Assessment of trace elements in critically ill patients with systemic inflammatory response syndrome: A systematic review

Background: Zinc (Zn), copper (Cu), and selenium (Se) are involved in immune and antioxidant defense. Their role in systemic inflammatory response syndrome (SIRS) treatment and outcomes remains unclear. This sys-tematic review aimed to describe trace element concentrations in different types of biological samples and their relationship with morbidity and mortality in patients with SIRS.Methods: Literature was systematically reviewed according to the preferred reporting items for systematic reviews and meta-analyses (PRISMA). The search re-sults were screened and evaluated for eligibility, and data were extracted and summarized in tables and figures.Results: Most of the 38 included studies evaluated Se (75%), followed by Zn (42%) and Cu (22%). Plasma was the main biological sample evaluated (58%). Thirteen studies found lower plasma/serum concentrations of Zn, Se, and Cu in SIRS patients than in controls upon admission, 11 studies on adults (intensive care unit-ICU) and two in pediatric ICU (PICU). Three ICU studies found no difference in erythrocyte trace element concentrations in patients with SIRS. In all studies, the two main outcomes investigated were organ failure and mortality. In seven ICU studies, patients with lower plasma or serum Zn/Se levels had higher mortality rates. A study conducted in the PICU reported an association between increased Se variation and lower 28-day mortality. In an ICU study, lower erythrocyte selenium levels were associated with higher ICU/hospital mortality, after adjustment. Five ICU studies associated lower plasma/serum Zn/Se levels with higher organ failure scores and one PICU study showed an association between higher erythrocyte Se levels and lower organ dysfunction scores. Conclusion: There was no difference in erythrocyte Se levels in patients with SIRS. Serum/Plasma Zn and serum/plasma/erythrocyte Se are associated with organ dysfunction, mortality, and inflammation. Trace element deficiencies should be diagnosed by erythrocyte, or complementary measurements in the presence of inflammation.