Patent ID: 7509957

Claim:
A pressure driver for a ventilation system for ventilating a patient, the pressure driver comprising: a gas source; a drive venturi connected to the ventilation system; a patient pressure sensor operative to measure pressure at the drive venturi; and an inspiration flow control valve interposed between the gas source and the patient and being operative to open and close in response to patient pressure measurements; and an exhalation system interconnecting the patient to the gas source and being arranged in parallel with the inspiration flow control valve, the exhalation system being operative to vent exhalation gases from the patient, wherein the exhalation system includes an exhalation valve and an expiratory check valve interconnecting the exhalation valve to the patient, the expiratory check valve being operative to prevent flow in a direction from the exhalation valve to the patient and wherein the exhalation system includes the drive venturi interposed between a voltage sensitive orifice (VSO) valve and the exhalation valve, the drive venture being operative to facilitate the flow of gas.