Reliability-enhanced apparatus operation for re-breathing and methods of effecting same

• US 20060241508A1
• Filed: 06/23/2006
• Published: 10/26/2006
• Est. Priority Date: 10/15/1998
• Status: Active Grant

• Current Assignee: RIC INVESTMENTS LLC (Respironics Incorporated)
• Original Assignee: RIC INVESTMENTS LLC (Respironics Incorporated)
• Inventors: Triunfo, John A. Jr., Jaffe, Michael B., Gunneson, Paul B., Rich, David R., Wigforss, Eric P.
• Granted Patent: US 7,775,207 B2
• Time in Patent Office: Days
• US Class Current: 600/532
• CPC Class Codes: A61M 16/0045 Means for re-breathing exhaled gases, e.g. for hyperventilation treatment
• CPC Class Codes: A61M 16/0051 with alarm devices
• CPC Class Codes: A61M 16/024 including calculation means, e.g. using a processor
• CPC Class Codes: A61M 16/0833 T- or Y-type connectors, e.g. Y-piece
• CPC Class Codes: A61M 16/085 Gas sampling
• CPC Class Codes: A61M 16/0858 Pressure sampling ports
• CPC Class Codes: A61M 2016/0027 pressure meter
• CPC Class Codes: A61M 2016/103 the CO2 concentration
• CPC Class Codes: A61M 2205/16 with back-up system in case of failure
• CPC Class Codes: A61M 2230/432 partial CO2 pressure (P-CO2)
• CPC Class Codes: Y10T 137/7761 Electrically actuated valve
• CPC Class Codes: Y10T 137/8326 Fluid pressure responsive indicator, recorder or alarm

Abstract

An apparatus and method for affording a re-breathing capability to a breathing circuit. The apparatus includes a valve that permits air flow through or re-breathing in the breathing circuit. A CO₂ sensor and an air flow sensor detects CO₂ a rate of air flow in the breathing circuit, respectively. A processor computes a parameter based on the CO₂ waveform feature and a volumetric CO₂ waveform feature based on signals from the air flow sensor and/or the CO₂ sensor. An alarm is triggered when the parameter deviates from a selected magnitude. In a further embodiment, at least one parameter associated with an energy source for actuating the valve is monitored. Deviation of the value from at least one selected value of the at least one parameter is corrected.

Claims

1. An apparatus for affording a re-breathing capability to a breathing circuit, comprising:

(a) a device for altering operation of the breathing circuit from a first mode permitting air flow through a first path in the breathing circuit to a second mode providing a re-breathing capability to the breathing circuit;

(b) a CO₂ sensor located to detect CO₂ in the breathing circuit between the device and a patient;

(c) an air flow sensor located to detect a rate of air flow in the breathing circuit between the device and the patient; and

(d) a processor for computing a parameter comprising at least one of;

(1) a CO₂ waveform feature responsive to signals from the CO₂ sensor,

(2) a volumetric CO₂ waveform feature responsive to signals from the air flow sensor and the CO₂ sensor, and

(3) triggering an alarm responsive to deviation of the computed parameter from a selected magnitude or range of magnitudes for the parameter.

2. The apparatus of claim 1, wherein the air flow sensor and the CO₂ sensor are combined.

3. The apparatus of claim 1, wherein the device comprises an airway valve having a first mode for permitting air flow substantially directly through the airway valve and a second mode for diverting air flow through an expanded volume within the breathing circuit.

4. The apparatus of claim 1, wherein the processor is adapted to:

(a) detect, during at least one inspiration by the patient, at least one of air flow rate, air pressure, and a selected gas within the breathing circuit between the device and the patient;

(b) generate at least one signal responsive to the detection of air flow, air pressure, and the selected gas as at least one waveform;

(c) analyze the at least one generated waveform to ascertain if the device is functioning properly, including whether the device is in an appropriate mode during the at least one inspiration; and

(d) trigger an alarm if the analysis of the generated waveforms indicates improper functioning of the device.

5. The apparatus of claim 4, wherein the selected gas is selected from (a) gases which exhibit a change in concentration as a result of addition or removal of he expanded volume or CO₂, or (b) the group consisting of N₂, O₂ and CO₂.

6. The apparatus of claim 4, wherein analyzing the at least one generated waveform comprises at least one of analyzing a waveform slope, an encompassed area, a peak height, and a peak location.

7. The appartus of claim 4, wherein analyzing the at least one generated waveform employs at least one of pattern recognition, syntactic waveform analysis, a neural network, and an adaptive filter.

8. A method of enhancing reliability of operation of a device for a breathing circuit, the device having a first mode permitting air flow through a first path in the breathing circuit to a second mode wherein air flow is through an expanded volume within the breathing circuit, the method comprising detecting air flow rate and CO₂ within the breathing circuit between the airway valve and a patient, the method comprising:

(a) computing a parameter comprising at least one of (1) end-tidal or end-inspired CO₂ concentration from the detected CO₂ and (2) inspired CO₂ volume from the detected air flow and CO₂; and

(b) triggering an alarm responsive to deviation of the computed parameter from a selected magnitude or range of magnitudes for the parameter.

9. The method of claim 8, further comprising providing an airway valve having a first mode for permitting air flow substantially directly through the airway valve and a second mode wherein air flow is through an expanded volume within the breathing circuit.

10. The method of claim 8, further comprising:

detecting, during at least one inspiration by the patient, at least one of air flow rate, air pressure, and a selected gas within the breathing circuit between the device and the patient, and generating at least one signal responsive to the detection as at least one waveform;

analyzing the at least one generated waveform to ascertain if the device is functioning properly, including whether the device is in an appropriate mode during the at least one inspiration; and

triggering an alarm if the analysis of the generated waveforms indicates improper functioning of the device.

11. The method of claim 10, wherein the selected gas includes a gas that exhibits a change in concentration as a result of addition or removal of the expanded volume or CO₂.

12. The method of claim 10, wherein the selected gas is selected from the group consisting of N₂, O₂ and CO₂.

13. The method of claim 10, wherein analyzing the at least one generated waveform comprises analyzing at least one of a waveform slope, an encompassed area, a peak height, and a peak location.

14. The method of claim 10, wherein analyzing the at least one generated waveform employs at least one of pattern recognition, syntactic waveform analysis, a neural network, and an adaptive filter.

15. A method of enhancing reliability of operation of an airway valve for a breathing circuit, the airway valve having a first mode for permitting air flow substantially directly through the airway valve and a second mode for providing a re- breathing capability to the breathing circuit, comprising:

detecting a value of at least one parameter associated with an energy source for actuating the airway valve; and

correcting detected value deviation from at least one selected value of the at least one parameter.

16. The method of claim 15, wherein the at least one selected value comprises a range of values.