Method and apparatus for optimizing the continuous positive airway pressure for treating obstructive sleep apnea
First Claim
1. A breathing device for optimizing the positive airway pressure to a patient, comprising:
- a source of breathing gas applied at a positive pressure to the airway of a patient;
a sensor configured to generate data values representative of an inspiratory flow of breathing gas to the patient;
a microprocessor configured to process the data values, wherein the microprocessor is further configured to calculate, a sinusoidal index as a correlation coefficient of an actual total inspiratory flow wave to a reference sinusoidal half wave, a flatness index as a representation of a degree of flatness or curvature present in the total inspiratory waveform, a respiratory effort index as a comparison of a peak value of the data values with a peak value of a derivative of the data values, and a relative flow index as a peak flow of an inspiratory flow waveform minus a peak flow of a previous inspiratory flow waveform indicating a flow limitation, divided by a running average of peak flows of non-limited breaths minus an average of peak flows of flow limited breaths; and
a controller coupled to the source of breathing gas and associated with the microprocessor, wherein the controller is configured to adjust the positive pressure in response to the microprocessor.
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Abstract
A breathing apparatus is provided for the treatment of obstructive sleep apnea that optimizes the positive pressure to the airway of a patient. The apparatus is configured to detect flow limitations in the patient airway from an analysis of inspiratory flow waveforms. The airway pressure setting is raised, lowered or maintained depending on whether a flow limitation has been detected and on the previous actions taken by the apparatus. The apparatus may include a blower, a flow sensor, a pressure sensor, a microprocessor, a pressure controller and a nasal fitting. The apparatus is configured to increase the airway pressure when a flow limitation is detected in the airway of the patient and to decrease the airway pressure when a flow limitation is not detected.
111 Citations
20 Claims
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1. A breathing device for optimizing the positive airway pressure to a patient, comprising:
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a source of breathing gas applied at a positive pressure to the airway of a patient;
a sensor configured to generate data values representative of an inspiratory flow of breathing gas to the patient;
a microprocessor configured to process the data values, wherein the microprocessor is further configured to calculate, a sinusoidal index as a correlation coefficient of an actual total inspiratory flow wave to a reference sinusoidal half wave, a flatness index as a representation of a degree of flatness or curvature present in the total inspiratory waveform, a respiratory effort index as a comparison of a peak value of the data values with a peak value of a derivative of the data values, and a relative flow index as a peak flow of an inspiratory flow waveform minus a peak flow of a previous inspiratory flow waveform indicating a flow limitation, divided by a running average of peak flows of non-limited breaths minus an average of peak flows of flow limited breaths; and
a controller coupled to the source of breathing gas and associated with the microprocessor, wherein the controller is configured to adjust the positive pressure in response to the microprocessor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A breathing device for optimizing the positive airway pressure to a patient, comprising:
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means for applying an initial level of positive airway pressure of a breathing gas to a patient;
means for storing data values representative of an inspiratory flow of breathing gas to the patient;
means for determining whether the stored data values indicate a flow limitation in the patient, wherein the means for determining includes means for using the stored data values to calculate a sinusoidal index, a flatness index, a effort index and a relative flow magnitude index; and
means for adjusting the positive airway pressure in response to the means for determining. - View Dependent Claims (14, 15, 16, 17, 18)
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19. A method for optimizing the positive airway pressure to a patient, comprising:
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applying breathing gas at a positive pressure to the airway of a patient;
generating data values representative of an inspiratory flow of breathing gas to the patient;
configuring a microprocessor to process the data values and to calculate, a sinusoidal index as a correlation coefficient of an actual total inspiratory flow wave to a reference sinusoidal half wave, a flatness index as a representation of a degree of flatness or curvature present in a total inspiratory waveform, a respiratory effort index as a comparison of a peak value of the data values with a peak value of a derivative of the data values, and a relative flow index as a peak flow of an inspiratory flow waveform minus a peak flow of a previous inspiratory flow waveform indicating a flow limitation, divided by a running average of peak flows of non-limited breaths minus an average of peak flows of flow limited breaths; and
adjusting the positive pressure to the airway of a patient in response to the microprocessor. - View Dependent Claims (20)
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Specification