Selenium and its substitution in critically ill patients

Introduction

In patients in the ICU of the Anaesthesiological Clinic we find generally decreased selenium (Se) in serum, which does not normalise under supplementation with standard doses of Se. Some recently published papers demonstrate that supplementation of high doses of Se significantly decreases the mortality of patients in critical states. We therefore started in a prospective clinical trial the supplementation of Se in high doses and followed its influence on selected laboratory parameters, on the mean arterial pressure (MAP) and on the survival of critically ill patients.

Methods

In a randomised clinical trial, 61 ICU patients were followed. Thirty-five of them (group 1) received standard daily doses of Se 0.4–0.8 mmol (30–60 mg) as part of nutritional support, 25 patients (group 2) received additional Na-selenite containing Se through infusions in the amount of 12.7 mmol (1000 mg) on the first day, and later 6.7 mmol (500 mg) daily until the 14th day. In blood samples, the following were examined every other day during this period: Se, prealbumin, albumin, cholesterol, C-reactive protein, procalcitonin, IgM. Altogether, 150 examinations in group 1 and 119 in group 2 were performed. Moreover, the glutation peroxidase (GSHPx) was investigated 67 times in group 1 and 34 times in group 2.

Results

Presented as medians and 95% CIs. Serum Se levels (μmol/l) group 1 = 0.292 (0.27; 0.33), group 2 = 0.57 (0.51; 0.72), P < 0.01; GSHPx (U/l) group 1 = 4059 (3854; 4346), group 2 = 4668 (4213; 4878), P < 0.01. Reference ranges: Se 0.58–1.82 mmol/l, GSHPx 4170–10,880 U/l. There was no statistically significant difference between both groups for all the other biochemical parameters followed. In the supplemented group 2, the MAP could more frequently be kept above 70 Torr (P < 0.01). Fifty-nine per cent of patients from group 1 and 72.7% from group 2 survived their ICU stay. Neither at the dismissal from the ICU or 1 month later was this difference statistically significant.

Conclusion

Patients with high Se supplementation had significantly higher levels of Se in serum and GSHPx in blood. There was no significantly higher surviving rate in the supplemented group. The MAP was positively influenced. No side effects were registered with high Se dosing. The study continues.