Endotracheal tube pressure monitoring system and method of controlling same

• US 6,450,164 B1
• Filed: 08/17/2000
• Issued: 09/17/2002
• Est. Priority Date: 08/17/2000
• 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: Euliano, Neil R., Banner, Michael J., Blanch, Paul B.
• Primary Examiner(s): Dawson, Glenn K.
• Application Number:
  US09/641,986
• Time in Patent Office: 761 Days
• Field of Search: 128/200.24, 128/200.18, 128/204.22, 128/204.23, 128/207.14, 128/207.15, 128/204.21
• US Class Current: 128/204.21
• CPC Class Codes: A61M 16/04 Tracheal tubes catheters in general A61M25/00
• CPC Class Codes: A61M 16/042 with separate conduits for in-and expiration gas, e.g. for limited dead volume
• CPC Class Codes: A61M 16/0833 T- or Y-type connectors, e.g. Y-piece
• CPC Class Codes: A61M 16/0858 Pressure sampling ports
• 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 2205/50 with microprocessors or computers

Abstract

An endotracheal tube pressure monitoring system for an endotracheal tube having at least one pressure line in fluid communication with a major lumen of the endotracheal tube, a purging subsystem in fluid communication with at least one of the pressure lines, and a pressure monitoring subsystem in operative communication with each respective pressure line to monitor the pressure of fluid within each respective pressure line. Each pressure line that is in fluid communication with the purging subsystem being selectively purged by the purging subsystem when pressure monitoring subsystem determines the respective pressure line has become obstructed. Purging the pressure line maintains the patency of the pressure line so that accurate pressure measurements within the endotracheal tube can be obtained for calculation of parameters in lung mechanics. 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 it will not be used to interpret or limit the scope or meaning of the claims.

Claims

1. An endotracheal tube pressure monitoring system comprising:

a. an endotracheal tube having an open distal end, an opposing open proximal end, and a major lumen extending within the tube from the proximal end to the distal end, the distal end of the tube in fluid communication with a trachea of a patient;

b. at least one pressure line in fluid communication with the major lumen of the endotracheal tube;

c. a purging subsystem in fluid communication with at least one pressure line; and

d. a pressure monitoring subsystem in operative communication with each respective pressure line, the pressure monitoring subsystem having means to monitor the pressure of fluid within each respective pressure line,

wherein, for each pressure line in fluid communication with the purging subsystem, the pressure monitoring subsystem generates a response signal after a first predetermined time period in which pressure within the pressure line with which the purging subsystem is in fluid communication remains substantially constant, and wherein the purging subsystem is responsive to the response signal of the pressure monitoring subsystem to supply a pressurized fluid to the pressure line with which the purging subsystem is in fluid communication for a second predetermined time period after generation of the response signal.

2. The endotracheal tube pressure monitoring system of claim 1, wherein the pressure monitoring subsystem generates a termination signal after the second predetermined time period, and wherein the purging subsystem is responsive to the termination signal of the pressure monitoring subsystem to terminate supply of the pressurized fluid to the pressure line with which the purging subsystem is in fluid communication.

3. The endotracheal tube pressure monitoring system of claim 2, wherein the purging subsystem comprises:

a. at least one source of pressurized fluid; and

b. at least one purging actuator, the source of pressurized fluid being in fluid communication with at least one pressure line at a juncture in the respective pressure line, wherein one purging actuator is operatively connected to the pressure line intermediate the pressure sensor and the juncture, and wherein the purging actuator, responsive to the response signal and the termination signal, is movable between an open position, in which fluid within the pressure line is communicated to the pressure sensor, and a closed position, in which fluid is prevented from being communicated to the pressure sensor.

4. The endotracheal tube pressure monitoring system of claim 3, wherein the source of pressurized fluid is a fluid pump that is responsive to the response signal to supply the pressurized fluid and is also responsive to the termination signal to terminate supply of the pressurized fluid.

5. The endotracheal tube pressure monitoring system of claim 3, wherein the source of pressurized fluid is a vessel of compressed fluid having a fluid actuator, and wherein the fluid actuator, responsive to the response signal and the termination signal, is movable between a closed position, in which the pressurized fluid is shut off from the pressure line, and an open position, in which the pressurized fluid is communicated to the pressure line.

6. The endotracheal tube pressure monitoring system of claim 1, wherein the at least one pressure line includes a first pressure line in fluid communication with the distal end of the endotracheal tube, and wherein the purging subsystem is in fluid communication with the first pressure line.

7. The endotracheal tube pressure monitoring system of claim 6, wherein the at least one pressure line includes a second pressure line in fluid communication with the proximal end of the endotracheal tube.

8. The endotracheal tube pressure monitoring system of claim 7, wherein the purging subsystem is in fluid communication with the second pressure line.

9. The endotracheal tube pressure monitoring system of claim 1, wherein the pressure monitoring means of the pressure monitoring subsystem comprises:

a. at least one pressure sensor; and

b. a computing apparatus connected to each respective pressure sensor,

wherein each pressure line has one pressure sensor operatively attached for sensing the pressure of the fluid within each respective pressure line.

10. An endotracheal tube pressure monitoring system comprising:

a. an endotracheal tube having an open proximal end, an opposing open distal end, and a major lumen extending within the tube from the proximal end to the distal end, the distal end of the endotracheal tube in fluid communication with a trachea of a patient;

b. a first pressure line in fluid communication with the distal end of the endotracheal tube;

c. a second pressure line in fluid communication with the proximal end of the endotracheal tube;

d. a pressure monitoring subsystem in operative communication with the first pressure line and the second pressure line, the pressure monitoring subsystem having a first pressure sensor for sensing the pressure of the fluid within the first pressure line, a second pressure sensor for sensing the pressure within the second pressure line, and a computing apparatus connected to the first pressure sensor and the second pressure sensor; and

e. a purging subsystem in fluid communication with the first pressure line,

wherein the computing apparatus of the pressure monitoring subsystem generates a first response signal after a first predetermined time period in which pressure within the first pressure line remains substantially constant and generates a first termination signal after a second predetermined time period after the generation of the first response signal, wherein the purging subsystem is responsive to the first response signal to supply a pressurized fluid to the first pressure line, and wherein the purging subsystem is responsive to the first termination signal to terminate supply of the pressurized fluid to the first pressure line.

11. The endotracheal tube pressure monitoring system of claim 10, wherein the purging subsystem comprises:

a. a source of pressurized fluid in fluid communication with the first pressure line at a first juncture in the first pressure line; and

b. a first purging actuator intermediate the first pressure sensor and the first juncture, wherein the first purging actuator, responsive to the first response signal and the first termination signal, is movable between an open position, in which fluid within the first pressure line is communicated to the first pressure sensor, and a closed position, in which fluid is prevented from being communicated to the first pressure sensor.

12. The endotracheal tube pressure monitoring system of claim 11, wherein the source of pressurized fluid is a fluid pump, wherein the fluid pump is responsive to the first response signal to supply the pressurized fluid to the first pressure line, and wherein the fluid pump is responsive to the first termination signal to terminate supply of the pressurized fluid to the first pressure line.

13. The endotracheal tube pressure monitoring system of claim 11, wherein the source of pressurized fluid is a vessel of compressed fluid having a fluid actuator, and wherein the fluid actuator, responsive to the response signal, is movable between a closed position, in which the pressurized fluid is shut off from the vessel to the pressure line, and an open position, in which pressurized fluid is communicated from the vessel to the pressure line.

14. The endotracheal tube pressure monitoring system of claim 11, wherein the source of pressurized fluid is in fluid communication with the second pressure line, wherein the computing apparatus of the pressure monitoring subsystem generates a second response signal after the first predetermined time period in which pressure within the second pressure line remains substantially constant and generates a second termination signal after the second predetermined time period after the generation of the second response signal, wherein the purging subsystem is responsive to the second response signal to supply the pressurized fluid to the second pressure line, and wherein the purging subsystem is responsive to the second termination signal to terminate supply of the pressurized fluid to the second pressure line.

15. The endotracheal tube pressure monitoring system of claim 14, wherein the purging subsystem has a second purging actuator, wherein the source of pressurized fluid is responsive to the second response signal and is in fluid communication with the second pressure line at a second juncture in the second pressure line, the second purging actuator intermediate the second pressure sensor and the second juncture, wherein the second purging actuator, responsive to the second response signal and the second termination signal, is movable between an open position, in which fluid within the second pressure line is communicated to the second pressure sensor, and a closed position, in which fluid is prevented from being communicated to the second pressure sensor.

16. The endotracheal tube pressure monitoring system of claim 15, wherein the source of pressurized fluid includes a first fluid pump and a second fluid pump, wherein the first fluid pump is in fluid communication with the first pressure line to supply the pressurized fluid to the first pressure line in response to the first response signal, wherein the first fluid pump is responsive to the first termination signal to terminate supply of the pressurized fluid to the first pressure line, wherein the second fluid pump is in fluid communication with the second pressure line to supply the pressurized fluid to the second pressure line in response to the second response signal, and wherein the second fluid pump is responsive to the second termination signal to terminate supply of the pressurized fluid to the second pressure line.

17. The endotracheal tube pressure monitoring system of claim 15, wherein the source of pressurized fluid is a vessel of compressed fluid having a plurality of fluid actuators, wherein the plurality of fluid actuators include a first fluid actuator and a second fluid actuator, wherein the first fluid actuator is intermediate the first juncture and the vessel of compressed liquid and is responsive to the first response signal and the first termination signal, the first fluid actuator movable between a closed position, in which the pressurized fluid is not communicated to the first pressure line, and an open position, in which the pressurized fluid is communicated to the first pressure line, and wherein the second fluid actuator is intermediate the second juncture and the vessel of compressed liquid and is responsive to the second response signal and the second termination signal, the second fluid actuator movable between a closed position, in which the pressurized fluid is not communicated to the second pressure line, and an open position, in which the pressurized fluid is communicated to the second pressure line.

18. The endotracheal tube pressure monitoring system of claim 10, wherein at least a portion of the first pressure line is formed from a secondary lumen, the secondary lumen extending within the endotracheal tube from the distal end of the endotracheal tube.

19. The endotracheal tube pressure monitoring system of claim 18, wherein the secondary lumen is a catheter.

20. The endotracheal tube pressure monitoring system of claim 18, further comprising a connector having a first end, an opposing second end, a tubular conduit extending between the first and second end, and a first port in communication with the tubular conduit, wherein the connector has an inside diameter sized to provide a frictional fit between the first end and a Y-connector of a ventilator breathing circuit and to provide a frictional fit between the second end and the proximal end of the endotracheal tube, and wherein the secondary lumen extends through the first port to the distal end of the endotracheal tube.

21. The endotracheal tube pressure monitoring system of claim 20, wherein the connector has a second port in communication with the tubular conduit, and wherein a proximal end of the second pressure line is connected to the second port.

22. The endotracheal tube pressure monitoring system of claim 10, further comprising a connector having a first end, an opposing end, a tubular conduit extending between the first and second end, and a first port in communication with the tubular conduit, wherein the connector has an inside diameter sized to provide a frictional fit between the first end and a Y-connector of a ventilator breathing circuit and to provide a frictional fit between the second end and the proximal end of the endotracheal tube, and wherein a proximal end of the second pressure line is connected to the first port.

23. A method of monitoring the pressure of fluid at a distal and proximal end of an endotracheal tube, the method comprising:

a. providing an endotracheal tube having an open proximal end, an opposing open distal end, and a major lumen extending within the tube from the proximal end to the distal end;

b. inserting the endotracheal tube into a trachea of a patient, the distal end of the endotracheal tube is in fluid communication with the trachea of the patient;

c. measuring the pressure of the fluid within a first pressure line which is in fluid communication with the distal end of the endotracheal tube;

d. measuring the pressure of the fluid within a second pressure line which is in fluid communication with the proximal end of the endotracheal tube;

e. determining an obstruction status of the first pressure line by monitoring the measured pressure of the fluid within the first pressure line and generating a first response signal if the measured pressure of the fluid in the first pressure line remains generally constant for a first predetermined period of time;

f. activating a purging subsystem, in response to the first response signal, to supply a pressurized fluid to the first pressure line;

g. generating a first termination signal a second predetermined period of time after the first response signal is generated; and

h. deactivating the purging subsystem, in response to the first termination signal, to terminated supply of the pressurized fluid to the first pressure line.

24. The method of claim 23, wherein the pressure of the fluid within the first pressure line is measured by a first pressure sensor in communication with a distal end of the first pressure line, wherein the purging subsystem comprises a source of pressurized fluid in communication with the first pressure line at a first juncture in the first pressure line and a first purging actuator intermediate the first pressure sensor and the first juncture, wherein the first purging actuator is movable between an open position, in which fluid within the first pressure line is communicated to the first pressure sensor, and a closed position, in which fluid is prevented from being communicated to the first pressure sensor, and wherein, in response to the first response signal, the first purging actuator is positioned in the closed position for the second predetermined period of time and, upon the elapse of the second predetermined period of time, in response to the first termination signal, the first purging actuator returns to the open position.

25. The method of claim 24, further comprising:

a. determining the obstruction status of the second pressure line by monitoring the measured pressure of the fluid within the second pressure line and generating a second response signal if the measured pressure of the fluid in the second pressure line remains constant for the first predetermined period of time;

b. activating the purging subsystem, in response to the second response signal, to supply pressurized fluid to the second pressure line;

c. generating a second termination signal the second predetermined time after the second response signal is generated; and

d. deactivating the purging subsystem, in response to the second termination signal, to terminated supply of the pressurized fluid to the second pressure line.

26. The method of claim 25, wherein the pressure of the fluid within the second pressure line is measured by a second pressure sensor in communication with the second pressure line, wherein the purging subsystem is in fluid communication with the second pressure line at a second juncture intermediate in second pressure line, and wherein the purging subsystem has a second purging actuator, the second purging actuator intermediate the second pressure sensor and the second juncture, wherein the second purging actuator is movable between an open position, in which fluid within the second pressure line is communicated to the second pressure sensor, and a closed position, in which fluid is prevented from being communicated to the second pressure sensor, wherein, in response to the second response signal, the second purging actuator is positioned in the closed position for the second predetermined period of time and, upon the elapse of the second predetermined period of time, in response to the second termination signal, the second purging actuator returns to the open position.

27. The method of claim 23, further comprising displaying the pressure of the fluid measured within the first pressure line and the second pressure line.

28. The method of claim 23, further comprising:

a. determining a partial obstruction status of the endotracheal tube by monitoring the measured pressure of the fluid within the first and second pressure lines and determining a trend pressure within the first and second pressure lines over a third predetermined period of time from the measured pressure of the fluid within the first and second pressure lines, and

b. displaying a partial endotracheal obstruction status message if the measured pressure of the fluid in the second pressure line increases above the trend pressure of the fluid within the first and second pressure lines.

29. The method of claim 23, further comprising:

a. determining an increase in resistance of the endotracheal tube by monitoring the measured pressure of the fluid within the first and second pressure lines and determining a trend pressure within the first and second pressure lines over a third predetermined period of time from the measured pressure of the fluid within the first and second pressure lines; and

b. displaying an endotracheal tube patency alert message if the measured pressure within the first pressure line decreases below the trend pressure of the fluid within the first and second pressure lines.

30. The method of claim 23, further comprising:

a. determining an increase in resistance of a ventilator breathing circuit by monitoring the measured pressure of the fluid within the second pressure line and determining a trend pressure within the second pressure line over a third predetermined period of time from the measured pressure of the fluid within the second pressure line; and

b. displaying a ventilator breathing circuit resistance alert if the measured pressure within the second pressure line becomes lower than the trend pressure of the fluid within the second pressure line.