Automatic oxygen titration with O2matic® to patients admitted with COVID-19 and hypoxemic respiratory failure.

Abstract

Introduction: Patients with coronavirus disease (COVID-19) and pneumonitis often have hypoxemic respiratory failure and a need of supplementary oxygen. Guidelines recommend controlled oxygen, for most patients with a recommended interval of SpO₂ between 92 and 96%. We aimed to determine if closed-loop control of oxygen was feasible in patients with COVID-19 and could maintain SpO₂ in the specified interval.

Methods: Patients were prospectively enrolled in an observational study on a medical ward dedicated to patients with COVID-19. Closed-loop controlled oxygen was delivered by O2matic® which can deliver 0-15 liters/min and adjusts flow every second based on 15 seconds averaging of SpO₂ measured by pulse oximetry. Lung function parameters were measured at admission.

Results: Fifteen patients (six women, nine men) participated in the study. Average age was 72 years. Lung function was severely impaired with FEV₁, FVC and PEF reduced to approximately 50%. The average stay on the ward was 3.2 days and O2matic was used on average for 66 hours, providing 987 hours of observation. O2matic maintained SpO₂ in the desired interval for 82.9% of the time. Time with SpO₂ > 2% below interval was 5.1% and time with SpO₂ > 2% above interval was 0.6%.

Conclusion: Closed-loop control of oxygen to patients with COVID-19 is feasible and can maintain SpO₂ in the specified interval in the majority of time. Closed-loop automated control could be of particular benefit for patients in isolation with decreased visibility, surveillance and monitoring. Further studies must examine the clinical benefits.