Background: Many clinical trials have assessed the benefits of inorganic selenocompounds in critically ill patients. However, serum selenium of populations throughout the world is very. We sought to determine the change in serum selenium level of surgical critically ill patients in Thailand.

Objective: To determine the serum selenium level of surgical Intensive Care Unit (ICU) patient and to compare the change in serum selenium level on day 3 and day 5 of ICU stay.

Material and Method: We collected 5 ml clot blood on day 1, day 3, and day 5 from patients admitted to surgical ICU between November 2012 and January 2013. Blood sample was centrifuged, and serum was collected. Serum selenium level was determined by using the Inductive Couple Plasma with Mass Spectrometry (ICP-MS) system. Basic information of patients including age, gender, diagnosis, underlying illness, indication of ICU admission, SOFA score, number of days for ventilator use, nutritional support, number of days of ICU stay, and death after day 5 of ICU stay was recorded.

Results: All 47 patients (100%) who admitted to surgical ICU had serum selenium level lower than average level of healthy Thai (106.95 μd/L) on day 1 and day 3 of ICU stay while 44 out of 47 patients (93.6%) had serum selenium level lower than average level of healthy Thai on day 5. Average serum selenium levels were below normal physiological range (70 to 150 μd/L) on all study day. Average serum selenium level on day 5 of ICU stay was 67.9 μg/L, which was increased significantly from day 1 level (61.8 μd/L) and day3 level (63.5 μd/L). No significant factor associated with the reduction in serum selenium level has been found.

Conclusion: Almost all patients who admitted surgical ICU had serum selenium level below average level of healthy population and over 50% of the sample were below normal range on all day of the study.

Keywords: Serum, Selenium, Surgical, ICU, Thailand, Inductively coupled plasma with mass spectrometry (ICP-MS)