Detection of apnea and obstruction of the airway in the respiratory system

A method of detecting partial obstruction of the airway of a patient, the method comprising the steps of:

• measuring patient respiratory air flow;
• detecting the inspiratory parts of said air flow;
• normalizing each said inspiratory part by scaling to unity duration, and to unity area with respect to amplitude and duration;
• and
• determining an index value of a mid-portion of one or more of said normalized inspiratory parts as a measure of partial obstruction.

An apparatus for detecting partial obstruction of the airway of a patient, the apparatus comprising:

• air flow measurement means for measuring patient respiratory air flow;
• data processing means coupled to said measurement means to receive said measured air flow, and having a plurality of processing elements including;
• a detection element for detecting the inspiratory parts of said air flow;
• and
• a computational means for determining an index value of a mid-portion of at least one said inspiratory part as a measure of partial obstruction.

A method for detecting partial obstruction of the airway of a patient, the method comprising the steps of:

• measuring patient respiratory air flow;
• detecting the inspiratory part of said air flow;
• and
• determining an index value of a mid-portion of said inspiratory part as a measure of partial obstruction.

A method for determining the degree of patency of the airway of a patient, the method comprising the steps of:

• applying an oscillatory pressure waveform of known frequency and magnitude to the patient's airway;
• measuring respiratory air flow from the patient;
• determining the magnitude of the component of said air flow at said known frequency induced by said oscillatory pressure waveform;
• and
• determining the degree of patency as the ratio of said induced air flow magnitude and said oscillatory pressure waveform magnitude.

Apparatus for detecting partial obstruction of the airway of a patient, the apparatus comprising:

• means for measuring respiratory air flow from the patient;
• means for detecting the inspiratory part of said air flow;
• means for normalising said inspiratory part;
• and
• means for determining an index value of a mid-portion of said normalised inspiratory part as a measure of partial obstruction.

Apparatus for controlling the administration of CPAP treatment to the airway of a patient comprising

• means controllable to supply breathable air to the patient's airway continually at a selectable pressure elevated above atmospheric pressure;
• controlling means for commencing or increasing CPAP treatment pressure if:
• (a) an apnea is occurring, determined by:
• measuring respiratory air flow from the patient as a function of time;
• and
• determining the variance of said measured air flow as an indication of an apnea occurring;
• or (b) there is partial obstruction of the airway, determined by:
• measuring respiratory air flow from the patient;
• detecting the inspiratory part of said air flow;
• normalising said inspiratory part;
• and
• determining an index value of a mid-portion of said normalised inspiratory part as a measure of partial obstruction;
• or (c) there is patency of the airway, determined by:
• (i) applying an oscillatory pressure waveform of known frequency to the patient's airway;
• measuring respiratory air flow from the patient;
• and
• determining that the airway is patent if there is a component of said air flow at said known frequency induced by said oscillatory pressure waveform;
• or (ii) measuring respiratory air flow from the patient;
• and
• analysing said measured air flow to detect the presence of cardiogenic air flow, and if so then the airway is declared patent.

An apparatus for the administration of CPAP treatment, said apparatus comprising:

• a mask to be worn by a patient to provide breathable gas at a pressure elevated above atmospheric pressure continuously to a patient's airway;
• a conduit coupled to said mask;
• a controllable turbine coupled to said conduit to supply at its outlet said pressurized breathable gas to said mask via said conduit;
• control means to control turbine outlet pressure in response to a control signal;
• air flow measurement means for measuring patient respiratory air flow;
• and
• data processing means coupled to said measurement means to receive said measured air flow and for generating said control signal, and having data processing elements including:
• a detection element for detecting the inspiratory parts of said air flow;
• and
• a computational means for determining an index value of a mid-portion of at least one said inspiratory part as a measure of partial obstruction of said patient airway, and if partial obstruction is detected, for causing said control signal to commence or increase said turbine outlet pressure of breathable gas.

An apparatus for detecting partial obstruction of the airway of a patient, the apparatus comprising:

• air flow measurement means for measuring patient respiratory air flow;
• data processing means coupled to said measurement means to receive said measured air flow, and having a plurality of processing elements including;
• a detection element for detecting the inspiratory parts of said air flow;
• and
• a computational means for determining an index value of a mid-portion of at least one said inspiratory part as a measure of partial obstruction;
• a means for applying an oscillatory pressure waveform of known frequency to said airway;
• and wherein said data processing means further includes a spectral analysis element for determining if there is a component of said air flow at said known frequency as induced by said oscillatory pressure waveform as being indicative of potency.

An apparatus for detecting partial obstruction of the airway of a patient, the apparatus comprising:

• air flow measurement means for measuring patient respiratory air flow;
• data processing means coupled to said measurement means to receive said measured air flow, and having a plurality of processing elements including;
• a detection element for detecting the inspiratory parts of said air flow;
• and
• a computational means for determining an index value of a mid-portion of at least one said inspiratory part as a measure of partial obstruction;
• a means far applying an oscillatory pressure waveform of known frequency and magnitude to said airway;
• and wherein said data processing means further includes a measuring element for determining the magnitude of a component of said air flaw at said known frequency induced by said oscillatory pressure waveform;
• and further wherein said computational element determines the degree of patency as a ratio of said measured component magnitude and said oscillatory pressure waveform magnitude.

An apparatus for detecting partial obstruction of the airway of a patient, the apparatus comprising:

• air flow measurement means for measuring patient respiratory air flow;
• data processing means coupled to said measurement means to receive said measured air flow, and having a plurality of processing elements including:
• a detection element for detecting the inspiratory parts of said air flow;
• and
• a computational means for determining an index value of a mid-portion of at least one said inspiratory part as a measure of partial obstruction, said computational means further determines the variance of said measured air flow, and said data processing means further includes a comparing element to compare said variance with a predetermined threshold value, and if said variance falls below said threshold value it is determined that an apnea is occurring,
• a means for applying an oscillatory pressure waveform of known frequency to said airway;
• and wherein said data processing means further includes a spectral analysis element for determining if there is a component of said air flaw at said known frequency as induced by said oscillatory pressure waveform as being indicative of potency.

An apparatus for detecting partial obstruction of an airway of a patient, the apparatus comprising:

• air flow measurement means for measuring patient respiratory air flow;
• data processing means coupled to said measurement means to receive said measured air flow, and having a plurality of processing elements including:
• a detection element for detecting the inspiratory parts of said air flow;
• and
• a computational means for determining an index value of a mid-portion of at least one said inspiratory part as a measure of partial obstruction, said computational means further determines the variance of said measured air flow, and said data processing means further includes a comparing element to compare said variance with a predetermined threshold value, and if said variance falls below said threshold value it is determined that an apnea is occurring;
• a means for applying an oscillatory pressure waveform of known frequency and magnitude to said airway and wherein said data processing means further includes a measuring element for determining magnitude of a component of said air flow at said known frequency induced by said oscillatory pressure waveform;
• and further wherein said computational element determines the degree of patency as a ratio of said measured component magnitude and said oscillatory pressure waveform magnitude.