Oxygen Delivery With an Open Oxygen Mask and Other Conventional Masks: A Simulation-Based Study

BACKGROUND: A recently introduced open oxygen mask design was marketed in 2021 (open mask A). The manufacturer claims that the mask “…provides one solution for all your oxygen delivery needs across your patients' continuum of care.” The new oxygen mask specifies flow (1–15 L/min and flush) with an expected F_IO2 from 0.25–0.85. This suggests that this mask eliminates the need for multiple oxygen delivery devices as F_IO2 requirements change. This study aimed to describe the F_IO2 performance of the new open oxygen mask and other commonly used oxygen masks.

METHODS: The following oxygen masks were studied: open mask A, open mask B, simple mask, partial rebreather, and non-rebreather. An adult mannequin head was attached to a breathing simulator, which recorded F_IO2 at the simulated alveolar level. The simulator was set to a closed-loop volume control mode: V_T = 320 mL, compliance = 50 mL/cm H₂O, resistance = 4 cm H₂O/L/s, breathing frequency = 15 breaths/min, increase = 25%, hold = 0%, and release = 30%. Oxygen was run through each mask at the recommended flows. Each flow was verified with a flow analyzer before attaching the mask for oxygen measurement. Each experiment was performed twice. The F_IO2 measurements were averaged and compared using a 2-way ANOVA with P < .05 indicating significance.

RESULTS: The F_IO2 delivery was significantly different for each device. The measured F_IO2 range was open mask A, 0.30–0.60; open mask B, 0.28–0.64; simple mask, 0.55–0.73; partial non-rebreather, 0.73–1.0; non-rebreather, 0.93–1.00.

CONCLUSIONS: The performance of each oxygen mask from highest to lowest F_IO2: non-rebreather, partial rebreather, simple mask, open mask A, and open mask B. These findings suggest that no oxygen mask tested serves as a substitute for the others across a flow range of 1–15 L/min and flush.