Method and apparatus for processing heart rate traces in a fetal monitor
First Claim
Patent Images
1. A method for determining the hear rate of a fetus, comprising the steps of:
- (a) obtaining a first signal indicative of the fetal heat rate of a first fetus and a second signal indicative of the fetal heart rate of a second fetus and/or the maternal heart rate of the mother of said first fetus;
(b) comparing said first signal with said second signal and producing a third signal indicative of the coincidence between said first and second signals;
(c) comparing said third signal to a limit; and
(d) generating a warning signal if said third signal bears a predefined relation to said limit.
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Abstract
A fetal monitor capable of recording the heart rate trace, preferably the beat-to-beat heart rate trace, of a fetus and a second heart rate trace of the mother or of a second fetus. Coincidence between the heart rate traces is detected by means of a direct or indirect comparison of the two traces and comparison of the difference with a predefined or adaptive limit. A warning signal is generated if coincidence is detected.
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Citations
47 Claims
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1. A method for determining the hear rate of a fetus, comprising the steps of:
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(a) obtaining a first signal indicative of the fetal heat rate of a first fetus and a second signal indicative of the fetal heart rate of a second fetus and/or the maternal heart rate of the mother of said first fetus; (b) comparing said first signal with said second signal and producing a third signal indicative of the coincidence between said first and second signals; (c) comparing said third signal to a limit; and (d) generating a warning signal if said third signal bears a predefined relation to said limit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 22)
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20. A method for determining the respective fetal heart rates of two fetuses, comprising the steps of:
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(a) obtaining a first signal indicative of fetal heart beats of a first fetus and a second signal indicative cf fetal heart beats of a second fetus; (b) processing one of said first and second signals with an adaptive filter with variable filter coefficients to obtain an output signal; (c) comparing said output signal with the other of said first and second signals and generating a difference signal based upon the comparison; (d) adapting said filter coefficients so that said difference signal is minimized; and (e) generating a warning signal if a sum of one or more of said filter coefficients bears a predefined relation to a limit.
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21. A method for determining the respective fetal heart rates of two fetuses, comprising the steps of:
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(a) obtaining a first signal indicative of fetal heart beats of a first fetus and a second signal indicative of fetal heart beats of a second fetus; (b) cross correlating said first and second signals with each other to produce a correlation function; and (c) generating a warning signal if said correlation function exceeds a limit.
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23. An apparatus for determining the heart rate of a fetus, comprising:
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(a) means for obtaining a first signal indicative of the fetal heart rate of a first fetus and a second signal indicative of the fetal heart rate of a second fetus and/or the maternal heart rate of the mother of said first fetus; (b) first comparison means for comparing said first signal with said second signal and producing a third signal indicative of the coincidence between said first and second signals; (c) means for comparing said third signal to a limit; and (d) means for generating a warning signal if said third signal bears a predefined relation to said limit. - View Dependent Claims (24, 25, 26, 27, 30, 31, 32)
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28. An apparatus for determining the respective fetal heart rates of two fetuses, comprising:
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(a) means for obtaining a first signal indicative of the fetal heart rate of a first fetus and a second signal indicative of the fetal heart rate of a second fetus; (b) means for processing one of said first and second signals with an adaptive filter with variable filter coefficients to obtain an output signal; (c) means for comparing said output signal with the other of said first and second signals and generating a difference signal based upon the comparison; (d) means for adapting said filter coefficients so that said difference signal is minimized; and (e) means for generating a warning signal if a sum of one or more of said filter coefficients bears a predefined relation to a limit.
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29. An apparatus for determining the respective fetal heart rates of two fetuses, comprising:
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(a) means for obtaining a first signal indicative of fetal heart beats of a first fetus and a second signal indicative of fetal heart beats of a second fetus; (b) means for cross correlating said first and second signals with each other to produce a correlation function; and (c) means for generating a warning signal if said correlation function exceeds a limit.
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33. A method for determining the heart rate of a fetus, comprising the steps of:
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(a) obtaining a first signal indicative of fetal heart beats of a first fetus and a second signal indicative of fetal heart beats of a second fetus and/or maternal heart beats; (b) detecting crossings of said first signal with said second signal, counting the number of crossings and producing a count indicative of the number of crossings; (c) comparing said count to a limit; and (d) generating a warning signal if said count bears a predefined relation to said limit. - View Dependent Claims (34, 35, 36, 37, 38)
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39. An apparatus for determining the heart rate of a fetus, comprising:
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(a) means for obtaining a first signal indicative of fetal heart beats of a first fetus, said first signal derived from an ultrasound signal, and means for obtaining a second signal indicative of fetal heart beats of a second fetus and/or maternal heart beats; (b) first comparison means for comparing said first signal with said second signal and producing a third signal indicative of the coincidence between said first and second signals; (c) means for comparing said third signal to a limit; (d) means for generating a warning signal if said third signal bears a predefined relation to said limit; and (e) means for focusing said ultrasound signal in response to said warning signal.
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40. An apparatus for determining the respective fetal heart rates of two fetuses, comprising:
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(a) means for obtaining a first signal indicative of fetal heart beats of a first fetus, said first signal derived from an ultrasound signal, and means for obtaining a second signal indicative of fetal heart beats of a second fetus and/or maternal heart beats of the mother of said first fetus; (b) means for processing one of said first and second signals with an adaptive filter with variable filter coefficients to obtain an output signal; (c) means for comparing said output signal with the other of said first and second signals and generating a difference signal based upon the comparison; (d) means for adapting said filter coefficients so that said difference signal is minimized; (e) means for generating a warning signal if a sum of one or more of said filter coefficients bears a predefined relation to a limit; and (f) means for focusing said ultrasound signal in response to said warning signal.
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41. An apparatus for determining the respective fetal heart rates of two fetuses, comprising:
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(a) means for obtaining a first signal indicative of fetal heart beats of a first fetus, said first signal derived from an ultrasound signal, and means for obtaining a second signal indicative of fetal heart beats of a second fetus and/or maternal heart beats; (b) means for cross correlating said first and second signals with each other to produce a correlation function; (c) means for generating a warning signal if said correlation function exceeds a limit; and (d) means for focusing said ultrasound signal in response to said warning signal.
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42. An apparatus for determining the heart rate of a fetus, comprising:
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(a) means for obtaining a first signal indicative of fetal heart beats of a first fetus and a second signal indicative of fetal heart beats of a second fetus and/or maternal heart beats; (b) first comparison means for comparing said first signal with said second signal and producing a third signal indicative of the coincidence between said first and second signals; (c) means for comparing said third signal to a limit; (d) means for generating a warning signal if said third signal bears a predefined relation to said limit; and e) means for obtaining an alternate signal indicative of heart beats of at least one of said first and second fetuses, and switching means for switching to a different combination of said first, second and alternate signals in response to said warning signal.
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43. An apparatus for determining the respective fetal heart rates of two fetuses, comprising:
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(a) means for obtaining a first signal indicative of fetal heart beats of a first fetus and a second signal indicative of fetal heart beats of a second fetus; (b) means for processing one of said first and second signals with an adaptive filter with variable filter coefficients to obtain an output signal; (c) means for comparing said output signal with the other of said first and second signals and generating a difference signal based upon the comparison; (d) means for adapting said filter coefficients so that said difference signal is minimized; (e) means for generating a warning signal if a sum of one or more of said filter coefficients bears a predefined relation to a limit; and (f) means for obtaining an alternate signal indicative of heart beats of at least one of said first and second fetuses, and switching means for switching to a different combination of said first, second and alternate signal in response to said warning signal.
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44. An apparatus for determining the respective fetal heart rates of two fetuses, comprising:
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(a) means for obtaining a first signal indicative of fetal heart beats of a first fetus and a second signal indicative of fetal heart beats of a second fetus; (b) means for cross correlating said first and second signals with each other to produce a correlation function; (c) means for generating a warning signal if said correlation function exceeds a limit; and (d) means for obtaining an alternate signal indicative of heart beats of at least one of said first and second fetuses, and switching means for switching to a different combination of said first, second and alternate signals in response to said warning signal.
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45. An apparatus for determining the heart rate of a fetus, comprising:
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(a) means for obtaining a first signal indicative of fetal heart beats of a first fetus and a second signal indicative of fetal heart beats of a second fetus and/or maternal heart beats of the mother of said first fetus; (b) first comparison means for comparing said first signal with said second signal and producing a third signal indicative of the coincidence between said first and second signals; (c) means for comparing said third signal to a limit; (d) means for generating a warning signal if said third signal bears a predefined relation to said limit; and (e) hysteresis means for avoiding jitter in said warning signal.
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46. An apparatus for determining the respective fetal heart rates of two fetuses, comprising:
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(a) means for obtaining a first signal indicative of fetal heart beats of a first fetus and a second signal indicative of fetal heart beats of a second fetus; (b) means for processing one of said first and second signals with an adaptive filter with variable filter coefficients to obtain an output signal; (c) means for comparing said output signal with the other of said first and second signals and generating a difference signal based upon the comparison; (d) means for adapting said filter coefficients so that said difference signal is minimized; and (e) means for generating a warning signal if a sum of one or more of said filter coefficients bears a predefined relation to a limit; (f) hysteresis means for avoiding jitter in said warning signal.
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47. An apparatus for determining the respective fetal heart rates of two fetuses, comprising:
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(a) means for obtaining a first signal indicative of fetal heart beats of a first fetus and a second signal indicative of fetal heart beats of a second fetus; (b) means for cross correlating said first and second signals with each other to produce a correlation function; (c) means for generating a warning signal if said correlation function exceeds a limit; and (d) hysteresis means for avoiding jitter in said warning signal.
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Specification