Abstract: A method for determining the respiratory flow of a patient receiving bi-level respiratory therapy is provided. The method may include measuring the total air flow through a breathing area at a time approximately when the patient has completed exhalation, measuring the pressure in the breathing area, determining a constant representing a corrective flow factor by dividing the measured total air flow by the square root of the measured pressure, and determining the patient's respiratory flow by subtracting from a subsequent total air flow the product of constant and the square root of a subsequent pressure.

Abstract: A breathing assistance system configured to determine pressure drop may include a gas delivery system configured to deliver gas toward a patient, one or more sensors configured to measure one or more parameters of gas delivered by the gas delivery system, a calibration module, and a pressure drop calculation module. The calibration module may be configured to perform one or more pressure drop calibration tests, each pressure drop calibration test measuring a pressure drop in gas flowing through a breathing assistance system apparatus at a particular flow rate; and based at least on the results of the one or more pressure drop calibration tests, generating a non-linear equation relating (a) pressure drop in gas flowing through the breathing assistance system apparatus with (b) flow rate of gas flowing through the breathing assistance system apparatus.

Abstract: A breathing assistance system configured to determine pressure drop may include a gas delivery system configured to deliver gas toward a patient, one or more sensors configured to measure one or more parameters of gas delivered by the gas delivery system, a calibration module, and a pressure drop calculation module. The calibration module may be configured to perform one or more pressure drop calibration tests, each pressure drop calibration test measuring a pressure drop in gas flowing through a breathing assistance system apparatus at a particular flow rate; and based at least on the results of the one or more pressure drop calibration tests, generating a non-linear equation relating (a) pressure drop in gas flowing through the breathing assistance system apparatus with (b) flow rate of gas flowing through the breathing assistance system apparatus.

Abstract: The disclosure provides a method for delivering pressurized gas to an airway of a subject. The disclosure also provides a system for delivering pressurized gas to an airway of a subject. The disclosure further provides a computer-readable storage medium containing a set of instructions executable on a processor that include routines to monitor a respiratory flow rate from a subject, generate a filtered flow and a dynamic flow from the respiratory flow rate, and control a gas generator connected to a breathing device.

Abstract: A method for providing positive airway pressure treatment may include delivering breathing gas toward a patient at a first pressure, detecting one or more sleep respiratory events associated with the patient, and in response to detecting the one or more sleep respiratory events, automatically triggering a ramp function to increase the pressure of the breathing gas delivered toward the patient from the first pressure to a second pressure at a predetermined rate.

Abstract: A method for determining the respiratory flow of a patient receiving bi-level respiratory therapy is provided. The method may include measuring the total air flow through a breathing area at a time approximately when the patient has completed exhalation, measuring the pressure in the breathing area, determining a constant representing a corrective flow factor by dividing the measured total air flow by the square root of the measured pressure, and determining the patient's respiratory flow by subtracting from a subsequent total air flow the product of constant and the square root of a subsequent pressure.