft tissues such as fascia and muscle layers), and Organ/space SSI (involving any anatomical part manipulated during the operation, such as the abdominal cavity or joint space). Epidemiologically, the incidence of SSI varies depending on the type of surgery, patient's underlying condition, and the hospital's infection control level. SSIs can lead to prolonged hospital stays, increased medical costs, and higher mortality rates, making them a core monitoring indicator for surgical care quality.

Step Two: Pathogenesis and Risk Factors
The occurrence of SSI results from the interaction of microbial contamination, surgical trauma, and host defense. Pathogens mainly originate from the patient's skin flora (e.g., Staphylococcus aureus), the operating room environment, and the hands or instruments of healthcare personnel. Risk factors are divided into three categories:

1. Patient-related: Advanced age, malnutrition, obesity, diabetes, immunosuppression, remote site of infection, tobacco use, prolonged preoperative hospital stay.
2. Surgery-related: Type of surgery (e.g., colorectal surgery), prolonged operative duration (>2 hours), extensive surgical trauma, tissue ischemia/necrosis, foreign body implantation (e.g., prosthesis), intraoperative hypothermia, unnecessary use of electrocautery, surgical team skill.
3. Microorganism-related: Contaminated or clean-contaminated wound class, inadequate preoperative skin preparation, inappropriate antimicrobial use.

Step Three: Evidence-Based Prevention and Control Measures (Preoperative Phase)

1. Patient Preparation: Actively treat remote site infections. Discontinue tobacco use for at least 30 days before elective surgery. Control blood glucose (especially for diabetic patients). Preoperative bathing with antimicrobial soap or chlorhexidine-based solution.
2. Hair Removal: Do not remove hair unless necessary. If removal is required, use electric clippers immediately before surgery; razors are prohibited.
3. Perioperative Antimicrobial Prophylaxis: Select a single dose of an appropriate-spectrum agent (typically a first- or second-generation cephalosporin) based on surgery type. Administer intravenously within 60-120 minutes before skin incision to ensure effective bactericidal tissue concentration at the time of incision. Re-dose if surgery duration exceeds twice the drug's half-life or with significant blood loss.
4. Surgical Team Hand Preparation: Perform surgical hand antisepsis strictly according to protocol using suitable antimicrobial hand scrub.

Step Four: Evidence-Based Prevention and Control Measures (Intraoperative Phase)

1. Operating Room Environment: Maintain positive pressure ventilation, limit personnel traffic and door openings. Ensure effective air filtration systems.
2. Aseptic Technique: Strictly adhere to aseptic practice, including proper draping and wearing sterile gowns and gloves.
3. Patient Warming: Use warming devices (e.g., forced-air warmers, warming blankets) to maintain normal patient core temperature and avoid hypothermia.
4. Surgical Technique: Handle tissue gently, achieve effective hemostasis, remove devitalized tissue, eliminate dead space, use appropriate suture materials.
5. Incision Protection: Consider using wound protectors in surgeries with high contamination risk.
6. Glycemic Control: Continuously monitor and control blood glucose within an appropriate range during surgery.
7. Oxygen Supply: During general anesthesia with endotracheal intubation, consider increasing the fraction of inspired oxygen (FiO2) to improve tissue oxygenation and aid neutrophil bactericidal function.

Step Five: Evidence-Based Prevention and Control Measures (Postoperative Phase)

1. Incision Care: Protect the incision with a sterile dressing for 24-48 hours postoperatively. Educate patients and families on keeping the incision clean and dry, and performing hand hygiene before and after contact.
2. Monitoring and Identification: Assess the incision daily for signs of infection (e.g., redness, swelling, heat, pain, purulent discharge). Establish follow-up mechanisms for discharged patients, as SSI can occur after discharge.
3. Antimicrobial Stewardship: Postoperative prophylactic antimicrobials typically should not exceed 24 hours and should not be prolonged due to drainage tubes. Once SSI is diagnosed, targeted therapy should be based on microbiological culture and susceptibility results.
4. Data Surveillance and Feedback: The hospital infection control department should regularly monitor SSI rates for different surgical categories and provide feedback to surgical departments for quality improvement.

Step Six: Special Considerations and Emerging Challenges

1. Drug-Resistant Infections: For carriers of organisms like Methicillin-resistant Staphylococcus aureus (MRSA), preoperative prophylaxis with agents like vancomycin may be required.
2. Ambulatory and Minimally Invasive Surgery: The SSI risk profile may differ, requiring adjusted monitoring and prevention strategies.
3. Care Bundles: Packaging multiple evidence-based preventive measures (e.g., the aforementioned preoperative and intraoperative measures) into a "bundle" that must be fully implemented can significantly reduce SSI rates.
4. Quality Indicator: SSI rate is a key indicator for measuring surgical and overall hospital quality, often linked to reimbursement and hospital ratings.