Conservative Oxygen Therapy in Mechanically Ventilated Patients

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/FIO2 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.