Determination of leak and respiratory airflow

In an apparatus with control circuitry for airway treatment for a patient, a method for determining a degree of certainty that a leak has suddenly decreased during airway treatment comprising the steps of:

• determining a measure of respiratory airflow to the patient;
• determining an extent A to which the measure has been negative for longer than expected;
• determining an extent B to which the measure is large and negative;
• determining the degree of certainty that a leak has suddenly decreased as a function of extent A and extent B.

In an apparatus with control circuitry for airway treatment for a patient, a method for determining an extent to which a leak has suddenly changed during airway treatment of a patient comprising the steps of:

• determining an increase-index of a degree of certainty to which the leak has suddenly increased;
• determining a decrease-index of a degree of certainty to which the leak has suddenly decreased;
• and
• determining the extent to which the leak has suddenly changed as a function of the increase-index and the decrease-index.

An apparatus for determining a degree of certainty that a leak has suddenly increased during airway treatment of a patient comprising:

• means for delivering a controlled supply of pressure support to a patient's airway;
• means for determining a flow signal representative of respiratory airflow to the patient;
• a control means in communication with the means for determining, the control means having programmed instructions for controlling a determination of a degree of certainty that a leak has suddenly increased, the instructions controlling steps comprising:
• determining a measure of respiratory airflow to the patient from the flow signal;
• determining an extent A to which the measure has been positive for longer than expected;
• determining an extent B to which the measure is large and positive;
• determining the degree of certainty that a leak has suddenly increased as a function of extent A and extent B.

An apparatus for determining a degree of certainty that a leak has suddenly increased during airway treatment of a patient comprising:

• means for delivering a controlled supply of pressure support to a patient's airway;
• means for determining a flow signal representative of respiratory airflow to the patient;
• a control means in communication with the means for determining, the control means having programmed instructions for controlling a determination of a degree of certainty that a leak has suddenly decreased, the instructions controlling steps of:
• determining a measure of respiratory airflow to the patient from the flow signal;
• determining an extent A to which the measure has been negative for longer than expected;
• determining an extent B to which the measure is large and negative;
• determining the degree of certainty that a leak has suddenly decreased as a function of extent A and extent B.

An apparatus with coded control circuitry for airway treatment for a patient for determining an extent to which a leak has suddenly changed during airway treatment of a patient comprising:

• means for delivering a controlled supply of pressure support to a patient's airway;
• means for determining a flow signal representative of respiratory airflow to the patient;
• a control means in communication with the means for determining, the control means having coded instructions for controlling a determination of a degree of certainty that a leak has suddenly changed, the instructions controlling steps comprising:
• determining an increase-index of a degree of certainty to which the leak has suddenly increased;
• determining a decrease-index of a degree of certainty to which the leak has suddenly decreased;
• and
• determining the extent to which the leak has suddenly changed as a function of the increase-index and the decrease-index.