Iodine absorption after intraoperative bowel irrigation with povidone-iodine

PURPOSE: Povidone-iodine is a commonly used intrarectal tumoricidal agent i n patients undergoing colorectal surgery. The aim of this study was to asse ss systemic absorption of total iodine and its effect on thyroid function a fter intrarectal application. METHODS: Twenty patients with carcinoma of th e rectum received intraoperative irrigation with either povidone-iodine (Gr oup A; n = 10) or physiologic saline (Group B; n = 10). Ten patients with c arcinoma of the sigmoid colon (group C) were treated the same as Group A. E lectrolyte, total iodine, triiodothyronine, thyroxine, and thyroid-stimulat ing hormone values were measured in serum preoperatively and before intraop erative irrigation and immediately, ten minutes, 1 hour, 6 hours, 24 hours, and two weeks after irrigation. RESULTS: No significant changes occurred i n serum electrolytes. A significant uptake of the total iodine was demonstr ated in each group. Total iodine levels examined immediately, ten minutes, and one hour after irrigation in Group C were significantly higher than tho se examined in Group B. Maximum values were obtained one hour after irrigat ion in Groups A and B and six hours after irrigation in Group C. No signifi cant changes occurred in triiodothyronine, thyroxine, and thyroid-stimulati ng hormone levels among the three groups. The decrease in triiodothyronine levels after surgery was demonstrated in each group. We noted a decrease af ter surgery in thyroxine levels for Groups A and B and in thyroid-stimulati ng hormone levels for Group B. Those hormones were not affected by the admi nistration of povidone-iodine. CONCLUSION: High serum levels of iodine did not cause organ toxicity, suggesting that a single use of intraoperative bo wel irrigation with povidone-iodine may be performed with practically negli gible risk.