Waveform interpreter for respiratory analysis

• US 20020082511A1
• Filed: 02/28/2002
• Published: 06/27/2002
• Est. Priority Date: 06/08/1999
• Status: Active Grant

• Current Assignee: Baruch Shlomo Krauss, Ephraim Carlebach
• Original Assignee: Baruch Shlomo Krauss, Ephraim Carlebach
• Inventors: Carlebach, Ephraim, Krauss, Baruch Shlomo
• Granted Patent: US 6,997,880 B2
• Time in Patent Office: Days
• US Class Current: 600/529
• CPC Class Codes: A61B 5/0836 Measuring rate of CO2 production

Abstract

A capnograph which performs an analysis of the breath waveforms measured by the carbon dioxide sensor, interprets the results of this analysis, and outputs to the operator diagnostic information about the respiratory status of the patient, or about the adequacy of the breathing support provided to the patient. The instrument compares a number of parameters characteristic of the waveforms of the patient'"'"'s breath with an internal library of the values of those parameters expected from normal waveforms stored in its memory. These parameters may either relate to specific features of the waveform in the time domain, or may characterize spectral components of the waveform in the frequency domain. The capnographic waveform analysis may be combined with further non-invasive measurements in order to provide an indication of the deviation of the value of EtCO₂ from PaCO₂.

Claims

1. Apparatus for the automatic interpretation of a waveform of a breath of a subject.

2. Apparatus according to claim 1 and wherein said waveform is obtained from a capnographic analyzer.

3. Apparatus for the diagnosis of the respiratory state of a subject by computer analysis of at least one breath waveform obtained from said subject.

4. Apparatus according to claim 3 and wherein said breath waveform is obtained from a capnographic analyzer.

5. Apparatus for computerized breath analysis comprising:

a breath receiver in fluid communication with a subject;

a breathing analyzer coupled to the breath receiver and operative to analyze breathing of said subject and provide at least one output; and

a respiration diagnosis generator providing an indication of the respiratory status of the subject based on at least one output of said breathing analyzer.

10. Apparatus according to claim 5 and wherein said breathing analyzer includes a capnograph.

13. Apparatus according to claim 5 and wherein said breathing analyzer performs analysis of at least one breath waveform.

20. Apparatus according to claim 5 and wherein said respiratory diagnosis generator provides an indication of the respiratory status of the subject based on a capnographic measurement, and also on at least one output of at least one of:

a breathing flow rate measurement;

a breathing volume measurement;

an analysis of the amount of at least one other gas in the breath;

a measurement of cardiac output;

a pulse oximetric measurement; and

an ECG measurement.

6. Apparatus for computerized breath analysis comprising:

a breath receiver in fluid communication with a subject; and

a breathing analyzer coupled to the breath receiver and operative to analyze breathing of the subject and to provide an indication of the difference between the end tidal carbon dioxide partial pressure and the arterial carbon dioxide partial pressure of said subject.

8. Apparatus for computerized breath analysis according to claim 6 and also comprising:

a respiration diagnosis generator providing an indication of the respiratory status of the subject based on said indication of said difference between end tidal carbon dioxide partial pressure and the arterial carbon dioxide partial pressure of the subject.

11. Apparatus according to claim 6 and wherein said breathing analyzer includes a capnograph.

14. Apparatus according to claim 6 and wherein said breathing analyzer performs analysis of at least one breath waveform.

16. Apparatus according to claim 13 and wherein said breathing analyzer operates in a frequency domain.

17. Apparatus according to claim 16 and wherein said breathing analyzer analyzes changes in the frequency spectrum of said breath waveform for detecting changes in the respiratory status of said subject.

18. Apparatus according to claim 13 and wherein said breathing analyzer compares at least part of said breath waveform with at least one reference.

19. Apparatus according to claim 13 and wherein said breathing analyzer analyzes variations in at least part of said breath waveform over time for detecting changes in the respiratory status of said subject.

7. Apparatus for computerized breath analysis comprising:

a breath receiver in fluid communication with a subject; and

a breathing analyzer coupled to the breath receiver and operative to analyze breathing of the subject and to provide an, indication of the arterial carbon dioxide partial pressure of the subject.

9. Apparatus for computerized breath analysis according to claim 7 and also comprising:

a respiration diagnosis generator providing an indication of the respiratory status of the subject based on said indication of the arterial carbon dioxide partial pressure of the subject.

12. Apparatus according to claim 7 and wherein said breathing analyzer includes a capnograph.

15. Apparatus according to claim 7 and wherein said breathing analyzer performs analysis of at least one breath waveform.

21. Apparatus for providing an indication of the respiratory state of a subject, comprising

a gas analyzer which provides at least one time-dependent waveform of the partial pressure of carbon dioxide in the breath of a subject;

an input circuit for receiving a sequence of digitized signals derived from said at least one waveform;

a signal processor for analyzing said at least one waveform for at least one parameter which characterizes a property of said waveform;

a parameter comparator for comparing said at least one parameter with a predefined parameter which characterizes the same property of a waveform obtained from a normal subject; and

a diagnosis generator which generates a message in accordance with the output of said parameter comparator.

22. Apparatus according to claim 21 and wherein said gas analyzer is a capnograph.

24. Apparatus according to claim 23 and wherein said gas analyzer is a capnograph.

25. Apparatus according to claim 23 and wherein said respiratory deficiencies arise from deficient ventilation.

23. Apparatus for providing an indication of the respiratory state of a subject, comprising:

a gas analyzer which provides a plurality of time-sequenced waveforms of the partial pressure of carbon dioxide in the breath of a subject;

an input circuit for receiving a sequence of digitized signals derived from said plurality of time-sequenced waveforms;

a signal processor for analyzing said plurality of time-sequenced waveforms for determining changes with time in at least one parameter of said plurality of time-sequenced waveforms;

a trend analyzing unit for comparing said changes with time in said at least one parameter of said plurality of time-sequenced waveforms, with predefined changes with time in the equivalent said at least one parameter of time-sequenced waveforms typical of patients with known respiratory deficiencies; and

a diagnosis generator which generates a message in accordance with the output of said trend analyzing unit.