Automatic Control System For Mechanical Ventilation For Active Or Passive Subjects
First Claim
1. A method for automatically controlling a ventilator, comprising:
- (a) determining ongoing volume and flow rate of gas to a patient during inspiration;
(b) providing respiratory elastance, K, and airway resistance, K′
, of the patient;
(c) generating control signals controlling pressure applied by the ventilator as a sum of elastic and resistive components of pressure, the elastic component of pressure having a proportionality factor, K1, proportional to the determined volume of the inspiratory gas, and the resistive component of pressure having a proportionality factor, K2, proportional to the determined flow rate of the inspiratory gas; and
(d) automatically adjusting a support level for elastic component of pressure, α
=K1/K, a support level for resistive component of pressure, α
′
=K2/K′
, and the proportionality factors K1 and K2, based on a comparison between a work of breathing for the patient determined by the ventilator and a previously determined work of breathing.
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Abstract
A method and an apparatus for controlling a ventilator to automatically adjust ventilation assistance to an active or passive subject. The method includes determining volume and flow rate of gas to the patient during inspiration on an ongoing basis, and generating control signals in proportion to the volume and flow rate of gas to the patient wherein proportionality factors, and support levels for the elastic and resistive components of pressure are automatically adjusted by the ventilator. The ongoing pressure applied by the ventilator is a sum of elastic and resistive pressures that are automatically controlled by the system. When the patient breathes spontaneously, the support levels are automatically adjusted based on the patient'"'"'s requirements. If the patient does not breathe spontaneously, the ventilator provides ventilation at an optimal level and rate. The method may be used in weaning or in a management phase of ventilation.
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Citations
35 Claims
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1. A method for automatically controlling a ventilator, comprising:
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(a) determining ongoing volume and flow rate of gas to a patient during inspiration; (b) providing respiratory elastance, K, and airway resistance, K′
, of the patient;(c) generating control signals controlling pressure applied by the ventilator as a sum of elastic and resistive components of pressure, the elastic component of pressure having a proportionality factor, K1, proportional to the determined volume of the inspiratory gas, and the resistive component of pressure having a proportionality factor, K2, proportional to the determined flow rate of the inspiratory gas; and (d) automatically adjusting a support level for elastic component of pressure, α
=K1/K, a support level for resistive component of pressure, α
′
=K2/K′
, and the proportionality factors K1 and K2, based on a comparison between a work of breathing for the patient determined by the ventilator and a previously determined work of breathing. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for automatically controlling a ventilator, comprising:
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(a) determining ongoing volume and flow rate of gas to a patient during inspiration; (b) providing respiratory elastance, K, and airway resistance, K′
, of the patient;(c) generating control signals controlling pressure applied by the ventilator as a sum of elastic and resistive components of pressure, the elastic component of pressure having a proportionality factor, K1, proportional to the determined volume of the inspiratory gas, and the resistive component of pressure having a proportionality factor, K2, proportional to the determined flow rate of the inspiratory gas; and (d) automatically adjusting a support level for elastic component of pressure, α
=K1/K, a support level for resistive component of pressure, α
′
=K2/K′
, and the proportionality factors K1 and K2, based on a comparison between a required ventilation for the patient and a measured ventilation for the patient. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. An apparatus for automatically controlling a ventilator, comprising:
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a computing system; digital readable memory coupled to the computing system; one or more transducers providing data to the computing system representing a patient'"'"'s respiratory elastance and airway resistance values and ongoing volume and flow rate of a gas to the patient during inspiration; and a program stored in the memory, the program when executed by the computing system determining support levels for elastic and resistive pressures based on a comparison between a work of breathing for the patient determined by the program and a previously determined level of work of breathing, and determining a level of ongoing pressure support to the patient as a sum of the elastic and resistive pressures based on the determined support levels and the data provided by the transducers, and the computing system generating control signals to the ventilator to achieve the determined support levels for elastic and resistive pressures and the level of ongoing pressure support. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27)
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28. An apparatus for automatically controlling a ventilator, comprising:
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a computing system; digital readable memory coupled to the computing system; one or more transducers providing data to the computing system representing ongoing volume and flow rate of a gas to a patient during inspiration; and a program stored in the memory, the program when executed by the computing system determining support levels for elastic and resistive pressures and a level of ongoing pressure support to the patient as a sum of the elastic and resistive pressures, wherein the support levels for elastic and resistive pressures are determined based on a comparison between a required ventilation for the patient and a measured ventilation for the patient performed by the program, and the ongoing pressure support to the patient is determined based on the support levels for elastic and resistive pressures and the data provided by the transducers, and the computing system generating control signals to the ventilator to achieve the determined support levels for elastic and resistive pressures and the level of ongoing pressure support. - View Dependent Claims (29, 30, 31, 32, 33, 34, 35)
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Specification