High-flow oxygen therapy — its application in COVID-19-related respiratory failure and beyond

Oxygen therapy is the primary method of treating acute respiratory failure during Sars-CoV-2 infection. Depending on the patient’s condition, treatment may be carried out using traditional nasal cannulas, oxygen masks, non-invasive ventilation or mechanical ventilation. A relatively modern method that has been used worldwide for about 10 years is High Flow Nasal Oxygen Therapy (HFNOT). Equipment for HFNOT allows you to obtain high (up to 60 L/min) flows in nasal cannulas and precisely set a high concentration of oxygen in the mixture of inhaled gases. Such high flow is also associated with the generation of constant positive pressure in the airways, which further supports the treatment of respiratory failure by maintaining airway patency, recruitment of alveoli and reducing the breathing workload. HFNOT also leads to a reduction in anatomical dead space and facilitates carbon dioxide washout from the upper respiratory tract which also reduces the work of breathing and increases the efficiency of ventilation. Moreover, this ventilation method is tolerated well by patients and does not require specialized and longterm personnel training. Therefore, the method was widely applied in hospital wards treating patients with severe respiratory failure during Coronavirus Disease 2019 (COVID-19). Additional applications for this relatively novel method of oxygen support in different fields of medicine were analysed