Impacts of a fraction of inspired oxygen adjustment protocol in COVID-19 patients under mechanical ventilation: A prospective cohort study

OBJECTIVE: We examined weather a protocol for fraction of inspired oxygen (FiO(2)) adjustment can reduce hyperoxemia and excess oxygen use in COVID-19 patients mechanically ventilated. DESIGN: Prospective cohort study. SETTING: Two intensive care units (ICUs) dedicated to COVID-19 patients in Brazil. PATIENTS: Consecutive patients with COVID-19 mechanically ventilated. INTERVENTIONS: One ICU followed a FiO(2) adjustment protocol based on SpO(2) (conservative-oxygen ICU) and the other, which did not follow the protocol, constituted the control ICU. MAIN VARIABLES OF INTEREST: Prevalence of hyperoxemia (PaO(2) >100 mmHg) on day 1, sustained hyperoxemia (present on days 1 and 2), and excess oxygen use (FiO(2) > 0.6 in patients with hyperoxemia) were compared between the two ICUs. RESULTS: Eighty two patients from the conservative-oxygen ICU and 145 from the control ICU were included. The conservative-oxygen ICU presented lower prevalence of hyperoxemia on day 1 (40.2% vs. 75.9%, p < 0.001) and of sustained hyperoxemia (12.2% vs. 49.6%, p < 0.001). Excess oxygen use was less frequent in the conservative-oxygen ICU on day 1 (18.3% vs. 52.4%, p < 0.001). Being admitted in the control ICU was independently associated with hyperoxemia and excess oxygen use. Multivariable analyses found no independent relationship between day 1 hyperoxemia, sustained hyperoxemia, or excess FiO(2) use and adverse clinical outcomes. CONCLUSIONS: Following FiO(2) protocol was associated with lower hyperoxemia and less excess oxygen use. Although those results were not associated with better clinical outcomes, adopting FiO(2) protocol may be useful in a scenario of depleted oxygen resources, as was seen during the COVID-19 pandemic.