Comparison of Low-cost, Electricity-free, CPAP (OXYJET) with High-Flow Nasal Cannula Treatment outside Critical Care: A Randomized Clinical Trial

Abstract Background: In Low- and Middle-income Countries (LMICs), the general wards typically are limited to providing low-flow oxygen therapy (up to 15L/min). However, high-flow treatment, such as noninvasive ventilation (NIV) administered in pre-ICU settings, has effectively reduced intensive care unit (ICU) admissions. Here, we describe a low-cost, electricity-free, pressure-driven, and 3D-printed continuous positive airway pressure (CPAP) device (‘OxyJet’) which can provide noninvasive ventilation support in the general wards. This study assesses whether the developed CPAP device can be alternative to a High-Flow Nasal Cannula (HFNC) device for supporting hypoxemic patient outside critical care. Methods: We performed an open-label, parallel-assignment, randomized controlled trial in 45 severely hypoxemic patients, between April 17 to July 9, 2021 (NCT04681859). The primary outcome was ventilator-free days at day 10 (VFD10). We compared changes from baseline in peripheral oxygen saturation, heart rate, respiratory rate, mortality hazard-ratio, death/intubation in 10 days, patient recovery, adverse events and oxygen consumption of the two treatment groups. Results: The trial results showed that the patients in CPAP group had a mean difference in the ventilator-free days at day 10 (VFD10) of 2.75 (95% CI -0.17—5.68; p=0.003). The mortality of the patients in CPAP group showed a low hazard-ratio (HR) of 0.65 (95% CI 0.31—1.37; p=0.041). The death/intubation in 10 days of the patients in CPAP group showed a low relative-risk (RR) of 0.52 (95% CI 0.25—1.05; p=0.033). Finally, the device consumed significantly less oxygen than HFNC, with a median difference of -16.11 L/min (95% CI -24.63 — -6.67; p=0.001). Conclusions: The study proposes a potential solution to address the lack of noninvasive ventilation support in wards or resource-limited settings hospitals.