Servo ventilation using negative pressure support

Patent metadata

Field	Value
Publication number	US-9463293-B2
Application number	US-201013521451-A
Country	US
Kind code	B2
Filing date	Dec 17, 2010
Priority date	Jan 14, 2010
Publication date	Oct 11, 2016
Grant date	Oct 11, 2016

Abstract

A system for delivering a flow of breathing gas to a patient's airway that includes a gas flow generator and a patient circuit for communicating the flow of gas to the patient's airway. A sensor measures a characteristic associated with the flow of gas, such as flow rate, maximum average inspiratory flow, tidal volume or minute ventilation. A controller determines a first characteristic based on the measured characteristic and provides positive pressure support to the patient if the first characteristic is below a first target and provides a negative support if the first characteristic is above a second target. When the positive pressure support is provided, the pressure provided during inspiration is higher than the pressure provided during expiration. When the negative pressure support is provided, the pressure provided during inspiration is lower than the pressure provided during expiration.

First claim

What is claimed is:

1. A system for delivering a flow of 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 the airway of the patient;
a sensor configured to generate output signals related to a characteristic associated with the flow of gas; and
a controller configured to selectively control the flow of gas to the airway of the patient, wherein flow into the patient is positive flow and flow out of the patient is negative flow, from the gas flow generator via the patient circuit by operating in:
1) a first pressure mode responsive to the characteristic being below a first threshold, wherein the first pressure mode comprises providing the gas to the patient at a first inspiratory pressure during inspiration and a first expiratory pressure during expiration, and wherein the first inspiratory pressure is higher than the first expiratory pressure; and
2) a second pressure mode responsive to the characteristic being above a second threshold, wherein the second pressure mode comprises providing the gas to the patient at a second inspiratory pressure during inspiration and a second expiratory pressure during expiration, wherein the second expiratory pressure is higher than the second inspiratory pressure, and wherein the controller is configured such that the first inspiratory pressure is a first inspiratory positive airway pressure (IPAP) level and the first expiratory pressure is a first expiratory positive airway pressure (EPAP) level, and wherein the first IPAP level is higher than the first EPAP level in the first pressure mode; and wherein the second inspiratory pressure is a second IPAP level and the second expiratory pressure is a second EPAP level, and wherein the second EPAP level is higher than the second IPAP level in the second pressure mode; and whereby the first IPAP, first EPAP, second IPAP, and second EPAP are positive gas pressure in a flow direction towards the patient.

2. The system of claim 1 , wherein the controller is configured to detect a predetermined breathing characteristic of the patient based on the characteristic associated with the flow of gas, and wherein the controller operates in the second pressure mode responsive to the predetermined breathing characteristic and the characteristic associated with the flow of gas being above the second threshold.

3. The system of claim 2 , wherein the characteristic associated with the flow of gas is a sleep disorder breathing event.

4. The system of claim 3 , wherein the controller alters the first threshold and the second threshold based on a determination that the patient is experiencing a sleep disordered breathing event.

5. The system of claim 3 , wherein the sleep disorder breathing event is Cheyne-Stokes Respiration, hypopnea, or apnea.

6. The system of claim 1 , wherein the characteristic associated with the flow of gas is Cheyne-Stokes Respiration, wherein the system further comprises an oxygen saturation monitor adapted to output a signal indicative of 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.

7. The system of claim 1 , wherein the characteristic associated with the flow of gas is a flow rate.

8. The system of claim 1 , wherein, responsive to the controller operating in the second pressure mode, the second expiratory pressure and the second inspiratory pressure are above atmospheric pressure.

9. The system of claim 1 , wherein the first threshold is the same as the second threshold.

10. The system of claim 1 , wherein the characteristic associated with the flow of gas is a Maximum Average Inspiratory Flow (Qave(max)), wherein the controller compares the Qave(max) to the first threshold and the second threshold, and wherein the controller controls the system based on this comparison.

11. The system of claim 1 , wherein the characteristic associated with the flow of gas is a tidal volume, wherein the controller compares the tidal volume to the first threshold and the second threshold, and wherein the controller controls the system based on this comparison.

12. The system of claim 1 , wherein the characteristic associated with the flow of gas is a minute ventilation, wherein the controller compares the minute ventilation to the first threshold and the second threshold, and wherein the controller controls the system based this comparison.

13. A method of ventilating a patient with a gas delivery system, the gas delivery system comprising a patient circuit, a sensor, and a controller, the method comprising:
delivering a flow of gas to an airway of the patient from a source of breathing gas via the patient circuit;
generating, with the sensor, output signals related to a characteristic associated with the flow of gas; and
selectively controlling, with the controller, delivery of the flow of gas to the patient, wherein flow into the patient is positive flow and flow out of the patient is negative flow, by:
1) providing the flow of gas according to a first pressure mode responsive to the characteristic being below a first threshold, wherein the first pressure mode comprises providing the gas to the patient at a first inspiratory pressure during inspiration and patient first expiratory pressure during expiration, and wherein the first inspiratory pressure is higher than the first expiratory pressure; and
2) providing the flow of gas according to a second pressure mode responsive to the characteristic being above a second threshold, wherein the second pressure mode comprises providing the gas to the patient at a second inspiratory pressure during inspiration and a second expiratory pressure during expiration, wherein the second expiratory pressure is higher than the second inspiratory pressure, and wherein the first inspiratory pressure is a first inspiratory positive airway pressure (IPAP) level and the first expiratory pressure is a first expiratory positive airway pressure (EPAP) level, and wherein the first IPAP level is higher than the first EPAP level in the first pressure mode; and wherein the second inspiratory pressure is a second IPAP level and the second expiratory pressure is a second EPAP level, and wherein the second EPAP level is higher than the second IPAP level in the second pressure mode; and whereby the first IPAP, first EPAP, second IPAP, and second EPAP are positive gas pressure in a flow direction towards the patient.

14. The method of claim 13 , wherein controlling the delivery of the flow of gas to the patient comprises detecting a predetermined breathing characteristic of the patient based on the characteristic associated with the flow of gas, and providing the flow of gas according to the second pressure mode to the patient responsive to the predetermined breathing characteristic being detected and the characteristic associated with the flow of gas being above the second threshold.

15. The method of claim 14 , wherein the predetermined breathing characteristic is a sleep disorder breathing event.

16. The method of claim 15 , wherein controlling the delivery of the flow of gas to the patient comprises altering the first threshold and the second threshold based on a determination that the patient is experiencing a sleep disordered breathing event.

17. The method of claim 15 , wherein the sleep disorder breathing event is Cheyne-Stokes Respiration, hypopnea, or apnea.

Assignees

• Shelly Benjamin Irwin
• Kane Michael Thomas
• Matthews Gregory Delano
• Koninklijke Philips Nv

Inventors

• Shelly Benjamin Irwin
• Kane Michael Thomas
• Matthews Gregory Delano

Classifications

• A61M2205/3355

  Controlling downstream pump pressure · CPC title

• A61M2205/3365

  Rotational speed · CPC title

• A61M2205/3337

  Controlling, regulating pressure or flow by means of a valve by-passing a pump · CPC title

• A61M2205/33

  Controlling, regulating or measuring · CPC title

• A61M2016/0015

  inhalation detectors · CPC title