The importance of lipid peroxidation measurement in exhaled breath condensate for diagnosis of ventilator-associated pneumonia

Abstract

Summary. Exhaled breath condensate was studied in 83 intubated patients and 38 healthy volunteers. Lipid peroxidation (diene conjugates, ketodienes, coupled trienes, Schiff's base, fatty acids with polyunsaturated links (substrate for oxidation), and antioxidant catalase) was measured by the spectrophotometric method. Nosocomial (ventilator-associated) pneumonia occurred in 38 patients intubated after surgical intervention or trauma. In those patients without pneumonia, levels of catalase and secondary / final lipid peroxidation products did not differ from that of healthy individuals but levels of conjugated dienes and polyunsaturated fatty acids were moderately increased (1.7-fold and 1.9-fold, respectively). Ventilator-associated pneumonia in intubated patients was accompanied by a significant increase in primary, secondary, and final lipid peroxidation products in exhaled breath condensate (11-fold; 9-fold and 8-fold, respectively, compared to the patients without pneumonia). The intensity of the oxidative stress in the lungs was related to the extension of pneumonia, severity of the respiratory insufficiency and poor outcome rate. To diagnose ventilator-associated pneumonia, cut-points for lipid peroxidation parameters were identified.