US9486148B2
Active / In Force
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⏱️ 7.6 years remaining
Method and apparatus for estimating depth of anethesia by using ECG signal
Assignee: Individual
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Filing: 2014-05-28
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Granted: 2016-11-08
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Expires: 2034-05-28
Abstract
Abstract A method and apparatus for estimating depth of anesthesia includes steps of acquiring an ECG signal from a subject, quantifying the regularity of respiratory sinus arrhythmia (RSA) from the ECG signal to obtain an index, and estimating depth of anesthesia based on the index.
Inventors
- 👤 Shu-Shya HSEU
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 15:11
CPC Classifications
A; A61; A61B; A61B5/00; A61B5/02; A61B5/0205; A61B5/0402; A61B5/0452; A61B5/24; A61B5/316; A61B5/318; A61B5/346; A61B5/349; A61B5/48; A61B5/4821; A61B5/024; A61B5/02405
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
100 words
A method for estimating depth of anesthesia, comprising steps of: (a) acquiring an ECG signal; (b) quantifying regularity of respiratory sinus arrhythmia (RSA) to obtain an index based on the ECG signal; and (c) estimating depth of anesthesia based on the index; wherein the index obtained from quantifying the regularity is a ratio of a respiratory non-rhythmic component to a respiratory rhythmic component (NRR), the respiratory rhythmic component is a value representing extent of heart rate variability (HRV) affected by respiration, and the respiratory non-rhythmic component is a value representing extent of heart rate variability (HRV) not affected by respiration.
Claim 2
Independent Claim
100 words
A method for estimating depth of anesthesia, comprising steps of: (a) acquiring an ECG signal; (b) quantifying regularity of respiratory sinus arrhythmia (RSA) to obtain an index based on the ECG signal; and (c) estimating depth of anesthesia based on the index; wherein the index obtained from quantifying the regularity is a ratio of a respiratory non-rhythmic component to a respiratory rhythmic component (NRR), the respiratory rhythmic component is a value representing extent of heart rate variability (HRV) affected by respiration, and the respiratory non-rhythmic component is a value representing extent of heart rate variability (HRV) not affected by respiration.
Claim 3
Dependent Claim
91 words
The method as claimed in claim 1 , wherein the respiratory rhythmic component is the sum of RRI (R-R intervals) power in a specific bandwidth where a fundamental rhythmic frequency is located and RRI (R-R intervals) power in a specific bandwidth where a multiple of the fundamental rhythmic frequency is located in a specific frequency range in a frequency to power spectrum of RRI, and the fundamental rhythmic frequency is a frequency of a maximal power in a specific frequency range in a frequency to power spectrum of EDR (ECG-derived respiration).
Claim 4
Dependent Claim
35 words
The method as claimed in claim 2 , wherein the respiratory non-rhythmic component is total RRI power in a specific frequency range in the frequency to power spectrum of RRI minus the respiratory rhythmic component.
Claim 5
Dependent Claim
106 words
The method as claimed in claim 3 , wherein the frequency to power spectrum of RRI and the frequency to power spectrum of EDR are an MTFR (multitaper time-frequency reassignment) spectrum of RRI and an MTFR spectrum of EDR respectively, and the respiratory non-rhythmic component, the respiratory rhythmic component, the fundamental rhythmic frequency, the multiple of the fundamental rhythmic frequency, the RRI power in a specific bandwidth where the fundamental rhythmic frequency is located, or the RRI power in a specific bandwidth where the multiple of the fundamental rhythmic frequency is located is derived from the MTFR spectrum of RRI and the MTFR spectrum of EDR.
Claim 6
Dependent Claim
52 words
The method as claimed in claim 4 , wherein the fundamental rhythmic frequency is defined as the following formula: f r ( t ) = arg max f ∈ R + MTFR EDR ( t , f ) , and fr(t) is the fundamental rhythmic frequency.
Claim 7
Dependent Claim
113 words
The method as claimed in claim 4 , wherein the respiratory rhythmic component is defined as the following formula: P r ( t ) = ∑ n = 1 k ∫ n · f r - b H z n · f r + b H z MTFR RRI ( t , f ) ⅆ f for k · f r < a Hz , Pr(t) is the respiratory rhythmic component, b is a bandwidth, k is a positive integer, and a is a maximum frequency used to define a specific frequency range.
Claim 8
Dependent Claim
95 words
The method as claimed in claim 6 , wherein the ratio of the respiratory non-rhythmic component power to the respiratory rhythmic component power (NRR) is defined as the following formula: NRR ( t ) = log 10 ( H F MR ( t ) - P r ( t ) P r ( t ) ) , NRR(t) is the ratio of the respiratory non-rhythmic component to the respiratory rhythmic component, and HFMR(t) is total RRI power in a specific frequency range in the MTFR spectrum of RRI.
Claim 9
Independent Claim
120 words
An apparatus for estimating depth of anesthesia, comprising: an ECG signal acquiring unit acquiring an ECG signal in a non-invasive way, and outputting a digitized ECG signal; and an ECG signal analysis unit coupled with the ECG signal acquiring unit for receiving the digitized ECG signal, and quantifying regularity of respiratory sinus arrhythmia (RSA) to obtain an index based on the ECG signal for estimating depth of anesthesia; wherein the index obtained from quantifying the regularity is a ratio of a non-respiratory rhythmic component to a respiratory rhythmic component (NRR), the non-rhythmic component is a value representing the extent of HRV affected by respiration, and the non-rhythmic component is a value representing the extent of HRV not affected by respiration.
Claim 10
Independent Claim
120 words
An apparatus for estimating depth of anesthesia, comprising: an ECG signal acquiring unit acquiring an ECG signal in a non-invasive way, and outputting a digitized ECG signal; and an ECG signal analysis unit coupled with the ECG signal acquiring unit for receiving the digitized ECG signal, and quantifying regularity of respiratory sinus arrhythmia (RSA) to obtain an index based on the ECG signal for estimating depth of anesthesia; wherein the index obtained from quantifying the regularity is a ratio of a non-respiratory rhythmic component to a respiratory rhythmic component (NRR), the non-rhythmic component is a value representing the extent of HRV affected by respiration, and the non-rhythmic component is a value representing the extent of HRV not affected by respiration.
Claim 11
Dependent Claim
91 words
The apparatus as claimed in claim 8 , wherein the respiratory rhythmic component is the sum of RRI (R-R intervals) power in a specific bandwidth where a fundamental rhythmic frequency is located and RRI (R-R intervals) power in a specific bandwidth where a multiple of the fundamental rhythmic frequency is located in a specific frequency range in a frequency to power spectrum of RRI, and the fundamental rhythmic frequency is a frequency of a maximal power in a specific frequency range in a frequency to power spectrum of EDR (ECG-derived respiration).
Claim 12
Dependent Claim
35 words
The apparatus as claimed in claim 9 , wherein the respiratory non-rhythmic component is total RRI power in a specific frequency range in the frequency to power spectrum of RRI minus the respiratory rhythmic component.
Claim 13
Dependent Claim
94 words
The apparatus as claimed in claim 10 , wherein the frequency to power spectrum of RRI and the frequency to power spectrum of EDR are an MTFR (multitaper time-frequency re-assignment) spectrum of RRI and a MTFR spectrum of EDR respectively, and the respiratory non-rhythmic component, the respiratory rhythmic component, the fundamental rhythmic frequency, the multiple of the fundamental rhythmic frequency, the RRI power in the fundamental rhythmic frequency, or the RRI power in a multiple of the fundamental rhythmic frequency are derived from the MTFR spectrum of RRI and the MTFR spectrum of EDR.
Claim 14
Dependent Claim
52 words
The apparatus as claimed in claim 11 , wherein the fundamental rhythmic frequency is defined as the following formula: f r ( t ) = arg max f ∈ R + MTFR EDR ( t , f ) , and fr(t) is the fundamental rhythmic frequency.
Claim 15
Dependent Claim
113 words
The apparatus as claimed in claim 11 , wherein the respiratory rhythmic component is defined as the following formula: P r ( t ) = ∑ n = 1 k ∫ n · f r - b H z n · f r + b H z MTFR RRI ( t , f ) ⅆ f for k · f r < a Hz , Pr(t) is the respiratory rhythmic component, b is a bandwidth, k is a positive integer, and a is a maximum frequency used to define a specific frequency range.
Claim 16
Dependent Claim
95 words
The apparatus as claimed in claim 13 , wherein the ratio of the respiratory non-rhythmic component to the respiratory rhythmic component is defined as the following formula: NRR ( t ) = log 10 ( H F MR ( t ) - P r ( t ) P r ( t ) ) , NRR(t) is the ratio of a respiratory non-rhythmic component to the respiratory rhythmic component, and HFMR(t) is the total RRI power in a specific frequency range in the frequency to power spectrum of RRI.
References Cited (Backward Citations)
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