Conservative oxygen supplementation during helmet continuous positive airway pressure therapy in patients with COVID-19 and respiratory failure: a pilot study

BACKGROUND: Respiratory failure is a severe complication in coronavirus disease 2019 (COVID-19) pneumonia that, in addition to oxygen therapy, may require continuous positive airway pressure (CPAP) support. It has been postulated that COVID-19 lung injury may share some features with those observed in hyperoxic acute lung injury. Thus, a correct target arterial oxygen tension (P(aO(2))) during oxygen supplementation may be crucial to protect the lung from further tissue damage. The aims of this study were: 1) to evaluate the effects of conservative oxygen supplementation during helmet CPAP therapy on mortality and intensive care unit (ICU) admission in patients with COVID-19 and respiratory failure, and 2) to evaluate the effect of conservative oxygen supplementation on new-onset organ failure and secondary pulmonary infections. METHODS: This was a single-centre, historically controlled study of patients with severe respiratory failure due to COVID-19 pneumonia, receiving either conservative or nonconservative oxygen supplementation during helmet CPAP. A cohort receiving conservative oxygen supplementation was studied prospectively in which oxygen supplementation was administered with a target P(aO(2)) <100 mmHg. Results of this cohort were compared with those of a cohort who had received liberal oxygen supplementation. RESULTS: 71 patients were included in the conservative cohort and 75 in the nonconservative cohort. Mortality rate was lower in the conservative cohort (22.5% versus 62.7%; p<0.001). Rates of ICU admission and new-onset organ failure were lower in the conservative cohort (14.1% versus 37.3%; p=0.001 and 9.9% versus 45.3%; p<0.001, respectively). CONCLUSIONS: In patients with COVID-19 and severe respiratory failure, conservative oxygen supplementation during helmet CPAP was associated with improved survival, lower ICU admission rate and less new-onset organ failure.