Systems and methods for delivering therapeutic gas to patients

1. A system for delivering therapeutic breathing gas to a patient, comprising:

a gas source;

a conserver between the gas source and the patient;

a sensor for detecting patient breath events and measuring the parameters of the breath events, said parameters including breath pressure level;

processor and control elements for acquiring signals from the sensor and controlling the delivery of gas to the patient, wherein the system supports at least one mode of operation such that a threshold breath pressure level detected by the sensor, which causes the processor and control elements to deliver a volume of gas to the patient, may be user selectable such that the volume of gas is delivered to the patient when the patient's threshold breath pressure level is at the level selected by the user; and

wherein the system provides a plurality of user selectable threshold pressure levels, said threshold pressure levels comprising a lower level adapted to trigger delivery of gas to the user when the user is asleep or in a state of inactivity such that the user's breath is shallower than normal.

2. The system of claim 1 , wherein the different levels of threshold breath pressure comprise two user-selectable levels, representing a night mode and a day mode, and the actual values of each level are determined by the patient's caregiver.

3. The system of claim 1 , wherein the gas is oxygen and the gas source is an oxygen concentrator.

4. A system for delivering therapeutic breathing gas to a patient, comprising:

a gas source;

a conserver between the gas source and the patient;

a sensor for detecting patient breath events and measuring the parameters of the breath events such as breath pressure level; and

processor and control elements for acquiring signals from the sensor and controlling the delivery of gas to the patient, wherein the system supports at least one auto-fire mode of operation such that the processor and control elements measure the time since the last breath detected by the sensor, and if no breath is detected after a predetermined time period and no gas is delivered to the patient in this predetermined time period, a volume of gas is delivered to the patient automatically.

5. The system of claim 4 , wherein after the automatic delivery of the volume of gas, the processor reduces the breath pressure level which will trigger bolus delivery for the next breath cycle.

6. The system of claim 4 , wherein the processor reduces the breath period for the next breath cycle.

7. The system of claim 4 , wherein the gas is oxygen and the gas source is an oxygen concentrator.

8. An apparatus for delivering a series of boluses of gas to a patient, comprising:

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, said controller determining the time elapsed since the last bolus was triggered, and altering the triggering parameters as a function of said elapsed time.

9. The apparatus of claim 8 , wherein said triggering parameters comprise a blind period during which said triggering delivery of gas boluses is disabled.

10. The apparatus of claim 8 , wherein said triggering parameters comprises a threshold inspiratory pressure of the patient.

11. The apparatus of claim 8 , wherein the controller triggers an auto-fire bolus when said elapsed time is greater than a predetermined time.

12. The apparatus of claim 8 , wherein each of the said triggering parameters is a function of the triggering parameters of one or more boluses previously delivered.