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

A method for optimizing the positive airway pressure to a patient, comprising the steps of:

• a) applying an initial level of positive airway pressure of a breathing gas to a patient;
• b) detecting the onset of an inspiratory flow of breathing gas to the patient;
• c) storing an inspiratory flow waveform of breathing gas to the patient;
• d) determining whether the stored inspiratory flow waveform indicates a flow limitation in the patient;
• e) repeating steps b) through d) for a plurality of patient inspirations to create a plurality of peak flow values for flow limited breaths and to create a plurality of peak flow values for non-flow limited breaths;
• f) correlating the inspiratory flow waveform with a pure sine wave to create a first index;
• g) comparing a regression fit of the inspiratory flow waveform with a regression fit of a pure sine wave to create a second index;
• h) comparing a peak value of the inspiratory flow waveform with a peak value of a derivative of the inspiratory flow waveform to create a third index;
• i) comparing a peak value of the inspiratory flow waveform with an average of the plurality of peak flow values for flow limited breaths and with an average of the plurality of peak flow values for non-flow limited breaths to create a fourth index;
• j) calculating a fifth index as a mathematical function of the first index, the second index, the third index and the fourth index, wherein each index includes a weighted coefficient having a range including a value of zero;
• and
• k) increasing the positive airway pressure when the fifth index indicates a flow limitation in the patient.

A method for optimizing the positive airway pressure to a patient, comprising the steps of:

• a) applying an initial level of positive airway pressure of a breathing gas to a patient;
• b) monitoring a first inspiratory flow of breathing gas to the patient;
• c) determining a first index indicative of whether the first inspiratory flow reveals a previous flow limitation in the patient;
• d) monitoring a second inspiratory flow of breathing gas to the patient;
• e) determining a second index indicative of whether the second inspiratory flow reveals a present flow limitation in the patient;
• f) calculating a majority function using the first index and the second index;
• and
• g) increasing the level of positive airway pressure when the second index and the majority function indicate a continued flow limitation in the airway of the patient.

A breathing device for optimizing the positive airway pressure to a patient, comprising:

• means for applying an initial level of positive airway pressure of a breathing gas to a patient;
• means for storing data values representative of the inspiratory flow of breathing gas to the patient;
• means for determining whether the stored data values indicate a flow limitation in the patient;
• and
• means for increasing the positive airway pressure when the stored data values indicate a flow limitation in the patient.

A breathing device for optimizing the positive airway pressure to a patient, comprising:

• a source of breathing gas at controlled positive pressure to the airway of a patient;
• a flow sensor configured to generate first data values representative of an inspiratory flow of breathing gas to the patient;
• computer memory configured to store the first data values generated by said flow sensor;
• a microprocessor configured to generate a first signal when the first data values indicate a flow limitation in the patient;
• and
• a pressure controller responsive to the first signal from said microprocessor and coupled to said source of breathing gas for increasing the positive pressure to the airway of the patient.

An apparatus for providing breathing gas to the airway of a patient, comprising:

• a source of breathing gas at positive pressure to the airway of a patient;
• a sensor configured to generate data values representative of inspiratory flow of breathing gas to the patient;
• a memory device configured to store first data values generated by said sensor, and to store second data values generated by said sensor;
• processing means coupled to said memory device for determining a first index indicative of whether the first data values reveal a first flow limitation in the patient, said processing means further configured to determine a second index indicative of whether the second data values reveal a second flow limitation in the patient and to calculate a majority function using the first index and the second index;
• and
• a pressure controller in operative relationship with said source of breathing gas, said pressure controller responsive to said processing means so as to increase the positive pressure to the airway of the patient when the second index and the majority function indicate a continued flow limitation in the airway of the patient.