Method and apparatus for maintaining patient airway patency

• US 5,845,636 A
• Filed: 08/16/1996
• Issued: 12/08/1998
• Est. Priority Date: 05/19/1989
• Status: Expired due to Fees

• Current Assignee: Nellcor Puritan Bennett LLC (Medtronic Plc)
• Original Assignee: Puritan Bennett Corp. (Medtronic Plc)
• Inventors: Trimble, Russell L., Gruenke, Roger A.
• Primary Examiner(s): Asher, Kimberly L.
• Application Number:
  US08/698,945
• Time in Patent Office: 844 Days
• Field of Search: 128/204.18, 128/204.21, 128/204.23, 128/204.26, 128/716, 128/719, 128/721
• US Class Current: 128/204.23
• 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 16/0069 the speed thereof being controlled by respiratory parameters, e.g. by inhalation
• CPC Class Codes: A61M 16/026 specially adapted for predicting, e.g. for determining an information representative of a flow limitation during a ventilation cycle by using a root square technique or a regression analysis
• CPC Class Codes: A61M 16/06 Respiratory or anaesthetic masks
• CPC Class Codes: A61M 16/0633 with forehead support
• CPC Class Codes: A61M 16/0666 Nasal cannulas or tubing devices for improving normal breathing through the nose A61F5/08; nose filters A62B23/06; outside holding devices A61M25/02
• CPC Class Codes: A61M 16/0683 Holding devices therefor
• CPC Class Codes: A61M 16/1055 bacterial
• CPC Class Codes: A61M 16/107 in the inspiratory path
• CPC Class Codes: A61M 2016/0021 with a proportional output signal, e.g. from a thermistor
• CPC Class Codes: A61M 2016/0027 pressure meter
• CPC Class Codes: A61M 2016/0036 in the breathing tube and used in both inspiratory and expiratory phase
• CPC Class Codes: A61M 2205/3561 local, e.g. within room or hospital
• CPC Class Codes: A61M 2210/0618 Nose

Abstract

An apparatus and method for facilitating the respiration of a patient are disclosed which are particularly useful in treating mixed and obstructive sleep apnea and certain cardiovascular conditions, among others, by increasing nasal air pressure delivered to the patient'"'"'s respiratory passages just prior to inhalation and by subsequently decreasing the pressure to ease exhalation effort. The preferred apparatus includes a patient-coupled gas delivery device for pressurizing the patient'"'"'s nasal passages at a controllable pressure, and a controller coupled with the delivery device having a pressure transducer for monitoring the nasal pressure and a microcontroller for selectively controlling the nasal pressure. In operation, the controller determines a point in the patient breathing cycle just prior to inhalation and initiates an increase in nasal pressure at that point in order to stimulate normal inhalation, and subsequently lowers the nasal pressure to ease exhalation efforts.

Claims

1. A method for controlling the airway pressure applied to a patient during inhalation, wherein positive pressure is maintained during inhalation and exhalation, comprising the steps of:

supplying breathable gas at a first positive and constant pressure level to an airway of a patient;

generating flow signals representative of instantaneous flow of breathable gas supplied to the patient;

determining airway patency from the flow signals; and

adjusting the pressure of the breathable gas supplied to the patient to a second positive and constant pressure level as a function of the determined airway patency.

2. The method of claim 1, wherein said adjusting step includes increasing, decreasing or maintaining the first pressure level of breathable gas in response to the determined airway patency.

3. A method for controlling the airway pressure applied to a patient during inhalation, wherein positive pressure is maintained during inhalation and exhalation, comprising the steps of:

supplying breathable gas at a first positive and constant pressure level to an airway of a patient;

generating flow signals representative of instantaneous flow of breathable gas supplied to the patient;

storing flow data corresponding to the flow signals;

determining airway patency from the stored flow data; and

adjusting the pressure of the breathable gas supplied to the patient to a second positive and constant pressure level as a function of the determined airway patency.

4. The method of claim 3, wherein said adjusting step includes increasing the first pressure level of breathable gas in response to the airway patency.

5. The method of claim 3, wherein said adjusting step includes decreasing the first pressure level of breathable gas in response to the airway patency.

6. The method of claim 3, wherein said adjusting step includes maintaining the first pressure level of breathable gas in response to the airway patency.

7. The method of claim 3, wherein said adjusting step includes comparing the stored flow data with templates stored in memory to quantify airway patency.

8. The method of claim 7, wherein adjusting step includes increasing, decreasing or maintaining the first pressure level of breathable gas in response to the determined airway patency.

9. A method for controlling the airway pressure applied to a patient during inhalation, wherein positive pressure is maintained during inhalation and exhalation, comprising the steps of:

supplying breathable gas at a first positive and constant pressure level to an airway of a patient;

generating a flow signal representative of instantaneous flow of breathable gas supplied to the patient;

storing flow data corresponding to the flow signal;

generating a pressure signal representative of instantaneous pressure of breathable gas supplied to the patient;

storing pressure data corresponding to the pressure signal;

determining airway patency from the flow data and the pressure data; and

adjusting the pressure of the breathable gas supplied to the patient to a second positive and constant pressure level as a function of the determined airway patency.

10. The method of claim 9, wherein said adjusting step includes increasing, decreasing or maintaining the first pressure level of breathable gas in response to the determined airway patency.

11. The method of claim 10, wherein said adjusting step includes comparing the flow data and the pressure data with templates stored in memory.

12. An apparatus for controlling the airway pressure applied to a patient during inhalation, wherein positive pressure is maintained during inhalation and exhalation, the apparatus comprising:

means for supplying breathable gas at a first positive and constant pressure level to an airway of a patient;

means for generating flow signals representative of instantaneous flow of breathable gas supplied to the patient;

means for determining airway patency from the flow signals; and

means for adjusting the first pressure level of the breathable gas to the patient to a second positive and constant pressure level as a function of the determined airway patency.

13. The apparatus of claim 12, wherein said means for adjusting includes means for increasing, decreasing and maintaining the first pressure level of breathable gas in response to the determined airway patency.

14. The apparatus of claim 13, wherein said means for supplying breathable gas includes a blower unit.

15. The apparatus of claim 14, wherein said means for supplying breathable gas further includes a vent valve assembly.

16. The apparatus of claim 15, wherein said means for supplying breathable gas further includes a nasal pillow.

17. An apparatus for controlling the airway pressure applied to a patient during inhalation, wherein positive pressure is maintained during inhalation and exhalation, the apparatus comprising:

means for supplying breathable gas at a first positive and constant pressure level to an airway of a patient;

means for generating flow signals representative of instantaneous flow of breathable gas supplied to the patient;

means for storing flow data corresponding to the flow signals;

means for determining airway patency from the stored flow data; and

means for adjusting the first pressure level of the breathable gas to the patient to a second positive and constant pressure level as a function of the determined airway patency.

18. The apparatus of claim 17, wherein said means for adjusting includes means for increasing, decreasing and maintaining the first pressure level of breathable gas in response to the determined airway patency.

19. The apparatus of claim 18, wherein said means for adjusting step includes processing means for comparing the stored flow data with templates to quantify airway patency.

20. The apparatus of claim 19, wherein said processing means includes a microcontroller.

21. The apparatus of claim 20, wherein said means for storing includes memory which contains the templates.

22. An apparatus for controlling the airway pressure applied to a patient during inhalation, wherein positive pressure is maintained during inhalation and exhalation, the apparatus comprising:

a source of breathable gas configured to deliver a first positive and constant pressure level to an airway of a patient;

a flow sensor configured to provide flow signals representative of the flow of breathable gas supplied to the patient; and

a microcontroller configured to determine airway patency from the flow signals and to adjust the first pressure level of the breathable gas to the patient to a second positive and constant pressure level as a function of determined the airway patency.

23. The apparatus of claim 22, wherein said microcontroller is further configured to determine the airway patency by comparing the flow signals to templates stored in memory associated with the microcontroller.

24. The apparatus of claim 22, wherein said source of breathable gas includes a blower unit operably connected to said microcontroller.

25. The apparatus of claim 24, further comprising a vent valve assembly in fluid communication with the blower unit and the airway of the patient, said vent valve assembly operably connected to said microcontroller for increasing, decreasing and maintaining the pressure of breathable gas.

26. An apparatus for controlling the airway pressure applied to a patient during inhalation, wherein positive pressure in maintained during inhalation and exhalation, the apparatus comprising:

means for supplying breathable gas at a first positive and constant pressure level to an airway of a patient;

means for generating a flow signal representative of flow of breathable gas supplied to the patient;

means for storing flow data corresponding to the flow signal;

means for generating a pressure signal representative of pressure of breathable gas supplied to the patient;

means for storing pressure data corresponding to the pressure signal;

means for determining airway patency from the flow data and the pressure data; and

means for adjusting the pressure level of the breathable gas to the patient to a second positive and constant pressure level as a function of the determined airway patency.

27. The apparatus of claim 26, wherein said means for adjusting includes means for increasing, decreasing and maintaining the first pressure level of breathable gas in response to the determined airway patency.

28. The apparatus of claim 27, wherein said means for adjusting includes means for comparing the flow data and the pressure data with templates stored in memory.