ObjectivesTo measure the blood concentrations of a number of trace elements and vitamins in critically ill patients and examine their elimination by continuous venovenous hemofiltration (CVVH).SettingIntensive care unit of a tertiary institution.DesignProspective, controlled, clinical study.PatientsEight critically ill patients requiring renal replacement therapy, nine patients requiring intensive care treatment but not requiring renal replacement therapy, and nine healthy controls.InterventionsMeasurement of trace element and vitamin concentrations in blood and ultrafiltrate.Measurements and Main ResultsCompared with normal volunteers, critically ill patients requiring CVVH had significantly lower median blood concentrations of vitamin C, vitamin E, selenium, and zinc. During the first 24 hrs of CVVH, there were no changes in the trace element and vitamin concentrations in blood, nor were there differences between pre- and postfilter samples. Micronutrient losses in the ultrafiltrate were small or undetectable except for Vitamin C, chromium, and copper. Compared with normal volunteers, critically ill patients not requiring CVVH also had significantly lower median blood concentrations of vitamin C, vitamin E, selenium, and zinc. There were no differences between the two critically ill groups.ConclusionsThe clinical significance of the reductions in blood concentrations of selenium, zinc, vitamin C, and vitamin E in critically ill patients and the ultrafiltrate losses of Vitamin C, copper, and chromium remains unclear. (Crit Care Med 1999; 27:220-223)