Time-Dependent Effect of Chlorhexidine Surgical Prep
ARMY INST OF SURGICAL RESEARCH FORT SAM HOUSTON TX
Pagination or Media Count:
Despite continued advances in preoperative preventive measures and aseptic technique, surgical site infections remain a problem. The purpose of this study was to evaluate the time-dependent effectiveness of chlorhexidine, a common surgical preparation solution, at various concentrations. Agar plates containing a MuellereHinton medium were inoculated with Staphylococcus aureus lux bacteria. The bacteria are genetically engineered to emit photons, allowing for quantification with a photon-counting camera system. Standardized amounts of aqueous chlorhexidine at three different concentrations group 14 group 22 group 30.4 were applied to the agar plates and comparisons in bacterial reduction were made. After 2 min of contact time, groups 1 and 2 had similar reductions in bacterial load with 30 bacterial load remaining in each group P0.512, whereas group 3 had a significantly higher bacterial load 33 when compared to both groups 1 and 2 1 vs 3, P 0.0001 2 vs 3, P0.0002. The bacterial load in all three groups continued to decrease out to the final time point 1 h with group 1 having the least amount of bacterial load remaining, 9 P 0.0001 and group 3 with the highest bacterial load remaining, 19 P 0.0001. This study demonstrates two key results first, dilution of chlorhexidine correlates directly with its bactericidal activity second, its effectiveness is directly related to its contact time. Based on the results of this study, the authors recommend using 4 chlorhexidine for surgical site preparation and allowing a minimum of 2 min of contact time prior to making the skin incision.
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