Apparatus for gas delivery

• US 6,397,845 B1
• Filed: 12/08/1998
• Issued: 06/04/2002
• Est. Priority Date: 10/31/1995
• Status: Expired due to Fees

• Current Assignee: Compumedics Limited
• Original Assignee: Compumedics Limited
• Inventors: Burton, David
• Primary Examiner(s): Weiss, John G.
• Assistant Examiner(s): WEISS JR, JOSEPH
• Application Number:
  US09/066,421
• Time in Patent Office: 1,274 Days
• Field of Search: 128/204.18, 128/204.21, 128/204.23, 128/204.26, 600/529, 600/533, 600/534
• US Class Current: 128/204.23
• CPC Class Codes: A61F 5/56 Devices for preventing snoring by influencing the respiratory system by gas treatment A61M16/00
• CPC Class Codes: A61M 16/0051 with alarm devices
• CPC Class Codes: A61M 16/024 including calculation means, e.g. using a processor
• CPC Class Codes: A61M 2016/0021 with a proportional output signal, e.g. from a thermistor
• 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 2230/10 Electroencephalographic signals
• CPC Class Codes: A61M 2230/18 Rapid eye-movements [REM]
• CPC Class Codes: A61M 2230/43 Composition of exhalation
• CPC Class Codes: A61M 2230/60 Muscle strain, i.e. measured on the user

Abstract

An apparatus for controlling gas delivery to a patient is disclosed, wherein delivery is adapted to maintain a physiological sleep state. The apparatus includes a monitoring device that monitors EEG, EOG, EMG, patient position and patient breathing. The apparatus also contains a microprocessor, which is programmed to derive sleep state specific indicators from the data received by the monitoring device and to determine if the sleep state is in a stable or deteriorating phase, where upon gas pressure will be automatically adjusted to maintain the sleep state if desired. The microprocessor is programmed with a unique automatic sleep staging algorithm and a gas pressure seek algorithm which work together to automatically adjust delivered respiratory gas pressure to a user based upon the determined sleep state and the sleep states condition.

Claims

1. An apparatus for controlling gas delivery to a patient to enhance sleep efficiency of the patient during the gas delivery, said apparatus including:

a monitoring component adapted to monitor at least one sleep state physiological variable of a patient during an application of a positive gas pressure to an airway of the patient, to provide monitoring information representing the at least one sleep state physiological variable; and

a digital processing component programmed to include a deriving component in communication with the monitoring component, said deriving component comprising a sleep staging algorithm to automatically derive a plurality of sleep states of the patient based on the monitoring information, the plurality of sleep states including at least two sleep states selected from the group comprising sleep stages 1-4, REM, micro-arousal, arousal and wake, corresponding to the at least one sleep state physiological variable;

said digital processing component further including a pressure value determining component receiving said plurality of sleep states to determine a plurality of gas pressure values, each one of the gas pressure values corresponding to each one of the sleep states,

said gas pressure values being applicable to control a gas delivery device to control said positive gas pressure in accordance with the gas pressure values.

2. The apparatus according to claim 1 wherein said at least one physiological variable is selected from the group of variables consisting of EEG, EOG, EMG, patient position, and patient breathing.

3. The apparatus according to claim 1 wherein the sleep staging algorithm is adapted for evaluating arousal states.

4. The apparatus according to claim 1 wherein the sleep staging algorithm is adapted for evaluating respiratory events.

5. The apparatus according to claim 1 wherein the determining component includes a pressure seek algorithm.

6. The apparatus according to claim 1 further including a patient state table for storing said data.

7. The apparatus according to claim 1 further including a pressure set look-up table for storing said pressure values.

8. The apparatus according to claim 1 further including an air delivery interface for receiving the gas pressure values, and a gas delivery device operably associated with the interface for delivering a gas to the patient in accordance with the gas pressure values.

9. The apparatus according to claim 1 wherein the sleep state physiological variable of the patient monitored by the monitoring component is the relative patient position.

10. A method for controlling gas delivery to a patient, said delivery being adapted to maintain patient sleep efficiency, said method including

monitoring at least one sleep state physiological variable of a patient, to provide monitoring information representing the at least one physiological variable;

using the monitoring information in an automatic sleep staging algorithm to derive, a plurality of sleep states of the patient, including at least two sleep states selected from the group including sleep stages 1-4, REM, micro-arousal, arousal and wake, corresponding to the at least one sleep state physiological variable;

using the plurality of sleep states to determine a plurality of gas pressure values, each one of the gas pressure values corresponding to each of the sleep states, each gas pressure value being optimal with respect to its associated sleep state in that a deviation from the gas pressure represented by the associated gas pressure value signifies a deterioration in the sleep efficiency; and

using the gas pressure values to control a delivery of a gas to the patient.

11. The method of claim 10 wherein the control of the delivery of a gas to the patient comprises controlling an application of a positive gas pressure to an airway of the patient.

12. The method according to claim 10 wherein said physiological variable is selected from the group consisting of EEG, EOG, EMG, patient position, and patient breathing.

13. The method according to claim 10 wherein said deriving and said determining are performed using a programmed processing device.

14. The method according to claim 10 wherein said determining comprises using a pressure seek algorithm.

15. The method according to claim 10 wherein said deriving comprises deriving the plurality of sleep states during respective epochs of a monitored period, and storing the data in a patient state table.

16. The method according to claim 10 further including storing the gas pressure values in a pressure set look-up table.

17. An apparatus for controlling the delivery of a gas to a patient in accordance with sleep states of the patient, including:

a monitoring device for monitoring at least one sleep state physiological variable of a patient, a digital processing device coupled to the monitoring device for deriving plurality of sleep states of the patient using an automatic sleep staging algorithm, at least two of the sleep states being selected from the group including sleep stages 1-4, REM, micro-arousal, arousal and wake;

a processor coupled to receive the data and including a pressure set look-up table containing a plurality of gas pressure values, each gas pressure value associated with one of the sleep states;

an interface coupled to the processor to receive the gas pressure values corresponding to the respective states; and

a gas delivery device operably associated with the interface to deliver the gas to the patient in accordance with the gas pressure values.

18. The apparatus of claim 17 wherein the gas delivery device includes a CPAP device.

19. An apparatus for controlling gas delivery to a patient to enhance sleep efficiency of the patient during the gas delivery, said apparatus including:

a monitoring component adapted to monitor at least one physiological variable of a patient during an application of a positive gas pressure to an airway of the patient, to provide monitoring information representing the at least one physiological variable, wherein the at least one physiological variable is selected from the group consisting of;

brain waves, eye movement, heartbeat, muscle function, and patient position; and

a digital processing component programmed to include a deriving component in communication with the monitoring component to receive the monitoring information and, based on the monitoring information, using an automatic sleep staging algorithm to derive a plurality of sleep states of the patient corresponding to the at least one physiological variable;

said processing component further including a pressure value determining component receiving said plurality of sleep states, and, based on the sleep states, determining a plurality of gas pressure values, one of the gas pressure values corresponding to each one of the sleep states, said gas pressure values being applicable to control a gas delivery device to control said positive gas pressure in accordance with the gas pressure values.

20. The apparatus according to claim 19, wherein said sleep states are selected from the group including sleep stages 1-4, REM, micro-arousal, arousal and wake.

21. The apparatus according to claim 19 further including an air delivery interface for receiving the gas pressure values, and a gas delivery device operably associated with the interface for delivering a gas to the patient in accordance with the gas pressure values.

22. An apparatus for controlling gas delivery to a patient to enhance sleep efficiency of the patient during the gas delivery, said apparatus including:

a gas delivery device for an application of a positive gas pressure to an airway of the patient;

a monitoring component adapted to monitor at least one physiological variable indicative of a sleep state of the patient during the application of the positive gas pressure, to provide monitoring information representing the at least one physiological variable; and

a digital processing component, said digital processing component programmed to include;

a sleep state deriving component, comprising an automatic sleep staging algorithm, in communication with the monitoring component to receive the monitoring information and, based on the monitoring information, to derive a plurality of sleep states of the patient corresponding to the at least one physiological variable; and

a pressure value determining component receiving said sleep states and, based on the sleep states, determining a plurality of gas pressure values for controlling the application of the positive gas pressure, each one of the gas pressure values corresponding to each one of the sleep states.

23. The apparatus of claim 22, wherein the at least one physiological variable is selected from the group consisting of brain waves, eye movement, heartbeat, muscle function, and patient position.

24. The apparatus of claim 22, wherein the automatic sleep staging algorithm is operable to determine probabilities of sleep and wake, percentages of delta, subdelta and beta bands, and an averaged amplitude of waveforms, from the at least one physiological variable.

25. The apparatus of claim 22, wherein the plurality of sleep states are selected from the group consisting of sleep stages 1-4, REM, micro-arousal, arousal and wake.

26. The apparatus of claim 22 wherein the at least one physiological variable monitored by the monitoring component is the relative patient position.

27. An apparatus for controlling gas delivery to a patient to enhance sleep efficiency of the patient during the gas delivery, said apparatus including:

a gas delivery device for an application of a positive gas pressure to an airway of the patient;

a monitoring component adapted to monitor relative position of the patient during the application of the positive gas pressure, to provide monitoring information representing relative patient position; and

a digital processing component, said digital processing component programmed to include;

a patient position deriving component, comprising a patient position algorithm, in communication with the monitoring component to receive the monitoring information and, based on the monitoring information, to derive a plurality of patient position conditions; and

a pressure value determining component receiving said patient position conditions and, based on the patient position conditions, determining a plurality of gas pressure values for controlling the application of the positive gas pressure, each one of the gas pressure values corresponding to each one of the patient position conditions.

28. An apparatus for controlling gas delivery to a patient to enhance sleep efficiency of the patient during the gas delivery, said apparatus including:

a monitoring component adapted to monitor at least one physiological variable of a patient during an application of a positive gas pressure to an airway of the patient, to provide monitoring information representing the at least one physiological variable, wherein the at least one physiological variable is selected from the group consisting of;

brain waves, eye movement, heartbeat, muscle function, and patient position; and

a digital processing component programmed to include a deriving component in communication with the monitoring component to receive the monitoring information and, based on the monitoring information, using an automatic sleep staging algorithm to derive a plurality of sleep slates of the patient corresponding to the at least one physiological variable; and

using a patient position algorithm to derive a plurality of patient position conditions corresponding to the patient position, said processing component further including a pressure value determining component receiving said plurality of sleep states and said plurality of patient position conditions, and, based on the sleep states and patient position conditions, determining a plurality of gas pressure values, one of the gas pressure values corresponding to each one of the sleep states, said gas pressure values being applicable to control a gas delivery device to control said positive gas pressure in accordance with the gas pressure values.