ABSTRACT
Background: Patients with coronavirus disease (COVID-19) can develop severe hypoxemia. Meeting the soaring demands of oxygen may be a challenge. Objective: To test the efficacy of an easily handmade system, the double-trunk mask (DTM), in reducing oxygen consumption while maintaining patient's oxygenation level. Methods: Hospitalized adults with COVID-19 and hypoxemia treated with low-flow oxygen therapy we recruited. The standard oxygen delivery system was replaced by the DTM with nasal cannula for 30 minutes with an oxygen output adapted to maintain an identical oxygen saturation by pulse oximetry. The standard oxygen delivery system was then reinstated for 30 minutes. Primary outcome was the absolute change in oxygen flow between the standard delivery systems and the DTM. Secondary outcomes were changes in blood gases, vital parameters and patient comfort. Results: Eleven patients were analyzed (mean age 61 years;27% male). Compared with standard delivery systems, the oxygen output was significantly reduced with the DTM (median, 5 vs 1.5 L/min (95% CI -4 to -1.5, p=0.003)) when oxygen saturation and arterial oxygen tension remained stable. The DTM was also associated with a significant but slight increase in arterial carbon dioxide tension (median, 36 mmHg vs 37 mmHg, p=0.006), and respiratory rate (median, 26 vs 30 breaths/min, p=0.05). Other parameters were unaltered. The DTM was generally judged less comfortable than the baseline oxygen delivery system, especially in patients requiring low oxygen flow at baseline. Conclusions: The DTM is a simple and efficient system to reduce oxygen consumption. This may have clinical implications in places where oxygen supplies are limited.