Autotitrating method and apparatus

A method of controlling positive airway pressure therapy, comprising the steps of:

• providing a flow of gas to a patient's airway at a supply pressure that does not include forced oscillation at a frequency greater than a breathing rate of a patient;
• obtaining information comprising a discrete energy spectrum from a frequency range of 0 to 25 Hz in a frequency domain of said flow:
• generating at least one information-bearing value from said frequency domain information, wherein said at least one information-bearing value comprises an energy in a first harmonic of said discrete energy spectrum, an energy in a second harmonic of said discrete energy spectrum, a sum of energies of said first harmonic through a thirteenth harmonic of said discrete energy spectrum, and a sum of energies of a fifth harmonic through said thirteenth harmonic of said discrete energy spectrum;
• and
• adjusting said pressure based on said information.

An apparatus for controlling positive airway pressure therapy, comprising:

• a blower for providing a flow of gas to a patient at a pressure that does not include forced oscillation at a frequency greater than a breathing rate of a patient;
• a sensor to measure a characteristic of said flow;
• a controller to obtain information comprising a discrete energy spectrum from a frequency range of 0 to 25 Hz in a frequency domain of said characteristic and to generate at least one information-bearing value from said frequency domain information, wherein said at least one information-bearing value comprises at least an energy in a first harmonic of said discrete energy spectrum and an energy in a second harmonic of said discrete energy spectrum;
• and
• a pressure regulator controlled by said controller for adjusting said pressure based on said information.