Automatic therapy advisor

• US 8,165,671 B2
• Filed: 05/24/2005
• Issued: 04/24/2012
• Est. Priority Date: 05/12/2004
• Status: Active Grant

• Current Assignee: Zoll Medical Corporation (Asahi Kasei Corporation)
• Original Assignee: Zoll Medical Corporation (Asahi Kasei Corporation)
• Inventors: Freeman, Gary A., Brewer, James E.
• Primary Examiner(s): Layno, Carl H
• Assistant Examiner(s): MALAMUD, DEBORAH LESLIE
• Application Number:
  US11/136,327
• Publication Number:
  US 20060025824A1
• Time in Patent Office: 2,527 Days
• Field of Search: 600508-509, 600/515, 600/518, 607 4- 6, 128/920, 128/923, 128/924, 128897-898, 706/924
• US Class Current: 607/5
• CPC Class Codes: A61B 5/363 Detecting tachycardia or bradycardia
• CPC Class Codes: A61B 5/7207 of noise induced by motion artifacts
• CPC Class Codes: A61B 5/7257 using Fourier transforms
• CPC Class Codes: A61B 5/726 using Wavelet transforms
• CPC Class Codes: A61B 5/7264 Classification of physiological signals or data, e.g. using neural networks, statistical classifiers, expert systems or fuzzy systems neural networks per se G06N3/00; expert systems per se G06N5/00
• CPC Class Codes: A61H 2201/5015 using specific interfaces or standards, e.g. USB, serial, parallel
• CPC Class Codes: A61H 2230/04 Heartbeat characteristics, e.g. E.G.C., blood pressure modulation
• CPC Class Codes: A61H 31/005 with feedback for the user
• CPC Class Codes: A61N 1/3925 Monitoring; Protecting
• CPC Class Codes: G09B 23/288 for artificial respiration or heart massage
• CPC Class Codes: G16H 40/60 for the operation of medical equipment or devices
• CPC Class Codes: G16H 50/20 for computer-aided diagnosis, e.g. based on medical expert systems
• CPC Class Codes: Y10S 128/92 Computer assisted medical diagnostics
• CPC Class Codes: Y10S 128/923 by comparison of patient data to other data
• CPC Class Codes: Y10S 128/924 using artificial intelligence
• CPC Class Codes: Y10S 706/924 Medical

Abstract

A method of automatically determining which type of treatment is most appropriate for (or the physiological state of) a patient. The method comprises transforming one or more time domain measurements from the patient into frequency domain data representative of the frequency content of the time domain measurements; processing the frequency domain data to form a plurality of spectral bands, the content of a spectral band representing the frequency content of the measurements within a frequency band; forming a weighted sum of the content of the spectral bands, with different weighting coefficients applied to at least some of the spectral bands; determining the type of treatment (or physiological state) based on the weighted sum.

Claims

1. A method of automatically determining which type of cardiac resuscitation treatment is most appropriate for a patient, the method comprising:

transforming one or more time domain ECG signal measurements from the patient into frequency domain data representative of the frequency content of the time domain measurements;

processing the frequency domain data to form a plurality of spectral bands, the content of each of the spectral bands representing the frequency content of the measurements within a different frequency band;

forming a weighted sum of the content of the spectral bands, with different weighting coefficients applied to at least some of the different spectral bands, wherein the magnitudes of the weighting coefficients are not linearly proportional to the frequency of the spectral band to which they are applied;

determining the type of cardiac resuscitation treatment based on the weighted sum.

2. The method of claim 1 wherein the weighting coefficients are ones chosen using a regression analysis comparing actual time domain measurements and actual outcome of therapy for a population of patients.

3. The method of claim 2 wherein the weighting coefficients have been chosen to improve a correlation between the weighted sum and the outcome of therapy.

4. The method of claim 1 wherein the weighting coefficients are different for at least two different therapy stages.

5. The method of claim 4 wherein the therapy stages comprise at least arrival at patient'"'"'s side, pre-shock, and post-shock.

6. The method of claim 5 wherein therapy stage is based at least in part on rescuer entered data indicative of at least what drugs have been delivered to the patient.

7. The method of claim 6 wherein the rescuer entered data is further indicative of whether the patient has been intubated, and whether an automatic external chest compressor has been used.

8. The method of claim 1 wherein the determining comprises comparing weighted sum to a threshold.

12. The method of claim 1 wherein the weighted sum for a normal sinus rhythm is significantly less than the weight sum for ventricular fibrillation.

13. The method of claim 1 wherein the spectral bands have a bandwidth of about 0.5 Hz.

14. The method of claim 1 wherein the spectral bands have a bandwidth of about 0.25 Hz.

15. The method of claim 1 wherein the spectral bands have a bandwidth of about 0.10 Hz.

16. The method of claim 15 wherein the spectral bands comprise adjacent frequency bands extending from about 3 Hz to about 20 Hz.

17. The method of claim 1 wherein the spectral bands have a bandwidth of about 1.0 Hz or less.

18. The method of claim 1 wherein the spectral bands have a bandwidth of about 0.5 Hz or less.

19. The method of claim 18 wherein the spectral bands comprise adjacent frequency bands extending from about 3 Hz to about 12 Hz.

20. The method of claim 1 wherein the spectral bands comprise adjacent frequency bands extending from about 3 Hz to about 12 Hz.

21. The method of claim 1 wherein the spectral bands comprise adjacent frequency bands extending from about 3 Hz to about 20 Hz.

22. The method of claim 1 wherein determining the type of cardiac resuscitation treatment comprises determining a probability that a defibrillation shock will be successful.

23. The method of claim 1 wherein determining the type of cardiac resuscitation treatment comprises determining whether to continue CPR or to deliver a defibrillation shock.

9. The method 8 wherein the threshold is different for at least two therapy stages.

10. The method of claim 9 wherein if the weighted sum exceeds the threshold the type of treatment determined to be appropriate is delivery of a defibrillation shock.

11. The method of claim 10 wherein, when the therapy stage is arrival at the patient'"'"'s side, the threshold used is lower than the threshold used for later therapy stages.