System and method for providing a breathing gas

A method of providing a breathing gas comprising:

• a) sensing a breathing gas pressure associated with delivery of the breathing gas;
• b) detecting a start of an inhalation state of a breathing cycle;
• c) changing a valve step position associated with a variable position valve in response to a difference between the sensed breathing gas pressure and a first predetermined breathing gas pressure value during the inhalation state;
• d) determining a transition from the inhalation state to an exhalation state of the breathing cycle based at least in part on the changing valve step position;
• e) changing the valve step position to cause a first change in the breathing gas pressure during an unload portion of the exhalation state based at least in part on the determined transition;
• and
• f) changing the valve step position to cause a second change in the breathing gas pressure during a load portion of the exhalation state based at least in part on the first predetermined breathing gas pressure value.

A method of providing a breathing gas comprising:

• a) sensing a breathing gas pressure associated with delivery of the breathing gas;
• b) determining a breath cycle time associated with at least a portion of a current inhalation state of a current breathing cycle and a portion of a previous breathing cycle;
• c) changing a valve step position associated with a variable position valve in response to a difference between the sensed breathing gas pressure and a first predetermined breathing gas pressure value during the current inhalation state;
• d) determining a transition from the current inhalation state to a current exhalation state of the current breathing cycle based at least in part on the changing valve step position;
• e) changing the valve step position to cause a first change in the breathing gas pressure during an unload portion of the current exhalation state based at least in part on the determined transition;
• and
• f) changing the valve step position to cause a second change in the breathing gas pressure during a load portion of the current exhalation state based at least in part on the first predetermined breathing gas pressure value.

A method of providing a breathing gas comprising:

• a) sensing a sensed parameter associated with delivery of the breathing gas;
• b) changing a control parameter associated with a flow/pressure control element in response to a difference between the sensed parameter and a first predetermined sensed parameter value during a first portion of a current breathing cycle;
• c) determining a transition from the first portion to a second portion of the current breathing cycle based at least in part on the changing control parameter;
• d) changing the control parameter to cause a first change in the sensed parameter during the second portion of the current breathing cycle based at least in part on the determined transition;
• and
• e) changing the control parameter to cause a second change in the sensed parameter during a third portion of the current breathing cycle based at least in part on the first predetermined sensed parameter value.

A method of providing a breathing gas comprising:

• a) sensing a breathing gas pressure associated with delivery of the breathing gas;
• b) changing a valve step position associated with a variable position valve in response to a difference between the sensed breathing gas pressure and a first predetermined breathing gas pressure value during a first portion of a current breathing cycle;
• c) determining a transition from the first portion to a second portion of the current breathing cycle based at least in part on the changing valve step position;
• d) changing the valve step position to cause a first change in the breathing gas pressure during the second portion of the current breathing cycle based at least in part on the determined transition;
• and
• e) changing the valve step position to cause a second change in the breathing gas pressure during a third portion of the current breathing cycle based at least in part on the first predetermined breathing gas pressure value.

A method of providing a breathing gas to a patient comprising:

• controlling a valve position to output a first target gas pressure level to the patient during at least a portion of the patient's inhalation breathing state;
• monitoring an actual gas pressure level output to the patient;
• determining a valve position setting based on the monitored gas pressure level;
• determining a valve position setting threshold;
• determining at least a second target gas pressure level that is less than the first target gas pressure level;
• if the valve position setting falls below the valve position setting threshold, controlling the valve position to output the second target gas pressure level to the patient for a predetermined time period during at least a first portion of the patient's exhalation breathing state;
• and
• controlling the valve position to output the first target gas pressure level to the patient after the predetermined time period has expired during at least a second portion of the patient's exhalation breathing state.