Experimental use of CPAP device for emergency high-flow nasal oxygen therapy

Abstract

<b>Background:</b> High-flow nasal oxygen (HFNO) therapy is a type of respiratory support used for efficient treatment of hypoxemic respiratory failure. Currently, in the COVID-19 pandemic, due to great interest in HFNO therapy, there is an acute shortage of devices from standard suppliers. <b>Aim:</b> To verify the technical assumptions of experimental treatment utilizing a conventional CPAP device and available consumables as an emergency HFNO. <b>Methods:</b> A commercially available CPAP (Prisma 20) with a heated hose circuit and nasal cannula Oxi Plus (Löwenstein medical, Germany) was used. Using certified measuring devices, air flows at individual CPAP pressures, inhaled air temperature, and a fraction of inspired oxygen (FiO2) at different oxygen flows were measured. The effectiveness of humidification was determined by water consumption during operation. <b>Results:</b> CPAP pressures and their corresponding air flows, as well as measured FiO2 values at oxygen flows of 5, 10, and 15 L/min, are summarized in the Table. The inhaled air temperature rose from initial 21°C (room temperature) to 25°C after half an hour and 31.5°C after 1 hour of operation and then remained stable. The water consumption in the humidifier reached 500 ml after 7.5 hours of operation. <b>Conclusion:</b> A commonly available CPAP device, used as an emergency HFNO, achieved the required technical parameters of the therapy. <b>Support:</b> VEGA 1/0220/17, APVV-16-0158 <b>Table:</b> Resulting FiO2 (%) depending on CPAP pressure and supplied oxygen flow