Oro-nasal masks

Made of hypoallergenic material Low resistance to airflow Reduced dead space Anti-asphyxia valve (oro-nasal mask). Swivel connector with 360° rotation Inexpensive Easy to clean... 

The site of the exhalation port affects CO2 rebreathing (37,38) with more effective CO2 clearing when the exhalation port is located within the oro-nasal mask. 

Oro-nasal masks may be preferred, in the presence of significant mouth breathing. Moreover, the improvement in arterial blood gases is less (26) and slower (35) with the... 

Figure 1 Rate of use of three different noninvasive interfaces (oro-nasal mask, nasal mask, nasal pillows), as reported by the studies where noninvasive ventilation was utilized to treat acute left) and chronic (right) patients. The oro-nasal mask is the interface of choice in patients with acute or acute on chronic ventilatory failure, while it is less commonly employed for domiciliary treatment of stable chrcniic ventilatory failure. The nasal mask is preferred for long-term treatment of chronic patients. Source From Refs. 39 and 40.

---