Philips Trilogy Evo, Evo O2, EV300, and Evo Universal ventilators provide breathing support, but dust and dirt in the air path may impact air flow to patients.

http://www.fda.gov/medical-devices/medical-device-recalls/philips-respironics-recalls-trilogy-evo-evo-o2-ev300-and-evo-universal-ventilators-after-finding