Use and misuse of oxygen administration

[4] In 2017, the British Thoracic Society (BTS) formulated specific guidelines recommending oxygen use when there is a specific indication and when peripheral saturation (SpO2) falls below 94%, or below 88% in patients with chronic obstructive pulmonary disease (COPD). A precise risk threshold for oxygen toxicity is unknown because it is impossible to carry out studies among healthy subjects for ethical reasons, but the evidence is clear about the harmfulness of high oxygen concentrations which play a decisive role in the retinopathy of prematurity,[7] respiratory distress syndrome, and bronchopulmonary dysplasia of the premature infant. A high oxygen concentration causes a direct injury to lung tissue with characteristic oxidative stress, oxygen free radical production, and exposes all body organs to risks of cytotoxicity and functional impairment.