Cardiopulmonary Resuscitation Feedback System

Abstract

To provide a system for assessing CPR applied by a person to a subject and providing CPR feedback to the person.SOLUTION: A CPR feedback system (20) comprises: an ECG system (22) configured to measure ECG signals of a subject; a biosignal system (24) configured to measure biosignals of the subject; a CPR assessment system (26) connected to the ECG system to receive ECG signals and connected to the biosignal system to receive biosignals; and a CPR feedback unit (28) connected to the CPR assessment system and configured to receive CPR feedback signals and issue CPR feedback to the person.SELECTED DRAWING: Figure 1

Description

Technical Field

[0003]

[0001] The present invention relates to a cardiopulmonary resuscitation (CPR) feedback system that uses an electrocardiogram (ECG) signal and a biosignal to evaluate CPR and provide CPR feedback to a person during the execution of CPR on a subject.

Background Art

[0002] Cardiopulmonary resuscitation feedback systems are used to treat subjects by instructing the person using the system to initiate and maintain high-quality cardiopulmonary resuscitation. CPR mainly involves compressing the subject's sternum to pump blood from the heart into the circulatory system in order to supply oxygenated blood to the subject's heart and brain. If the sternum compression is too shallow, too slow, or too fast, the heart cannot pump sufficient oxygenated blood. Changes in the sternum compression rate and sternum compression depth cause changes in the biosignals measured from the subject, and thus these biosignals can be used to guide a person regarding the performance of CPR. It is advantageous to provide CPR feedback to a person during CPR because it can improve the person's CPR performance.

Summary of the Invention

[0003] According to a first aspect of the present invention, there is provided a cardiopulmonary resuscitation (CPR) feedback system for evaluating cardiopulmonary resuscitation performed by a person on a subject and providing CPR feedback to that person, the CPR feedback system comprising: an electrocardiogram (ECG) system configured to measure an ECG signal of the subject; a biosignal system configured to measure a biosignal of the subject; a CPR evaluation system connected to the ECG system to receive the ECG signal and connected to the biosignal system to receive the biosignal; It comprises a CPR feedback unit that is connected to a CPR evaluation system and configured to receive CPR feedback signals and provide CPR feedback to a person, The CPR evaluation system is (i) The steps of setting a reference ECG signal metric and a target biosignal metric, (ii) A step of generating a CPR feedback signal that advises a person to initiate CPR, (iii) The steps of receiving ECG signals measured during multiple chest compressions and using those ECG signals to set the current ECG signal metric, (iv) The steps of receiving biosignals measured during multiple chest compressions and using those biosignals to set the current biosignal metric, (v) The steps of comparing the current ECG signal metric with a reference ECG signal metric and comparing the current biosignal metric with a target biosignal metric, (vi) A step of generating a CPR feedback signal that advises a person to improve CPR performance when the current ECG signal metric is smaller than a reference ECG signal metric and the current biosignal metric is smaller than a target biosignal metric, (vii) A step of generating a CPR feedback signal that advises a person to increase the target biosignal metric and improve CPR performance when the current ECG signal metric is smaller than the reference ECG signal metric and the current biosignal metric is greater than or equal to the target biosignal metric, (viii) If the current ECG signal metric is greater than or equal to the reference ECG signal metric, the system is configured to perform the step of setting the reference ECG signal metric to the same value as the current ECG signal metric and generating a CPR feedback signal that advises the person to maintain their current CPR performance.

[0004] In the present invention, the CPR feedback system provides dynamic CPR feedback to the person performing CPR on the subject, and the CPR feedback is based on repeated monitoring of chest compressions performed by the person on the subject using biosignal measurement and repeated monitoring of the subject's ECG.

[0005] A biosignaling system can be configured to measure one or more types of biosignals from a subject. These biosignals may include any of the following: chest impedance signals, end-tidal carbon dioxide signals, peripheral oxygen saturation signals, blood pressure signals, and chest compression depth signals. The biosignaling system may also include any of the following: an impedance signal measurement system, a capnograph, an oximeter, a blood pressure measurement system, or an accelerometer.

[0006] Setting a reference ECG signal metric may involve receiving ECG signals from an ECG system measured over a predetermined period prior to the start of CPR, and using those ECG signals to set the reference ECG signal metric.

[0007] Setting a reference ECG signal metric using an ECG signal may include setting a score for the ECG signal. The score may relate to the quality of the measured ECG signal. The score may be derived from one or more time-domain features of the ECG signal. Time-domain features may include the mean amplitude, peak amplitude, or median slope of the ECG signal. The score may be derived from one or more frequency-domain features of the ECG signal. Frequency-domain features may include the amplitude spectral domain (AMSA), power spectral analysis features, or centroid frequency. The score may be derived from one or more time-domain features and one or more frequency-domain features. Time-domain and frequency-domain features can be used as measures to estimate the subject's state.

[0008] Setting a target biosignal metric may include receiving a predetermined target biosignal metric. A predetermined target biosignal metric may include at least one target biosignal metric element for one or more types of biosignals. The at least one target biosignal metric element for one or more types of biosignals may include at least one target frequency biosignal metric element, at least one target amplitude biosignal metric element, or any one of at least one target frequency biosignal metric element and at least one target amplitude biosignal metric element.

[0009] Setting a target biosignal metric may include (i) receiving one or more types of biosignals measured during multiple chest compressions by a person, and (ii) setting a target biosignal metric using any or some of the one or more types of biosignals. The target biosignal metric may include at least one target biosignal metric element for any or some of the one or more types of biosignals. The at least one target biosignal metric element for any or some of the one or more types of biosignals may include at least one target frequency biosignal metric element, at least one target amplitude biosignal metric element, or any of the at least one target frequency biosignal metric element and at least one target amplitude biosignal metric element. The target biosignal metric element for each type of biosignal may provide an indicator of the person's target CPR performance during CPR chest compressions.

[0010] The target amplitude biosignal metric element may include any of the following: average amplitude, average maximum, average minimum, or the ratio of minimum to maximum. The target frequency biosignal metric element may include the dominant frequency.

[0011] Receiving ECG signals measured during multiple chest compressions may include receiving ECG signals measured over a predetermined duration window. The predetermined duration can be in the range of approximately 5 seconds to approximately 30 seconds.

[0012] Setting the current ECG signal metric using the ECG signal may include setting a score for the ECG signal. The score may relate to the quality of the measured ECG signal. The score may be derived from one or more time-domain features of the ECG signal. Time-domain features may include the mean amplitude, peak amplitude, or median slope of the ECG signal. The score may be derived from one or more frequency-domain features of the ECG signal. Frequency-domain features may include the amplitude spectral domain (AMSA), power spectral analysis features, or centroid frequency. The score may be derived from one or more time-domain features and one or more frequency-domain features. The time-domain and frequency-domain features can be used as measures to estimate the subject's state.

[0013] ECG signals can be evaluated to confirm the presence of ventricular fibrillation (VF) signals.

[0014] Receiving biosignals measured during multiple chest compressions may include receiving biosignals measured over a predetermined duration window. The predetermined duration can be in the range of approximately 5 seconds to approximately 30 seconds.

[0015] Receiving biosignals measured during multiple chest compressions may include receiving at least one type of biosignal measured during multiple chest compressions. Setting a current biosignal metric using biosignals measured during multiple chest compressions may include setting at least one current biosignal metric element for at least one type of biosignal. At least one current biosignal metric element for at least one type of biosignal may include at least one current frequency biosignal metric element, at least one current amplitude biosignal metric element, or at least one current frequency biosignal metric element and at least one current amplitude biosignal metric element. The current biosignal metric element for at least one type of biosignal may provide a measure of the actual CPR performance of the person during multiple CPR chest compressions.

[0016] The current amplitude biosignal metric element may include any of the following: average amplitude, average maximum, average minimum, or ratio of maximum to minimum. The current frequency biosignal metric element may include dominant frequency.

[0017] Comparing current biosignal metrics to target biosignal metrics may include comparing at least one current biosignal metric element for at least one type of biosignal with at least one of the same target biosignal metric elements for at least one type of biosignal.

[0018] Increasing the target biosignal metric can include increasing the metric by 1% to 50%.

[0019] CPR feedback signals that advise a person on how to adjust CPR are received by a feedback unit, which can then provide CPR feedback to the person in the form of "press harder" and / or "press faster." CPR feedback signals that advise a person on maintaining their current CPR performance are also received by a feedback unit, which can then provide CPR feedback to the person in the form of "good compressions."

[0020] The CPR evaluation system can be configured to repeat steps (iii) to (viii) over a predetermined period of time. The predetermined period may be 2 minutes. When the predetermined period of time is reached, the CPR evaluation system can be configured to generate a CPR feedback signal advising the person to stop CPR. Thereafter, the CPR evaluation system can be configured to repeat steps (i) to (viii).

[0021] The CPR evaluation system further... A step of generating a CPR feedback signal that advises a person to perform CPR chest compressions at a speed equal to the speed of an audible metronome signal emitted by a metronome of a CPR evaluation system, The steps include receiving the ECG signal measured during chest compressions and using that ECG signal to set the current ECG signal metric, The steps include comparing the current ECG signal metric with a reference ECG signal metric, If the current ECG signal metric is smaller than the reference ECG signal metric, the system adjusts the speed of the audible metronome signal and generates a CPR feedback signal advising the person to adjust the rate of CPR chest compressions to be equal to the speed of this adjusted audible metronome signal, and then returns to the second step. When the current ECG signal metric is greater than or equal to the reference ECG signal metric, it can be configured to perform a step of generating a CPR feedback signal for advising a person to maintain the execution speed of CPR chest compressions.

[0022] The CPR feedback signal for advising a person to adjust the execution speed of CPR chest compressions to be equal to the speed of the adjusted audible metronome signal is received by the feedback unit, and the feedback unit can provide CPR feedback to the person in forms such as "Push faster" or "Push slower". The CPR feedback signal for advising a person to maintain the execution speed of CPR chest compressions is received by the feedback unit, and the feedback unit can provide CPR feedback to the person in forms such as "Push harder" or "Good compression".

[0023] The ECG system can be configured to measure the ECG signal of a subject using signals received from one or more electrodes placed on the subject.

[0024] The biosignal system can be configured to measure the biosignal of a subject using signals received from one or more sensors placed on the subject.

[0025] The CPR feedback system may be a stand-alone system. The CPR feedback system may be part of a further system. The further system may be a defibrillator.

[0026] When the CPR feedback system is part of a further system, the CPR start signal may be received from the further system. When the CPR feedback system is part of a further system, the CPR stop signal may be received from the further system.

[0027] According to a second aspect of the present invention, a defibrillator is provided that includes a CPR feedback system according to a first aspect of the present invention. [Brief explanation of the drawing]

[0028] Next, one embodiment of the present invention will be described as an example with reference to the following drawings. [Figure 1] Figure 1 is a schematic diagram of the CPR feedback system according to the present invention. [Figure 2] Figure 2 is a flowchart of the steps performed by the CPR evaluation system of the CPR feedback system in Figure 1. [Modes for carrying out the invention]

[0029] Referring to Figure 1, the CPR feedback system 20 comprises an electrocardiogram (ECG) system 22, a biosignal system 24, a CPR evaluation system 26, and a feedback unit 28. The CPR feedback system 20 evaluates CPR performed by a person (not shown) on a subject (not shown) and provides CPR feedback to that person. The biosignal system 24 includes an impedance signal measurement system, a capnograph, an oximeter, a blood pressure measurement system, and an accelerometer.

[0030] It will be understood that the CPR feedback system 20 includes other elements such as an activation mechanism, an ECG processing system, a power supply, and a detection unit adapted to be worn on the subject.

[0031] In this embodiment, the ECG system 22 is connected to a detection unit including chest electrodes and is configured to measure the subject's ECG signal. The CPR feedback system 20 includes an algorithm that uses the ECG signal to determine when the subject is exhibiting ventricular fibrillation (VF).

[0032] In this embodiment, the impedance signal measurement system of the biosignal system 24 is connected to a detection unit including chest electrodes to measure the impedance signal of the subject during chest compressions performed by a person. The subject's impedance signal includes the chest impedance signal. The impedance signal includes a sine wave caused by CPR chest compressions. The capnograph, oximeter, blood pressure measurement system, and accelerometer of the biosignal system 24 are connected to sensors placed on the subject and receive the subject's biosignals from those sensors.

[0033] The CPR evaluation system 26 is connected to the ECG system 22 and the biosignal system 24. The CPR evaluation system 26 receives ECG signals and biosignals and evaluates human-performed CPR on a subject over multiple chest compressions performed by the person on the subject within a predetermined time. This involves performing several steps, as described below with reference to Figure 2.

[0034] During the evaluation of a person's CPR performance, the CPR evaluation system 26 generates various feedback signals. The feedback unit 28 is connected to the CPR evaluation system 26 and is configured to receive feedback signals and provide CPR feedback to the person.

[0035] Referring to Figure 2, a first embodiment of the steps performed by the CPR evaluation system 26 of the CPR feedback system 20 in Figure 1 will be described. In this embodiment, the biosignal system 24 measures the impedance signal of the subject using its impedance measurement system. The CPR evaluation system 26 receives one type of biosignal, namely the impedance signal.

[0036] The CPR evaluation system 26 first sets a baseline ECG metric. Before the start of CPR, the CPR evaluation system 26 receives an ECG signal from the ECG system 22 measured over a predetermined time, for example, 5 to 30 seconds. The ECG signal is used to set a baseline ECG signal metric. This involves using the ECG signal to set a baseline ECG score for the ECG signal. The baseline ECG score is related to the quality of the measured ECG signal. In this embodiment, the baseline ECG score is derived from one or more time-domain features of the ECG signal and one or more frequency-domain features of the ECG signal. The time-domain features include any of the mean amplitude, peak amplitude, or median slope of the ECG signal. The frequency-domain features include any of the amplitude spectral domain (AMSA), power spectral analysis features, or centroid frequency. The time-domain and frequency-domain features can be used as measures to estimate the subject's condition.

[0037] Subsequently, the CPR evaluation system 26 sets target biosignal metrics. In this embodiment, setting target biosignal metrics includes generating a CPR feedback signal advising a person to begin CPR, receiving biosignals including impedance signals measured during multiple chest compressions by the person, generating a CPR feedback signal advising a person to stop CPR, and setting target biosignal metrics using the biosignals. In this embodiment, the target biosignal metric includes one target biosignal metric element for one type of biosignal measured, namely an impedance signal. The target biosignal metric element includes a target amplitude biosignal metric element of the average amplitude of the peaks of the impedance signals measured during multiple chest compressions by the person. It will be understood that the target biosignal metric may include multiple target biosignal metric elements, which may be target amplitude biosignal metric elements and / or target frequency biosignal metric elements.

[0038] Subsequently, the CPR evaluation system 26 generates a CPR feedback signal advising the person to begin CPR. This is sent to the feedback unit 28, which uses the CPR feedback system 20 to provide CPR feedback to the person in the form of instructions such as "Begin CPR and press hard."

[0039] During multiple chest compressions performed by a person, the CPR evaluation system 26 receives ECG signals from the ECG system 22 measured over a window of approximately 5 to 30 seconds. The CPR evaluation system 26 sets the current ECG signal metric by using the ECG signals to set the current ECG score for the ECG signals. The current ECG score is related to the quality of the measured ECG signal. The current ECG score is derived from one or more time-domain features and one or more frequency-domain features of the ECG signal. Time-domain features include the mean amplitude, peak amplitude, or median slope of the ECG signal. Frequency-domain features include the amplitude spectral domain (AMSA), power spectral analysis features, or centroid frequency. The time-domain and frequency-domain features can be used as measures to estimate the subject's condition.

[0040] During multiple chest compressions performed by a person on a subject, the CPR evaluation system 26 also receives impedance signals from the impedance measurement system of the biosignal system 24. The impedance signals are measured over the same window of approximately 5 to 30 seconds. The CPR evaluation system 26 uses the impedance signals to set the current biosignal metric. In this embodiment, the current biosignal metric includes one current biosignal metric element for the impedance signals. The current biosignal metric element includes a current amplitude biosignal metric element of the average amplitude of the peaks of the impedance signals measured during the window.

[0041] The CPR evaluation system 26 compares the current ECG signal metric to a reference ECG signal metric and the current impedance signal metric to a target impedance signal metric. This includes comparing the reference ECG score to the current ECG score, as well as comparing the target amplitude biosignal metric element of the mean amplitude of the impedance signal peak to the current amplitude biosignal metric element of the mean amplitude of the impedance signal peak. If the current ECG signal metric is smaller than the reference ECG signal metric (suggesting a deterioration in the subject's condition) and the current biosignal metric is smaller than the target biosignal metric (suggesting that CPR chest compressions are not optimal), the CPR evaluation system 26 generates a CPR feedback signal to advise the person on how to adjust CPR. This feedback signal is sent to a feedback unit 28, which provides CPR feedback to the person using the CPR feedback system 20 in the form of an instruction such as "press harder."

[0042] If the current ECG signal metric is lower than the reference ECG signal metric (similarly indicating a deterioration in the subject's condition) and the current biosignal metric is greater than or equal to the target biosignal metric (indicating that the target impedance signal metric can be improved), the CPR evaluation system 26 generates a CPR feedback signal advising the person to increase the target biosignal metric and improve CPR performance. This feedback signal is sent to the feedback unit 28, which issues CPR feedback to the person using the CPR feedback system 20 in the form of an instruction such as "push harder."

[0043] If the current ECG signal metric is equal to or greater than the baseline ECG signal metric (indicating an improvement in the subject's condition), the CPR assessment system sets the baseline ECG signal metric to be equal to the current ECG signal metric and generates a CPR feedback signal advising the person to maintain their current CPR performance. This feedback signal is sent to the feedback unit 28, which issues CPR feedback to the person using the CPR feedback system 20 in the form of an instruction such as "Good compressions."

[0044] In this embodiment, the CPR evaluation system 26 is configured to repeat some of the steps described above over a predetermined period of time. The predetermined period is 2 minutes and is measured by the clock of the CPR evaluation system 26. When the clock has not reached the predetermined period, the CPR evaluation system 26 returns to the step of receiving ECG signals measured during additional chest compressions performed by the person. These additional chest compressions do not overlap with the previous chest compressions. Therefore, the analysis of biosignals, including ECG and impedance signals, and feedback to the subject continue over the additional chest compressions performed within the 2-minute period. When the clock has reached the predetermined period, the CPR evaluation system 26 generates a CPR feedback signal advising the person to stop CPR. This feedback signal is sent to the feedback unit 28, which issues CPR feedback to the person using the CPR feedback system 20 in the form of an instruction to "Stop CPR."

[0045] In this embodiment, the CPR evaluation system 26 then returns to the step of setting a reference ECG signal metric and a target biosignal metric, and repeats the further steps described above. This continues as long as deemed necessary.

[0046] Referring to Figure 2, a second embodiment of the steps performed by the CPR evaluation system 26 of the CPR feedback system 20 in Figure 1 will be described. In this embodiment, the biosignal system 24 measures the subject's peripheral oxygen saturation signal and CPR chest compression depth signal using its oximeter and accelerometer. The CPR evaluation system 26 receives two types of biosignals, namely the oxygen signal and the CPR chest compression depth signal.

[0047] The CPR evaluation system 26 first sets a baseline ECG metric. Before the start of CPR, the CPR evaluation system 26 receives an ECG signal from the ECG system 22 measured over a predetermined period of time, for example, 5 to 30 seconds. The ECG signal is used to set a baseline ECG signal metric. This involves using the ECG signal to set a baseline ECG score for the ECG signal. The baseline ECG score is related to the quality of the measured ECG signal. In this embodiment, the baseline ECG score is derived from one or more time-domain features of the ECG signal and one or more frequency-domain features of the ECG signal. The time-domain features include any of the mean amplitude, peak amplitude, or median slope of the ECG signal. The frequency-domain features include any of the amplitude spectral domain (AMSA), power spectral analysis features, or centroid frequency. The time-domain and frequency-domain features can be used as indicators for estimating the subject's condition.

[0048] Subsequently, the CPR evaluation system 26 sets target biosignal metrics. In this embodiment, setting target biosignal metrics includes receiving predetermined target biosignal metrics. A predetermined target biosignal metric includes at least one target biosignal metric element for each type of biosignal measured. In this embodiment, the target biosignal metric elements include a target amplitude biosignal metric element for the average amplitude of the oxygen signal and a target amplitude biosignal metric element for the average CPR chest compression depth signal. It should be understood that the target biosignal metric may include multiple target biosignal metric elements, which may be target amplitude biosignal metric elements and / or target frequency biosignal metric elements.

[0049] Subsequently, the CPR evaluation system 26 generates a CPR feedback signal advising the person to begin CPR. This is sent to the feedback unit 28, which uses the CPR feedback system 20 to issue CPR feedback to the person in the form of an instruction: "Begin CPR and press hard."

[0050] During multiple chest compressions performed by a person, the CPR evaluation system 26 receives ECG signals from the ECG system 22 measured over a window of approximately 5 to 30 seconds. The CPR evaluation system 26 sets the current ECG signal metric by using the ECG signals to set the current ECG score for the ECG signals. The current ECG score is related to the quality of the measured ECG signal. The current ECG score is derived from one or more time-domain features and one or more frequency-domain features of the ECG signal. Time-domain features include the mean amplitude, peak amplitude, or median slope of the ECG signal. Frequency-domain features include the amplitude spectral domain (AMSA), power spectral analysis features, or centroid frequency. The time-domain and frequency-domain features can be used as indicators to estimate the subject's condition.

[0051] During multiple chest compressions performed by a person on a subject, the CPR evaluation system 26 receives an oxygen signal from the oximeter of the biosignal system 24 and a CPR chest compression depth signal from the accelerometer of the biosignal system 24. The oxygen signal and the CPR chest compression depth signal are measured over the same window of approximately 5 to 30 seconds. The CPR evaluation system 26 uses the oxygen signal and the CPR chest compression depth signal to set the current biosignal metric. In this embodiment, the current biosignal metric includes a current amplitude biosignal metric element for the oxygen signal, which is the average amplitude of the oxygen signal, and a current amplitude biosignal metric element for the CPR chest compression depth signal, which is the average CPR chest compression depth.

[0052] The CPR evaluation system 26 compares the current ECG signal metric to a reference ECG signal metric. This includes comparing the reference ECG score to the current ECG score. The CPR evaluation system 26 further compares the current signal metric to a target signal metric. This includes comparing the target amplitude biosignal metric element of the oxygen signal to the current amplitude biosignal metric element of the oxygen signal, as well as comparing the target amplitude biosignal metric element of the CPR chest compression depth signal to the current amplitude biosignal metric element of the CPR chest compression depth signal.

[0053] If the current ECG signal metric is lower than the baseline ECG signal metric (suggesting a deterioration in the subject's condition) and the current biosignal metric is lower than the target biosignal metric (suggesting that CPR chest compressions are not optimal), the CPR evaluation system 26 generates a CPR feedback signal to advise the person to improve their CPR performance. This feedback signal is sent to the feedback unit 28, which then provides CPR feedback to the person using the CPR feedback system 20 in the form of instructions such as "push faster," "push slower," or "push harder."

[0054] If the current ECG signal metric is lower than the reference ECG signal metric (suggesting a deterioration in the subject's condition) and the current biosignal metric is greater than or equal to the target biosignal metric (suggesting that the target impedance signal metric can be improved), the CPR evaluation system 26 generates a CPR feedback signal advising the person to increase the target biosignal metric and improve CPR performance. This feedback signal is sent to the feedback unit 28, which then issues CPR feedback to the person using the CPR feedback system 20 in the form of an instruction such as "push harder."

[0055] If the current ECG signal metric is equal to or greater than the baseline ECG signal metric (indicating an improvement in the subject's condition), the CPR assessment system sets the baseline ECG signal metric to be equal to the current ECG signal metric and generates a CPR feedback signal advising the person to maintain their current CPR performance. This feedback signal is sent to the feedback unit 28, which issues CPR feedback to the person using the CPR feedback system 20 in the form of an instruction such as "Good compressions."

[0056] In this embodiment, the CPR evaluation system 26 is configured to repeat some of the steps described above over a predetermined period of time. The predetermined period is 2 minutes and is measured by the clock of the CPR evaluation system 26. When the clock has not reached the predetermined period, the CPR evaluation system 26 returns to the step of receiving ECG signals measured during further chest compressions by the person. These further chest compressions do not overlap with the previous chest compressions. Therefore, the analysis of the ECG and biosignals, including the oxygen signal and the CPR chest compression depth signal, as well as the feedback to the person, continues over the chest compressions during the 2-minute period. When the clock has reached the predetermined period, the CPR evaluation system 26 generates a CPR feedback signal advising the person to stop CPR. This feedback signal is sent to the feedback unit 28, which issues CPR feedback to the person using the CPR feedback system 20 in the form of an instruction to "Stop CPR."

[0057] In this embodiment, the CPR evaluation system 26 then returns to the step of setting a reference ECG signal metric and a target biosignal metric, and repeats the further steps described above. This continues as long as deemed necessary.

[0058] Therefore, the CPR feedback system 20 provides dynamic CPR feedback to the person performing multiple sets of CPR chest compressions on the subject, and the CPR feedback is based on monitoring of sets of chest compressions using biosignals including impedance signals, oxygen signals, and CPR chest compression depth signals, as well as monitoring of the subject's ECG. It will be understood that other types of biosignals can be used.

[0059] In these embodiments, the CPR feedback system 20 is described as a standalone device. It will be understood that the CPR feedback system 20 may be part of a further system, such as a defibrillator.

Claims

1. A CPR feedback system for evaluating cardiopulmonary resuscitation (CPR) performed by a person on a subject and providing CPR feedback to that person, An electrocardiogram (ECG) system configured to measure the ECG signal of a subject, A biosignal system configured to measure the biosignals of a subject, A CPR evaluation system connected to the aforementioned ECG system to receive ECG signals, and connected to the aforementioned biosignal system to receive biosignals, The system comprises a feedback unit connected to the CPR evaluation system and configured to receive a CPR feedback signal and emit CPR feedback to a person, The aforementioned CPR evaluation system, (i) Setting a reference ECG signal metric based on a portion of the ECG signals detected before initiating multiple chest compressions, and setting a target biosignal metric; (ii) A step of generating a CPR feedback signal to advise a person to start CPR, (iii) Steps to set the current ECG signal metric, (iv) The step of setting the current biosignal metric, (v) The steps of comparing the current ECG signal metric with a reference ECG signal metric and comparing the current biosignal metric with the target biosignal metric, (vi) A step of generating a CPR feedback signal that advises a person to improve CPR performance when the current ECG signal metric is smaller than a reference ECG signal metric and the current biosignal metric is smaller than a target biosignal metric, (vii) A step of generating a CPR feedback signal that advises a person to increase the target biosignal metric and improve CPR performance when the current ECG signal metric is smaller than the reference ECG signal metric and the current biosignal metric is greater than or equal to the target biosignal metric, (viiii) A step of generating a CPR feedback signal that advises a person to maintain their current CPR performance by setting the reference ECG signal metric to the same value as the current ECG signal metric if the current ECG signal metric is greater than or equal to the reference ECG signal metric. It is configured to perform, The CPR evaluation system sets the reference ECG signal metric based on a portion of the ECG signals detected before initiating multiple chest compressions. The median slope of a portion of the ECG signal detected before initiating multiple chest compressions, A portion of the amplitude spectral range (AMSA) of the ECG signal detected before initiating multiple chest compressions, The power spectral analysis characteristics of a portion of the ECG signal detected before initiating multiple chest compressions, and A CPR feedback system characterized by being configured to perform the calculation by calculating a score based on one or more of the centroid frequencies of a portion of the ECG signals detected before initiating multiple chest compressions.

2. In the CPR feedback system according to claim 1, The CPR feedback system is characterized in that the biosignal system is configured to measure one or more types of biosignals of a subject.

3. In the CPR feedback system according to claim 2, A CPR feedback system characterized in that the biosignal includes any one of the following: a chest impedance signal, an end-tidal carbon dioxide signal, a peripheral oxygen saturation signal, a blood pressure signal, or a chest compression depth signal.

4. In the CPR feedback system according to any one of claims 1 to 3, The aforementioned CPR evaluation system, The peak amplitude of a portion of the ECG signal detected before initiating multiple chest compressions, The average amplitude of a portion of the ECG signal detected before initiating multiple chest compressions, The median slope of a portion of the ECG signal detected before initiating multiple chest compressions, The amplitude spectral region (AMSA) of a portion of the ECG signal detected before initiating multiple chest compressions, The power spectral analysis features of a portion of the ECG signal detected before initiating multiple chest compressions, and A CPR feedback system characterized by being configured to calculate the score based on the center of gravity frequency of a portion of the ECG signal detected before initiating multiple chest compressions.

5. In the CPR feedback system according to any one of claims 1 to 4, A CPR feedback system characterized in that setting a target biosignal metric includes receiving a predetermined target biosignal metric which includes at least one target biosignal metric element for one or more types of biosignals, wherein the at least one target biosignal metric element for one or more types of biosignals includes any of the following: at least one target frequency biosignal metric element, at least one target amplitude biosignal metric element, and at least one target frequency biosignal metric element and at least one target amplitude biosignal metric element.

6. In the CPR feedback system according to any one of claims 1 to 4, A CPR feedback system characterized in that setting the target biosignal metric is based on a portion of the biosignals detected during multiple chest compressions.

7. In the CPR feedback system according to claim 6, The aforementioned target biosignal metric is The average amplitude of the biosignal measured during multiple chest compressions, The mean maximum value of the biosignals measured during multiple chest compressions, The mean minimum of biosignals measured during multiple chest compressions, The ratio of the maximum and minimum values ​​of the biosignals measured during multiple chest compressions, and, A CPR feedback system characterized by being based on one or more dominant frequencies of biosignals measured during multiple chest compressions.

8. In the CPR feedback system according to any one of claims 1 to 7, The current ECG signal metric is, Some of the peak amplitudes of the ECG signal detected during multiple chest compressions, The average amplitude of a portion of the ECG signals detected during multiple chest compressions, The median slope of a portion of the ECG signals detected during multiple chest compressions, A portion of the amplitude spectral range (AMSA) of the ECG signal detected during multiple chest compressions, Some power spectral analysis features of the ECG signals detected during multiple chest compressions, and, A CPR feedback system characterized by being based on one or more of the centroid frequencies of a subset of ECG signals detected during multiple chest compressions.

9. In the CPR feedback system according to any one of claims 1 to 8, A CPR feedback system characterized in that setting the current biosignal metric includes setting at least one current biosignal metric element for at least one type of biosignal, wherein the at least one current biosignal metric element for at least one type of biosignal includes any of the following: at least one current frequency biosignal metric element, at least one current amplitude biosignal metric element, and at least one current frequency biosignal metric element and at least one current amplitude biosignal metric element.

10. In the CPR feedback system according to claim 9, A CPR feedback system characterized in that comparing the current biosignal metric with a target biosignal metric includes comparing at least one current biosignal metric element for at least one type of biosignal with at least one identical target biosignal metric element for at least one type of biosignal.

11. A CPR evaluation system according to any one of claims 1 to 10, A CPR evaluation system characterized by being configured to repeat steps (iii) to (viiii) over a predetermined period of time, and to generate a CPR feedback signal that advises a person to stop CPR when the predetermined time is reached.

12. A CPR evaluation system according to any one of claims 1 to 11, A CPR evaluation system characterized by being configured to repeat steps (i) to (viiii).

13. A CPR evaluation system according to any one of claims 1 to 12, A step of generating a CPR feedback signal that advises a person to perform CPR chest compressions at a speed equal to the speed of an audible metronome signal emitted by the metronome of a CPR evaluation system, The steps include receiving the ECG signal measured during chest compressions and using that ECG signal to set the current ECG signal metric, The steps include comparing the current ECG signal metric with a reference ECG signal metric, If the current ECG signal metric is smaller than the reference ECG signal metric, the system generates a CPR feedback signal that adjusts the speed of an audible metronome signal and advises the person to adjust the rate of CPR chest compressions to be equal to the speed of this adjusted audible metronome signal, and then returns to step (ii). A step of generating a CPR feedback signal that advises a person to maintain the rate of CPR chest compressions if the current ECG signal metric is greater than or equal to a reference ECG signal metric, and A CPR evaluation system characterized by being configured to perform the following.

14. A CPR feedback system according to any one of claims 1 to 13, characterized in that it is part of a defibrillator.

15. In the CPR feedback system according to any one of claims 1 to 14, The aforementioned CPR feedback will help that person to improve their current condition. Press hard Press quickly, or A CPR feedback system characterized by advising users to press slowly.

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