Background and aims To assess the effects of changes in plasma selenium on the outcome in critically ill children

Methods Plasma selenium concentrations were prospectively measured in 99 children with acute systemic inflammatory response. The exposure variable was defined as the difference between plasma selenium concentrations between the 5th day post admission and the admission to the ICU (delta selenium). Age, malnutrition, red cell GPx-1 activity, serum C-reactive protein, Paediatric Index of Mortality 2 and Paediatric Logistic Organ Dysfunction scores were analysed as covariates for the outcomes. The outcome variables were ventilator-free days, ICU-free days and 28-day mortality. Selenium was given only as part of the enteral diets.

Results Plasma selenium concentrations below the 2.5 percentile for age were found in 72% and in 59% of patients on admission and day 5, respectively. Values increased from admission (median 23.4 µg/L, interquartile range 12.0–30.8) to 5th day (median 25.1 µg/L, interquartile range 16.0–39.0; p = 0.018). After adjustment for confounding factors, a ‘delta selenium’ increase of 10 µg/L was associated with reductions in ventilator days (1.4 days, 95% C. I. 0.4–2.5; p = 0.016), ICU days (1.6 days, 95% C. I. 0.6–2.6; p < 0.002), and with decreased 28-day mortality on univariate model (p = 0.036). The mean daily selenium intake (6.82 µg; range 0 to 48.66 µg) was correlated with the increase in selenium concentrations on day 5.

Conclusion In children with systemic inflammation, the increase in plasma selenium concentration was independently associated with shorter times of mechanical ventilation and ICU stay. These results raise the question of selenium supplementation in children with critical illness.