JP2008061910A - Blood vessel elasticity monitoring apparatus - Google Patents

Blood vessel elasticity monitoring apparatus Download PDF

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JP2008061910A
JP2008061910A JP2006244874A JP2006244874A JP2008061910A JP 2008061910 A JP2008061910 A JP 2008061910A JP 2006244874 A JP2006244874 A JP 2006244874A JP 2006244874 A JP2006244874 A JP 2006244874A JP 2008061910 A JP2008061910 A JP 2008061910A
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plethysmogram
blood pressure
blood vessel
vascular
monitoring device
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JP5062809B2 (en
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Toshio Tsuji
敏夫 辻
Kenji Shiba
建次 柴
Takahiro Mitsunari
貴浩 三成
Masashi Kawamoto
昌志 河本
Noboru Saeki
昇 佐伯
Takaharu Nakamura
隆治 中村
Sadaji Ugawa
貞二 鵜川
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Hiroshima University NUC
Nippon Koden Corp
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Nippon Koden Corp
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a blood vessel elasticity monitoring apparatus which is easy to use on a medical site. <P>SOLUTION: This blood vessel elasticity monitoring apparatus 1 is equipped with a plethysmogram measuring instrument 2, an automatic sphygmomanometer 3, and a blood vessel wall impedance estimating instrument 4. In this case, the plethysmogram measuring instrument 2 measures the plethysmogram of a living body. The automatic sphygmomanometer 3 measures the highest blood pressure and the lowest blood pressure of the living body. The blood vessel wall impedance estimating instrument 4 estimates the rigidity and the viscosity of the blood vessel wall of the living body from the plethysmogram which has been measured by the plethysmogram measuring instrument 2, and the highest blood pressure and the lowest blood pressure which have been measured by the automatic sphygmomanometer 3. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

本発明は、プレチスモグラム測定器によって測定されたプレチスモグラムに基づいて、生体の血管壁の剛性及び粘性を推定する血管弾性モニタリング装置に関する。   The present invention relates to a vascular elasticity monitoring device that estimates rigidity and viscosity of a vascular wall of a living body based on a plethysmogram measured by a plethysmogram measuring device.

血管は、刺激に応じて、その直径が小さくなって収縮したり、直径が大きくなって弛緩したりして、状態が変化する。この状態変化を示したものがプレチスモグラムである。図１２は、血管の状態変化を説明するための図である。このような血管の力学特性を解析することにより、例えば手術中の診断を支援することが試みられている（例えば、特許文献１参照）。   In response to the stimulus, the blood vessel changes its state by decreasing its diameter and contracting, or increasing its diameter and relaxing. A plethysmogram shows this state change. FIG. 12 is a diagram for explaining changes in the state of blood vessels. Attempts have been made, for example, to support diagnosis during surgery by analyzing such mechanical characteristics of blood vessels (see, for example, Patent Document 1).

図１３は、血管壁インピーダンスを説明するための図である。血管壁の機械インピーダンスは、血管壁の半径方向に沿って加わる応力と、血管壁の歪とに基づいて、血管壁の慣性Ｍ、粘性Ｂ及び剛性Ｋによって表される。   FIG. 13 is a diagram for explaining blood vessel wall impedance. The mechanical impedance of the blood vessel wall is expressed by the inertia M, the viscosity B, and the stiffness K of the blood vessel wall based on the stress applied along the radial direction of the blood vessel wall and the strain of the blood vessel wall.

図１４は、従来の血管弾性モニタリング装置の構成を説明するための模式図である。従来の血管弾性モニタリング装置は、人体の一方の腕の指先のプレチスモグラムＰｌ（ｔ）を測定するプレチスモグラム測定器を備えている。プレチスモグラム測定器の一例として、指先の血管に赤外線を照射する発光素子と、血管を透過した赤外線を受光する受光素子とを含んでいるものがある。発光素子から血管に照射された赤外線は、血管によってその一部が吸収され、残りの赤外線は、受光素子に入射する。このため、受光素子に入射した赤外線の量に基づいて、血管を流れる血液の量の変動、及び血管の容積（半径）の変動が分かる。プレチスモグラム測定の他の例としては、腕や指など人体の外周囲の長さの変化を基に、血管を流れる血液の量の変動、及び血管の容積（半径）の変動を測定するものもある。 FIG. 14 is a schematic diagram for explaining a configuration of a conventional vascular elasticity monitoring device. A conventional vascular elasticity monitoring device includes a plethysmogram measuring device that measures a plethysmogram P l (t) of a fingertip of one arm of a human body. As an example of the plethysmogram measuring instrument, there is one including a light emitting element that irradiates infrared rays to a blood vessel of a fingertip and a light receiving element that receives infrared rays that have passed through the blood vessel. A part of the infrared ray irradiated to the blood vessel from the light emitting element is absorbed by the blood vessel, and the remaining infrared ray enters the light receiving element. For this reason, based on the amount of infrared light incident on the light receiving element, the variation in the amount of blood flowing through the blood vessel and the variation in the volume (radius) of the blood vessel are known. Another example of plethysmogram measurement is to measure changes in the amount of blood flowing through blood vessels and changes in the volume (radius) of blood vessels based on changes in the length of the outer circumference of the human body such as arms and fingers. .

血管弾性モニタリング装置には、カテーテルが設けられている。カテーテルは、プレチスモグラム測定器により赤外線が照射された指を有する腕の動脈血圧Ｐｂ（ｔ）を測定する。   The vascular elasticity monitoring device is provided with a catheter. The catheter measures the arterial blood pressure Pb (t) of the arm having the finger irradiated with infrared rays by the plethysmogram measuring device.

図１５は、血管壁インピーダンスモデルを説明するための模式図である。血管壁の機械インピーダンスを推定するためには、応力と歪とを計測する必要がある。血管（動脈）の内膜に作用する法線応力は、動脈血圧と等しいので、法線応力は、動脈血圧Ｐｂ（ｔ）と等しい。血管壁の歪は、直接測定することは困難であるが、プレチスモグラムＰｌ（ｔ）によって表すことができる。よって、プレチスモグラム測定器によって測定されたプレチスモグラムＰｌ（ｔ）に基づいて血管壁の歪を求め、カテーテルによって測定された動脈血圧Ｐｂ（ｔ）に基づいて血管壁の法線応力を求め、血管壁の粘性Ｂ及び剛性Ｋを推定することができる。 FIG. 15 is a schematic diagram for explaining a blood vessel wall impedance model. In order to estimate the mechanical impedance of the blood vessel wall, it is necessary to measure stress and strain. Since the normal stress acting on the intima of the blood vessel (artery) is equal to the arterial blood pressure, the normal stress is equal to the arterial blood pressure Pb (t). Vessel wall distortion is difficult to measure directly, but can be represented by a plethysmogram P l (t). Therefore, the strain of the blood vessel wall is obtained based on the plethysmogram P l (t) measured by the plethysmogram measuring device, the normal stress of the blood vessel wall is obtained based on the arterial blood pressure Pb (t) measured by the catheter, and the blood vessel wall Can be estimated.

図１６は、血管壁の剛性Ｋ及び粘性Ｂを推定する従来のアルゴリズムを説明するための
模式図である。プレチスモグラム測定器によって測定されたプレチスモグラムＰｌ（ｔ）のある時刻ｔ０からの変化量
ｄＰｌ（ｔ）＝Ｐｌ（ｔ）−Ｐｌ（ｔ０）
を表す波形と、プレチスモグラムＰｌ（ｔ）を微分したプレチスモグラム速度のある一定時刻ｔ０からの変化量を表す波形と、カテーテルによって測定された動脈血圧Ｐｂ（ｔ）のある一定時刻ｔ０からの変化量
ｄＰｌ（ｔ）＝Ｐｌ（ｔ）−Ｐｌ（ｔ０）
を表す波形とを用い、図１６に示す血管の力学モデルの式に基づいて最小二乗法でフィッティングを行うことにより、血管壁の剛性Ｋ及び粘性Ｂを推定する。
特開２００６−１２９９５８号公報（平成１８年５月２５日（2006.5.25）公開） FIG. 16 is a schematic diagram for explaining a conventional algorithm for estimating the stiffness K and viscosity B of the blood vessel wall. A change dP l (t) = P l (t) −P l (t0) from a certain time t0 of the plethysmogram P l (t) measured by the plethysmogram measuring device.
, A waveform representing the amount of change in the plethysmogram velocity obtained by differentiating the plethysmogram P l (t) from a certain time t0, and the amount of change in the arterial blood pressure Pb (t) measured by the catheter from a certain time t0 dP l (t) = P l (t) −P l (t0)
16 is used to estimate the rigidity K and viscosity B of the blood vessel wall by performing the fitting by the least square method based on the equation of the dynamic model of the blood vessel shown in FIG.
JP 2006-129958 A (published on May 25, 2006 (2006.5.25))

しかしながら、上記従来の構成では、動脈血圧の連続波形に基づいて、最小二乗法により血管壁の剛性及び粘性を推定する処理が複雑であり、医療現場で使い難いという問題があった。   However, the conventional configuration has a problem that the processing for estimating the stiffness and viscosity of the blood vessel wall by the least square method based on the continuous waveform of arterial blood pressure is complicated, and is difficult to use in the medical field.

本発明は、上記の問題点に鑑みてなされたものであり、その目的は、医療現場で使いやすい血管弾性モニタリング装置を提供することにある。   The present invention has been made in view of the above problems, and an object of the present invention is to provide a vascular elasticity monitoring device that is easy to use in a medical field.

本発明に係る血管弾性モニタリング装置は、上記課題を解決するために、生体のプレチスモグラムを測定するプレチスモグラム測定手段と、前記生体の最高血圧及び最低血圧を測定する血圧測定手段と、前記プレチスモグラム測定手段によって測定されたプレチスモグラムと、前記血圧測定手段によって測定された最高血圧及び最低血圧とに基づいて、前記生体の血管壁の剛性を推定する血管壁インピーダンス推定手段とを備えたことを特徴とする。   In order to solve the above problems, a vascular elasticity monitoring device according to the present invention includes a plethysmogram measurement unit that measures a plethysmogram of a living body, a blood pressure measurement unit that measures a maximum blood pressure and a minimum blood pressure of the living body, and a plethysmogram measurement unit. Vascular wall impedance estimating means for estimating rigidity of the vascular wall of the living body based on the measured plethysmogram and the systolic blood pressure and the systolic blood pressure measured by the blood pressure measuring means.

上記の特徴によれば、血圧測定手段によって測定された最高血圧及び最低血圧とに基づいて、前記生体の血管壁の剛性及び粘性を推定するので、汎用的な自動血圧計を使用して、血管壁の剛性及び粘性を推定することができる。このため、医療現場で使いやすい血管弾性モニタリング装置を提供することができる。   According to the above feature, the rigidity and viscosity of the blood vessel wall of the living body are estimated based on the maximum blood pressure and the minimum blood pressure measured by the blood pressure measuring means. Wall stiffness and viscosity can be estimated. Therefore, it is possible to provide a vascular elasticity monitoring device that is easy to use in the medical field.

本発明に係る血管弾性モニタリング装置では、前記プレチスモグラム測定手段は、前記生体の血管に光線を照射する発光素子と、前記血管を透過した光線を受光する受光素子とを含むことが好ましい。   In the vascular elasticity monitoring device according to the present invention, it is preferable that the plethysmogram measurement means includes a light emitting element that irradiates light on the blood vessel of the living body and a light receiving element that receives the light transmitted through the blood vessel.

上記構成によれば、簡単な構成により生体のプレチスモグラムを測定することができる。   According to the above configuration, a plethysmogram of a living body can be measured with a simple configuration.

本発明に係る血管弾性モニタリング装置では、前記プレチスモグラム測定手段は、人体の指先のプレチスモグラムを測定することが好ましい。   In the vascular elasticity monitoring device according to the present invention, it is preferable that the plethysmogram measuring means measures a plethysmogram of a human fingertip.

上記構成によれば、人体のプレチスモグラムを容易に測定することができる。   According to the said structure, the plethysmogram of a human body can be measured easily.

本発明に係る血管弾性モニタリング装置では、前記プレチスモグラム測定手段は、人体の一方の腕の指先のプレチスモグラムを測定し、前記血圧測定手段は、前記一方の腕の最高血圧及び最低血圧を測定することが好ましい。   In the vascular elasticity monitoring device according to the present invention, the plethysmogram measurement means measures a plethysmogram of a fingertip of one arm of a human body, and the blood pressure measurement means measures a maximum blood pressure and a minimum blood pressure of the one arm. preferable.

上記構成によれば、同一の腕から、プレチスモグラムを測定し、最高血圧及び最低血圧を測定するので、血管壁の剛性及び粘性精度を向上させることができる。   According to the above configuration, since the plethysmogram is measured from the same arm and the maximum blood pressure and the minimum blood pressure are measured, the rigidity and viscosity accuracy of the blood vessel wall can be improved.

本発明に係る血管弾性モニタリング装置では、前記血管壁インピーダンス推定手段は、前記プレチスモグラムから取得した血管径の最大伸長比率及び最大収縮比率と、前記血圧測定手段によって測定された最高血圧及び最低血圧とに基づいて前記生体の血管壁の剛性を推定することが好ましい。   In the vascular elasticity monitoring device according to the present invention, the vascular wall impedance estimation means includes the maximum elongation ratio and the maximum contraction ratio of the blood vessel diameter acquired from the plethysmogram, and the maximum blood pressure and the minimum blood pressure measured by the blood pressure measurement means. It is preferable to estimate the rigidity of the blood vessel wall of the living body based on the above.

本発明に係る血管弾性モニタリング装置では、前記血管壁インピーダンス推定手段は、前記血管径の最大伸長比率及び最大収縮比率より得られる血管径の変動比率と、前記血圧測定手段によって測定された血圧の変動幅との比率に基づいて前記生体の血管壁の剛性を推定することが好ましい。   In the vascular elasticity monitoring device according to the present invention, the vascular wall impedance estimating means includes a fluctuation ratio of the vascular diameter obtained from the maximum expansion ratio and the maximum contraction ratio of the vascular diameter, and a change in blood pressure measured by the blood pressure measurement means. It is preferable to estimate the rigidity of the blood vessel wall of the living body based on the ratio to the width.

本発明に係る血管弾性モニタリング装置では、前記血管壁インピーダンス推定手段は、前記血管壁の粘性を推定する場合は、前記プレチスモグラムの微分値を利用することが好ましい。   In the vascular elasticity monitoring apparatus according to the present invention, it is preferable that the vascular wall impedance estimating means uses a differential value of the plethysmogram when estimating the viscosity of the vascular wall.

本発明に係る血管弾性モニタリング装置では、前記血管壁インピーダンス推定手段は、前記血管壁の粘性を推定する場合は、前記プレチスモグラムより得られる血管径の変動速度を利用することが好ましい。   In the vascular elasticity monitoring device according to the present invention, it is preferable that the vascular wall impedance estimating means uses a blood vessel diameter fluctuation rate obtained from the plethysmogram when estimating the viscosity of the vascular wall.

本発明に係る血管弾性モニタリング装置では、前記プレチスモグラム測定手段と前記血圧測定手段とは、心臓の鼓動一拍単位内での測定を行い、前記血管壁インピーダンス推定手段は、前記一拍単位で前記生体の血管壁の剛性及び粘性を推定することが好ましい。   In the vascular elasticity monitoring device according to the present invention, the plethysmogram measuring means and the blood pressure measuring means perform measurement within a heart beat unit, and the vascular wall impedance estimation unit is configured to measure the living body in units of one beat. It is preferable to estimate the stiffness and viscosity of the blood vessel wall.

本発明に係る血管弾性モニタリング装置では、前記光線は、赤外線であることが好ましい。   In the vascular elasticity monitoring device according to the present invention, the light beam is preferably infrared light.

本発明に係る血管弾性モニタリング装置は、以上のように、前記生体の最高血圧及び最低血圧を測定する血圧測定手段と、前記プレチスモグラム測定手段によって測定されたプレチスモグラムと、前記血圧測定手段によって測定された最高血圧及び最低血圧とに基づいて、前記生体の血管壁の剛性を推定する血管壁インピーダンス推定手段とを備えているので、医療現場で使いやすい血管弾性モニタリング装置を提供することができるという効果を奏する。   As described above, the blood vessel elasticity monitoring device according to the present invention is measured by the blood pressure measuring means for measuring the maximum blood pressure and the minimum blood pressure of the living body, the plethysmogram measured by the plethysmogram measuring means, and the blood pressure measuring means. Since it includes the blood vessel wall impedance estimating means for estimating the rigidity of the blood vessel wall of the living body based on the maximum blood pressure and the minimum blood pressure, it is possible to provide a blood vessel elasticity monitoring device that is easy to use in the medical field. Play.

本発明の一実施形態について図１ないし図１１に基づいて説明すると以下の通りである。図１は、実施の形態に係る血管弾性モニタリング装置１の構成を模式的に示すブロック図である。   An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a block diagram schematically showing a configuration of a vascular elasticity monitoring device 1 according to an embodiment.

血管弾性モニタリング装置１は、プレチスモグラム測定器２を備えている。プレチスモグラム測定器２は、人体の一方の腕の指先のプレチスモグラムを測定する。   The vascular elasticity monitoring device 1 includes a plethysmogram measuring device 2. The plethysmogram measuring device 2 measures the plethysmogram of the fingertip of one arm of the human body.

図２は、プレチスモグラム測定器２の構成を模式的に示す回路図である。プレチスモグラム測定器２は、指先７の血管に赤外線を照射する発光素子５と、この血管を透過した赤外線を受光する受光素子６とを含んでいる。発光素子５はＬＥＤによって構成されており、受光素子６はフォトダイオードによって構成されている。発光素子５から血管に照射された赤外線は、血管によってその一部が吸収され、残りの赤外線は、受光素子６に入射する。このため、受光素子６に入射した赤外線の量に基づいて、血管を流れる血液の量の変動、及び血管の容積（半径）の変動が分かる。   FIG. 2 is a circuit diagram schematically showing the configuration of the plethysmogram measuring instrument 2. The plethysmogram measuring instrument 2 includes a light emitting element 5 that irradiates the blood vessel of the fingertip 7 with infrared light, and a light receiving element 6 that receives the infrared light transmitted through the blood vessel. The light emitting element 5 is composed of an LED, and the light receiving element 6 is composed of a photodiode. A part of the infrared ray irradiated to the blood vessel from the light emitting element 5 is absorbed by the blood vessel, and the remaining infrared ray enters the light receiving element 6. For this reason, based on the amount of infrared light incident on the light receiving element 6, the variation in the amount of blood flowing through the blood vessel and the variation in the volume (radius) of the blood vessel are known.

血管に赤外線を照射する例を示しているが、本発明はこれに限定されず、例えば、超音波またはレーザを照射するように構成してもよい。また、指先に照射する例を示しているが、本発明はこれに限定されず、例えば、足先または耳たぶに照射するように構成してもよい。また、ストレンゲージプレチスモグラフィーによってプレチスモグラム測定器２を構成してもよい。   Although the example which irradiates a blood vessel with infrared rays is shown, the present invention is not limited to this, and may be configured to irradiate ultrasonic waves or lasers, for example. Moreover, although the example which irradiates a fingertip is shown, this invention is not limited to this, For example, you may comprise so that it may irradiate a foot tip or an earlobe. Moreover, you may comprise the plethysmogram measuring device 2 by strain gauge plethysmography.

血管弾性モニタリング装置１には、自動血圧計３が設けられている。自動血圧計３は、人体の一方の腕の最高血圧及び最低血圧を測定する。自動血圧計３は、市販の汎用的な自動血圧計によって構成することができる。なお、本実施の形態では、自動血圧計を使用する例を示すが、本発明はこれに限定されない。例えば、カテーテルによって血圧測定手段を構成してもよい。   The blood vessel elasticity monitoring device 1 is provided with an automatic blood pressure monitor 3. The automatic sphygmomanometer 3 measures the maximum blood pressure and the minimum blood pressure of one arm of the human body. The automatic sphygmomanometer 3 can be configured by a commercially available general-purpose automatic sphygmomanometer. In this embodiment, an example in which an automatic sphygmomanometer is used is shown, but the present invention is not limited to this. For example, the blood pressure measuring means may be constituted by a catheter.

血管弾性モニタリング装置１は、血管壁インピーダンス推定器４を備えている。血管壁インピーダンス推定器４は、プレチスモグラム測定器２によって測定された指先のプレチスモグラムと、自動血圧計３によって測定された腕の最高血圧及び最低血圧とに基づいて、人体の血管壁の剛性及び粘性を推定する。   The vascular elasticity monitoring device 1 includes a vascular wall impedance estimator 4. The vascular wall impedance estimator 4 calculates the rigidity and viscosity of the vascular wall of the human body based on the plethysmogram of the fingertip measured by the plethysmogram measuring instrument 2 and the systolic blood pressure and the diastolic blood pressure measured by the automatic sphygmomanometer 3. presume.

図３は血管壁インピーダンス推定器４によって推定される血管壁の剛性を説明するためのグラフであり、図４はプレチスモグラム測定器２によって測定されたプレチスモグラムＰｌ[％]を示すグラフであり、図５は自動血圧計３によって測定された最高血圧Ｐｂｍａｘ及び最低血圧Ｐｂｍｉｎを示すグラフである。 FIG. 3 is a graph for explaining the rigidity of the blood vessel wall estimated by the blood vessel wall impedance estimator 4, and FIG. 4 is a graph showing the plethysmogram Pl [%] measured by the plethysmogram measuring device 2. These are graphs showing the maximum blood pressure P bmax and the minimum blood pressure P bmin measured by the automatic sphygmomanometer 3.

図４における横軸は時間を示し、縦軸はプレチスモグラムＰｌ[％]を示している。プレチスモグラムＰｌ[％]は、心臓の心拍に応じて周期的に変動する。血管壁インピーダンス推定器４は、心臓の心拍ごとに血管壁の剛性及び粘性を推定する。   The horizontal axis in FIG. 4 indicates time, and the vertical axis indicates the plethysmogram Pl [%]. The plethysmogram Pl [%] varies periodically according to the heart rate of the heart. The vascular wall impedance estimator 4 estimates the rigidity and viscosity of the vascular wall for each heartbeat of the heart.

図５における横軸は時間を示し、縦軸は動脈血圧Ｐｂ[ｍｍＨｇ]を示している。動脈血圧Ｐｂ[ｍｍＨｇ]も心臓の心拍に応じて周期的に変動し、自動血圧計３は、１周期中の最高血圧Ｐｂｍａｘと最低血圧Ｐｂｍｉｎとを計測する。 The horizontal axis in FIG. 5 indicates time, and the vertical axis indicates arterial blood pressure Pb [mmHg]. The arterial blood pressure Pb [mmHg] also varies periodically according to the heartbeat of the heart, and the automatic sphygmomanometer 3 measures the maximum blood pressure P bmax and the minimum blood pressure P bmin during one cycle.

図３における横軸はプレチスモグラムＰｌ[％]を示し、縦軸は動脈血圧Ｐｂ[ｍｍＨｇ]を示している。図３には、動脈血圧ＰｂとプレチスモグラムＰｌとのリサージュ波形が示されている。   In FIG. 3, the horizontal axis represents the plethysmogram Pl [%], and the vertical axis represents the arterial blood pressure Pb [mmHg]. FIG. 3 shows a Lissajous waveform of the arterial blood pressure Pb and the plethysmogram Pl.

血管壁の剛性は、血管径の変動に対する血圧の変動量の割合を表していることから、図３に示すように、プレチスモグラムＰｌと、動脈血圧Ｐｂの最低血圧Ｐｂｍｉｎと最高血圧Ｐｂｍａｘとを結ぶ直線の傾きで近似する。 Since the rigidity of the blood vessel wall represents the ratio of the fluctuation amount of the blood pressure to the fluctuation of the blood vessel diameter, as shown in FIG. 3, the plethysmogram Pl, the minimum blood pressure P bmin and the maximum blood pressure P bmax of the arterial blood pressure Pb are obtained. Approximate by the slope of the connecting line.

図６は血管壁インピーダンス推定器４によって推定される血管壁の粘性を説明するためのグラフであり、図７はプレチスモグラム測定器２によって測定された図４に示すプレチスモグラムを微分したプレチスモグラム速度を示すグラフである。   FIG. 6 is a graph for explaining the viscosity of the blood vessel wall estimated by the blood vessel wall impedance estimator 4, and FIG. 7 is a graph showing the plethysmogram velocity obtained by differentiating the plethysmogram shown in FIG. 4 measured by the plethysmogram measuring device 2. It is.

血管壁の粘性は、血管径の速度の変動に対する血圧の変動量の割合を表していることから、図６に示すように、プレチスモグラム速度と、動脈血圧Ｐｂの最低血圧Ｐｂｍｉｎと最高血圧Ｐｂｍａｘとを結ぶ直線の傾きで近似する。 Since the viscosity of the blood vessel wall represents the ratio of the blood pressure fluctuation amount to the blood vessel diameter speed fluctuation, as shown in FIG. 6, the plethysmogram speed, the arterial blood pressure Pb minimum blood pressure P bmin and the maximum blood pressure P bmax Approximate by the slope of the straight line connecting

このようにして、一心拍ごとに推定を繰り返すことにより、血管の状態変化を捉えることが可能となる。   In this way, it is possible to capture a change in the state of the blood vessel by repeating the estimation for each heartbeat.

このように、最低血圧Ｐｂｍｉｎと最高血圧Ｐｂｍａｘとのみによって血管壁の剛性及び粘性を推定することが出来るので、血圧の測定には自動血圧計を使用すれば足り、少ない計算量によって血管の状態変化を捉えることができる。 As described above, since the rigidity and viscosity of the blood vessel wall can be estimated only by the minimum blood pressure P bmin and the maximum blood pressure P bmax , it is sufficient to use an automatic sphygmomanometer for blood pressure measurement, and the blood vessel can be measured with a small amount of calculation. Can capture state changes.

本実施の形態において提案した推定アルゴリズムの推定精度の検証を試みた。胸部交感神経遮断術を行った患者（被験者Ａ，Ｂ）について血管弾性モニタリング装置の血管壁インピーダンス推定実験を行った。プレチスモグラム測定器とカテーテルとから計測した連続動脈血圧を用いた従来手法に加え、プレチスモグラム測定器と自動血圧計とから計測した最高・最低血圧を用いた本実施の形態に係る手法による推定を行った。プレチスモグラムと動脈血圧の測定にはベッドサイドモニタＢＳＳ−９８００（日本光電工業株式会社）を用いて計測し、パーソナルコンピュータに記録した。   An attempt was made to verify the estimation accuracy of the estimation algorithm proposed in the present embodiment. A vascular wall impedance estimation experiment of a vascular elasticity monitoring device was performed on patients (subjects A and B) who had undergone chest sympathetic blockade. In addition to the conventional method using the continuous arterial blood pressure measured from the plethysmogram measuring instrument and the catheter, the estimation according to the present embodiment using the maximum and minimum blood pressure measured from the plethysmogram measuring instrument and the automatic sphygmomanometer was performed. . The plethysmogram and arterial blood pressure were measured using a bedside monitor BSS-9800 (Nippon Koden Kogyo Co., Ltd.) and recorded on a personal computer.

胸部交感神経遮断術は、多汗症患者に対して行われる手術である。多汗症とは、胸部の背骨の横に連なっている交感神経の機能亢進により、手のひらや脇の下の発汗が通常の人よりも多い病気であり、同時に血管が収縮し、血液循環が悪い状態にある。この手術は、交感神経をクリップで遮断し、発汗を止めるために行われる。それに伴い血管が弛緩し、血管壁の剛性が下がることが知られている。   Chest sympathetic blockade is a surgery performed on hyperhidrosis patients. Hyperhidrosis is a disease in which sweating on the palms and armpits is more common than in normal people due to hyperactivity of the sympathetic nerves that lie next to the spine of the chest, and at the same time blood vessels contract and blood circulation is poor. is there. This operation is performed to block the sympathetic nerve with a clip and stop sweating. Along with this, it is known that the blood vessel relaxes and the rigidity of the blood vessel wall decreases.

血管弾性モニタリング装置の実験結果を図８及び図９に示す。図８に示すグラフは、交感神経遮断術の被験者Ａの血管壁の剛性値及び粘性値を示しており、図９に示すグラフは、被験者Ｂの剛性値及び粘性値を示している。本実施の形態に係る推定方法による推定結果は、従来の方法による推定結果と精度良く一致していることが分かる。   The experimental results of the vascular elasticity monitoring device are shown in FIGS. The graph shown in FIG. 8 shows the stiffness value and the viscosity value of the blood vessel wall of the subject A in sympathetic nerve blockage, and the graph shown in FIG. 9 shows the stiffness value and the viscosity value of the subject B. It can be seen that the estimation result by the estimation method according to the present embodiment matches the estimation result by the conventional method with high accuracy.

自動血圧計を利用した本実施の形態に係る推定方法を用いた血管壁インピーダンス推定を、肝切除患者（被験者Ｃ、被験者Ｄ）に対して試みた。血管弾性モニタリング装置の実験では心電図、プレチスモグラム、動脈血圧をベッドサイドモニタＢＳＳ−９８００（日本光電工業株式会社）を用いて計測し、パーソナルコンピュータに記録した。繞骨動脈にカテーテルを挿入して動脈血圧を計測し、同側の指尖部よりプレチスモグラムを計測した。また、カテーテルを挿入した逆側の腕から自動血圧計を用いて動脈血圧を計測した。   The vascular wall impedance estimation using the estimation method according to the present embodiment using an automatic sphygmomanometer was attempted for a hepatectomy patient (subject C, subject D). In the experiment of the vascular elasticity monitoring apparatus, an electrocardiogram, a plethysmogram, and arterial blood pressure were measured using a bedside monitor BSS-9800 (Nihon Kohden Co., Ltd.) and recorded on a personal computer. A catheter was inserted into the radial artery to measure arterial blood pressure, and a plethysmogram was measured from the ipsilateral fingertip. In addition, the arterial blood pressure was measured using an automatic sphygmomanometer from the opposite arm where the catheter was inserted.

図１０〜図１１は、血管弾性モニタリング装置１によって推定された血管壁の剛性及び粘性と、従来の方法によって推定された血管壁の剛性及び粘性とを示す実験結果のグラフである。図１０は被験者Ｃについての血管弾性モニタリング装置の実験結果を示しており、図１１は被験者Ｄについての血管弾性モニタリング装置の実験結果を示している。   10 to 11 are graphs of experimental results showing the rigidity and viscosity of the blood vessel wall estimated by the blood vessel elasticity monitoring device 1 and the rigidity and viscosity of the blood vessel wall estimated by the conventional method. FIG. 10 shows the experimental result of the vascular elasticity monitoring apparatus for the subject C, and FIG. 11 shows the experimental result of the vascular elasticity monitoring apparatus for the subject D.

血管壁の粘性、剛性ともに、本実施の形態に係る推定方法による推定結果は、従来の方法による推定結果と精度良く一致する傾向が得られるとともに、両手法の推定結果に高い相関を確認することができた。従って、最高・最低血圧とプレチスモグラムを用いて血管粘弾性を推定する手法の有効性を確認することができた。   Both the viscosity and stiffness of the blood vessel wall have a tendency that the estimation results obtained by the estimation method according to the present embodiment agree with the estimation results obtained by the conventional method with high accuracy, and high correlation is confirmed between the estimation results of both methods. I was able to. Therefore, the effectiveness of the technique for estimating vascular viscoelasticity using the maximal / minimum blood pressure and plethysmogram could be confirmed.

本発明は上述した実施形態に限定されるものではなく、請求項に示した範囲で種々の変更が可能である。すなわち、請求項に示した範囲で適宜変更した技術的手段を組み合わせて得られる実施形態についても本発明の技術的範囲に含まれる。   The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims. That is, embodiments obtained by combining technical means appropriately modified within the scope of the claims are also included in the technical scope of the present invention.

本発明は、プレチスモグラム測定器によって測定されたプレチスモグラムに基づいて、生体の血管壁の剛性及び粘性を推定する血管弾性モニタリング装置に適用することができる。   The present invention can be applied to a vascular elasticity monitoring device that estimates the rigidity and viscosity of a vascular wall of a living body based on a plethysmogram measured by a plethysmogram measuring device.

実施の形態に係る血管弾性モニタリング装置の構成を模式的に示すブロック図である。It is a block diagram which shows typically the structure of the vascular elasticity monitoring apparatus which concerns on embodiment. 上記血管弾性モニタリング装置に設けられたプレチスモグラム測定器の構成を模式的に示す回路図である。It is a circuit diagram which shows typically the structure of the plethysmogram measuring device provided in the said vascular elasticity monitoring apparatus. 上記血管弾性モニタリング装置に設けられた血管壁インピーダンス推定器によって推定される血管壁の剛性を説明するためのグラフである。It is a graph for demonstrating the rigidity of the blood vessel wall estimated by the blood vessel wall impedance estimator provided in the said blood vessel elasticity monitoring apparatus. 上記プレチスモグラム測定器によって測定されたプレチスモグラムを示すグラフである。It is a graph which shows the plethysmogram measured by the said plethysmogram measuring device. 上記血管弾性モニタリング装置に設けられた自動血圧計によって測定された最高血圧及び最低血圧を示すグラフである。It is a graph which shows the maximum blood pressure and the minimum blood pressure measured by the automatic blood pressure meter provided in the said vascular elasticity monitoring apparatus. 上記血管壁インピーダンス推定器によって推定される血管壁の粘性を説明するためのグラフである。It is a graph for demonstrating the viscosity of the blood vessel wall estimated by the said blood vessel wall impedance estimator. 上記プレチスモグラム測定器によって測定されたプレチスモグラムを微分したプレチスモグラム速度を示すグラフである。It is a graph which shows the plethysmogram speed | rate which differentiated the plethysmogram measured by the said plethysmogram measuring device. 実施の形態に係る血管弾性モニタリング装置によって推定された血管壁の剛性及び粘性と、従来の方法によって推定された血管壁の剛性及び粘性とを示す実験結果のグラフである。It is a graph of the experimental result which shows the rigidity and viscosity of the blood vessel wall estimated by the blood vessel elasticity monitoring apparatus which concerns on embodiment, and the rigidity and viscosity of the blood vessel wall estimated by the conventional method. 実施の形態に係る血管弾性モニタリング装置によって推定された血管壁の剛性及び粘性と、従来の方法によって推定された血管壁の剛性及び粘性とを示す他の実験結果のグラフである。It is a graph of the other experimental result which shows the rigidity and viscosity of the blood vessel wall estimated by the vascular elasticity monitoring apparatus which concerns on embodiment, and the rigidity and viscosity of the blood vessel wall estimated by the conventional method. 実施の形態に係る血管弾性モニタリング装置によって推定された血管壁の剛性及び粘性と、従来の方法によって推定された血管壁の剛性及び粘性とを示すさらに他の実験結果のグラフである。It is the graph of the further another experimental result which shows the rigidity and viscosity of the blood vessel wall estimated by the blood vessel elasticity monitoring apparatus which concerns on embodiment, and the rigidity and viscosity of the blood vessel wall estimated by the conventional method. 実施の形態に係る血管弾性モニタリング装置によって推定された血管壁の剛性及び粘性と、従来の方法によって推定された血管壁の剛性及び粘性とを示すさらに他の実験結果のグラフである。It is the graph of the further another experimental result which shows the rigidity and viscosity of the blood vessel wall estimated by the blood vessel elasticity monitoring apparatus which concerns on embodiment, and the rigidity and viscosity of the blood vessel wall estimated by the conventional method. 血管の状態変化を説明するための図である。It is a figure for demonstrating the state change of the blood vessel. 血管壁インピーダンスを説明するための図である。It is a figure for demonstrating the vascular wall impedance. 従来の血管弾性モニタリング装置の構成を説明するための模式図である。It is a schematic diagram for demonstrating the structure of the conventional vascular elasticity monitoring apparatus. 血管壁インピーダンスモデルを説明するための模式図である。It is a schematic diagram for demonstrating a vascular wall impedance model. 血管壁の剛性及び粘性を推定する従来のアルゴリズムを説明するための模式図である。It is a schematic diagram for demonstrating the conventional algorithm which estimates the rigidity and viscosity of a blood vessel wall.

符号の説明Explanation of symbols

１ 血管弾性モニタリング装置
２ プレチスモグラム測定器（プレチスモグラム測定手段）
３ 自動血圧計（血圧測定手段）
４ 血管壁インピーダンス推定器（血管壁インピーダンス推定手段）
５ 発光素子
６ 受光素子
７ 指先 1 Blood vessel elasticity monitoring device 2 Plethysmogram measuring device (plethysmogram measuring means)
3 automatic sphygmomanometer (blood pressure measuring means)
4 Vessel wall impedance estimator (Vessel wall impedance estimation means)
5 Light emitting element 6 Light receiving element 7 Fingertip

Claims (10)

生体のプレチスモグラムを測定するプレチスモグラム測定手段と、
前記生体の最高血圧及び最低血圧を測定する血圧測定手段と、
前記プレチスモグラム測定手段によって測定されたプレチスモグラムと、前記血圧測定手段によって測定された最高血圧及び最低血圧とに基づいて、前記生体の血管壁の剛性を推定する血管壁インピーダンス推定手段とを備えたことを特徴とする血管弾性モニタリング装置。 A plethysmogram measuring means for measuring a plethysmogram of a living body;
Blood pressure measuring means for measuring the maximum blood pressure and the minimum blood pressure of the living body;
Vascular wall impedance estimating means for estimating the rigidity of the vascular wall of the living body based on the plethysmogram measured by the plethysmogram measuring means and the systolic blood pressure and the diastolic blood pressure measured by the blood pressure measuring means. Characteristic vascular elasticity monitoring device. 前記プレチスモグラム測定手段は、前記生体の血管に光線を照射する発光素子と、
前記血管を透過した光線を受光する受光素子とを含む請求項１記載の血管弾性モニタリング装置。 The plethysmogram measuring means includes a light emitting element that irradiates light on the blood vessels of the living body,
The blood vessel elasticity monitoring device according to claim 1, further comprising: a light receiving element that receives a light beam transmitted through the blood vessel. 前記プレチスモグラム測定手段は、人体の指先のプレチスモグラムを測定する請求項１記載の血管弾性モニタリング装置。   The vascular elasticity monitoring device according to claim 1, wherein the plethysmogram measuring unit measures a plethysmogram of a fingertip of a human body. 前記プレチスモグラム測定手段は、人体の一方の腕の指先のプレチスモグラムを測定し、
前記血圧測定手段は、前記一方の腕の最高血圧及び最低血圧を測定する請求項１記載の血管弾性モニタリング装置。 The plethysmogram measuring means measures a plethysmogram of a fingertip of one arm of a human body,
The vascular elasticity monitoring device according to claim 1, wherein the blood pressure measurement unit measures a maximum blood pressure and a minimum blood pressure of the one arm. 前記血管壁インピーダンス推定手段は、前記プレチスモグラムから取得した血管径の最大伸長比率及び最大収縮比率と、前記血圧測定手段によって測定された最高血圧及び最低血圧とに基づいて前記生体の血管壁の剛性を推定する請求項１記載の血管弾性モニタリング装置。   The blood vessel wall impedance estimating means determines the rigidity of the blood vessel wall of the living body based on the maximum elongation ratio and the maximum contraction ratio of the blood vessel diameter acquired from the plethysmogram and the maximum blood pressure and the minimum blood pressure measured by the blood pressure measuring means. The vascular elasticity monitoring device according to claim 1 to be estimated. 前記血管壁インピーダンス推定手段は、前記血管径の最大伸長比率及び最大収縮比率より得られる血管径の変動比率と、前記血圧測定手段によって測定された血圧の変動幅との比率に基づいて前記生体の血管壁の剛性を推定する請求項５記載の血管弾性モニタリング装置。   The blood vessel wall impedance estimating means is configured to determine the ratio of the blood vessel diameter obtained from the maximum elongation ratio and the maximum contraction ratio of the blood vessel diameter to the blood pressure fluctuation range measured by the blood pressure measuring means based on the ratio of the blood pressure fluctuation width. The vascular elasticity monitoring apparatus according to claim 5, wherein the vascular wall rigidity is estimated. 前記血管壁インピーダンス推定手段は、前記血管壁の粘性を推定する場合は、前記プレチスモグラムの微分値を利用する請求項１記載の血管弾性モニタリング装置。   The vascular elasticity monitoring device according to claim 1, wherein the vascular wall impedance estimating means uses a differential value of the plethysmogram when estimating the viscosity of the vascular wall. 前記血管壁インピーダンス推定手段は、前記血管壁の粘性を推定する場合は、前記プレチスモグラムより得られる血管径の変動速度を利用する請求項１記載の血管弾性モニタリング装置。   The vascular elasticity monitoring device according to claim 1, wherein the vascular wall impedance estimating means uses a blood vessel diameter fluctuation speed obtained from the plethysmogram when estimating the viscosity of the vascular wall. 前記プレチスモグラム測定手段と前記血圧測定手段とは、心臓の鼓動一拍単位内での測定を行い、
前記血管壁インピーダンス推定手段は、前記一拍単位で前記生体の血管壁の剛性を推定する請求項１記載の血管弾性モニタリング装置。 The plethysmogram measurement means and the blood pressure measurement means perform measurement within a heart beat unit.
The vascular elasticity monitoring device according to claim 1, wherein the vascular wall impedance estimation unit estimates the rigidity of the vascular wall of the living body in units of one beat. 前記光線は、赤外線である請求項２記載の血管弾性モニタリング装置。   The vascular elasticity monitoring device according to claim 2, wherein the light beam is an infrared ray.
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