FLOW RESPONSIVE RESPIRATION APPARATUS

• US 3,817,246 A
• Filed: 12/11/1972
• Issued: 06/18/1974
• Est. Priority Date: 12/11/1972
• Status: Expired due to Term

• Current Assignee: James Weigl
• Original Assignee: James Weigl
• Inventors: Weigl, James
• Primary Examiner(s): Gaudet, Richard A.
• Assistant Examiner(s): Dunne, G. F.
• Application Number:
  US05/313,983
• Time in Patent Office: 554 Days
• Field of Search: 128/145.8,145.6,145.7,145.5,145 137/842
• US Class Current: 128/204.24
• CPC Class Codes: A61M 16/00 Devices for influencing the respiratory system of patients by gas treatment, e.g. mouth-to-mouth respiration; Tracheal tubes stimulating the respiratory movement by mechanical, pneumatic or electrical means, iron lungs combined with gas breathing means A61H31/00
• CPC Class Codes: A61M 16/0063 Compressors
• CPC Class Codes: A61M 16/0866 Passive resistors therefor
• CPC Class Codes: A61M 16/107 in the inspiratory path
• CPC Class Codes: A61M 2016/003 with a flowmeter
• CPC Class Codes: A61M 2205/42 Reducing noise
• CPC Class Codes: G01F 23/161 for discrete levels G01F23/162 - G01F23/165 take precedence
• CPC Class Codes: Y10T 137/2273 Device including linearly-aligned power stream emitter and power stream collector

Abstract

Respiration apparatus for IPPB therapy in which the inspiratory effort of the patient to initiate an inspiration phase is sensed by a flow sensor which operates by directing a laminar jet of gas across a conduit of the apparatus toward a receiver, to produce a normal pressure in the receiver when there is no flow in the conduit. A second receiver establishes a reference pressure, and the change in the pressure relationship between the receivers, resulting when the patient creates a cross-flow across the jet, is used as a pilot signal to operate an actuator for opening a flow control valve. Similarly, as the flow rate is reduced near the end of the inspiration phase, the pressure relationship is restored and the actuator closes the control valve. One embodiment uses a laminar jet that is directed into an aligned receiver to raise the pressure therein relative to a receiver spaced from the jet, and referenced to actual patient delivery pressure, until a cross-flow disturbance changes the jet to turbulent, thereby reducing the pressure in the aligned receiver. Another embodiment uses a turbulent jet directed between two longitudinally spaced receivers, disposed in close proximity to one another, to establish equal pressures therein until the jet is deflected longitudinally toward one of the receivers and away from the other in response to a cross-flow.

Claims

1. Flow responsive respiration apparatus for administering intermittent positive pressure breathing therapy to a patient from a source of gas under pressure and through delivery means into which the patient breaths to initiate an inspiration phase of a respiration cycle, said apparatus having, in combination:

conduit means connectible between said source and said delivery means for carrying gas intermittently therebetween;

a flow control valve in said conduit means having an inlet port connected to said source by said conduit means, an outlet port connected to said delivery means by said conduit means, a closure member movable between a first position establishing communication between said ports and a second position disconnecting said ports, and pressure-responsive means for moving said closure member to said first positive in response to a first pressure signal, and to said second position in response to a second pressure signal;

a flow sensor in said conduit means adjacent said delivery means comprising means for directing a jet of gas across said conduit means, and a receiver spaced from said jet-directing means to be pressurized thereby in accordance with the condition of said jet, to a first pressure level when there is no cross-flow in said conduit means and to a second pressure level when there is a cross-flow resulting from breathing by the patient;

actuator means connected to said flow control valve and to said flow sensor and operable to produce said first pressure signal when said first pressure level exists in said receiver, and to produce said second pressure signal when said second pressure level exists in said receiver, thereby to open said flow control valve and initiate the inspiration phase in response to breathing by the patient through said flow sensor; and

means for reducing the rate of flow of gas through said apparatus to the patient in response to increasing back pressure therein as the lungs of the patient are inflated, and thereby to reduce the flow rate through said flow sensor during said inspiration phase until said first pressure level is restored, to close said flow control valve and terminate the inspiration phase.

2. Flow responsive respiration apparatus for administering intermittent positive pressure breathing therapy to a patient from a source of gas under pressure and through delivery means into which the patient breaths to initate an inspiration phase of a respiration cycle, said apparatus having, in combination:

conduit means connectible between said source and said delivery means for carrying gas intermittently therebetween;

a flow control valve in said conduit means having an inlet port connected to said source by said conduit means, an outlet port connected to said delivery and means for reducing the rate of flow of gas through said apparatus to the patient in response to increasing back pressure therein as the lungs of the patient are inflated, and thereby to reduce the flow rate through said flow sensor during said inspiration phase until said first pressure level is restored, to close said flow control valve and terminate the inspiration phase; and

wherein said flow sensor has a first receiver aligned with said jet, said jet-directing means maintains laminar flow in said jet at said first receiver only until said cross-flow disturbs the jet, and the resulting change to turbulent flow produces a marked pressure drop in said first receiver, said sensor also having a second receiver spaced from said first receiver to establish a reference pressure level with respect to which said first and second pressure levels are detectable in said actuator means.

3. Flow responsive respiration apparatus for administering intermittent positive pressure breathing thereApy to a patient from a source of gas under pressure and through delivery means into which the patient breathes to initiate an inspiration phase of a respiration cycle, said apparatus having, in combination:

conduit means connectible between said source and said delivery means for carrying gas intermittently therebetween;

a flow control valve in said conduit means having an inlet port connected to said source by said conduit means, an outlet port connected to said delivery means by said conduit means, a closure member movable between a first position establishing communication between said ports and a second position disconnecting said ports, and pressure-responsive means for moving said closure member to said first position in response to a first pressure signal, and to said second position in response to a second pressure signal;

a flow sensor in said conduit means adjacent said delivery means comprising means for directing a jet of gas across said conduit means, and a receiver spaced from said jet-directing means to be pressurized thereby in accordance with the condition of said jet, to a first pressure level when there is no cross-flow in said conduit means and to a second pressure level when there is a cross-flow resulting from breathing by the patient;

actuator means connected to said flow control valve and to said flow sensor and operable to produce said first pressure signal when said first pressure level exists in said receiver, and to produce said second pressure signal when said second pressure level exists in said receiver, thereby to open said flow control valve and initiate the inspiration phase in response to breathing by the patient through said flow sensor; and

means for reducing the rate of flow of gas through said apparatus to the patient in response to increasing back pressure therein as the lungs of the patient are inflated, and thereby to reduce the flow rate through said flow sensor during said inspiration phase until said first pressure level is restored, to close said flow control valve and terminate the inspiration phase; and

wherein said flow sensor has two receivers connected to said actuator means and longitudinally spaced apart on opposite sides of the path of said jet, to be equally pressurized by the jet while there is no cross-flow through said sensor, and to be pressurized unequally when the jet is deflected toward one of said receivers by a cross-flow.

4. Respiration apparatus for administering intermittent positive pressure breathing therapy to a patient from a source of gas under pressure and through delivery means into which the patient breathes to initiate a respiration cycle, said apparatus having, in combination;

conduit means connectible to said source for carrying gas therefrom intermittently to said delivery means;

a flow control valve in said conduit means operable to close the latter in a first condition of the valve and to open the same in a second condition;

a pressure-responsive flow regulator for reducing the flow rate through said conduit means to said delivery means as back pressure builds up in said conduit means during inflation of a patient'"'"''"'"'s lungs; and

a flow sensor in said conduit means for actuating said flow control valve between the open and closed conditions in response to breathing-in by said patient through said conduit means, said flow sensor including means for directing a jet across said conduit means, first and second receivers opening into said conduit means, said first receiver being positioned across said conduit means from said jet-directing means to be pressurized by said jet, thereby to produce a first pressure relationship between said receivers when there is no flow through said conduit means and a second and different pressure relationship when there is a disturbance of said jet by a flow through said conduit means resulting from breathing by the patient; and

actuator means responsive to the change from said first pressure relationship to thE second and operable to produce an amplified pressure signal and thereby to actuate said flow control valve and initiate an inspiration phase of said apparatus in response to said flow.

5. In a respiration apparatus for administering intermittent positive pressure breathing therapy to a patient from a source of gas under pressure through delivery means into which the patient breaths to initiate a respiratory cycle, the combination of:

conduit means connectible to said source for carrying gas therefrom to said delivery means;

a flow control valve for opening and closing said conduit means;

flow sensing means including means for directing a jet of gas across said conduit means, and receiver means positioned across said conduit means to receive gas from said jet-directing means and produce a pressure signal having one value when there is no flow transversely of said jet resulting from breathing of the patient through said conduit means; and

actuator means responsive to changes in said signal, for producing an amplified pressure signal to open and close said valve.

6. In a respiration apparatus for administering intermittent positive pressure breathing therapy to a patient, and including a source of gas under pressure, delivery means for administering the gas to the patient, conduit means connecting said source to the patient to carry the gas to the delivery means, and a selectively operable flow control valve for opening and closing said conduit means between said source and said delivery means, the combination of:

means for directing a jet of gas under pressure across a portion of said conduit means through which the patient breathes in drawing a breath through said delivery means;

receiver means positioned across said portion of said conduit to be pressurized by said jet to a first level when said jet is undisturbed, and to a second level when said jet is disturbed by cross-flow in said portion of said conduit means resulting from breathing by the patient; and

actuator means responsive to the change in the pressure in said receiver means from said first level to said second level for producing an amplified pressure signal to open said control valve.

7. A respiration apparatus as defined in claim 6, in which said receiver means include a first receiver positioned across said portion of said conduit means in alignment with said jet, and in which said jet-directing means produces a jet which remains laminar at said first receiver as long as the jet is undisturbed, and changes to turbulent at said first receiver when disturbed by a cross-flow.

8. A respiration apparatus as defined in claim 7 further including a second receiver in said conduit means spaced from said first receiver to establish a reference pressure with respect to which said first and second levels are detectable in said means for opening said control valve.

9. A respiration apparatus as defined in claim 7 further including a disturbance amplifier in said portion of said conduit means, having an edge alongside the path of said jet, adjacent said first receiver.

10. A respiration apparatus as defined in claim 9 further including a plurality of flow-straightening vanes in said portion of said conduit means for directing the cross-flow perpendicular to said jet.

11. A respiration apparatus as defined in claim 6 in which said portion of said conduit is a first restricted conduit communicating with said delivery means, and further including a second, larger conduit also communicating with said delivery means around said first conduit, and having check means therein for directing said cross-flow through said first conduit and passing the flow of gas from said source to said delivery means.

12. A respiration apparatus as defined in claim 6 in which said receiver means comprise two receivers spaced apart on opposite sides of the path of said jet to be pressurized equally thereby when there is no cross-flow in said portion of said conduit means, one of said receiveRs being positioned to be pressurized to a higher level as said jet is deflected by said cross-flow.

13. A respiration apparatus as defined in claim 12 in which said portion of said conduit means is a tube adjacent said delivery means through which the patient breathes and through which all of the gas is supplied to the patient.