Method and apparatus for optimizing the continuous positive airway pressure for treating obstructive sleep apnea
First Claim
1. An apparatus for the treatment of an obstruction in the airway of a patient, comprising:
- a source of breathing gas configured to provide breathing gas flow to a patient and to provide positive pressure in the airway of the patient;
a sensor to detect the flow of the breathing gas to the patient;
a signal processor operatively connected to the sensor and configured to define a waveform contour of an inspiratory flow of the breathing gas to the patient, and further configured to utilize the waveform contour to detect the presence or absence of an obstruction in the airway of the patient; and
a controller operatively connected to the signal processor, the controller being configured to adjust the positive airway pressure to the patient when the signal processor detects the presence or absence of an obstruction in the airway of the patient.
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Abstract
In the treatment of obstructive sleep apnea, a method and apparatus are disclosed for optimizing the controlled positive pressure to minimize the flow of air from a flow generator while still ensuring that flow limitation in the patient'"'"'s airway does not occur. In particular, the invention relates to a breathing device and method of use to adjust a controlled positive pressure to the airway of a patient by detecting flow limitation from analysis of an inspiratory flow waveform. Once the presence of flow limitation has been analyzed, the system determines an action to take for adjustment of the controlled positive pressure. The pressure setting is raised, lowered or maintained depending on whether flow limitation has been detected and on the previous actions taken by the system. The preferred breathing apparatus consists of a flow generator, a flow sensor, an analog to digital converter, a microprocessor, and a pressure controller, a patient supply hose, a nasal fitting, and, optionally, a pressure transducer. Using the method of the present invention, the microprocessor adjusts the air pressure in the patient supply hose when flow limitation is detected in the airway of the patient.
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Citations
20 Claims
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1. An apparatus for the treatment of an obstruction in the airway of a patient, comprising:
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a source of breathing gas configured to provide breathing gas flow to a patient and to provide positive pressure in the airway of the patient;
a sensor to detect the flow of the breathing gas to the patient;
a signal processor operatively connected to the sensor and configured to define a waveform contour of an inspiratory flow of the breathing gas to the patient, and further configured to utilize the waveform contour to detect the presence or absence of an obstruction in the airway of the patient; and
a controller operatively connected to the signal processor, the controller being configured to adjust the positive airway pressure to the patient when the signal processor detects the presence or absence of an obstruction in the airway of the patient. - View Dependent Claims (2)
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3. An apparatus for optimizing the positive pressure in an airway of a patient, comprising:
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means for providing positive pressure of a breathing gas to an airway of a patient;
means for generating a signal corresponding to a waveform contour of an inspiratory flow of breathing gas to the patient;
means for utilizing the wave form contour signal to detect a flow limitation in the airway of the patient; and
means for increasing the positive airway pressure when the means for utilizing detects a flow limitation in the airway of the patient. - View Dependent Claims (4, 5, 6, 7)
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8. An apparatus for optimizing the positive pressure in an airway of a patient, comprising:
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a source of positive pressure of breathing gas provided to an airway of a patient;
a first sensor configured to generate a first signal corresponding to a waveform contour of an inspiratory flow of breathing gas to the patient;
a memory device configured to store the first signal generated by the first sensor;
a microprocessor configured to utilize the first signal to generate a second signal indicative of a flow limitation in the patient; and
a controller operably connected to the source of breathing gas and responsive to the second signal from the microprocessor so as to increase the positive pressure of the breathing gas in response to the second signal. - View Dependent Claims (9, 10, 11, 12, 13)
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14. A method for optimizing the positive pressure in an airway of a patient, comprising:
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providing air at positive pressure to an airway of a patient;
monitoring the flow of air to the patient;
defining an inspiratory waveform contour of the flow of air to the patient;
analyzing the inspiratory waveform contour to determine the presence or absence of a patient airway obstruction; and
adjusting the positive pressure of air to the patient in response to the presence or absence of a patient airway obstruction. - View Dependent Claims (15)
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16. A method for optimizing the positive pressure of breathing gas to an airway of a patient, comprising:
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applying breathing gas at positive pressure to an airway of a patient;
detecting an inspiratory flow of breathing gas to the patient;
generating a signal corresponding to a waveform contour of the inspiratory flow of breathing gas to the patient;
determining whether the waveform contour signal indicates a flow limitation in the airway of the patient; and
increasing the positive pressure of breathing gas when the signal indicates a flow limitation in the airway of the patient. - View Dependent Claims (17, 18, 19, 20)
calculating a first index by comparing the signal with a pure sine wave;
calculating a second index by comparing a regression fit of the signal with a regression fit of a pure sine wave;
calculating a third index by comparing a peak value of the signal with a peak value of a derivative of the signal;
determining peak flow values for a plurality of flow limited breaths;
determining peak flow values for a plurality of non-flow limited breaths; and
calculating a fourth index by comparing a peak value of the signal with an average of the peak flow values for the plurality flow limited breaths and with an average of the peak flow values for the plurality of non-flow limited breaths.
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19. The method of claim 17, wherein determining whether the signal indicates a flow limitation in the airway of the patient further includes calculating a fifth index as a function of the first index, the second index, the third index and the fourth index, wherein the fifth index indicates the presence of flow limitation in the patient.
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20. The method of claim 17, wherein determining whether the signal indicates a flow limitation in the airway of the patient further includes calculating a fifth index as a function of the first index, the second index, the third index and the fourth index, wherein the function includes a weighted coefficient for each of the first, second, third and fourth indexes.
Specification