Automatic external defibrillator having a ventricular fibrillation detector

• US 6,263,238 B1
• Filed: 04/16/1999
• Issued: 07/17/2001
• Est. Priority Date: 04/16/1998
• Status: Expired due to Term

• Current Assignee: Zoll Medical Corporation (Asahi Kasei Corporation)
• Original Assignee: SurVivaLink Corporation (Cardica Incorporated)
• Inventors: Donohoo, Ann M., Brewer, James E., Olson, Kenneth F.
• Primary Examiner(s): Kamm, William E.
• Application Number:
  US09/293,263
• Time in Patent Office: 823 Days
• Field of Search: 607/5
• US Class Current: 607/5
• CPC Class Codes: A61N 1/3925 Monitoring; Protecting

Abstract

In an automatic external defibrillator (AED) having a ventricular fibrillation detector, the ventricular fibrillation detector may generally be defined as a filter containing both an adaptive non-linear section and a linear section. The non-linear section is preferably a complex-domain neural network that can be trained to differentiate between various rhythm patterns and produce linear data for input to the linear section. The linear section is preferably an ongoing, continuous operation based on a sliding window of a predetermined time period, e.g., a tapped time-delay filter. In combination the non-linear section and linear section of the filter operate to detect and extract artifacts from a patient'"'"'s ECG signal in a substantially accurate fashion so that the determination to deliver a defibrillation pulse may be accurately made.

Claims

1. An automatic external defibrillator (AED) having a ventricular fibrillation detector, comprising:

first detector means for receiving a cardiac rhythm signal, wherein said cardiac rhythm signal is submitted to said first detector means in a series of segments, and for producing a first output for each segment, wherein said first output is representative of the absence or presence of ventricular fibrillation;

second detector means operably connected to said first detector means, said second detector means for receiving said first outputs and for producing a second output, wherein said second output is representative of a weighted combination of at least two of said first outputs; and

third detection means operably connected to said second detection means, wherein said third detection means compares said second output against a predetermined criterion determining therefrom if ventricular fibrillation is present.

2. The AED of claim 1, wherein said series of segments are continuous.

3. The AED of claim 1, wherein said at least two of said first outputs are in series.

4. The AED of claim 1, wherein said first detector means is selected from the group consisting of:

a complex-domain feed-forward neural network, a complex-domain recurrent neural network, a power spectral density analyzer, a cross-spectral density analyzer, a coherence analyzer, a cepstrum analyzer, and a time-frequency domain analyzer.

5. The AED of claim 1, wherein said second detector means is selected from the group consisting of:

a moving average filter, an autoregressive filter, an autoregressive moving average filter, a digitally implemented analog prototyped IIR filter, a Butterworth filter, a type I Chebyshev filter, a type II Chebyshev filter, an elliptic filter, a Bessel filter, a Kalman filter, a multivariate linear predictor, a multivariate nonlinear predictor, and a bayesian predictor.

6. An automatic external defibrillator (AED) having a ventricular fibrillation detector, comprising:

a first detector portion, wherein said first detector portion receives a cardiac rhythm signal in a series of segments and wherein said first detector portion produces a first output for each of said segments that is representative of either the absence or presence of ventricular fibrillation,

a second detector portion operably connected to said first detector portion, wherein said second detector portion receives said first outputs and produces a second output, wherein said second output is representative of a weighted combination of at least two of said first outputs; and

a third detector portion operably connected to said second detector portion, wherein said third detector portion receives said second output and compares said second output against a predetermined criterion determining therefrom if ventricular fibrillation is present.

7. The AED of claim 6, wherein said series of segments are continuous.

8. The AED of claim 6, wherein said at least two of said first outputs are in series.

9. The AED of claim 6, wherein said first detector portion is selected from the group consisting of:

a complex-domain feed-forward neural network, a complex-domain recurrent neural network, a power spectral density analyzer, a cross-spectral density analyzer, a coherence analyzer, a cepstrum analyzer, and a time-frequency domain analyzer.

10. The AED of claim 6, wherein said second detector portion is selected from the group consisting of:

a moving average filter, an autoregressive filter, an autoregressive moving average filter, a digitally implemented analog prototyped IIR filter, a Butterworth filter, a type I Chebyshev filter, a type II Chebyshev filter, an elliptic filter, a Bessel filter, a Kalman filter, a multivariate linear predictor, a multivariate nonlinear predictor, and a bayesian predictor.

11. An automatic external defibrillator (AED), comprising:

an electrocardiographic (ECG) system adapted to be connected to a patient for obtaining a cardiac rhythm signal,

ventricular fibrillation detector operably connected said ECG system, wherein said detector comprises;

a first detector portion, wherein said first detector portion receives said cardiac rhythm signal in a series of segments and wherein said first detector portion produces a first output for each of said segments that is representative of either the absence or presence of ventricular fibrillation,

a second detector portion operably connected to said first detector portion, wherein said second detector portion receives said first outputs and produces a second output, wherein said second output is representative of a weighted combination of at least two of said first outputs; and

a third detector portion operably connected to said second detector portion, wherein said third detector portion receives said second output and compares said second output against a predetermined criterion determining therefrom if ventricular fibrillation, requiring the delivery of a defibrillation pulse, is present; and

a defibrillation pulse delivery system operably connected to said ventricular fibrillation detector, wherein said defibrillation pulse delivery system delivers said defibrillation pulse upon the determination by said ventricular fibrillation detector that ventricular fibrillation, requiring the delivery of a defibrillation pulse is present.

12. The AED of claim 11, wherein said series of segments are continuous.

13. The AED of claim 11, wherein said at least two of said first outputs are in series.

14. The AED of claim 11, wherein said first detector portion is selected from the group consisting of:

a complex-domain feed-forward neural network, a complex-domain recurrent neural network, a power spectral density analyzer, a cross-spectral density analyzer, a coherence analyzer, a cepstrum analyzer, and a time-frequency domain analyzer.

15. The AED of claim 11, wherein said second detector portion is selected from the group consisting of:

a moving average filter, an autoregressive filter, an autoregressive moving average filter, a digitally implemented analog prototyped IIR filter, a Butterworth filter, a type I Chebyshev filter, a type II Chebyshev filter, an elliptic filter, a Bessel filter, a Kalman filter, a multivariate linear predictor, a multivariate nonlinear predictor, and a bayesian predictor.

16. In an automatic external defibrillator (AED), a method for detecting ventricular fibrillation, comprising the steps of:

receiving a cardiac rhythm signal in a series of segments;

determining the absence or presence of ventricular fibrillation in each of said segments;

performing a weighted combination of the determinations from at least two of said segments;

comparing said weighted combination against a predetermined criterion and determining therefrom if ventricular fibrillation is present.

17. The method of claim 16, further comprising the step of initiating the delivery of a defibrillation pulse from the automated external defibrillator if ventricular fibrillation is present.