Invacare Polaris EX CPAP with SoftX ISP3000 Operator's Manual page 11

At low pressures, the flow through the exhalation ports may
be inadequate to clear all exhaled air from the tubing. Some
rebreathing may occur.
Positive airway pressure devices may allow rebreathing of
exhaled air. To avoid rebreathing, the following should be
observed:
• The mask should only be worn when it is connected to
the CPAP unit and the unit is turned on with the
therapy mode activated.
• DO NOT block, seal, or cover the exhalation ports of
your mask.
Part No 1110559
SECTION 1—GENERAL GUIDELINES
11 Invacare® Polaris™EX™