Method and apparatus for providing proportional positive airway pressure to treat sleep disordered breathing
First Claim
1. A Proportional Positive Airway Pressure Apparatus for delivering pressurized breathing gas to the airway of a patient, said apparatus comprising:
- means for continuously delivering breathing gas at a minimally sufficient pressure to prevent airway collapse at any given moment during at least a portion of a breathing cycle where the minimally sufficient gas pressure may continuously vary during the at least a portion of a breathing cycle and is responsive to a sensed rate of flow of gas, said minimally sufficient gas pressure being the summation of a pressure needed to prevent airway collapse and a pressure needed to overcome respiratory effort,gas flow generator means for providing a source of gas;
conduit means for delivering gas to the airway of a patient from said source of gas;
circuitry means for providing a command signal to regulate a pressure controller means;
sensor means for continuously detecting the rate of flow of gas within said conduit means and for continuously transmitting signals to said circuitry means corresponding to said rate of flow of gas within said conduit means;
first control means operatively connected to said circuitry means for selectively establishing a first gain to be applied by said circuitry means to first flow rate signals continuously transmitted by said sensor means to said circuitry means, said first flow rate signals corresponding to flow within said conduit means indicative of inspiration;
second control means operatively connected to said circuitry means for selectively establishing a second gain to be applied by said circuitry means to second flow rate signals continuously transmitted by said sensor means to said circuitry means, said second flow rate signals corresponding to flow within said conduit means indicative of expiration, andpressure controller means co-operable with said gas flow generator means for delivering said gas flow within said conduit means and within the airway of a patient at said minimally sufficient gas pressure during the at least a portion of a breathing cycle in proportion to both said first gain and said continuously transmitted first flow rate signals during inspiration and in proportion to both said second gain and said continuously transmitted second flow rate signals throughout expiration in response to said command signal.
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Accused Products
Abstract
A system including methods and apparatus for treatment of Obstructive Sleep Apnea Syndrome (OSAS), Chronic Obstructive Pulmonary Disorder (COPD) and other respiratory disorders. The system involves applying separate and independent gains to flow rates of pressurized gas delivered to a patient during inspiratory and expiratory phases of a respiratory cycle to deliver the pressurized gas in proportion to the respective gains during inspiration and expiration. A base pressure may be applied in addition to the gain-modified pressures and an elevated pressure profile may be employed to assist or control inspiration. The system may be fully automated responsive to feedback provided by a flow sensor that determines the estimated patient flow rate. A leak computer can be included to instantaneously calculate gas leakage from the system. The system may be utilized in connection with conventional continuous positive airway pressure (CPAP) or bi-level positive airway pressure (bi-level PAP) equipment to effect various beneficial respiratory disorder treatment applications.
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Citations
28 Claims
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1. A Proportional Positive Airway Pressure Apparatus for delivering pressurized breathing gas to the airway of a patient, said apparatus comprising:
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means for continuously delivering breathing gas at a minimally sufficient pressure to prevent airway collapse at any given moment during at least a portion of a breathing cycle where the minimally sufficient gas pressure may continuously vary during the at least a portion of a breathing cycle and is responsive to a sensed rate of flow of gas, said minimally sufficient gas pressure being the summation of a pressure needed to prevent airway collapse and a pressure needed to overcome respiratory effort, gas flow generator means for providing a source of gas; conduit means for delivering gas to the airway of a patient from said source of gas; circuitry means for providing a command signal to regulate a pressure controller means; sensor means for continuously detecting the rate of flow of gas within said conduit means and for continuously transmitting signals to said circuitry means corresponding to said rate of flow of gas within said conduit means; first control means operatively connected to said circuitry means for selectively establishing a first gain to be applied by said circuitry means to first flow rate signals continuously transmitted by said sensor means to said circuitry means, said first flow rate signals corresponding to flow within said conduit means indicative of inspiration; second control means operatively connected to said circuitry means for selectively establishing a second gain to be applied by said circuitry means to second flow rate signals continuously transmitted by said sensor means to said circuitry means, said second flow rate signals corresponding to flow within said conduit means indicative of expiration, and pressure controller means co-operable with said gas flow generator means for delivering said gas flow within said conduit means and within the airway of a patient at said minimally sufficient gas pressure during the at least a portion of a breathing cycle in proportion to both said first gain and said continuously transmitted first flow rate signals during inspiration and in proportion to both said second gain and said continuously transmitted second flow rate signals throughout expiration in response to said command signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method of providing Proportional Positive Airway Pressure to the airway of a patient, said method comprising the steps of:
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providing means for continuously delivering breathing gas at a minimally sufficient pressure to prevent airway collapse at any given moment during at least a portion of a breathing cycle where the minimally sufficient gas pressure may continuously vary during the at least a portion of a breathing cycle and is responsive to a sensed rate of flow of gas, said minimally sufficient gas pressure being the summation of a pressure needed to prevent airway collapse and a pressure needed to overcome respiratory effort, providing a source of gas; supplying gas to the airway of a patient from said source of gas; substantially continuously determining the flow rate of gas between said source and the airway of a patient; applying a first gain to a determined flow rate of gas indicative of inspiration; applying a second gain to a determined flow rate of gas indicative of expiration; and delivering said minimally sufficient gas pressure in proportion to said first gain and said determined flow rate during inspiration and in proportion to said second gain and said determined flow rate throughout expiration. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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26. A method of providing Proportional Positive Airway Pressure to the airway of a patient, said method comprising the steps of:
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providing means for continuously delivering breathing gas at a minimally sufficient pressure to prevent airway collapse at any given moment during expiration where the minimally sufficient gas pressure may continuously vary during expiration and is responsive to a sensed rate of flow of gas, said minimally sufficient gas pressure being the summation of a pressure needed to prevent airway collapse and a pressure needed to overcome respiratory effort, providing a source of gas; supplying gas to the airway of a patient from said source of gas; substantially continuously determining the flow rate of gas between said source and the airway of a patient; applying a gain to a determined flow rate of gas indicative of expiration; and delivering continuous positive airway pressure during inspiration and said minimally sufficient gas pressure in proportion to said second gain and in proportion to said determined flow rate throughout expiration.
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27. A method of providing Proportional Positive Airway Pressure to the airway of a patient, said method comprising the steps of:
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providing means for continuously delivering breathing gas at a minimally sufficient pressure to prevent airway collapse at any given moment during expiration where the minimally sufficient gas pressure may continuously vary during expiration and is responsive to a sensed rate of flow of gas said minimally sufficient gas pressure being the summation of a pressure needed to prevent airway collapse and a pressure needed to overcome respiratory effort, providing a source of gas; supplying gas to the airway of a patient from said source of gas; substantially continuously determining the flow rate of gas between said source and the airway of a patient; applying a gain to a determined flow rate of gas indicative of expiration; and delivering inspiratory positive airway pressure during inspiration and, throughout expiration, providing expiratory positive airway pressure at a lower pressure than said inspiratory positive airway pressure in addition to gas pressure in proportion to said second gain and said determined flow rate.
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28. A method of providing Proportional Positive Airway Pressure to the airway of a patient, said method comprising the steps of:
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providing means for continuously delivering breathing gas at a minimally sufficient pressure to prevent airway collapse at any given moment during a portion (t1 to t0) of a breathing cycle where the minimally sufficient gas pressure may continuously vary during the portion (t1 to t0) of a breathing cycle and is responsive to a sensed rate of flow of gas, said minimally sufficient gas pressure being the summation of a pressure needed to prevent airway collapse and a pressure needed to overcome respiratory effort, providing 0a source of gas; supplying gas to the airway of a patient; substantially continuously determining the flow rate of gas between said source and the airway of a patient; and delivering gas pressure to the airway of a patient in accordance with the equations;
space="preserve" listing-type="equation">P.sub.inhalation (t.sub.0 to t.sub.1)=IPAPand
space="preserve" listing-type="equation">P.sub.inhalation (t.sub.1 to t.sub.2)=P.sub.base +AutoGain.sub.Insp * Flow at t.sub.1and
space="preserve" listing-type="equation">P.sub.exhalation =P.sub.base +Gain.sub.Exp * Flow,where Flow is the continuously determined estimated flow rate, t0 is the time at the start of breath, t1 is the time when the estimated flow rate is a predetermined percentage of peak inspiratory flow rate, t2 is the time at start of exhalation, IPAP is a continuously applied inspiratory positive airway pressure, Pinhalation (t0 to t1) is the pressure delivered to the patient from tO to t1, Pbase is a continuous base pressure, AutoGainInsp equals (IPAP-Pbase)/Flow at t1, Pinhalation t1 to t2 is the pressure delivered to the patient from t1 to t2, GainExp is the constant used during exhalation to reduce pressure delivered to the patient and Pexhalation is the pressure delivered to the patient throughout exhalation.
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Specification