Iodine toxicity treated with hemodialysis and continuous venovenous hemodiatiltration

Continuous mediastinal irrigation with povidone-iodine is used commonly for treating severe postoperative mediastinitis. However, concurrent iodine toxicity has been reported, particularly in patients with renal dysfunction (likely because absorbed iodine is renally excreted). The authors were consulted on a 45-year-old patient with mediastinitis who had renal and hepatic dysfunction while being treated with mediastinal irrigation of povidone-iodine. The povidone-iodine irrigation was discontinued because he had toxic plasma iodine levels. Despite this, his condition worsened, and the iodine levels remained elevated. Thus, hemodialysis (HD) was initiated using high-flux membranes followed by continuous venovenous hemodiafiltration (CVVHDF; 2 L/h of hemofiltration and 2 L/h of HD). Plasma and effluent iodine levels were measured repeatedly to determine iodine clearance by these 2 modalities (HD, 120 mL/min; CVVHDF, 37 mL and 44 mL/min on days 1 and 2, respectively). Hepatic and renal functions improved with decreasing plasma iodine levels. Based on this experience and after reviewing the literature the authors conclude that: (1) iodine irrigation can increase blood iodine levels significantly, especially in the setting of renal failure, and lead to increased morbidity and mortality; (2) plasma iodine levels should be monitored in patients with renal insufficiency; and (3) HD and CVVHDF are effective at clearing iodine. The authors suggest that patients that are at high risk or already developing signs of iodine toxicity should have the iodine irrigation discontinued and may benefit from renal replacement therapy (RRT). Alternatively, concomitant RRT during iodine irrigation may be attempted to maintain the systemic iodine levels at nontoxic levels.