Current oxygen management in mechanically ventilated patients: A prospective observational cohort study

Purpose: Oxygen (O₂) is the most common therapy in mechanically ventilated patients, but targets and dose are poorly understood. We aimed to describe current O₂ administration and titration in such patients in an academic intensive care unit. Materials and Methods: In consecutive ventilated (>48 hours) patients we prospectively obtained fraction of inspired O₂ (Fio₂), pulse oximetry O₂ saturation (Spo₂) and arterial O₂ tension (Pao₂) every 6 hours. We calculated the amount of excess O₂ delivery and the intensivists' response to hyperoxemia (Spo₂ >98%). Results: During 358 mechanical ventilation days in 51 critically ill patients, median calculated excess O₂ delivery was 3472 L per patient. Patients spent most of their time with their Spo₂ >98% (59% [29-83]) and Pao₂ between 80 and 120 mm Hg (59% [38-72]). In addition, 50% of all observations showed hyperoxemia and 4% severe hyperoxemia (Pao₂ >202.5 mm Hg). Moreover, 71% of the calculated total excess 263,841 L of O₂ was delivered when the Fio₂ was 0.3 to 0.5. When hyperoxemia occurred with an Fio₂ between 0.3 and 0.4, for 88% of episodes, no Fio₂ adjustments were made. Conclusions: Excess O₂ delivery and liberal O₂ therapy were common in mechanically ventilated patients. Current O₂ therapy practice may be suboptimal and further investigations are warranted.