Analysis of Oxidative Stress in Exhaled Breath Condensate From Patients With Severe Pulmonary Infections

ObjectiveOxidative stress is an intrinsic part of the chain of events leading to inflammation of the airways caused by bacterial infection. The aim of this study was to determine whether analysis of exhaled breath condensate from patients with severe lung infections reveals changes in the redox state at the airway surface.Patients and methodsThe study included a total of 48 subjects divided into 4 groups: individuals without respiratory disease (n=14), patients with multilobar pneumonia (n=13), patients who had chronic obstructive pulmonary disease with superinfection (n=14), and mechanically ventilated patients with severe pneumonia (n=7). A sample of exhaled breath condensate was obtained within the first 72 hours of hospital admission and the concentrations of nitrite, nitrate, 8-isoprostane, and myeloperoxidase (MPO) were determined.ResultsSignificant differences in the concentrations of nitrite, 8-isoprostane, and MPO were observed between patients and individuals without respiratory disease but no differences were found between the 3 patient groups. The concentration of MPO was correlated with the concentrations of 8-isoprostane and nitrate, which were normalized to the nitrite concentration.ConclusionsAnalysis of the concentrations of 8-isoprostane and MPO in exhaled breath condensate allows assessment of oxidative stress in the airways of patients with severe lung infections.

ObjetivoEl estrés oxidativo forma parte esencial de la cadena de acontecimientos que conducen al estado inflama-torio de la vía aérea tras la agresión bacteriana. El objetivo del presente trabajo ha sido investigar si el análisis del condensado del vapor exhalado (CER) de pacientes con infección pulmonar grave refleja las alteraciones del estado oxidativo de la interfase aérea.Pacientes y métodosSe ha estudiado a un total de 48 pacientes divididos en 4 grupos: sujetos sin enfermedad respiratoria (n = 14), pacientes con neumonía multilobular (n = 13), con enfermedad pulmonar obstructiva crónica sobreinfectados (n = 14) y con neumonía grave ventilados mecánicamente (n = 7). Se obtuvo una muestra de CER en las primeras 72 h tras el ingreso y se determinó la concentración de nitrito, nitrato, 8-isoprostano y mieloperoxidasa (MPO).ResultadosSe apreciaron variaciones significativas de la concentración de nitrito, 8-isoprostano y MPO en los pacientes respecto del grupo control, pero no entre los diferentes grupos de pacientes. La concentración de MPO se rela-cionó con las concentraciones de 8-isoprostano y nitrato normalizadas para el valor de nitrito.ConclusionesEl análisis de la concentración de 8-isoprostano y MPO en el CER permite apreciar el estrés oxidativo en la interfase aérea de los pacientes con infección pulmonar grave.