Ventilation analysis and monitoring

• US 9,987,452 B2
• Filed: 06/30/2009
• Issued: 06/05/2018
• Est. Priority Date: 06/30/2008
• Status: Active Grant

• Current Assignee: Oridion Medical 1987 Limited (Medtronic Plc)
• Original Assignee: Oridion Medical 1987 Limited (Medtronic Plc)
• Inventors: Colman, Joshua Lewis, Botesazan, Zion
• Primary Examiner(s): Mallari, Patricia
• Assistant Examiner(s): TOTH, KAREN E
• Application Number:
  US12/999,111
• Publication Number:
  US 20110105935A1
• Time in Patent Office: 3,262 Days
• Field of Search: 600529-543
• CPC Class Codes: A61B 5/0836 Measuring rate of CO2 production
• CPC Class Codes: A61B 5/087 Measuring breath flow
• CPC Class Codes: A61M 16/0003 Accessories therefor, e.g. sensors, vibrators, negative pressure
• CPC Class Codes: A61M 16/1005 with O2 features or with parameter measurement
• CPC Class Codes: A61M 2016/003 with a flowmeter
• CPC Class Codes: A61M 2016/103 the CO2 concentration
• CPC Class Codes: A61M 2205/3334 Measuring or controlling the flow rate
• CPC Class Codes: A61M 2205/583 by visual feedback
• CPC Class Codes: A61M 2230/432 partial CO2 pressure (P-CO2)

Abstract

A ventilation analysis system comprising an interface module adapted to receive a carbon dioxide (CO2) signal and a breath flow dynamics signal, and control logic adapted to produce a ventilation indicator, based on a mutual analysis of the CO2 signal and the breath flow dynamics signal. The ventilation indicator may be, for example, an estimated CO2 waveform, an End-Tidal CO2 (ETCO2) value, and/or a minute CO2 value.

Claims

1. A method for ventilation analysis, the method comprising:

receiving discrete partial pressure (PCO₂) signals from a CO₂ sensor and breath flow dynamics (BFD) signals from a BFD sensor;

wherein said CO₂ sensor has a response time of more than 100 ms;

constructing, using a processor, an estimated CO₂ waveform by way of mutual analysis of the PCO₂ and BFD signals, wherein said estimated CO₂ waveform depicts partial pressure of CO₂ in exhaled breath as a function of time, and wherein constructing the estimated CO₂ waveform comprises

determining a start point and an end point of exhalation and a duration of said exhalation based on said BFD signals;

determining, based on said CO₂ signals, an average PCO₂ value obtained during the exhalation determined based on said BFD signals;

constructing an estimated PCO₂ waveform based on a shape of a common CO₂ waveform, the determined said start point of exhalation, the determined said end point of exhalation, the determined said duration of the exhalation, and on the determined average PCO₂ value; and

relaying the estimated PCO₂ waveform to a clinician by displaying on a display.

2. The method according to claim 1, further comprising calculating an estimated EtCO₂ value.

3. The method according to claim 1, further comprising calculating an estimated minute CO₂ value.

4. The method according to claim 1, wherein the receiving of the CO₂ signal comprises wirelessly receiving the CO₂ signal.

5. The method according to claim 1, wherein the CO₂ signal comprises discrete PCO₂ readings taken every 500 ms or more.

6. The method according to claim 1, wherein the CO₂ signal comprises discrete PCO₂ readings taken every 900 ms or more.

7. The method according to claim 1, wherein the receiving of the breath flow dynamics signal comprises wirelessly receiving the breath flow dynamics signal.

8. The method according to claim 1, wherein the breath flow dynamics signal comprises a flow measurement.

9. The method according to claim 1, wherein the breath flow dynamics signal comprises an acoustic measurement.

10. The method according to claim 1, wherein the breath flow dynamics signal comprises a thermal measurement.

11. The method according to claim 1, wherein the breath flow dynamics signal comprises a chest movement measurement.

12. The method according to claim 1, wherein the breath flow dynamics signal comprises a computer-aided video analysis.

13. The method according to claim 1, wherein the breath flow dynamics signal comprises a Doppler radar signal.

14. The method according to claim 1, further comprising receiving an SpO₂ signal.

15. A ventilation analysis system comprising:

a CO₂ sensor configured to measure discrete partial pressure (PCO₂) in exhaled breath of a subject;

said CO₂ sensor having a response time of more than 100 ms;

a breath flow dynamics (BFD) sensor configured to measure the BFD of the subject;

an interface module configured to receive discrete partial pressure PCO₂ signals from the CO₂ sensor and BFD signals from the BFD sensor;

a control logic configured to receive the PCO₂ signals, construct an estimated CO₂ waveform by way of mutual analysis of the PCO₂ and BFD signals, wherein said estimated CO₂ waveform depicts partial pressure of CO₂ in exhaled breath as a function of time, and wherein constructing the estimated CO₂ waveform comprises;

determining a start point and an end point of exhalation and a duration of said exhalation based on said BFD signals;

determining, based on said CO₂ signals, an average PCO₂ value obtained during the exhalation determined based on said BFD signals; and

constructing an estimated CO₂ waveform based on a shape of a common CO₂ waveform, the determined said start point of exhalation, the determined said end point of exhalation, the determined said duration of the exhalation, and on the determined average PCO₂ value; and

a display configured to relay the estimated CO₂ waveform to a clinician.

16. The ventilation analysis system according to claim 15, wherein said breath flow dynamics sensor comprises a wireless breath flow dynamics sensor, a flow sensor, an acoustic sensor, a thermal sensor, a chest movement detector, a computer-aided video analyzer and/or a Doppler radar.

17. The ventilation analysis system according to claim 15, wherein said control logic is further configured to calculate an estimated End-Tidal CO₂ (EtCO2) value.

18. The ventilation analysis system according to claim 15, wherein said control logic is further configured to calculate an estimated minute CO₂ value.

19. The ventilation analysis system according to claim 15, wherein said CO₂ sensor comprises a wireless CO₂ sensor.

20. The ventilation analysis system according to claim 15, wherein said CO₂ sensor comprises a CO₂ sensor having a response time of 500 ms or more.

21. The ventilation analysis system according to claim 15, wherein said CO₂ sensor comprises a CO₂ sensor having a response time of 900 ms or more.

22. The ventilation analysis system according to claim 15, wherein said interface module is further configured to receive a Saturation of Peripheral Oxygen (SpO₂) signal.

23. The ventilation analysis system according to claim 22, further comprising a SpO₂ sensor configured to produce said SpO₂ signal.