Detecting ventilator system anomalies while in a speaking mode

• US 20080060656A1
• Filed: 08/17/2007
• Published: 03/13/2008
• Est. Priority Date: 09/11/2006
• Status: Active Grant

• Current Assignee: Philips RS North America LLC (Koninklijke Philips N.V.)
• Original Assignee: RIC INVESTMENTS LLC (Koninklijke Philips N.V.)
• Inventors: Isaza, Fernando
• Granted Patent: US 8,161,972 B2
• Time in Patent Office: Days
• US Class Current: 128/207.16
• CPC Class Codes: A61M 16/042 with separate conduits for in-and expiration gas, e.g. for limited dead volume
• CPC Class Codes: A61M 16/0468 with valves at the proximal end limiting exhalation, e.g. during speaking or coughing air passages from trachea to oesophagus or to pharynx, artificial epiglottis A61F2/203
• CPC Class Codes: A61M 16/0833 T- or Y-type connectors, e.g. Y-piece
• 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: A61M 2016/0027 pressure meter
• CPC Class Codes: A61M 2039/1005 Detection of disconnection
• CPC Class Codes: A61M 2202/0208 Oxygen

Abstract

A method of operating a ventilator assembly having inhalation and exhalation passages communicating with one another, and a respiration assembly that can perform repetitive respiratory cycles. The method includes (a) repetitively cycling the respiration assembly so that during the inhalation phase, gas in the inhalation passage flows to the patient, and during the exhalation phase, an exhalation valve is maintained relatively closed and the exhaled gases flow pass the vocal cords and out of the mouth thereby facilitating the patient'"'"'s ability to speak, (c) monitoring the pressure within at least one of the passages during the exhalation phase, and (d) determining whether a circuit disconnect or an occlusion exists based on the pressure monitoring.

Claims

1. A method of operating a ventilator assembly comprising:

providing a ventilator assembly that includes inhalation and exhalation passages communicating with one another, and a respiration assembly capable of performing repetitive respiratory cycles each including;

(1) an inhalation phase during which (a) an inhalation valve communicating with the inhalation passage is relatively open for the passage of gas therethrough into the inhalation passage and to patient, and (b) an exhalation valve between the exhalation passage and an exhalation outlet in the ventilator assembly is relatively closed, and (2) an exhalation phase during which the inhalation valve is relatively closed, the method comprising;

repetitively cycling the respiration assembly so that (a) during the inhalation phase, the gas in the inhalation passage flows through an endotracheal tube and into the patient'"'"'s airway and lungs below the patient'"'"'s vocal cords, and (b) during the exhalation phase, the exhalation valve is maintained relatively closed and the patient is allowed to exhale the gases in the patient'"'"'s airway and lungs, pass the patient'"'"'s vocal cords and out of the patient'"'"'s mouth, thereby facilitating the patient'"'"'s ability to speak;

monitoring a pressure within at least one of the passages during the exhalation phase; and

determining whether a circuit disconnect or an occlusion exists based on a the pressure monitoring.

2. The method of claim 1, wherein the endotracheal tube is devoid of a check valve so that gas exhaled by the patient during each exhalation phase is communicated with the passages while both inhalation and exhalation valves are closed.

3. The method of claim 1, wherein the endotracheal tube has a check valve so that the gas exhaled by the patient during each exhalation phase is prevented from communicating with the passages.

4. The method of claim 1, wherein determining whether a circuit disconnect exits includes:

determining a peak pressure during the exhalation phase; and

comparing the peak pressure to a first threshold.

5. The method of claim 4, wherein determining whether a circuit disconnect exits further comprises:

determining a minimum pressure during the exhalation phase;

determining a delta pressure as a difference between the minimum pressure and the peak pressure; and

comparing the delta pressure to a second threshold.

6. The method of claim 1, wherein determining whether an occlusion exists includes:

comparing the pressure to a threshold; and

monitoring an amount of time that the pressure exceeds the threshold.

7. The method of claim 1, wherein determining whether an occlusion exists includes:

determining an occlusion criterion, wherein the occlusion criteria is a time varying function based on the pressure;

comparing the pressure to the occlusion criteria.

8. The method of claim 1, wherein determining whether an occlusion exists includes:

determining a critical volume of gas expected to leave the patient in the presence of an obstruction; and

comparing a volume of gas delivered from the ventilator assembly to the critical volume.

9. The method of claim 1, wherein determining whether an occlusion exists includes:

determining an exhaled volume delivered by the ventilator assembly;

determining an inhaled volume delivered by the ventilator assembly;

comparing the exhaled volume to the inhaled volume or a volume determined based on the inhaled volume.

10. The method of claim 1, wherein during the exhalation phase, the inhalation valve or the exhalation valve is controlled to regulate pressure in the conduit to facilitate the patient'"'"'s ability to speak.

11. The method of claim 1, where in the pressure in the conduit is regulated by controlling opening and closing of at least one of the valves so as to provide a desired pressure in the conduit to facilitate the patient'"'"'s ability to speak.

12. A patient ventilator assembly comprising:

a conduit adapted to be connected to an exterior open end of an endotracheal tube, wherein the conduit includes inhalation and exhalation passages communicating with one another;

inhalation and exhalation valves in the inhalation and exhalation passages, respectively;

a pressure sensor adapted to monitor a pressure within at least one of the passages during the exhalation phase; and

a controller for controlling the inhalation valve and the exhalation valve so as to provide repetitive respiratory cycles, each respiratory cycle including an inhalation phase and an exhalation phase, wherein during the inhalation phase the inhalation valve is relatively open and the exhalation valve is relatively closed and a flow of gas is allowed to pass through the inhalation passage and the tube into the patient'"'"'s airway and lungs, the controller controlling the exhalation valve for use in two exhalation phase modes, the two modes including;

(1) a first mode wherein the exhalation valve is relatively open during the exhalation phase, allowing the gas in the patient'"'"'s airway and lungs after the preceding inhalation phase to pass through the relatively open exhalation valve and through an outlet of the ventilator assembly, and

(2) a second mode wherein the exhalation valve is maintained relatively closed so that the patient causes the gas in the patient'"'"'s airway and lungs after the preceding inhalation phase to flow passed the patient'"'"'s vocal cords and out of the patient'"'"'s mouth, thus facilitating the patient'"'"'s ability to talk, and

wherein the controller is adapted to determine whether a circuit disconnect or an occlusion exists based on the monitored pressure.

13. The patient ventilator assembly of claim 12, wherein the controller comprises an exhalation controller module that controls the exhalation valve and an inhalation controller module that controls the inhalation valve.

14. The patient ventilator assembly of claim 12, wherein the controller comprises a first algorithm for controlling the inhalation valve, a second algorithm for controlling the exhalation valve, and a third for determining whether the circuit disconnect or the occlusion exists.

15. The patient ventilator assembly of claim 12, wherein the exhalation valve is controlled by the controller to be closed sufficiently during the inhalation phase to enable a desired pressure to build within the conduit.

16. The patient ventilator assembly of claim 12, wherein the exhalation valve is controlled by the controller to be closed sufficiently during the exhalation phase to maintain a desired pressure in the conduit.

17. The patient ventilator assembly of claim 12, wherein the endotracheal tube is devoid of a check valve so that communication between the passages and the patient'"'"'s airway and lungs while the exhalation valve is in the first mode thereof is through the exterior tube end in both directions.

18. The patient ventilator assembly of claim 12, wherein the controller determines whether a circuit disconnect exists by determining a peak pressure during the exhalation phase, and comparing the peak pressure to a first threshold.

19. The patient ventilator assembly of claim 18, wherein the controller determines whether a circuit disconnect exits by:

determining a minimum pressure during the exhalation phase;

determining a delta pressure as a difference between the minimum pressure and the peak pressure; and

comparing the delta pressure to a second threshold.

20. The patient ventilator assembly of claim 12, the controller determines whether an occlusion exists by comparing the pressure to a threshold, and monitoring an amount of time that the pressure exceeds the threshold.

21. The patient ventilator assembly of claim 12, the controller determines whether an occlusion exists by determining an occlusion criteria, wherein the occlusion criteria is a time varying function based on the pressure, and comparing the pressure to the occlusion criteria.

22. The patient ventilator assembly of claim 12, the controller determines whether an occlusion exists by determining a critical volume of gas expected to leave the patient in the presence of an obstruction, and comparing a volume of gas delivered from the ventilator assembly to the critical volume.

23. The patient ventilator assembly of claim 12, the controller determines whether an occlusion exists by determining an exhaled volume delivered by the ventilator assembly, determining an inhaled volume delivered by the ventilator assembly, and comparing the exhaled volume to the inhaled volume or a volume determined based on the inhaled volume.

24. A patient ventilating apparatus comprising:

an endotracheal tube constructed and arranged to be installed into a patient'"'"'s trachea below the patient'"'"'s vocal cords so that an exterior open end thereof is exterior of the patient and an interior open end thereof communicates with the patient'"'"'s airway and lungs;

a conduit connected with the exterior open end of the tube and providing inhalation and exhalation passages communicating with one another;

a respiration assembly constructed and arranged to provide repetitive respiratory cycles, each including (a) an inhalation phase during which an inhalation valve in the inhalation passage is relatively open and an exhalation valve in the exhalation passage is relatively closed, and wherein a flow of gas is allowed to pass through the inhalation passage and the endotracheal tube into the patient'"'"'s airway and lungs and (b) an exhalation phase during which the inhalation valve is relatively closed and the exhalation valve is maintained relatively closed;

a check valve operatively coupled to the endotracheal tube, the check valve enabling the patient at the end of each inhalation phase to cause the gas in the patient'"'"'s airway and lungs to pass through the patient'"'"'s vocal cords and out of the patient'"'"'s mouth, thus facilitating the patient'"'"'s ability to speak, the check valve being operable to trap pressure within the patient'"'"'s lungs at the end of the inhalation phase when both the inhalation and exhalation valves are relatively closed so as to allow pressure in the passages at the end of each inhalation phase to substantially equalize with the pressure within the patient'"'"'s airway and lungs during the exhalation phase; and

a pressure monitor adapted to monitor a pressure in at least one of the inhalation and exhalation passages during an exhalation phase; and

a controller that controls operation of the inhalation valve and the exhalation valve, and determines whether a circuit disconnect or an occlusion exists based on the monitored pressure.

25. The patient ventilating apparatus of claim 24, wherein during the inhalation phase, the flow of gas is allowed to pass through the exhalation valve.

26. The patient ventilating apparatus of claim 24, wherein the controller determines whether a circuit disconnect exists by determining a peak pressure during the exhalation phase, and comparing the peak pressure to a first threshold.

27. The patient ventilating apparatus of claim 25, wherein the controller determines whether a circuit disconnect exits by:

determining a minimum pressure during the exhalation phase;

determining a delta pressure as a difference between the minimum pressure and the peak pressure; and

comparing the delta pressure to a second threshold.

28. The patient ventilating apparatus of claim 24, wherein the controller determines whether an occlusion exists by comparing the pressure to a threshold, and monitoring an amount of time that the pressure exceeds the threshold.

29. The patient ventilating apparatus of claim 24, wherein the controller determines whether an occlusion exists by determining an occlusion criteria, wherein the occlusion criteria is a time varying function based on the pressure, and comparing the pressure to the occlusion criteria.

30. The patient ventilating apparatus of claim 24, wherein the controller determines whether an occlusion exists by determining a critical volume of gas expected to leave the patient in the presence of an obstruction, and comparing a volume of gas delivered from the ventilator assembly to the critical volume.

31. The patient ventilating apparatus of claim 24, wherein the controller determines whether an occlusion exists by determining an exhaled volume delivered by the ventilator assembly, determining an inhaled volume delivered by the ventilator assembly, and comparing the exhaled volume to the inhaled volume or a volume determined based on the inhaled volume.