Os efeitos da ventila？？o mecanica no estresse oxidativo

objective: mechanical ventilation is a mainstay of therapy in intensive care units; however, its deleterious effects need to be assessed. therefore, we aimed to assess oxidative stress in patients admitted to an intensive care unit undergoing invasive mechanical ventilation. methods: this cross-sectional study included 12 invasive mechanical ventilation patients. blood samples (3 ml) were collected on the first and last days on invasive mechanical ventilation. thiobarbituric acid-reacting substances (tbars) were assessed in plasma, and superoxide dismutase (sod) and catalase (cat) were assessed in erythrocytes. results: the mean age was 64.8 ± 17.6 years, the tidal volume (vt) 382 ± 44.5 ml, and the apache ii score 15 ± 7. when initial and final tbars were compared, a significant difference was identified (3.54 ± 0.74 vs. 4.96 ± 1.47, p = 0.04). antioxidant enzymes showed no significant differences. correlations between pao2/fio2 and tbars (r = 0.4), sod and pao2/fio2 (r = 0.51) and apache ii and sod (r = 0.56) were identified. six patients died. conclusion: patients undergoing invasive mechanical ventilation can develop redox state changes, showing increased tbars and reduced antioxidant enzymes.