The OxyMask(™) development and performance in healthy volunteers

Abstract

Background: The OxyMask(™) is a unique, open-style, oxygen mask that was originally developed in 2005. The original mask was modified, using computational fluid dynamics numerical simulations, with the goal of allowing it to produce a wider range of FiO(2). This analysis was used to guide the modification of the mask shell and the location for the oxygen diffuser.

Methods: The new OxyMask was attached to 10 healthy subjects and used to deliver escalating levels of oxygen (1.5, 2, 2.5, 3, 5, 10, 15, 20, 25 and 30 LPM) for 90 seconds at each level and the resulting FiO(2) was recorded (at the lips) from 5 consecutive measurements at each oxygen flow rate.

Results: Mean FiO(2) was 25.4% at 1.5 LPM of oxygen, 30.1% at 2 LPM, 36.5% at 2.5 LPM, 41.8% at 3 LPM, 57.6% at 5 LPM, 74.4% at 10 LPM, and 80.1% at 15 LPM. Each FiO(2) achieved at these escalating oxygen levels was significantly greater than all the previous levels. The mean FiO(2) was 82.8 at 20 LPM, 84.2% at 25 LPM and 84.3% at 30 LPM. All of these values on average were not significantly greater than the FiO(2) achieved with 15 LPM. In a few subjects a maximum FiO(2) of 90% was reached.

Conclusion: The original OxyMask was successfully modified so that the second generation of the mask can provide a wide range of FiO(2), from 25% to 90%, while keeping its unique open design.

Keywords: OxyArm™; OxyMask™; biomedical engineering; clinical trial; computational fluid dynamics (CFD); equipment design; oxygen; oxygen masks; oxygen therapy.

Figure 1

Geometry and numerical mesh for OxyMask^TM. The structure of the mask is depicted in black and the openings are in red.

Figure 2

The oxyMasks: a) oxyMask – second generation, and b) oxyKid (Southmedic Inc, Barrie, Ontario, Canda).

Figure 3

Computational fluid dynamics calculated mass fraction of oxygen as a function of axial distance from diffuser for 5 oxygen delivery flow rates.

Figure 4

Contours of oxygen mass fraction and velocity vectors for an oxygen delivery flow rate of 20 LPM.

Figure 5

Box plots of FiO₂ values versus oxygen delivery flow rates (LPM).

Figure 6

Oxygen concentrations at an axial distance of 3 cm from the diffuser. The plots show a comparison between the computational fluid dynamics result (black line) and the clinical trial (blue line = max, red line = min) results.