Tracheal pressure ventilation respiratory system

• US 6,571,796 B2
• Filed: 02/08/2001
• Issued: 06/03/2003
• Est. Priority Date: 02/08/2001
• Status: Expired due to Fees

• Current Assignee: University of Florida (State University System of Florida)
• Original Assignee: University of Florida (State University System of Florida)
• Inventors: Banner, Michael J., Blanch, Paul Bradford
• Primary Examiner(s): Lo, Weilun
• Assistant Examiner(s): EREZO, DARWIN P
• Application Number:
  US09/779,170
• Publication Number:
  US 20020104537A1
• Time in Patent Office: 845 Days
• Field of Search: 128/204.21, 128/207.15, 128/200.24, 128/200.18, 128/204.22, 128/204.23, 128/207.14, 128/202.22, 128/204.18, 128/204.27, 128/204.28, 128/205.24, 128/207.16, 128/207.18, 128/204.25
• US Class Current: 128/204.26
• CPC Class Codes: A61M 16/0012 by Venturi means
• CPC Class Codes: A61M 16/0434 Cuffs
• CPC Class Codes: A61M 16/127 by Venturi effect, i.e. entrainment mixers
• CPC Class Codes: A61M 16/20 Valves specially adapted to medical respiratory devices
• CPC Class Codes: A61M 16/203 Proportional
• CPC Class Codes: A61M 16/207 Membrane valves with pneumatic amplification stage, i.e. having master and slave membranes
• CPC Class Codes: A61M 2016/0021 with a proportional output signal, e.g. from a thermistor

Abstract

Embodiments of the present invention described and shown in the specification and drawings include a respiratory system for automatically and variably controlling the supply of a pressurized breathing gas to a patient via a breathing circuit that is in fluid communication with the lungs of the patient. The respiratory system has a demand valve in fluid communication with a source of pressurized gas. The demand valve is switchable between a open position, in which an inhalation conduit of the breathing circuit is in fluid communication with the source of pressurized gas, and a closed position, in which the inhalation conduit is not in fluid communication with the source of pressurized gas. The demand valve is proportionally moveable between the open and closed positions in response to a pressure within a reference chamber which is in fluid communication with the trachea of the patient. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that is will not be used to interpret or limit the scope or meaning of the claims. 37 C.F.R. § 1.72(b).

Claims

1. A respiratory system comprising:

a. an endotracheal tube having a proximal end and a distal end;

b. a tracheal pressure conduit in fluid communication with the distal end of the endotracheal tube;

c. an inhalation conduit in fluid communication with the proximal end of the endotracheal tube;

d. an exhalation conduit having an exhalation valve, the exhalation conduit in fluid communication with the proximal end of the endotracheal tube;

e. a pressurized gas source; and

f. a pressure regulator having a reference chamber and a demand valve in selective fluid communication with the pressurized gas source and the inhalation conduit, wherein the reference chamber is in fluid communication with the tracheal pressure conduit, wherein the demand valve is responsive to pressure within the reference chamber to open and close in proportion to a baseline pressure, wherein the demand valve is proportionally moveable between a first position during inhalation, in which the demand valve is opened so that the inhalation conduit is in fluid communication with the pressurized gas source, and a second position during exhalation, in which the demand valve is closed so that the inhalation conduit is not in fluid communication with the pressurized gas source, and wherein the demand valve opens proportionally upon a pressure drop in the reference chamber relative to the baseline pressure and is closed when pressure in the reference chamber is equal to or greater than the baseline pressure.

2. The respiratory system of claim 1, wherein the inhalation conduit further comprises a gas reservoir and a venturi tube having an inlet, an outlet, and an augmentation valve, the inlet of the venturi tube in fluid communication with the demand valve and the outlet of the venturi tube in fluid communication with the proximal end of the endotracheal tube, wherein the augmentation valve is in fluid communication with the gas reservoir.

3. The respiratory system of claim 2, wherein the augmentation valve is movable between a closed position during exhalation, in which the venturi tube is not in fluid communication with the gas reservoir, and an opened position during inhalation, in which the venturi tube is in fluid communication with the gas reservoir.

4. The respiratory system of claim 2, wherein the exhalation valve of the exhalation conduit has an exhalation valve control conduit in fluid communication with the inhalation conduit intermediate the inlet of the venturi tube and the demand valve of the pressure regulator, the exhalation valve responsive to pressure in the exhalation valve control conduit so that the exhalation valve opens in proportion to a pressure drop in the exhalation valve control conduit relative to pressure in the exhalation conduit and is closed when pressure in the exhalation valve control conduit is equal to or greater than pressure in the exhalation conduit.

5. The respiratory system of claim 4, wherein the exhalation valve control conduit has a selectable restrictor valve movable from an open position, in which fluid flow through the exhalation valve control conduit is unrestricted, towards a closed position, in which fluid flow through the exhalation valve control conduit is restricted so that, when the exhalation valve control conduit is restricted, resistance of the exhalation valve to open is lowered.

6. The respiratory system of claim 1, wherein the demand valve of the pressure regulator is adjustable so that the baseline pressure is selectable.

7. The respiratory system of claim 1, further comprising a pressure sensor having an indicator to display pressure, the pressure sensor in fluid communication with the tracheal pressure conduit so that pressure within the tracheal pressure conduit may be displayed.

8. The respiratory system of claim 1, further comprising a mandatory breath support ventilation subsystem to supply gas from the pressurized gas source to the inhalation conduit at a predetermined inspiratory time interval and a predetermined expiratory time interval.

9. The respiratory system of claim 8, wherein the mandatory breath ventilation subsystem comprises:

a. a mandatory breath ventilation subsystem source of pressurized gas;

b. a first normally-open cartridge valve connected to the tracheal pressure conduit;

c. a second normally-open cartridge valve connected to the mandatory breath ventilation subsystem source of pressurized gas;

d. a normally-closed cartridge valve connected to the tracheal pressure conduit intermediate the first normally-open cartridge valve and the reference chamber of the pressure regulator, the normally-closed cartridge valve having an outlet port in selective fluid communication with atmosphere;

e. a fluid conduit connected to the first normally-open cartridge valve, the second normally-open cartridge valve, and the normally-closed cartridge valve, the fluid conduit having a fluid conduit line resistor in selective fluid communication with atmosphere;

f. an exhalation fluid line connected to the second normally-open cartridge valve, the exhalation fluid line having a first one-way valve and an expiratory resistor, the expiratory resistor in selective fluid communication with atmosphere, the first one-way valve intermediate the second normally-open cartridge and the expiratory resistor and oriented to allow fluid flow toward the expiratory resistor;

g. an inhalation fluid line connected to the fluid conduit and to the exhalation fluid line intermediate the second normally-open cartridge valve and the first one-way valve, the inhalation fluid line having a second one-way valve and an inhalation resistor, the inhalation resistor in selective fluid communication with the exhalation fluid line, the second one-way valve intermediate the fluid conduit and the inhalation resistor and oriented to allow fluid flow toward the inhalation resistor; and

h. a back-pressure conduit connected to the inhalation fluid line intermediate the second one-way valve and the inhalation resistor and connected to the exhalation fluid line intermediate the first one-way valve and the exhalation resistor.

10. The respiratory system of claim 9, wherein the mandatory breath support ventilation subsystem is switchable from a first position, in which gas from the pressurized gas source is supplied to the inhalation conduit upon demand for the predetermined expiratory time interval, to a second position, in which the reference chamber of the pressure regulator is vented to atmosphere through the outlet port of the normally-closed cartridge valve and gas from the pressurized gas source is supplied to the inhalation conduit for the predetermined inspiratory time interval.

11. The respiratory system of claim 10, wherein, in the first position, the first normally-open cartridge valve is open so that a distal end of the tracheal pressure conduit is in fluid communication with the reference chamber of the pressure regulator, the second normally-open cartridge valve is closed so that the mandatory breath ventilation subsystem source of pressurized gas is not in fluid communication with the fluid conduit, and the normally-closed cartridge valve is closed so that the reference chamber of the pressure regulator is not in fluid communication with atmosphere, and wherein, in the second position, the first normally-open cartridge valve is closed so that the distal end of the tracheal pressure conduit is not in fluid communication with the reference chamber of the pressure regulator, the second normally-open cartridge valve is opened so that the mandatory breath ventilation subsystem source of pressurized gas is in fluid communication with the fluid conduit, and the normally-closed cartridge valve is opened so that the reference chamber of the pressure regulator is in fluid communication with atmosphere.

12. The respiratory system of claim 9, wherein the inhalation resistor and the exhalation resistor are adjustable so that the predetermined inspiratory time interval and the predetermined expiratory time interval are selectable.

13. A respiratory system comprising:

a. an endotracheal tube having a proximal end and a distal end;

b. a tracheal pressure conduit in fluid communication with the distal end of the endotracheal tube;

c. an inhalation conduit in fluid communication with the proximal end of the endotracheal tube;

d. an exhalation conduit having an exhalation valve, the exhalation conduit in fluid communication with the proximal end of the endotracheal tube;

e. a pressurized gas source;

f. a demand valve in selective fluid communication with the pressurized gas source and the inhalation conduit, the demand valve movable between a first position, in which the demand valve is opened so that the inhalation conduit is in fluid communication with the pressurized gas source, and a second position, in which the demand valve is closed so that the inhalation conduit is not in fluid communication with the pressurized gas source; and

,

g. means for proportionally opening the demand valve in response to pressure within a reference chamber which is in fluid communication with the tracheal pressure conduit.

14. The respiratory system of claim 13, wherein the means for proportionally opening the demand valve opens and closes the demand valve in proportion to a baseline pressure so that the demand valve opens proportionally upon a pressure drop in the reference chamber relative to the baseline pressure and closes when pressure in the reference chamber is equal to or greater than the baseline pressure.

15. The respiratory system of claim 13, wherein the inhalation conduit further comprises a gas reservoir and a venturi tube having an inlet, an outlet, and an augmentation valve, the inlet of the venturi tube in fluid communication with the demand valve and the outlet of the venturi tube in fluid communication with the proximal end of the endotracheal tube, wherein the augmentation valve is in fluid communication with the gas reservoir.

16. The respiratory system of claim 15, wherein the augmentation valve is movable between a closed position during exhalation, in which the venturi tube is not in fluid communication with the gas reservoir, and an open position during inhalation, in which the venturi tube is in fluid communication with the gas reservoir.

17. The respiratory system of claim 15, wherein the exhalation valve has an exhalation valve control conduit in communication with the inhalation conduit intermediate the inlet of the venturi tube and the demand valve, the exhalation valve responsive to pressure in the exhalation valve control conduit so that the exhalation valve opens in proportion to a pressure drop in the exhalation valve control conduit relative to pressure in the exhalation conduit and is closed when pressure in the exhalation valve control conduit is equal to or greater than pressure in the exhalation conduit.

18. The respiratory system of claim 17, wherein the exhalation valve control conduit has a selectable restrictor valve movable from an open position, in which fluid flow through the exhalation valve control conduit is unrestricted, towards a closed position, in which fluid flow through the exhalation valve control conduit is restricted so that, when the exhalation valve control conduit is restricted, resistance of the exhalation valve to open is lowered.

19. The respiratory system of claim 13, wherein the demand valve is adjustable so that the baseline pressure is selectable.

20. The respiratory system of claim 13, further comprising a pressure sensor having an indicator to display pressure, the pressure sensor in operative communication with the tracheal pressure conduit so that pressure within the tracheal pressure conduit may be displayed.

21. The respiratory system of claim 13, wherein the opening means includes a spring operatively connected to the demand valve for opening the demand valve.

22. The respiratory system of claim 13, further comprising a mandatory breath support ventilation subsystem to supply gas from the pressurized gas source to the inhalation conduit at a predetermined inspiratory time interval and a predetermined expiratory time interval.

23. The respiratory system of claim 22, wherein the mandatory breath ventilation subsystem comprises:

a. a mandatory breath ventilation subsystem source of pressurized gas;

b. a first normally-open cartridge valve connected to the tracheal pressure conduit;

c. a second normally-open cartridge valve connected to the mandatory breath ventilation subsystem source of pressurized gas;

d. a normally-closed cartridge valve connected to the tracheal pressure conduit intermediate the first normally-open cartridge valve and the reference chamber of the pressure regulator, the normally-closed cartridge valve having an outlet port in selective fluid communication with atmosphere;

e. a fluid conduit connected to the first normally-open cartridge valve, the second normally-open cartridge valve, and the normally-closed cartridge valve, the fluid conduit having a fluid conduit line resistor in selective fluid communication with atmosphere;

f. an exhalation fluid line connected to the second normally-open cartridge valve, the exhalation fluid line having a first one-way valve and an expiratory resistor, the expiratory resistor in selective fluid communication with atmosphere, the first one-way valve intermediate the second normally-open cartridge and the expiratory resistor and oriented to allow fluid flow toward the expiratory resistor;

g. an inhalation fluid line connected to the fluid conduit and to the exhalation fluid line intermediate the second normally-open cartridge valve and the first one-way valve, the inhalation fluid line having a second one-way valve and an inhalation resistor, the inhalation resistor in selective fluid communication with the exhalation fluid line, the second one-way valve intermediate the fluid conduit and the inhalation resistor and oriented to allow fluid flow toward the inhalation resistor; and

h. a back-pressure conduit connected to the inhalation fluid line intermediate the second one-way valve and the inhalation resistor and connected to the exhalation fluid line intermediate the first one-way valve and the exhalation resistor.

24. The respiratory system of claim 23, wherein the mandatory breath support ventilation subsystem is switchable from a first position, in which gas from the pressurized gas source is supplied to the inhalation conduit upon demand for the predetermined expiratory time interval, to a second position, in which the reference chamber is vented to atmosphere through the outlet port of the normally-closed cartridge valve and gas from the pressurized gas source is supplied to the inhalation conduit for the predetermined inspiratory time interval.

25. The respiratory system of claim 24, wherein, in the first position, the first normally-open cartridge valve is open so that a distal end of the tracheal pressure conduit is in fluid communication with the reference chamber, the second normally-open cartridge valve is closed so that the mandatory breath ventilation subsystem source of pressurized gas is not in fluid communication with the fluid conduit, and the normally-closed cartridge valve is closed so that the reference chamber is not in fluid communication with atmosphere, and wherein, in the second position, the first normally-open cartridge valve is closed so that the distal end of the tracheal pressure conduit is not in fluid communication with the reference chamber, the second normally-open cartridge valve is opened so that the mandatory breath ventilation subsystem source of pressurized gas is in fluid communication with the fluid conduit and the normally-closed cartridge valve is opened so that the reference chamber is in fluid communication with atmosphere.

26. The respiratory system of claim 23, wherein the inhalation resistor and the exhalation resistor are adjustable so that the predetermined inspiratory time interval and the predetermined expiratory time interval are selectable.

27. A respiratory system comprising:

a. an endotracheal tube having a proximal end and a distal end;

b. a tracheal pressure conduit in fluid communication with the distal end of the endotracheal tube;

c. an inhalation conduit having a venturi tube and a gas reservoir, the inhalation conduit in fluid communication with the proximal end of the endotracheal tube, the venturi tube having an augmentation valve in fluid communication with the gas reservoir;

d. an exhalation conduit including an exhalation valve, the exhalation conduit in fluid communication with the proximal end of the endotracheal tube;

e. a pressurized gas source; and

f. a pressure regulator having a reference chamber and a demand valve in selective fluid communication with the pressurized gas source with the inhalation conduit, wherein the reference chamber is in fluid communication with the tracheal pressure conduit, wherein the demand valve is responsive to pressure within the reference chamber to open and close in proportion to a baseline pressure, wherein the demand valve is proportionally moveable between a first position during inhalation, in which the demand valve is opened so that the inhalation conduit is in fluid communication with the pressurized gas source, and a second position during exhalation, in which the demand valve is closed so that the inhalation conduit is not in fluid communication with the pressurized gas source, and wherein the demand valve opens proportionally upon a pressure drop in the reference chamber relative to the baseline pressure and is closed when pressure in the reference chamber is equal to or greater than the baseline pressure.

28. The respiratory system of claim 27, wherein the venturi tube further includes an inlet and an outlet, the inlet of the venturi tube in communication with the demand valve and the outlet of the venturi tube in communication with the proximal end of the endotracheal tube.

29. The respiratory system of claim 27, wherein the augmentation valve is movable between a closed position during exhalation, in which the venturi tube is not in fluid communication with the gas reservoir, and an opened position during inhalation, in which the venturi tube is in fluid communication with the gas reservoir.

30. The respiratory system of claim 28, wherein the exhalation valve of the exhalation conduit has an exhalation valve control conduit in fluid communication with the inhalation conduit intermediate the inlet of the venturi tube and the demand valve of the pressure regulator, the exhalation valve responsive to pressure in the exhalation valve control conduit so that the exhalation valve opens in proportion to a pressure drop in the exhalation valve control conduit relative to pressure in the exhalation conduit and is closed when pressure in the exhalation valve control conduit is equal to or greater than pressure in the exhalation conduit.

31. The respiratory system of claim 30, wherein the exhalation valve control conduit has a selectable restrictor valve movable from an open position, in which fluid flow through the exhalation valve control conduit is unrestricted, towards a closed position, in which fluid flow through the exhalation valve control conduit is restricted so that, when the exhalation valve control conduit is restricted, resistance of the exhalation valve to open is lowered.

32. The respiratory system of claim 27, wherein the demand valve of the pressure regulator is adjustable so that the baseline pressure is selectable.

33. The respiratory system of claim 27, further comprising a pressure sensor having an indicator to display pressure, the pressure sensor in fluid communication with the tracheal pressure conduit so that pressure within the tracheal pressure conduit may be displayed.

34. The respiratory system of claim 27, further comprising a mandatory breath support ventilation subsystem to supply gas from the pressurized gas source to the inhalation conduit at a predetermined inspiratory time interval and a predetermined expiratory time interval.

35. The respiratory system of claim 34, wherein the mandatory breath ventilation subsystem comprises:

a. a mandatory breath ventilation subsystem source of pressurized gas;

b. a first normally-open cartridge valve connected to the tracheal pressure conduit;

c. a second normally-open cartridge valve connected to the mandatory breath ventilation subsystem source of pressurized gas;

d. a normally-closed cartridge valve connected to the tracheal pressure conduit intermediate the first normally-open cartridge valve and the reference chamber of the pressure regulator, the normally-closed cartridge valve having an outlet port in selective fluid communication with atmosphere;

e. a fluid conduit connected to the first normally-open cartridge valve, the second normally-open cartridge valve, and the normally-closed cartridge valve, the fluid conduit having a fluid conduit line resistor in selective fluid communication with atmosphere;

f. an exhalation fluid line connected to the second normally-open cartridge valve, the exhalation fluid line having a first one-way valve and an expiratory resistor, the expiratory resistor in selective fluid communication with atmosphere, the first one-way valve intermediate the second normally-open cartridge and the expiratory resistor and oriented to allow fluid flow toward the expiratory resistor;

g. an inhalation fluid line connected to the fluid conduit and to the exhalation fluid line intermediate the second normally-open cartridge valve and the first one-way valve, the inhalation fluid line having a second one-way valve and an inhalation resistor, the inhalation resistor in selective fluid communication with the exhalation fluid line, the second one-way valve intermediate the fluid conduit and the inhalation resistor and oriented to allow fluid flow toward the inhalation resistor; and

,

h. a back-pressure conduit connected to the inhalation fluid line intermediate the second one-way valve and the inhalation resistor and connected to the exhalation fluid line intermediate the first one-way valve and the exhalation resistor.

36. The respiratory system of claim 35, wherein the mandatory breath support ventilation subsystem is switchable from a first position, in which gas from the pressurized gas source is supplied to the inhalation conduit upon demand for the predetermined expiratory time interval, to a second position, in which the reference chamber of the pressure regulator is vented to atmosphere through the outlet port of the normally-closed cartridge valve and gas from the pressurized gas source is supplied to the inhalation conduit for the predetermined inspiratory time interval.

37. The respiratory system of claim 36, wherein, in the first position, the first normally-open cartridge valve is open so that a distal end of the tracheal pressure conduit is in fluid communication with the reference chamber of the pressure regulator, the second normally-open cartridge valve is closed so that the mandatory breath ventilation subsystem source of pressurized gas is not in fluid communication with the fluid conduit, and the normally-closed cartridge valve is closed so that the reference chamber of the pressure regulator is not in fluid communication with atmosphere, and wherein, in the second position, the first normally-open cartridge valve is closed so that the distal end of the tracheal pressure conduit is not in fluid communication with the reference chamber of the pressure regulator, the second normally-open cartridge valve is opened so that the mandatory breath ventilation subsystem source of pressurized gas is in fluid communication with the fluid conduit, and the normally-closed cartridge valve is opened so that the reference chamber of the pressure regulator is in fluid communication with atmosphere.

38. The respiratory system of claim 35, wherein the inhalation resistor and the exhalation resistor are adjustable so that the predetermined inspiratory time interval and the predetermined expiratory time interval are selectable.