How to remove accumulated iodine in burn-injured patients

Absorption of large quantities of iodine, as induced by the use of topical antimicrobial povidone-iodine in burn-injured patients, may cause metabolic and electrolyte abnormalities as well as renal failure. To diminish iodine levels, haemodialysis was previously reported to be a suitable therapy. We therefore studied the kinetics of iodine in order to define the most optimal dialysis strategy.

Two patients with elevated iodine levels (93.6 and 81.2 mg/L) underwent continuous dialysis with blood flows Q(B) 150 and 120 mL/min. Blood was sampled from the inlet and outlet dialysis line at several time points during a 7-h and 39-h 10-min period, respectively. Samples were analysed for iodine with the inductively coupled plasma mass spectrometry (ICPMS) method. Kinetic analysis was performed using one and two compartmental models, deriving kinetic parameters: plasmatic volume V(1), extraplasmatic volume V(2) and intercompartmental clearance K(12). The calibrated kinetic model of Patient 2 was further used to simulate different dialysis strategies: 12-h per day with Q(B) 240, 6-h per day with Q(B) 480 and 240, and 12-h every 2 days with Q(B) 240. For each strategy, the mean average plasmatic and extraplasmatic concentration (TAC(p) and TAC(ep)) was calculated during 48 h.

Iodine seemed to follow one compartmental kinetics when serum sample collections were limited to the first 7 h of dialysis (Patient 1), but iodine appeared to be distributed in two volumes (V(1)=19.4 L, V(2)=38.0 L and K(12)=55 mL/min) when a longer observation period was taken into account (Patient 2). The simulations disclosed that 12-h dialysis per day with Q(B) 240 or continuous dialysis with Q(B) 120 resulted in the lowest TAC(p) (18.2 and 19.0 microg/L) and TAC(ep) (34.4 and 36.1 microg/L).

In patients with elevated iodine levels, especially when associated with renal failure, haemodialysis with a minimum 12-h duration with sufficient blood flow should be the first choice to remove iodine.