Southmedic OxyMask(TM) compared with the Hudson RCI(®) Non-Rebreather Mask(TM): Safety and performance comparison

The non-rebreather mask (NRBM) is used for many applications and in many patient care scenarios in which hypoxemia and resultant hypoxia are a concern. The NRBM is a low-flow oxygen delivery system that is easily deployed and capable of delivering a relatively high fraction of inspired oxygen (FiO2).The potential for ineffective carbon dioxide (CO2) removal at low flow rates is a safety concern.

The authors hypothesized that the use of an OxyMask (Southmedic Inc, Canada) would mitigate these safety concerns while still delivering a relatively high FiO2.

Bench studies were performed in a third-party laboratory by qualified engineers (Piper Medical, USA). A Harvard Respirator Pump (Harvard Apparatus, USA), oxygen source, CO2 source and a mannequin head were used to simulate varying respiratory conditions. End tidal CO2 (EtCO2), FiO2, fraction of inspired CO2 and percent drop in CO2 in the first second of exhalation were measured at different mask flow rates and respiratory rates. There were two categories of flow rates: high-flow (15 L/min) and low-flow (2 L/min). In each flow group, the above parameters were measured using a tidal volume of 400 mL, inspiratory/expiratory ratio of 1:2, EtCO2 of 5% and a breathing frequency of 15, 20 or 24 breaths/min. Mask performance measurements were obtained and compared.

The OxyMask outperformed the traditional NRBM in each tested category. There was a higher inspired oxygen level, lower inspired CO2 level, and more efficient CO2 clearance at each mask flow level and simulated patient minute volume. This was especially true during conditions in which there were very low mask flow rates.