What is the preferred preoperative skin antisepsis for a patient with hypertension, type 2 diabetes mellitus, and stage 2 colon adenocarcinoma undergoing colon resection: chlorhexidine gluconate (CHG) in alcohol or povidone iodine in alcohol?

Chlorhexidine Gluconate in Alcohol is the Preferred Preoperative Skin Antisepsis for Colon Resection

Chlorhexidine gluconate in alcohol should be used as the preoperative skin antisepsis for KR's colon resection to prevent surgical site infection. 1, 2, 3

Evidence-Based Rationale

Superiority of Chlorhexidine-Alcohol Combinations

Chlorhexidine gluconate (CHG) in alcohol provides superior protection against surgical site infections compared to povidone iodine. The evidence supporting this recommendation includes:

• Meta-analysis data shows that CHG-alcohol solutions with concentrations of 0.5% or 2.0% have significantly lower risk ratios for surgical site infections compared to povidone-iodine (RR = 0.71 and RR = 0.52, respectively) 2

• A landmark study demonstrated that preoperative cleansing with chlorhexidine-alcohol is superior to povidone-iodine for preventing surgical site infections after clean-contaminated surgery, with overall infection rates of 9.5% vs. 16.1% 3

• Enhanced Recovery After Surgery (ERAS) Society guidelines specifically recommend chlorhexidine-alcoholic solutions for reducing surgical site infections 1

Concentration Considerations

While both 0.5% and 2.0% CHG in alcohol are effective:

• Meta-analysis evidence indicates that 0.5% CHG in alcohol is sufficient to prevent SSIs 2
• No significant additional benefit has been observed with CHG concentrations higher than 2.0% 2

Patient-Specific Factors for KR

For KR specifically, chlorhexidine-alcohol is particularly appropriate because:

• She has diabetes mellitus, which increases her risk for surgical site infections
• She is undergoing a clean-contaminated procedure (colon resection)
• She has no documented allergies to chlorhexidine

Application Protocol

To maximize effectiveness and safety:

1. Apply chlorhexidine gluconate in alcohol using standardized back-and-forth strokes covering the entire surgical field
2. Allow the solution to completely dry before draping (typically 3 minutes)
3. Avoid pooling of the solution to prevent skin irritation and potential chemical burns

Important Precautions

• Keep away from eyes, ears, and mouth as chlorhexidine can cause serious and permanent eye injury 4
• Do not use on open wounds that involve more than superficial layers of skin 4
• Ensure proper drying time before electrocautery use to prevent fire hazards from alcohol-based solutions
• Monitor for skin reactions and discontinue use if irritation or sensitization occurs 4

Recent Evidence Challenging Previous Assumptions

While the preponderance of evidence supports chlorhexidine-alcohol, a recent 2024 multicenter randomized clinical trial by Widmer and colleagues found that povidone iodine in alcohol was noninferior to chlorhexidine gluconate in alcohol for preventing SSIs after cardiac or abdominal surgery (5.1% vs. 5.5% infection rates) 5.

However, this single study does not outweigh the larger body of evidence supporting chlorhexidine-alcohol's superiority, particularly for abdominal surgery in patients with comorbidities like diabetes.

Conclusion

Based on the strongest available evidence prioritizing morbidity and mortality outcomes, chlorhexidine gluconate in alcohol remains the preferred preoperative skin antiseptic for KR's colon resection, with particular attention to proper application technique and safety precautions.