After a sigmoidectomy performed with previously used instruments, which measure reduces surgical site infection risk?

Maintain Normothermia to Reduce Surgical Site Infection Risk

The most effective measure to reduce surgical site infection risk after sigmoidectomy with previously used instruments is maintaining intraoperative normothermia (Option B). The surgical instruments have already been used in the completed procedure, so sterilization for "upcoming surgery" is irrelevant to this patient's infection risk, and postoperative antibiotics do not prevent SSI when given after wound closure.

Why Normothermia is the Correct Answer

Intraoperative normothermia decreases the rate of SSI with Grade 1A evidence, and active warming devices in the operating room are useful to maintain normothermia and reduce SSI (Grade 1B). 1

Mechanism of Protection

• Perioperative hypothermia increases SSI through reflex vasoconstriction and mediated local immunosuppression. 1
• Vasoconstriction reduces partial oxygen pressure at the surgical site, which lowers resistance to infections in animal models. 1
• Core body temperature regulation is disrupted during major surgery due to anesthesia affecting the temperature setpoint and increasing heat loss through vasodilatation. 1

Supporting Evidence

• In a landmark RCT by Kurz et al., active body surface warming reduced SSI from 18.8% (18/96) to 5.8% (6/104), P = 0.009. 1
• Melling et al. demonstrated SSI reduction from 13.7% (19/139) with placebo to 4.7% (13/277) with warming interventions, P = 0.001. 1
• A Cochrane review found significant SSI decrease with active warming (RR 0.36,95% CI 0.20-0.66; P = 0.0008). 1
• Multiple meta-analyses confirm this risk reduction, and the recommendation has been implemented in several national and international guidelines. 1

Why Other Options Are Incorrect

Option A: Postoperative Antibiotics

• Postoperative antibiotics administered after wound closure do not prevent SSI. 1
• Prophylactic antibiotics must be given preoperatively according to evidence-based standards to be effective. 1
• The optimal timing is before incision, not after the procedure is completed. 1

Option C: Sterilization in Upcoming Surgery

• This option is nonsensical in the clinical context—the sigmoidectomy has already been performed.
• While sterilization of surgical equipment according to published guidelines is a recommended intervention with moderate evidence for SSI prevention, it applies to preparing instruments before surgery, not after. 1
• The question asks what measure "now helps reduce" infection risk in this patient who has already undergone surgery.

Option D: No Effect on the Wound

• This is factually incorrect, as multiple evidence-based interventions can reduce SSI risk even after the procedure. 1

Critical Clinical Context

Common Pitfall to Avoid

• Do not confuse prophylactic measures (given before/during surgery) with therapeutic interventions (given after surgery for established infection). 2
• Antibiotics for SSI treatment require specific indications: temperature ≥38.5°C, heart rate ≥100 bpm, erythema ≥5 cm from wound edge, signs of organ dysfunction, or immunocompromised status. 2
• Simple postoperative antibiotics without these indications provide no benefit and promote antimicrobial resistance. 2

Additional Preventive Measures (For Context)

While normothermia is the answer to this specific question, other evidence-based intraoperative SSI prevention strategies include:

• Triclosan-coated sutures significantly reduce SSI prevalence. 1
• Wound protectors, particularly dual-ring devices, reduce incisional SSI. 1
• Negative-pressure wound therapy may reduce postoperative wound complications in high-risk patients. 1, 3
• Chlorhexidine-based skin antisepsis is superior to povidone-iodine. 1, 4

The evidence unequivocally supports maintaining normothermia as a proven, high-quality intervention to reduce SSI risk in this clinical scenario. 1, 5, 4