Effect of selenium supplementation on biochemical markers and outcome in critically ill patients

This study aimed to assess the effect of high dose selenium (Se) supplementation on Se status in blood, oxidative stress, thyroid function and possible effects on requirement for renal replacement therapy (RRT) in severely septic patients admitted to the intensive care unit (ICU).

This prospective single-centre study was carried out in 40 septic ICU patients who were randomized to high dose Se (Se+ group, N=18 (474, 316, 158 microg/day), each for 3 consecutive days followed by a standard dose of 31.6 microg/day of Se given as sodium selenite whereas the control group (Se-, N=22) received only the standard dose of Se. Plasma Se, glutathione peroxidase (GSH-Px), F2 isoprostanes, thyroid function tests (total T4 and total T3), C-reactive protein (CRP) and red blood cell (RBC) GSH-Px were estimated on day 0, 3, 7, 14.

In the Se+ group, plasma Se increased by day 3 and 7 (P<0.0001) and day 14 (P=0.02), plasma GSH-Px increased by day 3 and 7 (P=0.01) as compared to Se- group. There was a significant negative correlation between plasma Se and SOFA (sepsis related organ failure assessment) (r=-0.36, P=0.03) along with low plasma Se and high CRP at the time of admission. Requirement for renal replacement therapy was not significantly different between the groups.

Although high dose Se supplementation increased plasma Se and GSH-Px activity, it did not reduce oxidative damage or the requirement for RRT. Se levels in blood are influenced by redistribution and severity of illness and therefore should be interpreted with caution.