A BiPAP is a bi-level positive airway pressure machine, a ventilation apparatus that maintains an airflow through a noninvasive face mask keeping the upper airways of the lungs open, explains About.com. The air is pressurized by a machine with a higher pressure for inhalation and a lower pressure for exhalation.
BiPAP machines are typically used in the treatment of chronic obstructive pulmonary disease, explains About.com. The air is delivered to the face mask through plastic tubing. BiPAP is the proprietary name from Respironics, Inc. Machines that perform the same function but are made by other companies are called noninvasive positive pressure ventilation or noninvasive ventilation.