METHOD AND SYSTEM FOR VENTILATION

• US 20110197888A1
• Filed: 10/22/2009
• Published: 08/18/2011
• Est. Priority Date: 10/24/2008
• Status: Active Grant

• Current Assignee: Hospitech Respiration Ltd
• Original Assignee: Hospitech Respiration Limited Matalon Center Building Wing-A 3RD Floor
• Inventors: Efrati, Shai, Deutsch, Israel
• Granted Patent: US 9,474,469 B2
• Time in Patent Office: Days
• US Class Current: 128/204.23
• CPC Class Codes: A61B 5/085 Measuring impedance of respiratory organs or lung elasticity
• CPC Class Codes: A61M 16/0051 with alarm devices
• 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 16/0434 Cuffs
• CPC Class Codes: A61M 16/044 External cuff pressure control or supply, e.g. synchronisation with respiration
• CPC Class Codes: A61M 16/0463 combined with suction tubes, catheters or the like; Outside connections
• CPC Class Codes: A61M 16/0479 above the cuff, e.g. giving access to the upper trachea
• CPC Class Codes: A61M 16/0484 at the distal end
• CPC Class Codes: A61M 16/0486 Multi-lumen tracheal tubes
• 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 2016/0413 with detectors of CO2 in exhaled gases
• CPC Class Codes: A61M 2205/15 Detection of leaks
• CPC Class Codes: A61M 2205/3306 Optical measuring means
• CPC Class Codes: A61M 2205/3317 Electromagnetic, inductive or dielectric measuring means
• CPC Class Codes: A61M 2205/3331 Pressure; Flow
• CPC Class Codes: A61M 2205/3375 Acoustical, e.g. ultrasonic, measuring means
• CPC Class Codes: A61M 2209/02 Equipment for testing the apparatus

Abstract

A method of monitoring tracheal pressure of a subject is disclosed. The subject is ventilated with breathing gas flowing via an endotracheal tube having an inflatable cuff. The method comprises monitoring sealing of the trachea by the cuff using a close loop control, varying a ventilation pressure thereby varying flow level of the breathing gas, monitoring a response pressure within the cuff in response to the variation, and calculating the tracheal pressure using the ventilation pressure variations, the cuff response pressure and the flow level. In some embodiments, an under-pressure is applied for suctioning fluid carrying secretions, synchronously with variations in the tracheal pressure.

Claims

1. A method of monitoring tracheal pressure of a subject, the subject being ventilated with breathing gas flowing via an endotracheal tube having an inflatable cuff, the method comprising:

monitoring sealing of the trachea by said cuff using a close loop control;

varying a ventilation pressure thereby varying a flow level of the breathing gas;

monitoring a response pressure within said cuff in response to said variation; and

calculating the tracheal pressure using said ventilation pressure variations, said cuff response pressure and said flow level.

7. The method of any of claim 1, further comprising suctioning secretions from the endotracheal tube in synchronization with said monitored tracheal pressure.

16. The method of any of claim 1, wherein said monitoring said sealing of the trachea comprises measuring a level of at least one measure being indicative of leakage of secretion past said cuff to the lungs;

and the method further comprises adjusting inflation of said cuff based on said level of said at least one measure so as to generally minimize leakage of secretion from above said cuff to the lungs, while minimizing pressure associated damages to the trachea.

17. The method of any of claim 1, further comprising delivering at least one identifiable additive through said endotracheal tube.

18. The method of claim 17, wherein said monitoring said sealing of the trachea comprises monitoring a level of said at least one identifiable additive at a monitoring location in the body of the subject;

and the method further comprises adjusting inflation of said cuff based on said monitoring so as to generally minimize leakage of secretion from above said cuff to the lungs, while minimizing pressure associated damages to the trachea.

54. The method of claim 1, wherein said tracheal pressure is calculated using a derivative of said ventilation pressure with respect to said response pressure.

2. A method of monitoring tracheal pressure of a subject, the subject being ventilated with breathing gas flowing via an endotracheal tube having an inflatable cuff, the method comprising:

calculating an effective internal radius of the endotracheal tube and a pressure drop or tube resistance resulting from said effective internal radius while monitoring sealing of the trachea by said cuff using a close loop control; and

calculating the tracheal pressure using said pressure drop or tube resistance.

3. The method of claim 2, further comprising calculating obstruction level of said endotracheal tube wherein said effective internal radius is calculated based on said obstruction level.

4. The method of claim 3, further comprising:

varying a ventilation pressure of the breathing gas; and

monitoring a response pressure within said cuff in response to said variation;

wherein said calculation of said obstruction level is based on said ventilation pressure variations and said cuff response pressure.

5. The method of claim 2, further comprising measuring muscular contribution to pressure at the esophagus of the subject, wherein said calculation of said tracheal pressure is based on said muscular contribution.

6. The method of claim 2, further comprising, following a sequence of calculations of the tracheal pressure, calculating a direct relationship between the tracheal pressure and said cuff response pressure, and using said direct relationship for estimating the tracheal pressure over a predetermined time-period following said calculation of said direct relationship.

24. The method of claim 6, wherein said direct relationship is a linear relationship.

25. The method of claim 6, wherein said predetermined time-period is equivalent to at least 10 breaths of the subject.

53. The method of claim 3, wherein said obstruction level is estimated using a derivative of said ventilation pressure with respect to said response pressure.

8. A method, comprising:

ventilating a subject with breathing gas flowing via an endotracheal tube having an inflatable cuff;

monitoring sealing of the trachea by said cuff using a close loop control, thereby also monitoring cuff inflation pressure; and

suctioning secretions from the endotracheal tube in synchronization with said monitored cuff inflation pressure.

9. The method of claim 8, wherein said suctioning is at a suctioning location within the endotracheal tube.

10. The method of claim 8, wherein said suctioning is at a plurality of suctioning locations.

11. The method of claim 8, wherein said suctioning is at a suctioning pressure being adapted responsively to said monitored cuff inflation pressure.

12. The method of claim 8, wherein said monitoring comprises identifying exhale period wherein said suctioning is synchronized with said exhale period.

13. The method of claim 8, further comprising introducing an aerosol of dilution liquid into the endotracheal tube, wherein said suctioning is further synchronized with said introduction of said aerosol.

14. The method of claim 8, wherein said suctioning is via a suction conduit formed with a plurality of openings facing a main lumen of the endotracheal tube, said suction conduit being located at a dorsal side of the subject'"'"'s trachea.

15. A method of estimating obstruction level in a cuffed endotracheal tube positioned in a trachea of a ventilated subject, the method comprising:

monitoring sealing of the trachea by said cuff using a close loop control;

varying a ventilation pressure of the breathing gas;

monitoring a response pressure within said cuff in response to said variation; and

estimating the obstruction level using said ventilation pressure variations and said cuff response pressure.

19. A system for calculating tracheal pressure of a subject, the subject being ventilated with breathing gas flowing via an endotracheal tube having an inflatable cuff, the system comprising:

a cuff

a controller, for adjusting said inflation of said cuff so as to provide a minimal cuff inflation pressure being sufficient to ensure sealing of the trachea by said cuff, and for varying a ventilation pressure and flow level of the breathing gas;

a pressure sensor for sensing a response pressure within said cuff in response to said variation; and

a tracheal pressure calculator for calculating the tracheal pressure using said ventilation pressure variations, said cuff response pressure and said flow level.

23. The system of claim 19, further comprising:

a relationship calculator, for receiving a sequence of calculated tracheal pressures and calculating a direct relationship between the tracheal pressure and said cuff response pressure; and

a tracheal pressure estimator for estimating the tracheal pressure using said direct relationship over a predetermined time-period following said calculation of said direct relationship.

26. The system of claim 19, further comprising a suctioning device configured for suctioning secretions from the endotracheal tube, wherein said controller is configured for synchronizing said suctioning according to said monitored tracheal pressure.

32. The system of claim 19, further comprising the endotracheal tube.

33. The system of claim 32, wherein said endotracheal tube comprises a main lumen for carrying said breathing gas, and a suction conduit formed with a plurality of openings facing said main lumen for allowing suctioning of fluids from said main lumen into said suction conduit.

34. The system of claim 33, wherein said plurality of openings are distributed along a portion of said endotracheal tube which overlaps said cuff.

35. The system of claim 33, wherein at least one of said plurality of openings is at a distance of at least 2 cm from a distal end of said endotracheal tube.

36. The system of claim 33, wherein at least one of said plurality of openings has a slanted cross section adapted for allowing entry of fluid to said opening only when a flow within said main lumen is directed from a distal end to a proximal end of said endotracheal tube.

39. The system of claim 19, further comprising a ventilator for providing the breathing gas into said endotracheal tube.

20. A system for calculating tracheal pressure of a subject, the subject being ventilated with breathing gas flowing via an endotracheal tube having an inflatable cuff, the system comprising:

a cuff inflating unit for inflating said cuff;

a controller, for adjusting said inflation of said cuff so as to provide a minimal cuff inflation pressure being sufficient to ensure sealing of the trachea by said cuff;

an effective internal radius and pressure drop calculator for calculating an effective internal radius of the endotracheal tube and a pressure drop resulting from said effective internal radius; and

a tracheal pressure calculator for calculating the tracheal pressure using said pressure drop.

21. The system of claim 20, further a comprising a stenosis level calculator for calculating stenosis level of said endotracheal tube wherein said effective internal radius is calculated based on said stenosis level.

22. The system of claim 21, wherein said controller is configured for varying a ventilation pressure of the breathing gas, wherein the system further comprises a pressure sensor for sensing a response pressure within said cuff in response to said inflating unit for inflating said cuff;

variation, and wherein said calculation of said stenosis level is based on said ventilation pressure variations and said response pressure.

27-31. -31. (canceled)

37. (canceled)

38. (canceled)

40-52. -52. (canceled)