Time course and relationship between plasma selenium concentrations, systemic inflammatory response, sepsis, and multiorgan failure

Background: Selenium plays an important role in defence against acute illness.We investigated, in intensive care unit (ICU) patients, thetime course of plasma selenium concentrations and their relationshipto systemic inflammatory response syndrome (SIRS), organ dysfunction/failure,infection, and ICU outcome. Methods: Plasma selenium and laboratory indices of organ dysfunction/failure,tissue inflammation, and infection were measured daily duringthe ICU stay in 60 consecutive ICU patients, 15 in each of foura priori defined subgroups: ICU controls (no SIRS); uncomplicatedSIRS; severe SIRS; and severe sepsis/septic shock. Results: Plasma selenium concentrations were below standard values forhealthy subjects (74 µg litre^–1) in 55 patients(92%). Selenium concentrations decreased during the ICU stayin all groups, except controls, to a minimum value that waslower in patients with organ failure, particularly in thosewith infection. The minimum plasma selenium was inversely correlatedto admission Acute Physiology and Chronic Health EvaluationII and Simplified Acute Physiology System II scores, indicatorsof inflammation, and the maximal degree of organ dysfunction/failureduring the ICU stay. Plasma selenium was positively correlatedwith minimum platelet count, minimum plasma antithrombin activity,and protein C activity. In a receiver operator characteristicanalysis, SAPS II score [area under the curve (AUC) = 0.903]and minimum selenium concentration (AUC = 0.867) were the strongestpredictive factors for ICU mortality. Conclusions: In critically ill surgical patients, plasma selenium concentrationsare generally low with a greater decrease during the ICU stayin patients with organ failure, especially when attributed toinfection. Lower plasma selenium concentrations are associatedwith more tissue damage, the presence of infection or organdysfunction/failure, and increased ICU mortality.