Lång M, et al. - The impact of two different fractions of inspired oxygen on blood concentrations of reactive oxygen species (ROS), interleukin 6 (IL-6) and neuron-specific enolase (NSE) was compared among severe traumatic brain injury (TBI) patients on mechanical ventilation. Twenty-seven patients were included in the FiO₂ 0.40 group and 38 in the FiO₂ 0.70 group. In this patient population, no increase in the blood concentrations of markers of oxidative stress, inflammation or neurological injury or the incidence of pulmonary complications was noted as a result of receiving higher fraction of inspired oxygen.