Vitamin E (Vit E) is an important component of the lung's defense against oxidant injury. The aim of this study was to determine a) if adult respiratory distress syndrome (ARDS) was associated with a decrease in Vit E plasma level linked to an enhancement of plasma lipoperoxidation, and b) if this Vit E deficiency might be explained by malnutrition and/or a consumption defect. Vit E, lipoperoxides (LP), total lipids, and fatty acid plasma levels were measured in 12 patients with ARDS (PaO2 less than or equal to 60 Torr with FIO2 0.6 on mechanical ventilation). At the onset of ARDS (T0), the decrease in Vit E plasma level was significant (p less than .001) 7.73 +/- 0.54 (n = 12) vs. 11.46 +/- 0.55 mg/L (n = 7) in the control group (healthy subjects breathing room air). A significant (p less than .05) increase in LP was simultaneously observed (4.12 +/- 0.35 [n = 12] vs. 2.94 +/- 0.30 nmol/ml [n = 17]) in the control group. At T0, LP were inversely correlated with Vit E plasma levels (r = .78, p less than .01). Vit E deficiency was associated with low levels of total plasma lipids (3.68 +/- 0.25 g/L) and plasma cholesterol (0.97 +/- 0.07 g/L). Thus, the Vit E/total lipids ratio (2.18 +/- 0.17 mg/g) was always above the accepted normal limit value for this ratio (0.8 mg/g).(ABSTRACT TRUNCATED AT 250 WORDS)