JP4590630B2 - Blood vessel wall monitoring device, control program, computer-readable recording medium recording program - Google Patents

Description

  The present invention relates to a blood vessel monitoring apparatus that can monitor mechanical properties such as viscosity, rigidity, and inertia of the blood vessel wall when the blood vessel wall is modeled as a viscoelastic model.

  The peripheral circulation in the blood vessels of the human body is adjusted according to the stimulus to the human body. This is because the sympathetic nerve of the autonomic nerve reacts in response to a stimulus from the outside of the human body, and the blood vessels are contracted and relaxed by the reaction of the sympathetic nerve.

  Therefore, during the operation of the human body, the peripheral circulation is easily affected, and it is important to monitor the mechanical characteristics of the blood vessels in order to grasp the change in the state of the peripheral circulation.

  In particular, in the chest exchange nerve blockade performed for hyperhidrosis patients, monitoring of the mechanical properties of blood vessels is very important. The reason for this will be described below.

  In this chest exchange nerve blocker, sweating is suppressed by blocking the sympathetic nerve with a clip, but it is difficult to determine whether the sympathetic nerve is properly blocked during the operation. It is determined whether the sympathetic nerve is properly blocked by observing whether the patient is sweating later. Therefore, when it was determined that this blockage was not properly performed, it was necessary to perform a reoperation, which put a burden on the patient.

On the other hand, it is conventionally known that blood vessels relax when sympathetic nerves are properly blocked. Therefore, if the mechanical characteristics of the patient's blood vessels can be monitored during the operation, it can be confirmed during the operation whether or not the sympathetic nerve is properly blocked, and the follow-up and re-operation after the operation described above are unnecessary. For these reasons, in thoracic exchange nerve blockage, it is highly necessary to monitor the mechanical characteristics of the blood vessel wall and grasp the state of the blood vessel wall.
Akira Sakane et al .: Sensing of arterial wall impedance, Proc. Of the 4th SICE System Integration Division Annual Conference, 1G4-4, pp.237-238, 2003.

  Therefore, according to Non-Patent Document 1 described above, a measuring device that models a blood vessel wall into a viscoelastic model and outputs elements such as inertia, viscosity, and rigidity of the blood vessel wall is proposed. According to this apparatus, based on the patient's electrocardiogram, blood pressure value, and plethysmogram of blood flowing in the blood vessel, the above-described mechanical characteristics of the inertia, viscosity, and rigidity of the blood vessel wall can be output. Therefore, if this technique is used for a patient who is undergoing surgery, it is possible to monitor the mechanical characteristics such as the inertia, viscosity, and rigidity of the patient's blood vessel, and to grasp the state of the patient's blood vessel wall.

  However, according to the apparatus disclosed in Non-Patent Document 1, a blood pressure value at the insertion point is measured by inserting a catheter into the blood vessel wall and collecting blood from the catheter. Therefore, in order to monitor the mechanical properties such as inertia, viscosity, and rigidity of the patient's blood vessels, the catheter must be inserted into the patient's blood vessels, which is accompanied by extra bleeding other than bleeding due to surgery, For this, an extra burden will arise.

  An object of the present invention is to provide a blood vessel monitoring device that suppresses a burden on a patient, a control program, and a computer-readable recording medium that records the program.

  To achieve the above object, the blood vessel wall monitoring device of the present invention detects an electrocardiogram output means for outputting an electrocardiogram of a subject, a plethysmogram output means for outputting a plethysmogram in the blood vessel of the subject, and a blood pressure value in the blood vessel. Blood pressure value output means, and based on the electrocardiogram, plethysmogram, and blood pressure value, at least one or more of viscosity, stiffness, and inertial mechanical characteristic values when the vascular wall of the subject is modeled as a viscoelastic model A blood vessel wall monitoring device including a control means for outputting a characteristic value, wherein the blood pressure value output means is an indirect arterial pressure measuring device.

  In the blood vessel wall monitoring device, when outputting at least one characteristic value of viscosity, rigidity, and inertial mechanical characteristic values when the subject's blood vessel wall is modeled as a viscoelastic model, the subject's electrocardiogram, plethysmogram, It is necessary to measure blood pressure at a minimum. Here, according to the blood vessel wall monitoring device of the conventional configuration, since the blood pressure of the subject was detected by inserting the catheter into the blood vessel of the subject, the subject was accompanied by bleeding.

  On the other hand, according to the structure of this invention, the indirect arterial pressure measuring device which can detect a blood pressure non-invasively is used as a means to detect a test subject's blood pressure value. Therefore, as compared with the conventional configuration in which the blood pressure of the subject is detected by the catheter inserted up to the blood vessel, there is an effect that the degree of burden on the subject can be greatly reduced.

In the blood vessel wall monitoring apparatus according to the present invention, in addition to the above configuration, the control means sets the appearance timing of the R wave in the electrocardiogram to be t _0, and sets the time from the appearance timing to the appearance timing of the next R wave as t. When the blood pressure value is P _b (t), the first function setting means for outputting dP _b (t) = P _b (t) −P _b (t ₀ ), and the plethysmogram as P _l (t) , P _l (t) ′, which is the first derivative of P _l (t), and P _l (t) ″, which is the second derivative of P _l (t), dP, _{l (t) = P l (} t) -P l (t 0), dP l (t) '= P l (t)'-P l (t 0) ', dP l (t)'' = P l (T) ″-P _l (t ₀ ) ″ outputting second function setting means, and the above dP _b (t), dP _l (t), dP _l (t) ', the _dP l (t)'' as a _{sample, dP b (t) = M'} · dP l (t)'' + B'· dP l (t)' + K'dP l (t) ( M ′ is the inertia, B ′ is the viscosity, and K ′ is the stiffness), and a calculation unit that outputs M ′, B ′, and K ′ is included. .

When modeling the vascular wall of the subject viscoelastic _{model, dP b (t) = M'} · dP l (t)'' + B'· dP l (t) '+ K'dP l (t) is satisfied It is known. Therefore, if the regression calculation is performed using the above dP _b (t) and dP _l (t) as samples, it is possible to calculate the inertia, the viscosity, and the rigidity.

In the blood vessel wall monitoring apparatus according to the present invention, in addition to the above-described configuration, the control means may include an inflection point appearance timing at the dP _b (t) and an inflection point appearance timing at the dP _l (t). It includes a correcting means for outputting a time difference n and correcting the dP _b (t) to the dP _b (t−n).

  According to the conventional configuration, the blood pressure value of the blood vessel is detected by directly inserting the catheter into the blood vessel. However, according to the blood vessel wall monitoring device of the present invention, an indirect arterial pressure measuring device that does not directly contact the blood vessel is used. Since the blood pressure is detected, the detected blood pressure value is delayed by the time that the blood pressure in the blood vessel is transmitted to the indirect arterial pressure measuring device, and the output inertia, viscosity, and rigidity are adversely affected. The possibility of effect arises.

On the other hand, dP _b (t) is based on the blood pressure value, and dP _l (t) is based on the plethysmogram. Therefore, since the waveform shown by both shows the same behavior as the waveform showing the behavior of the pulse, the inflection point appearance timing of the waveform is considered to be substantially identical.

Therefore, according to the above-described configuration, output and appearance timing of the inflection point in the _dP b (t), the time difference n between the appearance timing of the inflection point in the _dP l (t), the _dP b (t) Is corrected to dP _b (t−n). Thereby, even if the behavior of the waveform indicated by dP _b (t) is delayed from the original due to the delay of the detected blood pressure value, the timing of dP _b (t) and dP _l (t) The above delay can be corrected by relatively matching the timing. Thereby, the possibility of adversely affecting the output inertia, viscosity, and rigidity can be suppressed.

  The blood vessel wall monitoring device may be realized by a computer. In this case, the blood vessel wall monitoring device can be realized by a control program that causes the computer to operate as the control means. A computer-readable recording medium that records the above control program also falls within the scope of the present invention.

  As described above, the blood vessel wall monitoring device according to the present invention includes an electrocardiogram output unit that outputs an electrocardiogram of a subject, a plethysmogram output unit that outputs a plethysmogram in the blood vessel of the subject, and a blood pressure value output that detects a blood pressure value in the blood vessel. Based on the means and the electrocardiogram, plethysmogram, and blood pressure value, output at least one characteristic value among the mechanical characteristic values of viscosity, stiffness, and inertia when the blood vessel wall of the subject is modeled as a viscoelastic model A blood vessel wall monitoring device comprising: a control means for controlling the blood pressure value, wherein the blood pressure value output means is an indirect arterial pressure measuring device.

  Therefore, compared to the conventional configuration in which the blood pressure of the subject is detected by the catheter inserted up to the blood vessel, there is an effect that the degree of burden on the subject can be greatly reduced.

  An embodiment of the present invention will be described below with reference to the drawings. As described below, the blood vessel wall monitoring apparatus according to the present embodiment models an arterial blood vessel wall (hereinafter simply referred to as “blood vessel wall”) as a viscoelastic model based on the subject's electrocardiogram, blood pressure value, and plethysmogram. In this case, the viscosity, rigidity (elasticity), and inertial mechanical characteristic values of the blood vessel wall are output. Hereinafter, for convenience of explanation, first, the modeling, the plethysmogram, and the calculation method of the mechanical characteristic value will be described in order, and then the configuration of the blood vessel wall monitoring apparatus will be described.

(Vessel wall modeling)
As shown in FIG. 2, the blood vessel wall 10 of the human body is composed of three layers of an intima 11, an intima 12, and an outer membrane 13, and each layer includes a specific constituent factor.

  The outer membrane 13 includes factors affecting arterial stiffness and compliance such as connective tissue, elastin, and collagen, and also includes vascular blood vessels that supply nutrients to the vascular wall of the aorta.

  The intima 11 contains vascular endothelium that produces endothelium-derived vasoactive substances such as carbon monoxide and EDHF (endothelium-derived hyperpolarizing factor).

  The media 12 includes smooth muscle such as elastin and collagen. Here, smooth muscle contracts when stimulated by sympathetic nerves or hormones, and has a function of lowering blood flow.

  Accordingly, the blood vessel wall 10 contracts or relaxes by the action of smooth muscle contained in the media 12. Therefore, in the present embodiment, the blood vessel wall 10 is modeled as a viscoelastic model as means for numerically expressing the degree of contraction or relaxation of the blood vessel wall 10.

  FIG. 3 shows a viscoelastic model of the blood vessel wall 10. Each mechanical characteristic value of M (inertia), B (viscosity), and K (rigidity) in the viscoelastic model shown in FIG.

  In [Expression 1], r (t) ′ represents the first derivative of r (t), and r (t) ″ represents the second derivative of r (t).

Here, assuming that the displacement start time of the blood vessel wall 10 is t ₀ , the respective mechanical characteristic values at time t show the relationship of [Equation 2].

  Here, in order to estimate M, B, and K based on [Equation 2], it is necessary to calculate F (t) and r (t).

  Since F (t) is proportional to the blood pressure acting on the blood vessel wall 10, F (t) is calculated based on the blood pressure value. Specifically, F (t) is calculated based on the following [Equation 3].

  On the other hand, since it is difficult to directly measure the blood vessel radius r (t), r (t) is determined based on the plethysmogram of blood in the blood vessel. The principle of determining r (t) based on the plethysmogram will be described in detail below.

(Plethysmogram)
Pulse waves include a pressure pulse wave that records blood pressure fluctuations in blood vessels and a volume pulse wave that records changes in blood volume. The plethysmogram in this specification corresponds to the volume pulse wave. is there.

  A method for detecting a plethysmogram of blood vessels will be described below. For this detection, a photoelectric pulse wave meter 103 composed of an LED (light emitting diode) and a photodiode as shown in FIG. 5 is used.

  When light emitted from the LED is applied to the finger of the human body, this light passes through the finger and the blood vessel inside the finger and reaches the photodiode. In this case, the following formula is given according to Lambert-Beer's law: 4] is established.

Note that in [Equation 4], D is the concentration of the diameter of the vessel, A _D is the light attenuation on vascular diameter D, C is light absorbing material (vessel and blood), I _O is the intensity of incident light, I _D is the transmitted light intensity , E is the extinction coefficient of the light-absorbing substance.

Here, when the diameter of the blood vessel changes from D to D + ΔD (t), the light attenuation becomes A (t) and the transmitted light intensity becomes I _D −ΔI (t). [Delta] A (t) is expressed by the following [Equation 5].

  And what measured this variation | change_quantity (DELTA) A (t) of the light attenuation corresponds to the above-mentioned plethysmogram. However, in [Equation 5], C includes an uncertain element that depends on the individual measurement conditions, such as depending on the blood concentration. Therefore, ΔA (t) is directly calculated by [Equation 5]. It is not possible.

  Therefore, in this embodiment, an approximate expression for [Equation 5] is set, and ΔA (t) is obtained by this approximate expression. Below, the setting method of this approximate expression is demonstrated.

As described above, when light emitted from the LED is applied to a blood vessel having a diameter D, the transmitted light intensity of the blood vessel periodically fluctuates as shown in the graph of the reference symbol a in FIG. Here, I _s shown in FIG. 4 is a transmissive light intensity of blood vessels in cardiac systole (Systolic), I _d is the transmitted light intensity of blood vessels in cardiac diastole (Diastolic).

Here, the transmitted light intensity _{I D} of the transmitted light intensity variation of the vessel that has shifted to the systolic from the state showing the _{ΔI s (t) = I D} -I S (t), from the state showing the transmitted light intensity _{I D} the variation of attenuation of the blood vessels that transition to systole from the ΔA s _(t), transmitted light intensity I [Delta] I the transmitted light intensity variation of the vessel that has shifted to diastole from a state indicating _D d _(t ) = I _d (t) −I _D , where ΔA _d (t) is the variation in the attenuation of the blood vessel that has entered the diastole from the state showing transmitted light intensity I _D , Equation 7] holds.

Here, since ΔI _d (t) = 0 in the systole and ΔI _s (t) = 0 in the diastole, the variation ΔA (t) in the dimming degree is expressed by the following [Equation 8]. be able to.

Further, since the variation of the transmitted light intensity is ΔI (t) = ΔI _s (t) + ΔI _d (t), it is possible to determine that ΔI (t) / _ID is sufficiently small in [Equation 8]. Therefore, in [Equation 8], the terms after the second order can be ignored, and the variation ΔA (t) of the blood vessel attenuation and the plethymogram P _l (t) should be approximated as [Equation 9]. Can do.

  Further, since ΔA (t) is considered to be proportional to the displacement of the blood vessel wall due to contraction or relaxation, the following [Equation 10] is established.

Note that k _p is a proportionality constant, and r _v (t) is the radius of the blood vessel wall at the measurement site. The following [Equation 11] can be obtained from [Equation 9] and [Equation 10].

Hereinafter, based on the above-described P _b (t) and P _l (t), M (inertia), B (viscosity), and K (rigidity) mechanical characteristic values when a blood vessel is modeled as a viscoelastic model. The calculation method of will be described.

(Calculation method of mechanical property value)
Substituting r _v (t) of [Equation 11] for r (t) of [Equation 2] and rearranging the equation using [Equation 3],

Is obtained.

Therefore, the blood pressure and plethysmogram of the subject are measured, and the measured blood pressure is defined as P _b (t), and the measured plethysmogram is defined as P _l (t). Then, by using this P _b (t) and P _l (t) as samples and performing regression calculation using [Equation 12], each dynamic of M ′ (inertia), B ′ (viscosity), and K ′ (rigidity) The characteristic value can be estimated.

(Configuration of blood vessel wall monitoring device)
Next, the configuration of the blood vessel wall monitoring apparatus 100 that can monitor the state of the blood vessel wall of the subject will be described. The blood vessel wall monitoring apparatus 100 outputs M ′ (inertia), B ′ (viscosity), and K ′ (rigidity) of the blood vessel wall when the blood vessel wall of the subject is modeled as a viscoelastic model. Thereby, the operator can monitor the state (contraction or relaxation degree) of the blood vessel wall of the subject. As shown in FIG. 1, the blood vessel wall monitoring device 100 uses FINAPRESS (trade name) as blood pressure measurement means. ) 101, an electrocardiograph (electrocardiogram output means) 102, a photoelectric pulse wave meter (plethysmogram output means) 103, a computer 104, and a display unit 105.

As shown in FIG. 6, the fina press (blood pressure value output means) 101 wears a cuff on any finger of the subject, detects blood pressure data of blood vessels in this finger for each pulse, and this blood pressure data is stored in a computer. An indirect arterial pressure measuring device for inputting to 104, for example, a Ohnaeda FINAPRESS is used. Here, a _P b (t) described above blood pressure data (signals) output from the finapres 101.

  The electrocardiograph 102 is a device that detects electrocardiogram data of a subject and inputs the electrocardiogram data to the computer 104.

As shown in FIG. 5, the photoelectric pulse wave meter 103 is composed of an LED and a photodiode, and is a device that detects a plethysmogram in a blood vessel of a subject's finger. Specifically, the LED and the photodiode are arranged to face each other through any finger of the subject, light is emitted from the LED toward the finger, and the light transmitted through the finger is received by the photodiode. To do. And the transmittance | permeability of the light which permeate | transmits a blood vessel is detected from the emitted light amount of LED, and the received light amount of a photodiode, and a test subject's plethysmogram data is calculated | required from a detection result. Further, the photoelectric pulse wave meter 103 inputs the detected plethysmogram data to the computer 104. Here, the plethysmogram data (signal) output from the photoelectric pulse wave meter 103 is defined as P _l (t) described above.

  In addition, it is preferable that the finger | toe which wears the cuff of the fina press 101 and the finger | toe which opposes LED and a photodiode of the photoelectric pulse wave meter 103 are the same arms and mutually different fingers. Specifically, when the blood vessel wall monitoring apparatus 100 of the present embodiment is tested and operated, the cuff of the fina press 101 is attached to the subject's left hand middle finger, and the LED of the photoelectric pulse wave meter 103 is passed through the subject's left hand thumb. And the photodiode were opposed.

  The computer 104 processes data input from the FINA press 101, the electrocardiograph 102, and the photoelectric pulse wave meter 103, and outputs the processing result to the display unit 105. Details of the configuration of the computer 104 will be described later.

  The display unit 105 is a device for displaying information processed by the computer 104 as an image, and a liquid crystal display is used. However, the present invention is not limited to the liquid crystal display, and may be a plasma display, a CRT (cathode ray tube), an organic EL (Electro Luminescence) display, or an inorganic EL display, for example.

  Next, the configuration of the computer 104 will be described. The computer 104 includes digital filters 110a and 110b, a control unit 120, and a storage unit 130. The control unit 120 includes a first function setting unit 121, a differential calculation unit 122, a second function setting unit 123, a regression calculation unit 124, and a display control unit 125.

The digital filter 110a inputs P _b (t) from the fina press 101, removes the noise component from P _b (t) by adjusting the frequency characteristic of the input P _b (t), and removes the noise component This is a circuit that inputs P _b (t) to the control unit 120. Further, the digital filter 110b receives P _l (t) from the photoelectric pulse wave meter 103, adjusts the frequency characteristic of the input P _l (t), and thereby removes a noise component from P _l (t). This is a circuit for inputting P _l (t) from which components have been removed to the control unit 120.

  As these digital filters, LPF (low pass filter) or HPF (high pass filter) can be used.

  The control unit (control means) 120 controls the operations of various components in the blood vessel wall monitoring device 100 as a whole, and performs various data processing. The control unit 120 includes a CPU (Central Processing Unit), a RAM (Random Access Memory), and a write / read memory as needed. And operation control of various composition is performed by making a CPU run a control program. For example, the control program may be in a form that is read from a removable medium such as a CD-ROM (Compact Disc Read Only Memory) and written in the RAM, and the CPU accesses the RAM for use. The configuration may be such that what is installed in the storage unit 130 or the like is read out and expanded in a RAM, and the CPU accesses and uses the RAM. Further, when the control unit 120 is connected to a communication network such as the Internet, a mode in which the control program is downloaded via the communication network, installed in the storage unit 130, and executed is also conceivable. Details of the configuration of the control unit 120 will be described later.

  The storage unit 130 is configured by a nonvolatile storage device such as a hard disk or a flash memory. Examples of the contents stored in the storage unit 130 include the above-described control program, OS (Operating System) program, and various other programs. In the present embodiment, the expression (a) in [Expression 12] described above is used. Is stored as a regression equation.

  Next, details of the configuration of the control unit 120 will be described.

The first function setting unit (first function setting means) 121 inputs electrocardiogram data from the electrocardiograph 102 and inputs P _b (t) from the digital filter 110a. Then, the first function setting unit 121 sets the appearance timing of the R wave of the electrocardiogram data as t ₀ (t ₀ = 0) and sets dP _b (t) = P _b (t) −P _b (t ₀ ). A function is set, and this function is input to the regression calculation unit 124.

That is, the first function setting unit 121 extracts dP _b (t) for each period, with a period from the timing when the R wave appears in the electrocardiogram data to the timing when the R wave appears next as one period. Yes. Therefore, the first function setting unit 121 inputs the extracted dP _b (t) for each period to the regression calculation unit 124. Incidentally, in FIG. 8 (d), the show examples of one cycle of _dP b (t).

The differential calculation unit (differential calculation means) 122 receives P _l (t) from the digital filter 110b. The differentiating unit 122 _calculates a _P l (t) 'is the first derivative of _P l _(t), and _P l (t)'' a second differential of _P l (t), _{P l} (t), P _l (t) ′, and P _l (t) ″ are input to the second function setting unit 123.

The second function setting unit (second function setting means) 123 receives the electrocardiogram data from the electrocardiograph 102 and also receives the P _l (t), P _l (t) ′, and P _l (t) from the differential calculation unit 122. Enter "". Then, the second function setting unit 123 sets dP _l (t) = P _l (t) −P _l (t ₀ ), dP _{l with} the appearance timing of the R wave of the electrocardiogram data as t ₀ (t = 0). _{(t) '= P l (} t)'-P l (t 0) ', dP l (t)'' = P l (t)''-P l (t 0) to set the functions and'' These dP _l (t), dP _l (t) ′, and dP _l (t) ″ are input to the regression calculation unit 124.

That is, the second function setting unit 123 sets dP _l (t), dP _l () for each period, with a period from the timing when the R wave appears in the electrocardiogram data to the timing when the R wave appears next as one period. t) ′ and dP _l (t) ″ are extracted. Therefore, the second function setting unit 123, the extracted cycle every _{dP l (t), dP l} (t) ', the entering the _dP l (t)'' to regression calculation section 124. 8A shows an example of dP _l (t) for one cycle, FIG. 8B shows an example of dP _l (t) ′ for one cycle, and FIG. 2 shows an example of dP _l (t) ″ for one cycle.

The regression calculation unit (calculation unit) 124 reads the regression calculation formula (Equation (a) in [Equation 12]) stored in the storage unit 130 and inputs dP _b (t), dP _l (t), dP _{Using l} (t) ′ and dP _l (t) ″ as samples, regression calculation is performed based on the read regression calculation formula, and M ′, B ′, and K ′ in the regression calculation formula are calculated.

  In addition, the regression calculation unit 124 calculates M ′, B ′, and K ′ in the entire period, and creates a graph showing the degree of variation in M ′, B ′, and K ′ with respect to the entire measurement time.

  The display control unit 125 is a block that inputs the graph created by the regression calculation unit 124 and performs control for displaying the graph on the display unit 105. In addition, in FIG.7 (b), the example of the graph which showed the variation degree of M ', B', K 'is shown.

  According to the above configuration, M (inertia) and B (viscosity) when the subject's blood vessel is modeled as a viscoelastic model from the subject's electrocardiogram, blood pressure data of blood vessels in any finger of the subject, and plethysmogram. , K (rigidity) can be displayed on the display unit 105 in real time.

  Therefore, for example, in chest replacement nerve blockage, if the blood vessel wall monitoring apparatus 100 according to the present embodiment is used to monitor the mechanical characteristics such as the inertia, viscosity, and rigidity of the patient's blood vessel, the state of the patient's blood vessel wall is being operated on. It becomes possible to grasp during the operation whether or not the exchange nerve is properly blocked.

  Further, according to the blood vessel wall monitoring apparatus 100 of the present embodiment, the FINAPRESS 101 capable of detecting blood pressure in a non-invasive manner is used as means for detecting the blood pressure value of the subject. Therefore, compared with the structure of the nonpatent literature 1 which detected the test subject's blood pressure with the catheter which inserts a tube to a blood vessel, the burden degree with respect to a test subject can be reduced significantly.

  Furthermore, using a measuring device and a blood vessel wall monitoring device 100 of Non-Patent Document 1, for a patient who has undergone a chest exchange nerve blockade, M (inertia), B (viscosity), K ( The result of outputting (rigidity) is shown in FIG. FIG. 7A shows data output by the measuring device of Non-Patent Document 1, and FIG. 7B shows data output by the blood vessel wall monitoring device 100.

  7A and 7B, the patients are the same, and the measurement times are also the same. Further, in the configuration of Non-Patent Document 1 and the blood vessel wall monitoring apparatus 100, a plethysmogram in the blood vessel of the middle finger was detected by bringing a photoelectric pulse wave meter close to the left thumb of the patient. However, in the configuration of Non-Patent Document 1, a blood pressure is measured by inserting a catheter into the patient's left radial artery, and in the blood vessel wall monitoring apparatus 100, a fina press cuff is attached to the patient's left middle finger. Blood pressure was measured.

  7 (a) and 7 (b), the time indicated by the reference symbol A indicates the time when the patient's exchange nerve is blocked with a clip.

  In both of FIG. 7A and FIG. 7B, B (viscosity) and K (rigidity) tend to increase in the time zone before the time indicated by the reference symbol A. This is because it is considered that the blood vessels are contracted and hardened because stimulation is given to the patient in a situation where a doctor's operation is performed.

  7 (a) and FIG. 7 (b), both B (viscosity) and K (rigidity) tend to decrease in the time zone after the time indicated by the reference symbol A. This is because the blood vessels are thought to relax if the exchange nerve is properly blocked by the clip.

  As described above, according to the blood vessel wall monitoring device 100 of the present embodiment, compared with the conventional measurement device (measurement device of Non-Patent Document 1), M (inertia), B (viscosity), and K (rigidity) are large and small. Although there is a slight difference, the timings of the increase and decrease of the values are the same, so it can be said that the state of the blood vessel wall can be sufficiently estimated even by the blood vessel wall monitoring device 100 of the present embodiment. .

  In the conventional measuring device, the blood pressure value of the blood vessel is detected by directly inserting the catheter into the blood vessel. However, according to the blood vessel wall monitoring device 100 of the present embodiment, the blood pressure is detected by the fina press 101. Therefore, the detected blood pressure value is delayed by the time during which the blood pressure in the blood vessel is transmitted to the cuff. As a result, the output M (inertia), B (viscosity), and K (rigidity) may be adversely affected.

  Therefore, hereinafter, the blood vessel wall monitoring apparatus 100 capable of correcting the above-described delay will be described with reference to FIG.

  Compared with the blood vessel wall monitoring apparatus 100 shown in FIG. 1, the blood vessel wall monitoring apparatus 100 shown in FIG. 9 includes a time difference correction unit 150, and the regression calculation shown in the following [Equation 13] in the storage unit 130. The difference is that the equations are stored, but the other configurations are the same.

The time difference correction unit (correction unit) 150 receives dP _b (t) in a certain cycle from the first function setting unit 121 and dP _l (t) in the cycle from the second function setting unit 123.

Then, the time difference correction unit 150 detects the t value indicating the timing of the inflection point existing from the rising edge in the waveform of dP _b (t) until reaching the maximum point, as t1. Moreover, the time difference correction | amendment part 150 detects t value which shows the timing of the inflection point which exists in the waveform of dP _l (t) from the rise to the maximum point.

  Further, the time difference correction unit 150 calculates t1−t2 = n, reads the regression calculation formula shown in [Formula 13] from the storage unit 130, and substitutes n into this regression calculation formula. Then, the time difference correction unit 150 inputs this regression calculation formula to the regression calculation unit 124.

  The regression calculation unit 124 performs the above-described regression calculation using the regression calculation formula input from the time difference correction unit 150.

In the above configuration, dP _b (t) is based on the blood pressure value, and dP _l (t) is based on the plethysmogram. Therefore, since the waveforms shown by both show the same behavior as the waveform showing the behavior of the pulse, it is considered that the waveform rising timing, the maximum point arrival timing, and the inflection point appearance timing are essentially identical.

Therefore, according to the configuration of FIG. 9, the time difference correction unit 150 described above calculates t1−t2 = n and substitutes n into the regression calculation formula shown in [Equation 13]. Thus, in a regression calculations performed by the regression arithmetic unit 124, _dP b each value of (t) becomes to be corrected in _{dP b (t-n),} dP b timing and _dP l (t of (t) ) Timing can be relatively matched.

That is, even if the behavior of the waveform indicated by dP _b (t) is delayed from the original due to a delay in the detected blood pressure value, the timing of dP _b (t) and the dP _l (t) The timing can be relatively matched, and the delay can be corrected. As a result, the possibility of adversely affecting the output M (inertia), B (viscosity), and K (rigidity) can be suppressed.

  Although the blood vessel wall in the present embodiment is an arterial blood vessel wall, the blood vessel wall monitoring apparatus of the present embodiment is not limited to the device that measures the mechanical characteristics in the arterial blood vessel wall, but the mechanical characteristics in the venous blood vessel wall. It is also possible to measure.

  In this embodiment, a skeletal muscle impedance estimation model is used as a viscoelastic model as shown in FIG. 3, but the present invention is not limited to this. Forked model, Maxwell model, Kelvin model, etc. May be. Any viscoelastic model may be used, and various modifications are possible.

  Furthermore, the blood vessel wall monitoring apparatus 100 according to the present embodiment is suitable for monitoring a patient's blood vessel wall at an operation site, but the application is not limited to an operation site, and examples thereof include a training device and a massage device. It can also be applied to health equipment.

  In the above-described embodiment, the FINAPRESS is used as the blood pressure value output means, but any indirect arterial pressure measuring device may be used, and the invention is not limited to FINAPRESS.

  The blood vessel wall monitoring apparatus described in the above embodiment may be realized by causing a computer to read a control program, and this program may be recorded on a computer-readable recording medium. . As a result, it is possible to provide a portable recording medium on which the control program is recorded.

  As the recording medium, a memory (not shown) such as a ROM (Read Only Memory) itself, which is processed by a microcomputer, may be a program medium or illustrated. However, it may be a program medium provided with a program reading device as an external storage device and readable by inserting a recording medium therein.

  In any case, the stored program may be configured to be accessed and executed by the microprocessor, or in any case, the program is read and the read program is illustrated in the microcomputer. The program may be downloaded to a non-program storage area and executed. It is assumed that this download program is stored in the main device in advance.

  Here, the program medium is a recording medium configured to be separable from the main body, such as a tape system such as a magnetic tape or a cassette tape, a magnetic disk such as a floppy (registered trademark) disk or a hard disk, or a CD-ROM / MO /. Disk system for optical disks such as MD / DVD, card system such as IC card (including memory card) / optical card, mask ROM, EPROM (Erasable Programmable Read Only Memory), EEPROM (Electrically Erasable Programmable Read Only Memory), flash It may be a medium that carries a fixed program including a semiconductor memory such as a ROM.

  In the present embodiment, the computer 104 may be configured to be connectable to a communication network including the Internet, and may be a medium that carries the program in a fluid manner so as to download the program from the communication network. When the program is downloaded from the communication network as described above, the download program may be stored in the main device in advance, or may be installed from another recording medium. The above-described processing is executed by reading the recording medium by a program reading device provided in the computer 104.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and the embodiments can be obtained by appropriately combining the respective technical means disclosed in the above-described embodiments. The form is also included in the technical scope of the present invention.

  The blood vessel wall monitoring apparatus of the present invention is suitable for monitoring a blood vessel wall of a patient at the time of surgery, but is not limited thereto, and can be provided in a health device such as a training device or a massage device. In addition, the subject in the blood vessel wall monitoring apparatus of the present invention is not limited to a human, and an animal may be the subject.

It is a block diagram which shows the structure of the blood vessel wall monitoring apparatus which concerns on one Embodiment of this invention. It is the schematic diagram which showed the structure of the blood vessel of a human body. It is the schematic diagram which modeled the blood vessel shown in FIG. 2 in the viscoelastic model. It is the graph which showed the fluctuation | variation part of the transmitted light intensity | strength of a blood vessel, light attenuation, and light attenuation. It is a schematic diagram which shows the structure of the photoelectric pulse wave meter shown in FIG. It is a figure which shows the image of the external appearance structure of the fina press shown in FIG. It is the graph which showed the inertia, viscosity, and rigidity of a test subject's blood vessel, Comprising: (a) is a graph obtained by the continuation apparatus of the conventional structure, (b) is the blood vessel wall which concerns on one Embodiment of this invention. It is the graph obtained by the monitoring apparatus. Is a graph obtained by the vessel wall monitoring apparatus according to an embodiment of the present invention, (a) is a graph showing the function of time and plethysmogram, scratch (b), the plethysmogram P _{l (t)} (C) is a graph of a function obtained by second-order differentiation and subtracting the first-order differential value at the initial time, and (c) is obtained by second-order differentiation of the plethysmogram P _l (t) and subtracting the second-order differential value at the initial time. (D) is a graph showing a function of time and blood pressure value. It is a block diagram which shows the structure of the blood vessel wall monitoring apparatus which concerns on other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Blood vessel wall 11 Inner membrane 12 Middle membrane 13 Outer membrane 100 Blood vessel wall monitoring apparatus 101 FINAPRESS (blood pressure output means, indirect arterial pressure measuring device)
102 electrocardiograph (electrocardiogram output means)
103 photoelectric pulse wave meter (plethysmogram detection means)
104 Computer 105 Display unit 110a / 110b Digital filter 120 Control unit (control means)
121 First function setting unit (first function setting means)
122 Differential calculation unit (differential calculation means)
123 Second function setting unit (second function setting means)
124 regression calculation unit (calculation means)
125 Display control unit 130 Storage unit 150 Time difference correction unit (correction means)

Claims (3)

An electrocardiogram output means for outputting the electrocardiogram of the subject;
Plethysmogram output means for outputting a plethysmogram in the blood vessel of the subject,
Blood pressure value output means for detecting a blood pressure value in the blood vessel;
Control means for outputting at least one characteristic value among the mechanical characteristic values of viscosity, stiffness, and inertia when the blood vessel wall of the subject is modeled as a viscoelastic model based on the electrocardiogram, plethysmogram, and blood pressure value A blood vessel wall monitoring device comprising:
The blood pressure output unit Ri indirect arterial pressure meter der,
The control means includes
If the blood pressure values and P _{b (t),} the appearance timing of the R-wave in the electrocardiogram and t _0, and one cycle period from the appearance timing of the R wave in t ₀ to the appearance timing of the next R-wave, First function setting means for outputting dP _b (t) = P _b (t) −P _b (t ₀ ) for each period ;
When the plethysmogram is P _l (t), P _l (t) ′, which is the first derivative of P _l (t), and P _l (t) ″, which is the second derivative of P _l (t). Differential calculation means for calculating;
For each period, dP _l (t) = P _l (t) −P _l (t ₀ ), dP _l (t) ′ = P _l (t) ′ − P _l (t ₀ ) ′, dP _l (t ) ″ = P _l (t) ″ − P _l (t ₀ ) ″, second function setting means for outputting,
The inflection point appearance timing from the rise to the maximum point in the waveform of dP _b (t) and the rise timing from the rise in the waveform of dP _l (t) to the maximum point. A correction means for outputting a time difference n from the appearance timing of an existing inflection point and correcting dP _b (t) to dP _b (t−n);
Using the above dP _b (t−n), dP _l (t), dP _l (t) ′, dP _l (t) ″ as samples,
_{dP b (t-n) =} M'· dP l (t)'' + B'· dP l (t) '+ K'dP l (t)
(M ′ is the inertia, B ′ is the viscosity, and K ′ is the rigidity)
Computing means for performing a regression calculation on M and outputting M ′, B ′ and K ′;
Vessel wall monitoring apparatus which comprises a. A control program for controlling the blood vessel wall monitoring apparatus according to claim 1 , wherein the function of the control means is realized by a computer. A computer-readable recording medium on which the control program according to claim 2 is recorded.