Conservative oxygen therapy in mechanically ventilated patients: A pilot before-and-after trial

OBJECTIVES: To assess the feasibility and safety of a conservative approach to oxygen therapy in mechanically ventilated ICU patients. DESIGN: Pilot prospective before-and-after study. SETTING: A 22-bed multidisciplinary ICU of a tertiary care hospital in Australia. PATIENTS: A total of 105 adult (18 years old or older) patients required mechanical ventilation for more than 48 hours: 51 patients during the "conventional" before period and 54 after a change to "conservative" oxygen therapy. INTERVENTIONS: Implementation of a conservative approach to oxygen therapy (target SpO₂ of 90-92%). MEASUREMENTS AND MAIN RESULTS: We collected 3,169 datasets on 799 mechanical ventilation days. During conservative oxygen therapy the median time-weighted average SpO₂ on mechanical ventilation was 95.5% (interquartile range, 94.0-97.3) versus 98.4% (97.3-99.1) (p < 0.001) during conventional therapy. The median PaO₂ was 83 torr (71-94) versus 107 torr (94-131) (p < 0.001) with a change to a median FIO₂ of 0.27 (0.24-0.30) versus 0.40 (0.35-0.44) (p < 0.001). Conservative oxygen therapy decreased the median total amount of oxygen delivered during mechanical ventilation by about two thirds (15,580 L [8,263-29,351 L] vs 5,122 L [1,837-10,499 L]; p < 0.001). The evolution of the PaO₂/FIO ₂ ratio was similar during the two periods, and there were no difference in any other biochemical or clinical outcomes. CONCLUSIONS: Conservative oxygen therapy in mechanically ventilated ICU patients was feasible and free of adverse biochemical, physiological, or clinical outcomes while allowing a marked decrease in excess oxygen exposure. Our study supports the safety and feasibility of future pilot randomized controlled trials of conventional compared with conservative oxygen therapy.