OXIDANT ACTIVITY IN EXPIRED BREATH OF PATIENTS WITH ADULT RESPIRATORY DISTRESS SYNDROME

Abstract

Hydrogen peroxide levels were measured in the breath condensate of 43 patients receiving mechanical ventilation. In 16 patients the mean breath condensate peroxide level was 1[middle dot]68+/-0[middle dot]35 [mu]mol/l on the day they met diagnostic criteria for adult respiratory distress syndrome (ARDS). The peak breath condensate peroxide level in the 27 patients in whom ARDS did not develop was significantly lower (0[middle dot]34+/-0[middle dot]08 [mu]mol/l). Plasma lysozyme, a measure of in-vivo neutrophil turnover, was significantly higher in ARDS than in non-ARDS patients (9[middle dot]2+/-2[middle dot]2 U/ml v 3[middle dot]4+/-1[middle dot]1 U/ml). These findings support the hypothesis that neutrophil activation and oxidant production are involved in the pathogenesis of ARDS.