Servo ventilation using pressure drop from baseline

• US 9,044,560 B2
• Filed: 12/17/2010
• Issued: 06/02/2015
• Est. Priority Date: 01/14/2010
• Status: Active Grant

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips N.V.
• Inventors: Shelly, Benjamin Irwin, Kane, Michael Thomas, Matthews, Gregory Delano
• Primary Examiner(s): DOUGLAS, STEVEN O
• Application Number:
  US13/521,485
• Publication Number:
  US 20130125892A1
• Time in Patent Office: 1,628 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: A61M 16/0009 with sub-atmospheric pressure, e.g. during expiration
• CPC Class Codes: A61M 16/0066 Blowers or centrifugal pumps
• CPC Class Codes: A61M 16/0069 the speed thereof being controlled by respiratory parameters, e.g. by inhalation
• CPC Class Codes: A61M 16/024 including calculation means, e.g. using a processor
• CPC Class Codes: A61M 16/06 Respiratory or anaesthetic masks
• CPC Class Codes: A61M 16/0875 Connecting tubes
• CPC Class Codes: A61M 16/20 Valves specially adapted to medical respiratory devices
• CPC Class Codes: A61M 16/204 used for inhalation control
• CPC Class Codes: A61M 2016/0039 in the inspiratory circuit
• CPC Class Codes: A61M 2205/50 with microprocessors or computers
• CPC Class Codes: A61M 2205/502 User interfaces, e.g. screens or keyboards
• CPC Class Codes: A61M 2205/7518 bacterial
• CPC Class Codes: A61M 2209/01 Remote controllers for specific apparatus

Abstract

A system and method for delivering a flow of breathing gas to an airway of a patient that includes a gas flow generator and a patient circuit that communicates the flow of gas to an airway of a patient. A sensor measures a characteristic associated with the flow of gas, such as flow rate. A controller determines a first characteristic based on the measured characteristic and a target of the flow of gas to be delivered to the patient. The controller controls the delivery of gas to the patient by 1) providing a baseline positive pressure support amount to the patient and 2) providing a modified pressure support amount by reducing the baseline amount by a given amount if the first characteristic is above the target. The baseline pressure includes a pressure provided during inspiration that is higher than a pressure provided during expiration.

Claims

1. A system for delivering a flow of breathing gas to an airway of a patient, the system comprising:

a gas flow generator configured to generate the flow of gas;

a patient circuit coupled to the gas flow generator configured to communicate the flow of gas to an airway of the patient;

a sensor configured to generate output signals related to one or more parameters associated with the flow of gas; and

a controller configured to;

control the flow of breathing gas to the airway of the patient via the patient circuit,

provide an inspiratory pressure level during inspiration and an expiratory pressure level during expiration, and

determine the inspiratory pressure level and the expiratory pressure level based on the one or more parameters associated with the flow of gas such that, responsive to the one or more parameters indicating a hyperneic phase of Cheyne-Stokes Respiration, the expiratory pressure level becomes greater than the inspiratory pressure level.

2. The system of claim 1, wherein the controller determines whether the patient is experiencing a predetermined breathing characteristic based on the one or more parameters associated with the flow of gas, and wherein the controller alters the inspiratory pressure level, the expiratory pressure level, and/or both based on a determination that the patient is experiencing the predetermined breathing characteristic.

3. The system of claim 2, wherein the predetermined breathing characteristic is a sleep disorder breathing event comprising one or more of Cheyne-Stokes Respiration, hypopnea, or apnea.

4. The system of claim 2, wherein the predetermined breathing characteristic is Cheyne-Stokes Respiration, further comprising an oxygen saturation monitor configured to generate output signals related to an oxygen saturation of the patient, and wherein the controller determines whether the patient is experiencing Cheyne-Stokes Respiration based, at least in part, on an output of the oxygen saturation monitor.

5. The system of claim 1, wherein the one or more parameters associated with the flow of gas comprises a flow rate.

6. The system of claim 1, wherein the one or more parameters associated with the flow of gas comprises a Maximum Average Inspiratory Flow (Q_ave(max)).

7. The system of claim 1, wherein the one or more parameters associated with the flow of gas comprises a tidal volume.

8. The system of claim 1, wherein the one or more parameters associated with the flow of gas comprises a minute ventilation.

9. A method of ventilating a patient, comprising:

delivering a flow of gas to an airway of a patient from a source of breathing gas via a patient circuit;

measuring a first characteristic associated with the flow of gas;

determining a target of the flow of gas to be delivered to the patient; and

controlling the delivery of the flow of gas to the airway of the patient from a gas flow generator via the patient circuit by;

1) delivering the flow of gas to the airway of the patient at an inspiratory pressure level during inspiration and an expiratory pressure level during expiration,

2) determining the inspiratory pressure level and the expiratory pressure level based on the first characteristic associated with the flow of gas, and

3) controlling the flow of gas such that the expiratory pressure level is greater than the inspiratory pressure level responsive to the first characteristic indicating a hyperneic phase of Cheyne-Stokes Respiration.

10. The method of claim 9, wherein controlling the delivery of the flow of gas to the airway of the patient comprises maintaining the flow of gas below the target.

11. The method of claim 9, further comprising determining whether the patient is experiencing a predetermined breathing characteristic based on the measured first characteristic and altering the target based on a determination that such a patient is experiencing the predetermined breathing characteristic.

12. The method of claim 11, wherein the predetermined breathing characteristic is a sleep disorder breathing event.

13. The method of claim 12, wherein the sleep disorder breathing event is Cheyne-Stokes Respiration, hypopnea, or apnea.

14. The method of claim 9, wherein the first characteristic is a flow rate.

15. The method of claim 9, further comprising outputting a signal indicative of an oxygen saturation of the patient, and wherein the signal is used to determine whether the patient is experiencing Cheyne-Stokes Respiration.

16. The method of claim 9, wherein the first characteristic is a Maximum Average Inspiratory Flow (Q_ave(max)), a tidal volume, or a minute ventilation.

17. A system for ventilating a patient, comprising:

means to generate a flow of gas;

means to deliver a flow of gas to an airway of a patient from the means to generate the flow of gas;

means to generate output signals related to one or more parameters associated with the flow of gas;

means to control the flow of breathing gas to the airway of the patient via the patient circuit;

means to provide an inspiratory pressure level during inspiration and an expiratory pressure level during expiration; and

means to determine the inspiratory pressure level and the expiratory pressure level based on the one or more parameters associated with the flow of gas such that, responsive to the one or more parameters indicating a hyperneic phase of Cheyne-Stokes Respiration, the expiratory pressure level is greater than the inspiratory pressure level.

18. The system of claim 17, wherein the means to control the flow of gas to the airway of a patient determines, based on the one or more parameters associated with the flow of gas, whether the patient is experiencing a predetermined breathing characteristic, and wherein the means to control alters the inspiratory pressure level, the expiratory pressure level, and/or both based on a determination that the patient is experiencing the predetermined breathing characteristic.

19. The system of claim 18, wherein the predetermined breathing characteristic is a sleep disorder breathing event, Cheyne-Stokes Respiration, hypopnea, or apnea.

20. The system of claim 18, wherein the predetermined breathing characteristic is Cheyne-Stokes Respiration, further comprising means to output a signal indicative of an oxygen saturation of the patient, and wherein the means to control flow determines whether the patient is experiencing Cheyne-Stokes Respiration based, at least in part, on an output of the means to output a signal indicative of oxygen saturation.

21. The system of claim 17, wherein the one or more parameters associated with the flow of gas comprises a flow rate.

22. The system of claim 17, wherein the one or more parameters associated with the flow of gas comprises a Maximum Average Inspiratory Flow (Q_ave(max)).

23. The system of claim 17, wherein the one or more parameters associated with the flow of gas comprises a tidal volume.