A system for controlling and regulating breathing gas supplied to a patient that includes a pressure generator system that provides breathing gas to a patient and a patent circuit that delivers the breathing gas to the patient. The system includes an interface device coupled to the patient circuit to communicate the flow of gas to the patient airway. A sensor detects a parameter indicative of a flow of breathing gas delivered to the patient. A controller coupled to the sensor and the pressure generator system measures at least one characteristic of respiratory airflow of a patient and calculates a target breath-amplitude -based parameter and a time -based parameter of at least a portion of the patients respiratory cycle to be delivered to the patient based on the at least one characteristic of respiratory airflow.
