US Patent 7841343 Systems and methods for delivering therapeutic gas to patients

A system for delivering therapeutic breathing gas to patients is provided to deliver a variable bolus volume in response to the patient's breathing pattern. The system includes a gas source, a conserver between the gas source and the patient, a sensor which detects breaths by the patient and a controller which receives signals from the sensor and triggers delivery of gas boluses in accordance with predefined triggering parameters, with the controller determining the time elapsed since the last bolus was triggered and altering the triggering parameters as a function of the elapsed time.