Servo ventilation using negative pressure support
First Claim
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.
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Accused Products
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.
44 Citations
25 Claims
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1. A system for delivering a flow of gas to an airway of a patient, the system comprising:
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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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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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:
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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. - View Dependent Claims (14, 15, 16, 17, 18, 20, 21, 22, 23)
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19. The method of aim 13, wherein responsive to providing the flow of gas according to the second pressure mode, both the second expiratory pressure and the second inspiratory pressure are above atmospheric pressure.
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24. A system for ventilating a patient, the system comprising:
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means for generating a flow of gas; means for delivering the flow of gas to an airway of a patient via a patient circuit; means for generating output signals related to a characteristic associated with the flow of gas; and means for selectively controlling delivery of the flow of gas to the patient, wherein flow into the patient is positive and the flow out of the patient is negative flow, by; 1) operating in 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) operating in 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 the means for selectively controlling delivery of the flow of gas to the patient 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. - View Dependent Claims (25)
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Specification