Method and apparatus for optimizing the continuous positive airway pressure for treating obstructive sleep apnea

• US 20030055346A1
• Filed: 11/07/2002
• Published: 03/20/2003
• Est. Priority Date: 05/07/1992
• Status: Active Grant

• Current Assignee: David M. Rapoport, Robert G. Norman, Roger A. Gruenke
• Original Assignee: David M. Rapoport, Robert G. Norman, Roger A. Gruenke
• Inventors: Gruenke, Roger A., Norman, Robert G., Rapoport, David M.
• Granted Patent: US 6,793,629 B2
• Time in Patent Office: Days
• US Class Current: 600/489
• CPC Class Codes: A61B 5/0002 Remote monitoring of patients using telemetry, e.g. transmission of vital signals via a communication network A61B5/07 takes precedence; transmission systems for measured values G08C; transmission H04B; transmission of digital information H04L; wireless communication networks H04W
• CPC Class Codes: A61B 5/4818 Sleep apnoea
• CPC Class Codes: A61B 5/6803 Head-worn items, e.g. helmets, masks, headphones or goggles
• CPC Class Codes: A61B 5/7239 using differentiation including higher order derivatives
• CPC Class Codes: A61M 16/0069 the speed thereof being controlled by respiratory parameters, e.g. by inhalation
• CPC Class Codes: A61M 16/026 specially adapted for predicting, e.g. for determining an information representative of a flow limitation during a ventilation cycle by using a root square technique or a regression analysis
• CPC Class Codes: A61M 16/0677 Gas-saving devices therefor
• CPC Class Codes: A61M 2016/0036 in the breathing tube and used in both inspiratory and expiratory phase
• CPC Class Codes: A61M 2016/0039 in the inspiratory circuit
• CPC Class Codes: A61M 2230/005 Parameter used as control input for the apparatus
• CPC Class Codes: A61M 2230/04 Heartbeat characteristics, e.g. ECG, blood pressure modulation
• CPC Class Codes: A61M 2230/08 Other bio-electrical signals
• CPC Class Codes: A61M 2230/205 partial oxygen pressure (P-O2)
• CPC Class Codes: A61M 2230/62 Posture
• CPC Class Codes: A61M 39/228 with a tubular diaphragm constrictable by radial fluid force
• CPC Class Codes: G16H 20/40 relating to mechanical, radiation or invasive therapies, e.g. surgery, laser therapy, dialysis or acupuncture
• CPC Class Codes: G16H 40/63 for local operation
• CPC Class Codes: G16H 50/20 for computer-aided diagnosis, e.g. based on medical expert systems
• CPC Class Codes: G16H 50/30 for calculating health indices; for individual health risk assessment

Abstract

A diagnostic device having a nose fitting used without connection to a breathing gas supply for obtaining flow data values at ambient pressure. The nose fitting is connected to a pressure or flow sensor that supplies data values to a micro-processor. The detection and measurement of breathing gas flow is made from a tight sealing nose fitting (mask or prongs) configured with a resistive element inserted in the flow stream as breathing gas exits from and enters into the fitting. The nasal fitting is further provided with a port for connection to a flow or pressure transducer. The resistive element causes a pressure difference to occur between the upstream side and the downstream side when air flows through the element. The data values may be stored in computer memory to be analyzed for flow limitations.

Claims

1. A device for detecting flow limitation in an airway of a patient, comprising:

a nasal fitting in fluid communication with the airway of the patient, the nasal fitting having an inlet;

a restrictive element in fluid communication with the nasal fitting and disposed between the airway of the patient and the inlet of the nasal fitting;

a sensor in fluid communication with the nasal fitting and restrictive element;

a microprocessor operatively connected to the sensor and configured to define a waveform contour of an inspiratory flow of breathing gas to the patient and to generate first data values representative of the waveform contour, wherein the microprocessor is configured to utilize the waveform contour to detect a flow limitation in the airway of the patient and to generate second data values representative of the flow limitation; and

a computer memory configured to store the first data values and the second data values.

2. The device of claim 1, wherein the microprocessor is further configured to generate third data values representative of an expiratory flow of breathing gas from the patient, and the computer memory is further configured to store the third data values.

3. The device of claim 1, wherein the microprocessor includes processing means-for correlating the first data values with a sinusoidal contour.

4. The device of claim 1, wherein the microprocessor includes processing means for analyzing the first data values for flatness.

5. The device of claim 1, wherein the microprocessor includes processing means for analyzing the first data values for respiratory effort.

6. The device of claim 1, wherein the microprocessor includes processing means for analyzing the first data values for relative flow magnitude.

7. A device for detecting a flow limitation in an airway of a patient, comprising:

means for restricting airflow to an airway of a patient, the means for restricting having a restrictive element disposed between the airway of the patient and an inlet of the means for restricting;

means for sensing an inspiratory flow of breathable gas to the patient, the means for sensing being in fluid communication with the means for restricting and configured to generate a signal corresponding to a waveform contour of the inspiratory flow of breathable gas;

means for storing the signal corresponding to the waveform contour; and

means for detecting a flow limitation in the airway of the patient, the means for detecting being configured to use the stored waveform contour and to determine the amount of flow limiting.

8. The device of claim 7, wherein the means for detecting is configured to generate data values representative of the stored waveform contour to correlate the data values with a pure sine wave to determine a first index, to compare a regression fit of the data values with a regression fit of a pure sine wave to determine a second index, to compare a peak value of the data values with a peak value of a derivative of the data values to determine a third index, and to compare a peak value of the data values with an average of a plurality of peak flow values for flow limited breaths and with an average of a plurality of peak flow values for non-flow limited breaths to determine a fourth index.

9. The device of claim 8, wherein the means for detecting is further configured to determine a fifth index as a function of the first index, the second index, the third index and the fourth index, wherein each index includes a weighted coefficient.

10. A method for diagnosing a patient having obstructive sleep apnea, comprising:

providing a patient with a diagnostic breathing device having an inlet for breathing gas for use while the patient is asleep, the diagnostic breathing device having a flow restrictor positioned between the inlet and an airway of the patient;

generating first data values corresponding to a waveform contour of an inspiratory flow of breathing gas to the patient;

storing the first data values;

analyzing the first data values to determine the presence of a flow limitation in the airway of the patient; and

providing the patient with a self-adjusting therapy breathing device when a flow limitation is detected.

11. The method of claim 10, further comprising:

generating second data values corresponding to a waveform contour of an inspiratory flow of breathing gas to the patient;

generating third data values corresponding to a pressure in the airway of the patient;

storing the second data values and the third data values;

analyzing the second data values to determine the amount of flow limitation in the airway of the patient; and

providing the patient with a self-adjusting therapy breathing device when the third data values indicate large pressure fluctuations.