A portable patient ventilation apparatus comprising: an intake port connectible to a pressure source providing a predefined source flow rate of therapeutic breathing gas; a patient circuit output port connectible to a patient interface for fitment on a patient respiratory passageway; a valve with an input in pneumatic communication with the intake port and an output in pneumatic communication with the patient circuit output port, the valve having variable open and closed positions corresponding to specific restriction factors against the predefined source flow rate of the therapeutic breathing gas from the pressure source; a first pressure sensor arranged to measure a patient interface pressure, the patient interface being connectible to the first pressure sensor over a pressure sensor line; a second pressure sensor arranged to measure a valve output pressure; and a controller in communication with the first pressure sensor, the second pressure sensor, and the variable position valve, a patient inspiratory phase and a patient expiratory phase being detectable by the controller based upon measurements from the first pressure sensor and the second pressure sensor to induce oscillations in delivery of the therapeutic breathing gas to the patient circuit output port based upon a periodic switching of the valve in sequence between the variable open and closed positions during at least a selected one of the patient expiratory and inspiratory phases with an oscillation magnitude of the oscillations being controlled based on the measurement of the first pressure sensor. an intake port connectible to a pressure source providing a predefined source flow rate of therapeutic breathing gas; a patient circuit output port connectible to a patient interface for fitment on a patient respiratory passageway; a valve with an input in pneumatic communication with the intake port and an output in pneumatic communication with the patient circuit output port, a patient circuit output port connectible to a patient interface for fitment on a patient respiratory passageway; a valve with an input in pneumatic communication with the intake port and an output in pneumatic communication with the patient circuit output port, the valve having variable open and closed positions corresponding to specific restriction factors against the predefined source flow rate of the therapeutic breathing gas from the pressure source; a first pressure sensor arranged to measure a patient interface pressure, the patient interface being connectible to the first pressure sensor over a pressure sensor line; a second pressure sensor arranged to measure a valve output pressure; and a controller in communication with the first pressure sensor, the second pressure sensor, and the variable position valve, a patient inspiratory phase and a patient expiratory phase being detectable by the controller based upon measurements from the first pressure sensor and the second pressure sensor to induce oscillations in delivery of the therapeutic breathing gas to the patient circuit output port based upon a periodic switching of the valve in sequence between the variable open and closed positions during at least a selected one of the patient expiratory and inspiratory phases with an oscillation magnitude of the oscillations being controlled based on the measurement of the first pressure sensor. a first pressure sensor arranged to measure a patient interface pressure, the patient interface being connectible to the first pressure sensor over a pressure sensor line; a second pressure sensor arranged to measure a valve output pressure; and a controller in communication with the first pressure sensor, the second pressure sensor, and the variable position valve, a patient inspiratory phase and a patient expiratory phase being detectable by the controller based upon measurements from the first pressure sensor and the second pressure sensor to induce oscillations in delivery of the therapeutic breathing gas to the patient circuit output port based upon a periodic switching of the valve in sequence between the variable open and closed positions during at least a selected one of the patient expiratory and inspiratory phases with an oscillation magnitude of the oscillations being controlled based on the measurement of the first pressure sensor.