title: The effects of mechanical ventilation on oxidative stress.
abstract: 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.
  
  
  CONCLUSIONS
  Patients undergoing invasive mechanical ventilation can develop redox state changes, showing increased TBARS and reduced antioxidant enzymes.
authors.forename: João Batista Raposo
authors.initials: JB
authors.lastname: Mazullo Filho
authors.forename: Silvia
authors.initials: S
authors.lastname: Bona
authors.forename: Darlan Pase da
authors.initials: DP
authors.lastname: Rosa
authors.forename: Fabiano Gomes da
authors.initials: FG
authors.lastname: Silva
authors.forename: Luiz Alberto
authors.initials: LA
authors.lastname: Forgiarini Junior
authors.forename: Alexandre Simões
authors.initials: AS
authors.lastname: Dias
authors.forename: Norma Possa
authors.initials: NP
authors.lastname: Marroni