Preoperative antimicrobial preparation of the colon with povidone-iodine enema

To evaluate the efficacy of povidone-iodine enemas as a means of preoperative bowel preparation in colonic surgery, 52 mongrel dogs were randomized into two groups. Group 1 received oral neomycin-erythromycin combinations in the usual clinical doses, while Group 2 received a single 500-ml 5 percent povidone-iodine enema preoperatively. Quantitative bacterial counts obtained at the time of colonic resection revealed that povidone-iodine was equally effective in reducing the anaerobes, but was significantly superior to neomycin-erythromycin combinations in reducing the aerobic colony counts. Bursting pressures, measured three weeks later, were equal in both groups. Despite elevated blood-iodine levels, no systemic toxicity was noted in Group 2 dogs. It is concluded that half-strength povidone-iodine, given as a single enema preoperatively, is equally effective as standard preoperative antibiotic preparations and may be the ideal preparation in urgent or emergency colonic operations. Due to reported toxicity of povidone-iodine in burn wounds, we suggest that initial trials be limited to emergency cases where the potential benefits possibly will be greater than the theoretic risk of iodine toxicity.