Plasma lipid peroxidation in critically ill patients: importance of mechanical ventilation.

Oxygen free radicals may be implicated in the pathogenesis of both ischemia-reperfusion damage and in circulatory shock. The attack on the cell membrane by free radicals leads to lipid peroxidation, which can be assessed by the plasma malondialdehyde (MDA) level. The aim of this study was to determine the importance of lipid peroxidation in critically ill patients. The MDA level was measured by the thiobarbituric acid test. Nineteen patients at an early stage of circulatory shock, 11 patients in the weaning period of ventilation, 9 gastro-enterological patients without cardio-circulatory distress or sepsis, and 9 healthy volunteers were studied. The MDA level was higher in critically ill patients than in control subjects (61% in patients with shock and 40% in patients on mechanical ventilation). No correlation was found between the MDA level and the outcome: multiple organ failure or acute respiratory distress syndrome. This proposal leads to the question of systematic antioxidant therapy in intensive care patients.