Dynamic respiratory control

• US 6,631,716 B1
• Filed: 07/16/1999
• Issued: 10/14/2003
• Est. Priority Date: 07/17/1998
• Status: Expired due to Fees

• Current Assignee: Board of Trustees of the Leland Stanford Junior University (Stanford Management Co.)
• Original Assignee: Board of Trustees of the Leland Stanford Junior University (Stanford Management Co.)
• Inventors: Kalayjian, Nicholas R., Robinson, Terry E., White, Wallace C.
• Primary Examiner(s): Lo, Weilun
• Assistant Examiner(s): WEISS JR, JOSEPH
• Application Number:
  US09/354,627
• Time in Patent Office: 1,551 Days
• Field of Search: 128/204.21, 128/205.24, 482/5, 482/13, 482/111
• US Class Current: 128/204.21
• CPC Class Codes: A61M 16/20 Valves specially adapted to medical respiratory devices
• CPC Class Codes: A61M 16/204 used for inhalation control
• CPC Class Codes: A61M 16/205 used for exhalation control
• CPC Class Codes: A61M 2016/0021 with a proportional output signal, e.g. from a thermistor
• CPC Class Codes: F16K 1/22 with axis of rotation crossing the valve member, e.g. butterfly valves
• CPC Class Codes: F16K 3/03 with a closure member in the form of an iris-diaphragm

Abstract

A dynamic respiratory control device includes a fast-response valve capable of dynamically imposing multiple resistive loads on the flow of respiratory gas to and from a patient. The resistive loads are applied in response to measured flow rates, patient lung volumes, and/or mouthpiece pressures. The device can precisely constrain tidal breathing, provide precise volumetric control of the airway, and impose multiple specific inspiratory and/or expiratory loading functions to evaluate respiratory function. The device is useful for pulmonary function testing, CT and MRI imaging of the chest, combined CT imaging/interventional radiology, radiotherapy delivery to the thorax/abdomen, and/or as a resistive muscle trainer for weaning patients off ventilators and for respiratory muscle training.

Claims

1. A respiratory training apparatus for performing respiratory muscle training on a patient, comprising:

a respiratory function valve for dynamically controlling a respiratory gas flow for a patient;

a flow rate monitoring device positioned in a flow path of said respiratory gas, in fluidic communication with said valve, for measuring a flow rate of said respiratory gas; and

a control unit electrically connected to said flow rate monitoring device, and said valve, and programmed to perform the steps of;

receiving flow rate data from said flow rate monitoring device,

dynamically determining patient lung volume data from said flow rate data at each of a plurality of patient lung volumes in a breathing cycle,

selecting a plurality of predetermined respiratory training resistive load patterns to be applied to said patient, each respiratory training resistive load pattern defining a plurality of respiratory training resistive loads each to be applied at a patient lung volume value said plurality of resistive loads including a maximal resistive load, a minimal resistive load, and at least one intermediate resistive load higher than said minimal resistive load and lower than said maximal resistive load, and for

dynamically controlling said valve to apply said plurality of respiratory training resistive load patterns to said respiratory gas flow according to said lung volume data.

2. The apparatus of claim 1 wherein said control unit comprises electronics for dynamically controlling said valve to apply an intermediate inspiratory resistive load and an intermediate expiratory resistive load to said flow.

3. The apparatus of claim 1 wherein said control unit comprises electronics for dynamically controlling said valve to maintain a lung volume of said patient between a first predetermined value and a second predetermined value.

4. The apparatus of claim 1 wherein said control unit comprises electronics for dynamically controlling said valve to apply a plurality of intermediate resistive loads to said flow.

5. The apparatus of claim 1 wherein said control unit comprises electronics for controlling said resistive load to establish a predetermined time-dependence of a lung volume of said patient.

6. The apparatus of claim 1 wherein said monitoring device comprises a mass flow sensor.

7. The apparatus of claim 1 further comprising a treatment device electrically connected and responsive to said control unit, wherein said control unit comprises electronics for triggering said treatment device at a predetermined lung volume of said patient.

8. The apparatus of claim 7, wherein the treatment device is selected from a laser therapy and a radiotherapy device.

9. The apparatus of claim 1 further comprising a patient imaging device electrically connected and responsive to said control unit, wherein said control unit comprises electronics for triggering said patient imaging device at a predetermined lung volume of said patient.

10. The apparatus of claim 9, wherein the patient imaging device is selected from a CT and an MRI device.

11. The apparatus of claim 1 wherein said valve is a butterfly valve.

12. The apparatus of claim 11 wherein said butterfly valve comprises an occluding structure having at least two occluding flaps mounted on opposite sides of a rotatable shaft.

13. The apparatus of claim 11 wherein said butterfly valve comprises an occluding structure having a rigid scaling perimeter along a major surface of said occluding structure.

14. The apparatus of claim 1 wherein said valve is selected from an iris valve, a solenoid valve, and a scissors valve.

15. The apparatus of claim 1 wherein said valve has a response time of less than 100 ms.

16. The apparatus of claim 1, wherein the control unit comprises electronics for dynamically controlling the valve to maintain the lung volume sequentially between a plurality of upper and lower value pairs.

17. The apparatus of claim 16 further comprising a treatment device electrically connected to the control unit, wherein the control unit comprises electronics for triggering the treatment device at a plurality of lung volumes of the patient.

18. The apparatus of claim 16 further comprising a patient imaging device electrically connected to the control unit, wherein the control unit comprises electronics for triggering the patient imaging device at a plurality of lung volumes of the patient.

19. The apparatus of claim 1 further comprising a pressure sensor positioned in a path of said flow and electrically connected to said control unit, for monitoring a pressure of said flow.

20. A respiratory training method for performing respiratory training on a patient, comprising:

measuring a flow rate of a respiratory gas for the patient;

dynamically determining a patient lung volume from the flow rate at each of a plurality of patient lung volumes in a breathing cycle;

selecting a plurality of predetermined respiratory training resistive load patterns to be applied to the patient, each respiratory training resistive load pattern defining a plurality of respiratory training resistive loads each to be applied at a patient lung volume value, said plurality of resistive loads including a maximal resistive load, a minimal resistive load, and at least one intermediate resistive load higher than the minimal resistive load and lower than the maximal resistive load; and

applying the plurality of respiratory training resistive load patterns to the respiratory gas according to the lung volume.

21. The method of claim 20 comprising dynamically controlling said valve to apply an intermediate inspiratory resistive load and an intermediate expiratory resistive load to said flow.

22. The method of claim 20 comprising dynamically controlling said valve to maintain a lung volume of said patient between a first predetermined value and a second predetermined value.

23. The method of claim 20 comprising dynamically controlling said valve to apply a plurality of intermediate resistive loads to said flow.

24. The method of claim 20 comprising controlling said resistive load to establish a predetermined time-dependence of a lung volume of said patient.

25. The method of claim 20 wherein said flow rate data comprises a mass flow rate.

26. The method of claim 25 further comprising monitoring a pressure of said flow.

27. The method of claim 20 further comprising triggering a treatment device at a predetermined lung volume of said patient.

28. The method of claim 20 further comprising triggering a patient imaging device at a predetermined lung volume of said patient.

29. The method of claim 20 wherein said valve is a butterfly valve.

30. The method of claim 29 wherein said butterfly valve comprises an occluding structure having at least two occluding flaps mounted on opposite sides of a rotatable shaft.

31. The method of claim 29 further comprising establishing a seal along a major surface of an occluding structure of said valve, said seal occluding said flow.

32. The method of claim 20 wherein said valve is selected from an iris valve, a solenoid valve, and a scissors valve.

33. The method of claim 20 wherein said valve has a response time of less than 100 ms.

34. The method of claim 20, further comprising dynamically controlling the valve to maintain the volume sequentially between a plurality of upper and lower value pairs.

35. The method of claim 34 further comprising a treatment device electrically connected to the control unit, wherein the control unit comprises electronics for triggering the treatment device at a plurality of lung volumes of the patient.

36. The method of claim 34 comprising a patient-imaging device electrically connected to the control unit, wherein the control unit comprises electronics for triggering the patient imaging device at a plurality of lung volumes of the patient.

37. A respiratory training apparatus for performing respiratory muscle training on a patient, comprising:

a respiratory function valve for dynamically controlling a respiratory gas flow for a patient;

flow rate monitoring means positioned in a flow path of the respiratory gas, in fluidic communication with the valve, for measuring a flow rate of the respiratory gas; and

control means electrically connected to the flow rate monitoring means and the valve, and programmed to perform the steps of;

receiving flow rate data from the flow rate monitoring means,

dynamically determining patient lung volume data from the flow rate data at each of a plurality of patient lung volumes in a breathing cycle,

selecting a plurality of predetermined respiratory training resistive load patterns to be applied to the patient, each respiratory training resistive load pattern including a maximal resistive load, a minimal resistive load,

and at least one intermediate resistive load higher than the minimal

resistive load and lower than the maximal resistive load, and for dynamically controlling the valve to apply the plurality of respiratory training resistive load patterns to the respiratory gas flow according to the lung volume data.