Patent ID: 7077131

Claim:
A ventilator comprising: a positive relative pressure gas supply; a negative relative pressure gas supply; a gas delivery device for delivering gas to a patient; a diverter valve including a positive pressure port connected to said positive relative pressure gas supply, a negative pressure port connected to said negative relative pressure gas supply, and a gas supply port for communicating with said gas delivery device, wherein a gas supply from at least one of said positive relative pressure gas supply and said negative relative pressure gas supply is delivered to said gas delivery device for delivery of said gas to said patient, via said diverter valve: a feedback sensor that detects a gas supply difference between said gas supply and a predetermined gas supply and generates a feedback signal that is substantially related to said gas supply difference; and a diverter valve actuator communicating with said diverter valve and operating said diverter valve to communicate said positive relative pressure gas supply and said negative relative pressure gas supply to said gas supply port of said diverter valve based upon said feedback signal.