Serum selenium in critically ill patients: Profile and supplementation in a depleted region

Background General selenium supplementation to intensive care unit (ICU) patients in regions with selenium-rich soil does not improve outcomes. Still selenium supplementation may reduce morbidity and mortality in patients with low-serum selenium concentration (S-Se) in selenium-poor areas who respond to treatment. The primary aim of this observational study was to investigate S-Se in a selenium-deficient region at time of intensive care admission, and in addition to monitor S-Se during high-dose selenium supplementation for safety. Methods We measured S-Se in 100 consecutive patients admitted to a tertiary general ICU. After initial sampling, high-dose intravenous (iv) selenium supplementation was administered up to 20 days. Results At admission, in 95% of the cases, S-Se was below the saturation level for selenoenzymes, in 91%, below the Swedish reference level, and in 71%, below the level where selenoenzyme function may be impaired. At day 5 of substitution, all patients still remaining in the ICU (n = 26) were within the range for enzyme function, 12% were below reference, and 24% did not reach full enzymatic saturation. At day 10 and forward, all patients were within target for treatment. No patients were at risk for toxic S-Se concentration. Conclusions S-Se concentration was substantially lower compared to normal values at ICU admission in this cohort of unselected Swedish critical care patients. Selenium supplementation restituted S-Se to levels corresponding to enzymatic saturation and the Swedish reference interval for all subjects remaining in the ICU on day 5.