TW201343131A - Method for estimating central aortic blood pressure and apparatus using the same - Google Patents

Abstract

The present invention relates to a method for estimating central aortic blood pressures. An oscillometric waveform is derived from a pressure cuff. An aortic-to-brachial (A2B) pressure waveforms generalized transfer function is established. An aortic pressure waveform is reconstructed by the generalized transfer function according to the oscillometric waveform. Therefore, aortic blood pressures are obtained by the aortic pressure waveform. The present invention also relates to an apparatus capable of estimating central aortic blood pressures by using the foregoing method.

Description

Central arterial blood pressure estimation method and device thereof

The present invention relates to a method and apparatus for estimating central blood pressure, and more particularly to a method and apparatus for estimating central blood pressure based on a pressure oscillation waveform in a cuff and a transfer function.

The diagnosis of common blood pressure is determined by the Systolic Blood Pressure (SBP) and Diastolic Blood Pressure (DBP) of the upper arm artery, and the blood pressure values of the upper arm artery (including systolic blood pressure and diastolic blood pressure) are mostly measured. Use a traditional mercury column or an electronic sphygmomanometer to measure. However, many literatures and studies have pointed out that the correlation between blood systolic blood pressure (SBP-C) and epidemiology recorded by Central Aorta is much higher than that measured by the upper arm artery.

For example, the hemodynamics of the central artery of hypertensive patients often exhibit abnormalities, that is, there are enhancements of reflected waves, an increase in pulse wave velocity, and a decrease in compliance. Central arterial pressure has been shown to be an important predictor of clinical outcomes in hypertensive patients. The value of the brachial artery blood pressure measured by a conventional or electronic sphygmomanometer is peripheral arterial blood pressure, which is usually significantly higher than that of the central artery, such as the pressure measured by the ascending aorta or carotid artery. In other words, if the blood systolic blood pressure of the central artery can be accurately obtained, it will have a more significant effect on predicting hypertension and related cardiovascular diseases.

Regarding the measurement of the above-mentioned central arterial blood systolic pressure, it is roughly It is divided into two main ways: (1) direct measurement of invasiveness; (2) non-invasive indirect prediction. The value of the central arterial blood systolic blood pressure obtained by invasive direct measurement is quite accurate, but it requires a lot of resources and may even cause some adverse side effects such as thrombosis. A method or apparatus for non-invasively predicting central systolic blood pressure has been developed for many years, for example, a device of the model SphygmoCor (manufactured by AtCor Medical Pty Limited), a device of model HEM-9000AI (manufactured by Omron Healthcare Europe), a device of the model Arteriograph (produced by TensioMed Ltd) and algorithms proposed by ARCSolver.

The SphygmoCor device is based on the blood pressure waveform of the wrist and central artery (Aorta-to-Radial; A2R) and uses the generalized transfer function (GTF) for the prediction of the central arterial blood pressure waveform, in which the wrist artery blood pressure waveform It is obtained by an arterial tonometer. The systolic blood pressure and diastolic blood pressure measured by the electronic sphygmomanometer in the upper arm artery are further corrected by pressure on the recorded wrist artery blood pressure waveform, and then the corrected wrist artery blood pressure waveform is substituted into the A2R-GTF to obtain a predicted result. Central arterial blood pressure waveform. Although the device has been supported and verified by many documents, the personnel who operate the pressure recorder need to be trained to obtain a stable and correct waveform of the wrist artery blood pressure, and the device is expensive. The device of the model HEM-9000AI is operated in much the same way as the above-mentioned SphygmoCor, and it is also necessary for the professional who operates the pressure recorder to perform the relevant steps.

The model Arteriograph device uses the Pulse Volume Recording (PVR) waveform recorded by the Cuff to analyze the feature points during the electronic blood pressure measurement process. This device predicts the central arterial blood pressure waveform in a similar manner to the HEM-9000AI described above, and uses regression analysis to predict the value of central systolic blood pressure. Since the signal of the PVR will behave differently with the inherent characteristics of the venous zone, the characteristic points of the aforementioned waveforms will change due to different venous bands, that is, the same regression analysis model cannot be widely applied to other electronic sphygmomanometers. Another model of the ARCSolver model is an algorithm based on Artificial Neuro-network and trained to optimize the parameters. The disadvantage is similar to the Arteriograph described above. If different cuffs are used, it is necessary to re-train the neural network to obtain optimized parameters for the prediction of the central arterial blood pressure waveform.

In view of the problems encountered in the prior art described above, the present invention proposes a method for predicting a robust central arterial blood pressure, and a device capable of correctly estimating central arterial blood pressure and being easy to operate using such a method.

The present invention provides a method for estimating central blood pressure and a device therefor. Such estimation techniques can be widely applied to currently commercially available electronic sphygmomanometers, and the predicted results are not due to the different varicose veins of the electronic sphygmomanometer, resulting in unacceptable variations.

The invention provides a method for estimating central blood pressure, which comprises Including: drawing a pressure oscillation waveform in the cuff; establishing a generalized transfer function of the central artery to the brachial blood pressure waveform; generating a central arterial pressure waveform according to the pressure oscillation waveform and using the generalized transfer function; and according to the central artery The pressure waveform gives the pressure value of the central artery.

In one embodiment, the pressure oscillation waveform comprises a pulse volume recording waveform. The pulse volume recording waveform controls the pressure signal obtained by the pressure pulse at a fixed pressure.

In one implementation, the generalized transfer function is a set of Fourier transform functions, a set of fast Fourier transform functions, or a set of time domain versus frequency domain transfer functions. The set of Fourier transform functions or the set of fast Fourier transform functions is a discrete Fourier transform function.

In one embodiment described above, the discrete Fourier transform function synthesizes the pressure oscillation waveform using only a sine wave component or a cosine wave component below a predetermined frequency. The components below the predetermined frequency correspond to a fixed magnitude and a phase, respectively.

In one embodiment, the central artery refers to the carotid artery or the ascending aorta. The pressure values of the central artery include the pressure difference between systolic blood pressure and diastolic blood pressure, systolic blood pressure, mean blood pressure, and diastolic blood pressure.

The invention further provides a central arterial blood pressure estimating device, comprising: a pressure pulse band; a signal recording and storage unit for extracting and storing a pressure oscillation waveform in the pressure pulse band; and an operation and analysis unit, according to the pressure Oscillating the waveform and using a central artery to treat the brachial artery blood The generalized transfer function of the pressure waveform produces a central arterial pressure waveform and the pressure value of the central artery is obtained from the central arterial pressure waveform.

The purpose, technical content, features and effects achieved by the present invention will be more readily understood by the detailed description of the embodiments.

The invention is based on an intravascular pressure oscillation waveform recorded by an electronic sphygmomanometer during blood pressure measurement, and predicts a pressure waveform of a central artery (referring to a carotid artery or an ascending aorta) by a set of transfer functions, so that Quite similar to the blood pressure of the central artery, so as to correctly diagnose the occurrence of hypertension and related cardiovascular diseases.

1 is a block diagram of a central arterial blood pressure estimating device of the present invention. The central arterial blood pressure estimating device 10 includes a cuff 11 , a signal recording and storage unit 12 , a pressure change control unit 13 and an operation and analysis unit 14 , wherein the signal recording and storage unit 12 and the arithmetic and analysis unit 14 can be integrated into a single IC chip. element. In other embodiments, the signal recording and storage unit 12 and the arithmetic and analysis unit 14 can also perform the processing of the sub-unit functions by a plurality of IC chip components, and thus are not limited by the examples and the drawings. As is known to those skilled in the art, the storage function in the signal recording and storage unit 12 can be a memory.

The cuff 11 is used to be fixed to the upper arm of the user to capture the pressure oscillation waveform S in the cuff. In this embodiment, the pressure oscillation waveform includes a PVR waveform.

The signal recording and storage unit 12 captures the pressure oscillation waveform S, And storing the pressure oscillation waveform S.

The pressure change regulating unit 13 can control the pressurization, maintenance pressure or decompression in the cuff 11 . It should be particularly noted here that the pressure change regulating unit 13 can control the pressure in the cuff 11 to maintain a constant fixed pressure for a period of time. In the present embodiment, the pressure change regulating unit 13 can control the pressure in the cuff 11 to maintain a constant 60 mmHg for about 30 seconds, but the invention is not limited thereto. It is known to those skilled in the art that the pressure in the cuff can be adjusted between 40 and 70 mmHg.

The calculation and analysis unit 24 generates or predicts a central artery pressure waveform via the A2B-GTF based on the pressure oscillation waveform or the PVR waveform, and obtains a central artery pressure value BP based on the central artery pressure waveform.

2 is a flow chart of a method for estimating a central artery blood pressure according to the present invention. The present estimation method is applied to the above-described central arterial blood pressure estimating device 10, or can be applied to a general electronic blood pressure monitor to enhance its function. As shown in step S21, the cuff of the electronic sphygmomanometer is fixed to the upper arm of a user to capture the pressure oscillation waveform in the cuff. The analysis technique of the pressure oscillation waveform includes dynamic oscillation waveform analysis (the oscillation waveform recorded by the pressure pulse in the pressure drop process) and the static oscillation waveform analysis (the oscillation waveform recorded when the pressure of the pressure band drops to a certain fixed pressure, Also known as pulse volume recording (PVR) waveforms.

The general electronic sphygmomanometer measures the upper arm arterial blood pressure (the upper arm moves) After the blood pressure values include systolic blood pressure, mean blood pressure, diastolic blood pressure, and heart rate, the pressure in the cuff of the upper arm is adjusted to a constant 60 mmHg. At this point, blood passing through the upper arm artery causes an increase in the upper arm surface area and against the pressure exerted by the cuff. The pressure band will change the volume due to the increase of the upper arm surface area and the pressure. When the volume of the pressure band is reduced, the pressure in the cuff is changed. This change is called the PVR waveform. It is generally believed that there is a great correlation between the PVR waveform and the actual brachial artery blood pressure waveform, but the local feature points on the PVR waveform are changed due to the characteristics of different venous bands, which affects the accuracy of the central arterial blood pressure estimation. The present invention can improve the accuracy of prediction by combining the following steps, and does not affect the accuracy of the prediction result due to the different characteristics of the cuff.

Next, referring to step S22, a plurality of subjects receive an invasive measurement of the blood pressure signal to establish an aortic-to-brachial generalized transfer function (A2B-GTF). In this embodiment, the generalized transfer function may be a set of Fourier transfer functions, a set of fast Fourier transform functions, or a similar set of time domain versus frequency domain transfer functions. However, the invention is not limited thereto. The A2B-GTF taken in this embodiment is an invasive catheter operation, and simultaneously records two pressure waveforms of the central artery waveform and the upper arm artery of the subject, and then is calculated by Fast Fourier Transfer. Got it. The above description can be found in the manner proposed by Michael F O’Rourke, U.S. Patent No. 5,265,011. The procedure for establishing the function model and the verification method will be detailed later.

Then, the pressure oscillation waveform obtained in step S21 is further subjected to the central artery pressure waveform prediction by the A2B-GTF established in step S22, as shown in step S23. In this embodiment, the pressure oscillation waveform includes a PVR waveform. In the A2B-GTF of the embodiment, the Discrete Fourier Transform (DFT) converts the PVR waveform into a sine wave component or a cosine wave component of each frequency, if the waveform can be expressed as x[n], n=0. ~N-1, then the formula of DFT can be expressed as follows (the formulas listed below and the inverse formula are merely examples, and do not limit the implementation of the present invention, similar time domain to frequency domain transfer function are protection range) : Among them, the information represented by X[k] is a function of k, and k is directly proportional to the frequency. Therefore, these coefficients X[k] are generally referred to as "Spectrum", and the analysis for X[k] is commonly referred to as "Spectral Analysis". Therefore, these Fourier coefficients X[k] can be used to reverse or predict the central arterial pressure waveform x[n] as follows: Among them, if the central arterial pressure waveform x[n] has N points, then the converted signal X[k] will also have N points. In general, X[k] is a complex number whose magnitude is |(X[k])| and its phase is ∠X[k]. In this embodiment, the preferred parameters of the A2B-GTF are: frequency 0 Hz, the corresponding size is 1.00 and the phase is 0.00 radians; the frequency is 1 Hz, and the corresponding size is 1.04 and the phase is 0.18 radians; frequency 2 Hz, the corresponding size is 1.26 and the phase is 0.33 radians; the frequency is 3 Hz, the corresponding size is 1.76 and the phase is 0.36 radians; the frequency is 4 Hz, the corresponding size is 2.08 and the phase is -0.06 radians; frequency 5 Hz The corresponding size is 1.68 and the phase is -0.26 radians; the frequency is 6 Hz, the corresponding size is 1.97 and the phase is -0.15 radians; the frequency is 7 Hz, the corresponding size is 1.98 and the phase is -0.47 radians; frequency 8 Hz, which corresponds to a size of 1.24 and a phase of -0.44 radians; a frequency of 9 Hz, which corresponds to a size of 1.32 and a phase of -0.21 radians, although the invention is not limited by the set of parameters. The preferred parameters of the group can also be listed as follows:

Finally, referring to step S24, the pressure value BP of the central artery can be obtained based on the predicted central artery pressure waveform. In this embodiment, the pressure value BP of the central artery is systolic blood pressure, but those skilled in the art know that the predicted pressure value may also be the pressure difference between systolic blood pressure and diastolic blood pressure, mean blood pressure, diastolic blood pressure or other medical clinically. The pressure value that can be referenced.

In summary, the present invention applies the above generalized conversion function to the PVR waveform signal obtained by a commercially available electronic sphygmomanometer, and predicts the value of the central arterial blood pressure based on the PVR waveform signal. Therefore, it can avoid the inconvenience caused by the limitation of various instruments operated by professionals in the prior art, and improve the variability of the PVR waveform signal caused by different cuffs, so the evaluation of the central artery blood pressure value of the present invention can be performed. The technology is extended to general home care and clinical clinics.

Establishment of A2B-GTF model

This example performs a direct invasive measurement using a 2F customized high-fidelity pressure waveform recording catheter (model SSD-1059, Millar Instruments Inc., USA) containing two pressure recording probes inside, simultaneously implanted The central artery of the tester recorded the waveform of the central arterial pressure and the waveform of the upper arm artery recorded by the right arm artery. In addition, the left arm of the same subject was covered with a cuff, and the PVR signal in the cuff was recorded for about 30 seconds under a constant pressure (for example, an average of 60 mmHg), and the upper arm systolic pressure and diastolic pressure were recorded together.

The central arterial pressure waveform measured by each subject and the upper arm arterial pressure waveform were independently A2B-ITF (A2B-ITF), and 40 subjects were A2B. -ITF averages the above A2B-GTF, and the A2B-GTF of this embodiment is a fixed parameter, as shown in Table 1. Since the sine wave or cosine wave component of the high frequency portion contributes little to the waveform synthesis, the frequencies listed in Table 1 are 0 to 9 Hz. However, other embodiments may consider adding a sine wave component higher than 9 Hz. In this embodiment, the sinusoidal component of 0 to 9 Hz may be used in the subsequent prediction of the central arterial pressure waveform, or the sinusoidal component (for example, 0 to 4 Hz) of the low frequency portion may be used to predict the waveform.

Verification of A2B-GTF model

3A and 3B are comparisons of the A2B-GTF proposed by the present invention with the conversion function previously proposed by Karamanoglu et al. The A2B-GTF of this embodiment uses the parameter set shown in Table 1. The highest point of the amplitude of the curve occurs at 4 Hz, and the standard deviation accompanying the variation is small, especially the standard deviation of less than 4 Hz is even smaller. Referring to FIG. 3A, the magnitude spectrum of the A2B-GTF is quite similar to the size spectrum of the Karamanoglu, and in particular, the portions of 1 to 3 Hz are substantially overlapped.

The above A2B-GTF and its parameter sets were applied to two types of electronic blood pressure monitors, Microlife Watch BP Office and Omron VP-2000, both of which are commercially available electronic blood pressure monitors. Test Both of them received a high-fidelity pressure waveform recording catheter to record the central arterial pressure waveform, and the left arm recorded the PVR signal in the cuff zone under constant pressure (for example, an average of 60 mmHg, but not limited to this pressure value). The number of subjects using the Microlife WatchBP Office electronic sphygmomanometer was 40, and the number of subjects using the Omron VP-2000 electronic sphygmomanometer was 100. The recorded PVR signal is corrected by the systolic blood pressure and diastolic blood pressure measured by the electronic sphygmomanometer, and the A2B-GTF is used as the prediction of the central arterial pressure waveform.

The predicted central arterial pressure waveform is taken to be its maximum value and compared with the systolic blood pressure at central aorta (SBP-C) recorded synchronously. Figures 4A and 4B show the application of the present invention to Microlife, respectively. Both Omron's electronic sphygmomanometers have good predictive results. After statistical calculation, FIG. 4A shows an electronic sphygmomanometer used in the Microlife Watch BP Office of the present invention. The mean value of the systolic pressure and the actual systolic pressure between the predicted central arteries (mean) ± standard deviation (SD) is -2.9 ± 7.2 mmHg (Range R = 0.94). Figure 4B shows the mean (mean) ± standard deviation (SD) of the predicted systolic pressure and actual systolic pressure of the central artery applied to the Omron VP-2000 electronic sphygmomanometer as -2.1 ± 7.7 mmHg (R = 0.93). The error values for each point in the graph are the predicted central systolic pressure minus the central measured systolic blood pressure. The above verification results prove that the A2B-GTF and its parameter set of the present invention are applicable to different commercially available electronic sphygmomanometers, that is, can be combined with the electronic sphygmomanometers to correctly predict the blood pressure of the central artery. The value does not affect the accuracy of the prediction due to the difference in the pressure band.

The present invention has been described with reference to the preferred embodiments thereof, and the present invention is not intended to limit the scope of the present invention. Under the present invention, various equivalent changes can be considered by those skilled in the art. For example, the processing or correction sequence of waveform signals. Moreover, the block diagram of the central arterial blood pressure estimating device 20 can insert or add other functional blocks without affecting the technical content of the present invention, such as a filter or a screen displaying predicted values.

10‧‧‧ Central Arterial Blood Pressure Estimation Device

11‧‧‧Curve belt

12‧‧‧Signal Record and Storage Unit

13‧‧‧ Pressure Change Control Unit

14‧‧‧Operation and Analysis Unit

BP‧‧‧Central arterial pressure value

S‧‧‧ pressure oscillation waveform

S21, S22, S23, S24‧‧ steps

1 is a block diagram of a central arterial blood pressure estimating device of the present invention.

2 is a flow chart of a method for estimating a central artery blood pressure according to the present invention.

Fig. 3A is a graph comparing the size spectrum of the A2B-GTF proposed by the present invention with the conversion function proposed by the previous Karamanoglu et al.

Fig. 3B is a phase spectrum comparison diagram of the A2B-GTF proposed by the present invention and the conversion function proposed by the previous Karamanoglu et al.

4A is a statistical diagram of the systolic blood pressure and the actual systolic pressure error of the predicted central artery applied to the electronic sphygmomanometer of the Microlife Watch BP Office of the present invention.

Fig. 4B is a statistical diagram of the systolic blood pressure and the actual systolic pressure error of the predicted central artery of the electronic sphygmomanometer applied to the Omron VP-2000 of the present invention.

S21, S22, S23, S24‧‧ steps

Claims (21)

A method for estimating a central arterial blood pressure, comprising: drawing a pressure oscillation waveform in a cuff; establishing a generalized transfer function of a central artery to an upper arm artery blood pressure waveform; generating a middle arterial pressure according to the pressure oscillation waveform and using the generalized transfer function a waveform; and a pressure value of the central artery based on the central arterial pressure waveform. The method of estimating a central arterial blood pressure according to claim 1, wherein the pressure oscillation waveform comprises a pulse volume recording waveform. The method for estimating a central arterial blood pressure according to claim 2, wherein the pulse volume recording waveform is controlled by the pressure change regulating unit to control a pressure signal obtained by maintaining the pressure in the cuff at a constant pressure. The method of estimating a central arterial blood pressure according to claim 1, wherein the generalized transfer function is a set of Fourier transform functions, a set of fast Fourier transform functions, or a set of time domain versus frequency domain transfer functions. The method of estimating a central arterial blood pressure according to claim 4, wherein the set of Fourier transform functions or the set of fast Fourier transform functions is a discrete Fourier transform function. The method for estimating a central arterial blood pressure according to claim 5, wherein the discrete Fourier transform function is below a predetermined frequency The sine wave component or the cosine wave component of each frequency is combined to form the pressure oscillation waveform. The method for estimating a central arterial blood pressure according to claim 6, wherein the components of the frequencies below the predetermined frequency correspond to a fixed size and a phase, respectively. The central arterial blood pressure estimation method according to claim 7, wherein the set of Fourier transform function is expressed as: Wherein, the information represented by X[k] is a function of k; k is directly proportional to frequency; x[n] is a function of the predicted central arterial pressure waveform; X[k] is a complex number, the predetermined frequency (k) =N-1) The magnitude of the component of each of the following frequencies is |(X[k])| and the corresponding phase is ∠X[k]. The method for estimating a central arterial blood pressure according to claim 8, wherein the N is equal to 10, and the magnitude and phase corresponding to the components of the frequencies below the predetermined frequency are as follows: the frequency is 0 Hz, and the corresponding size is 1.00 and The phase is 0.00 radians; the frequency is 1 Hz, and its corresponding size is 1.04 and the phase is 0.18 radians; the frequency is 2 Hz, which corresponds to The size is 1.26 and the phase is 0.33 radians; the frequency is 3 Hz, the corresponding size is 1.76 and the phase is 0.36 radians; the frequency is 4 Hz, the corresponding size is 2.08 and the phase is -0.06 radians; the frequency is 5 Hz, which corresponds to The size is 1.68 and the phase is -0.26 radians; the frequency is 6 Hz, the corresponding size is 1.97 and the phase is -0.15 radians; the frequency is 7 Hz, the corresponding size is 1.98 and the phase is -0.47 radians; the frequency is 8 Hz, which corresponds to The size is 1.24 and the phase is -0.44 radians; the frequency is 9 Hz, which corresponds to a size of 1.32 and a phase of -0.21 radians. The method for estimating a central arterial blood pressure according to claim 1, wherein the pressure value of the central artery includes a pressure difference between systolic blood pressure and diastolic blood pressure, a systolic blood pressure, an average blood pressure, and a diastolic blood pressure. A central arterial blood pressure estimating device comprises: a pressure pulse band; a signal recording and storage unit for extracting and storing a pressure oscillation waveform in the pressure pulse band; and an operation and analysis unit, according to the pressure oscillation waveform and The generalized transfer function of the central artery to the upper arm artery blood pressure waveform produces a central arterial pressure waveform, and a central arterial pressure value is obtained based on the central arterial pressure waveform. The central arterial blood pressure estimating device according to claim 11, further comprising: a pressure change regulating unit that controls the pressure and the maintaining pressure in the pressure band Force or decompression. The central arterial blood pressure estimating device according to claim 11, wherein the pressure oscillation waveform comprises a pulse volume recording waveform. The central arterial blood pressure estimating device according to claim 13, wherein the pulse volume recording waveform is controlled by the pressure change regulating unit to control a pressure signal obtained by maintaining the pressure in the cuff at a constant pressure. The central arterial blood pressure estimating device according to claim 11, wherein the generalized transfer function is a set of Fourier transform functions, a set of fast Fourier transform functions, or a set of time domain versus frequency domain transfer functions. The central arterial blood pressure estimating device according to claim 15, wherein the set of Fourier transform functions or the set of fast Fourier transform functions is a discrete Fourier transform function. The central arterial blood pressure estimating device according to claim 16, wherein the discrete Fourier transform function synthesizes the pressure oscillation waveform by using a sine wave component or a cosine wave component of each frequency below a predetermined frequency. The central arterial blood pressure estimating device according to claim 17, wherein the components of the frequencies below the predetermined frequency correspond to a fixed size and a phase, respectively. The central arterial blood pressure estimating device according to claim 18, wherein the set of Fourier transform function is expressed as: Wherein, the information represented by X[k] is a function of k; k is directly proportional to frequency; x[n] is a function of the predicted central arterial pressure waveform; X[k] is a complex number, the predetermined frequency (k) =N-1) The magnitude of the component of each of the following frequencies is |(X[k])| and the corresponding phase is ∠X[k]. The central arterial blood pressure estimating device according to claim 19, wherein the N is equal to 10, and the magnitude and phase corresponding to the components of the respective frequencies below the predetermined frequency are as follows: the frequency is 0 Hz, and the corresponding size is 1.00 and The phase is 0.00 radians; the frequency is 1 Hz, the corresponding size is 1.04 and the phase is 0.18 radians; the frequency is 2 Hz, the corresponding size is 1.26 and the phase is 0.33 radians; the frequency is 3 Hz, the corresponding size is 1.76 and the phase is 0.36 radians; frequency 4 Hz, the corresponding size is 2.08 and the phase is -0.06 radians; the frequency is 5 Hz, the corresponding size is 1.68 and the phase is -0.26 radians; the frequency is 6 Hz, the corresponding size is 1.97 and the phase is -0.15 radians; frequency 7 Hz, which corresponds to a size of 1.98 and a phase of -0.47 radians; frequency 8 Hz, which corresponds to a size of 1.24 and a phase of -0.44 radians; frequency 9 Hz, Its corresponding size is 1.32 and the phase is -0.21 radians. The central arterial blood pressure estimating device according to claim 11, wherein the pressure value of the central artery includes a pressure difference between systolic blood pressure and diastolic blood pressure, a systolic blood pressure, an average blood pressure, and a diastolic blood pressure.