Oxygen therapy in COVID-19: practical considerations prior to invasive mechanical ventilation. Simple guide

Abstract

Patients with acute respiratory distress syndrome (ARDS) secondary to COVID-19 have an atypical presentation, with a discrepancy between acceptable lung mechanics and pronounced hypoxia. Each of the supplemental oxygen methods used in clinical practice in patients with COVID-19 infection has its indications, advantages, and disadvantages. The nasal cannula is the most common system, recommended in cases of mild hypoxia. Venturi system using accurate FiO₂ with higher oxygen flow, and the non-rebreather mask that would normally be used in the absence of response with the above-mentioned devices, are at risk of aerosolizing and transmitting infection. A very useful tool is the high-flow nasal cannula, which is well tolerated, can decrease the patient’s work of breathing, and can reduce the rate of tracheal intubation. It could be useful in the absence of available ventilators and when other supplemental oxygen methods are insufficient to achieve SatO₂ goals. There are reports where non-invasive ventilation is used, however, it is recommended that if the patient is candidate to invasive ventilation support, it must be initiated without delay. Indications for endotracheal intubation are both clinical and gasimetric, saturation goals are generally 90-96 %, and endotracheal intubation with mechanical ventilation should not be delayed if indicated. Further studies are needed in order to assess the clinical efficacy of supplemental oxygen devices for non-invasive respiratory support in these patients.