JP2004113368A - Indirect continuous blood pressure monitoring device - Google Patents

Indirect continuous blood pressure monitoring device Download PDF

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JP2004113368A
JP2004113368A JP2002279490A JP2002279490A JP2004113368A JP 2004113368 A JP2004113368 A JP 2004113368A JP 2002279490 A JP2002279490 A JP 2002279490A JP 2002279490 A JP2002279490 A JP 2002279490A JP 2004113368 A JP2004113368 A JP 2004113368A
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pulse wave
blood pressure
pressure
cuff
determined
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JP3688256B2 (en
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Hidekatsu Inukai
犬飼　英克
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Nippon Colin Co Ltd
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Nippon Colin Co Ltd
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Abstract

<P>PROBLEM TO BE SOLVED: To provide an indirect continuous blood pressure monitoring device capable of reducing burdens on a patient while maintaining high blood pressure monitoring precision. <P>SOLUTION: In this device, a pressure pulsation to blood pressure correspondence relation is decided on the basis of the value of pressure pulsation detected from a pressure pulsation sensor 46 pressurized to the wrist by prescribed pressurizing force and a blood pressure value decided by a blood pressure deciding means 72 by a correspondence relation deciding means 78, and a monitoring blood pressure value is continuously decided on the basis of the pressure pulsation to blood pressure correspondence relation and the pressure pulsation continuously detected from the pressure pulsation sensor 46. Cuff pulsation is detected in the state of turning a cuff pressure to a prescribed pulse wave detection pressure in every prescribed cycle by a cuff pulsation detection means 84, and the propriety of the mounting state of the pressure pulsation sensor 46 is determined on the basis of the comparison of the cuff pulsation and the pressure pulsation in a blood pressure monitoring accuracy determining means 90. It is unnecessary to frequently execute the blood pressure value deciding means 72 to update the pressure pulsation to blood pressure correspondence relation, thereby reducing the burdens on the patient. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、非観血的且つ連続的に血圧値を監視する血圧監視装置に関し、さらに詳しくは、非観血連続血圧監視装置において、血圧監視精度を維持しつつ患者の負担を軽減する技術に関する。
【０００２】
【従来の技術】
非観血連続血圧監視装置として、生体の所定の動脈から発生する圧脈波を検出して、その圧脈波から連続的に血圧値を監視する装置、すなわち、所謂トノメトリ法による血圧測定を用いた装置が知られている。この方式の非観血連続血圧監視装置は、上腕など生体の一部にカフを装着して、そのカフの圧迫圧力を徐速変化させる過程で血圧値を決定し、その血圧値と、生体の所定の動脈に向かって押圧させられる圧脈波センサを用いて検出した圧脈波とから、そ圧脈波の大きさと血圧値との間の圧脈波血圧対応関係を決定し、その圧脈波血圧対応関係を用い、逐次検出される圧脈波から連続的に血圧値を決定している（たとえば、特許文献１参照。）。
【０００３】
【特許文献１】
特開２０００−２３７１５１号公報
【０００４】
【発明が解決しようとする課題】
上記非観血連続血圧監視装置は、圧脈波センサの装着状態がずれる等の理由により、実際の圧脈波血圧対応関係が、血圧を測定して決定した圧脈波血圧対応関係からずれてしまうと、監視血圧値の精度が低下する。そこで、監視血圧値の精度低下を防ぐために、圧脈波血圧対応関係を比較的短い周期で更新する場合がある。短い周期で圧脈波血圧対応関係を更新すれば、実際の圧脈波血圧対応関係が徐々にずれていったとしても監視血圧値の精度低下を少なくすることができる。しかしながら、短い周期で圧脈波血圧対応関係を更新する場合には、それほど圧脈波血圧対応関係が変化しておらず更新の必要がない場合にまでその関係を更新することになる。圧脈波血圧対応関係を更新するためには、その度にカフを用いた血圧測定を実行しなければならず、カフを用いた血圧測定はカフの圧迫圧力を最高血圧値よりも高い圧力まで昇圧することから患者にとっては負担となる。従って、カフを用いた血圧測定の周期はできるだけ長い周期に設定されることが望まれる。
【０００５】
上記の通り、監視血圧値の精度を判定することができない場合には、監視血圧値の精度低下を防ぐために、圧脈波血圧対応関係を比較的頻繁に更新しなければならない。そこで、上記特許文献１では、圧脈波血圧対応関係が保たれている場合には、圧脈波センサからの押圧により血管壁の一部が略平坦とされ、その略平坦とされている血管壁の上部に位置する複数の圧力検出素子により検出される圧脈波は、略同じ形状となることを利用して、監視血圧値の精度を逐次判定している。すなわち、上記特許文献１では、圧脈波センサの押圧面に配置されている多数の圧力検出素子から最大脈波振幅を出力する最大圧力検出素子を決定し、その最大圧力検出素子から圧脈波を検出するとともに、最大圧力検出素子からの距離が第１距離および第２距離にある第１圧力検出素子および第２圧力検出素子からもそれぞれ圧脈波を検出して、最大圧力検出素子により検出された圧脈波と第１圧力検出素子から検出された圧脈波との間の第１相関係数、および最大圧力検出素子により検出された圧脈波と第２圧力検出素子により検出された圧脈波との間の第２相関係数を逐次算出し、その第１相関係数と第２相関係数とに基づいて監視血圧値の精度を逐次判定している。
【０００６】
前述のように、カフを用いた血圧測定の周期はできるだけ長い周期に設定されることが要求されるが、上記特許文献１の血圧監視装置のように、複数の圧力検出素子によりそれぞれ検出される圧脈波間の相関係数を用いて監視血圧値の精度を逐次判定する技術は、その要求に応えるほどには判定精度が十分ではなく、圧脈波血圧対応関係を更新するための血圧測定周期をある程度長くすることができるにとどまる。そのため、上記特許文献１に記載された監視血圧値の精度を判定する技術と組み合わせても用いることができ、また、その技術とは別に単独でも用いることができる、監視血圧値の精度を判定する技術の開発が望まれていた。
【０００７】
本発明は以上の事情を背景として為されたもので、その目的とするところは、高い血圧監視精度を維持しつつ、患者の負担を軽減することができる非観血連続血圧監視装置を提供することにある。
【０００８】
【課題を解決するための手段】
本発明者は、上記目的を達成するために種々検討を重ねた結果、以下の知見を見いだした。すなわち、カフの圧迫圧力を平均血圧値以下とした状態で生体からそのカフに伝達される圧力振動であるカフ脈波の形状は、トノメトリ法により検出される圧脈波の形状とよく似ていることを見いだした。また、カフは装着中にずれることが少ないことから、カフ脈波とトノメトリ法により検出される圧脈波とを比較すれば、圧脈波センサの装着状態が変化したかどうかを判定できるので、監視血圧値の精度の低下が判定できることを見いだした。本発明はかかる知見に基づいて成されたものである。
【０００９】
すなわち、上記目的を達成するための本発明は、（ａ）生体の一部に装着されるカフと、（ｂ）そのカフの圧迫圧力を制御するカフ圧制御手段と、（ｃ）そのカフ圧制御手段により前記カフの圧迫圧力が徐速変化させられる過程において得られる信号に基づいて、その生体の血圧値を決定する血圧値決定手段と、（ｄ）その生体の所定の動脈に向かって押圧させられる圧脈波センサを用いてその動脈から発生する圧脈波を逐次検出する圧脈波検出装置と、（ｅ）前記血圧値決定手段により決定された血圧値と前記圧脈波検出装置により検出された圧脈波の大きさとの間の圧脈波血圧対応関係を決定する対応関係決定手段と、（ｆ）その圧脈波血圧対応関係を用い、前記圧脈波検出装置により逐次検出される圧脈波の大きさから監視血圧値を連続的に決定する血圧値連続決定手段とを備えた非観血連続血圧監視装置であって、（ｇ）前記カフ圧制御手段により前記カフの圧迫圧力が平均血圧値よりも低い圧力とされた状態で、そのカフ内の圧力振動であるカフ脈波を検出するカフ脈波検出手段と、（ｈ）そのカフ脈波検出手段により検出されたカフ脈波と、そのカフ脈波の検出と同時期に前記圧脈波検出装置により検出された圧脈波との比較に基づいて、逐次、前記血圧値連続決定手段により決定された監視血圧値の精度を判定する血圧監視精度判定手段とを含むことを特徴とする。
【００１０】
【発明の効果】
この発明によれば、血圧監視精度判定手段により、圧脈波検出装置によって検出される圧脈波と、カフの圧迫圧力が平均血圧値より低い圧力で検出されるカフ脈波とが比較されて、血圧値連続決定手段により連続的に決定される監視血圧値の精度が判定されることから、監視血圧値の精度を維持するために、カフを用いた血圧測定を短い周期で行って圧脈波血圧対応関係を頻繁に更新する必要がなくなるので、患者の負担が軽減する。
【００１１】
【発明の他の態様】
ここで、前記血圧監視精度判定手段における圧脈波とカフ脈波との比較の仕方には種々考えられるが、たとえば、圧脈波とカフ脈波の特徴点の位置を比較することが考えられる。そのようにして監視血圧値の精度を判定する非観血連続血圧監視装置は、前記血圧値決定手段により血圧値が決定されたときに前記カフ脈波検出手段および前記圧脈波検出装置によりそれぞれ検出されたカフ脈波および圧脈波の大きさを同じにするために、そのカフ脈波および圧脈波の少なくとも一方を補正する補正係数を決定する補正係数決定手段と、該補正係数決定手段により決定された補正係数を用いて、逐次、前記カフ脈波検出手段により検出されたカフ脈波および前記圧脈波検出装置により検出された圧脈波の少なくとも一方を補正して、比較用の一組のカフ脈波および圧脈波を決定する比較脈波決定手段とを備え、前記血圧監視精度判定手段は、前記比較脈波決定手段により決定されたカフ脈波および圧脈波の互いの最小点を一致させた状態で、それらカフ脈波および圧脈波の所定の特徴点の位置を比較することによって、逐次、前記血圧値連続決定手段により決定された監視血圧値の精度を判定するものであることを特徴とする。
【００１２】
また、前記血圧監視精度判定手段において圧脈波の形状とカフ脈波の形状とを比較してもよい。そのようにして監視血圧値の精度を判定する非観血連続血圧監視装置は、前記血圧値決定手段により血圧値が決定されたときに前記カフ脈波検出手段および前記圧脈波検出装置によりそれぞれ検出されたカフ脈波および圧脈波の大きさを同じにするために、そのカフ脈波および圧脈波の少なくとも一方を補正する補正係数を決定する補正係数決定手段と、該補正係数決定手段により決定された補正係数を用いて、逐次、前記カフ脈波検出手段により検出されたカフ脈波および前記圧脈波検出装置により検出された圧脈波の少なくとも一方を補正して、比較用の一組のカフ脈波および圧脈波を決定する比較脈波決定手段とを備え、前記血圧監視精度判定手段は、前記比較脈波決定手段により決定されたカフ脈波および圧脈波の形状の比較に基づいて、逐次、前記血圧値連続決定手段により決定された監視血圧値の精度を判定するものであることを特徴とする。
【００１３】
また、圧脈波の形状とカフ脈波の形状とを比較して監視血圧値の精度を判定する装置では、前記血圧監視精度判定手段は、たとえば、前記血圧監視精度判定手段は、前記比較脈波決定手段により決定されたカフ脈波および圧脈波を、互いの最小点を一致させた状態で時間軸に垂直に複数の脈波区分に分割して、該複数の脈波区分毎に面積差を算出し、該複数の面積差のそれぞれの時間変化が所定の基準値を超えた脈波区分の数に基づいて、逐次、前記血圧値連続決定手段により決定された監視血圧値の精度を判定する。または、前記比較脈波決定手段により決定されたカフ脈波および圧脈波を、互いの最小点を一致させた状態で時間軸に垂直に複数の脈波区分に分割して、該複数の脈波区分毎に面積差を算出し、該複数の面積差の時間変化傾向が一致するか否かに基づいて、逐次、前記血圧値連続決定手段により決定された監視血圧値の精度を判定するものであってもよい。
【００１４】
また、前記血圧監視精度判定手段において圧脈波の面積とカフ脈波の面積とを比較してもよい。そのようにして監視血圧値の精度を判定する非観血連続血圧監視装置は、前記血圧監視精度判定手段が、前記カフ脈波検出手段により検出されたカフ脈波の面積の時間変化と、該カフ脈波の検出と同時期に前記圧脈波検出装置により検出された圧脈波の面積の時間変化との比較に基づいて、逐次、前記血圧値連続決定手段により決定された監視血圧値の精度を判定するものであることを特徴とする。
【００１５】
また、次のようにしてカフ脈波と圧脈波とを比較して監視血圧値の精度を判定してもよい。すなわち、前記血圧監視精度判定手段は、カフ脈波の大きさを表す軸と圧脈波の大きさを表す軸とからなる二次元グラフに、前記カフ脈波検出手段により検出されたカフ脈波と、前記圧脈波検出装置により検出された圧脈波のうち該カフ脈波に対応する圧脈波とにより描かれる波形相関図形に基づいて、逐次、前記血圧値連続決定手段により決定された監視血圧値の精度を判定するものであってもよい。
【００１６】
【発明の好適な実施の形態】
以下、本発明の実施の形態を図面に基づいて詳細に説明する。図１は本発明が適用された非観血連続血圧監視装置８の構成を説明するブロック図である。
【００１７】
図において、１０はゴム製袋を布製帯状袋内に有するカフであって、たとえば患者の右腕の上腕部１２に巻回される。カフ１０には、圧力センサ１４および排気制御弁１６が配管１８を介して接続され、さらに排気制御弁１６は、配管１９により空気ポンプ２０に接続されている。排気制御弁１６は、空気ポンプ２０において発生させられた圧力の高い空気をカフ１０内へ供給することを許容する供給許容状態、カフ１０内の圧力を維持する圧力維持状態、カフ１０内を徐々に排圧する徐速排圧状態、およびカフ１０内を急速に排圧する急速排圧状態の４つの状態に切り替えられるように構成されている。
【００１８】
圧力センサ１４は、カフ１０内の圧力ＰＫを検出してその圧力ＰＫを表す圧力信号ＳＰを静圧弁別回路２２および脈波弁別回路２４にそれぞれ供給する。静圧弁別回路２２はローパスフィルタを備えており、圧力信号ＳＰに含まれる定常的な圧力すなわちカフ１０の圧迫圧力（以下、この圧をカフ圧ＰＣという）を表すカフ圧信号ＳＣを弁別してそのカフ圧信号ＳＣをＡ／Ｄ変換器２６を介して電子制御装置２８へ供給する。脈波弁別回路２４はバンドパスフィルタを備えており、圧力信号ＳＰの振動成分であるカフ脈波信号ＳＭ１を弁別してそのカフ脈波信号ＳＭ１をＡ／Ｄ変換器３０を介して電子制御装置２８へ供給する。このカフ脈波信号ＳＭ１は、カフ１０により圧迫される図示しない上腕動脈からカフ１０に伝達される圧力振動であることからカフ脈波ＣＷを表す。
【００１９】
上記電子制御装置２８は、ＣＰＵ３１，ＲＯＭ３２，ＲＡＭ３３，および図示しないＩ／Ｏポート等を備えた所謂マイクロコンピュータにて構成されており、ＣＰＵ３１は、ＲＯＭ３２に予め記憶されたプログラムに従ってＲＡＭ３３の記憶機能を利用しつつ信号処理を実行することにより、Ｉ／Ｏポートから駆動信号を出力して図示しない駆動回路を介して排気制御弁１６および空気ポンプ２０を制御して、カフ１０内の圧力を制御するとともに、カフ脈波信号ＳＭ１が表すカフ脈波ＣＷの変化に基づいてオシロメトリック法により最高血圧値ＢＰＳＹＳおよび最低血圧値ＢＰＤＩＡなどの血圧値ＢＰを決定し、その決定した血圧値ＢＰを表示器３４に表示させる。
【００２０】
圧脈波検出装置として機能する圧脈波検出プローブ３６は、図２に詳しく示すように、容器状を成すセンサハウジング３７と、そのハウジング３７を収容するケース３８と、センサハウジング３７を橈骨動脈５６の幅方向に移動させるためにそのセンサハウジング３７に螺合され且つケース３８の駆動部３９内に設けられた図示しないモータによって回転駆動されるねじ軸４０とを備えている。また、上記ケース３８には装着バンド４１が取り付けられている。
【００２１】
このように構成された圧脈波検出プローブ３６は、センサハウジング３７の開口端が体表面４２に対向する状態で装着バンド４１により手首４３に着脱可能に取り付けられるようになっている。なお、圧脈波検出プローブ３６が取り付けられる手首４３は、カフ１０が装着されている側の手首であっても、それとは反対側の手首であってもよいが、手術中には一方の腕に点滴を実施する場合も多く、点滴をする場合には点滴用の管が挿入されている側の腕には、カフ１０も圧脈波検出プローブ３６も装着することができないことから、その場合には圧脈波検出プローブ３６はカフ１０と同じ側の腕に装着される。
【００２２】
上記センサハウジング３７の内部には、圧脈波センサ４６が、ダイヤフラム４４を介してセンサハウジング３７に対して相対移動可能かつセンサハウジング３７の開口端から突出し可能に設けられており、これらセンサハウジング３７およびダイヤフラム４４等によって圧力室４８が形成されている。この圧力室４８内には、図１に示すように、空気ポンプ５０から調圧弁５２を経て圧力の高い空気が供給されるようになっており、これにより、圧脈波センサ４６は圧力室４８内の圧力に応じた押圧力ＨＤＰ（Ｈｏｌｄ　Ｄｏｗｎ　Ｐｒｅｓｓｕｒｅ）で体表面４２に押圧させられる。
【００２３】
上記センサハウジング３７およびダイヤフラム４４は、圧脈波センサ４６を橈骨動脈５６に向かって押圧する押圧装置５８を構成しており、ねじ軸４０および図示しないモータは、圧脈波センサ４６が体表面４２に向かって押圧させられる押圧位置を、橈骨動脈５６の幅方向に移動させる幅方向移動装置６０を構成している。
【００２４】
上記圧脈波センサ４６の押圧面６２には、図３に示すように、多数の半導体感圧素子（以下、単に感圧素子という）Ｅが、橈骨動脈５６の幅方向すなわちねじ軸４０と平行な圧脈波センサ４６の移動方向において、橈骨動脈５６の直径よりも長くなるように、且つ一定の間隔（たとえば０．２ｍｍ間隔）で配列されている。
【００２５】
このように構成された圧脈波検出プローブ３６が、手首４３の体表面４２上から橈骨動脈５６に向けて押圧されると、圧脈波センサ４６により、橈骨動脈５６から発生して体表面４２に伝達される圧脈波ＰＷ（橈骨動脈波）が検出され、図１に示すように、圧脈波ＰＷを表す圧脈波信号ＳＭ２がＡ／Ｄ変換器６４を介して電子制御装置２８へ供給される。
【００２６】
電子制御装置２８のＣＰＵ３１は、前述したカフ１０内の圧力の制御、血圧値ＢＰの決定に加え、さらに、空気ポンプ５０および調圧弁５２へ図示しない駆動回路を介して駆動信号を出力して圧力室４８内の圧力の調節も行う。さらに、電子制御装置２８は、圧力室４８内の徐速圧力変化過程で逐次得られる圧脈波ＰＷに基づいて、橈骨動脈５６の血管壁の一部を略平坦とするための圧脈波センサ４６の最適押圧力ＨＤＰＯを決定し、その最適押圧力ＨＤＰＯを維持するように調圧弁５２を制御する。
【００２７】
図４は、ＣＰＵ３１の制御機能の要部を示す機能ブロック図である。カフ圧制御手段７０は、排気制御弁１６および空気ポンプ２０を制御することにより、以下に述べる血圧測定制御および脈波検出圧制御を実行する。血圧測定制御は、カフ圧ＰＣを、上腕部１２における最高血圧値ＢＰＳＹＳよりも高い値に予め設定された昇圧目標圧力値ＰＭ１（たとえば１８０ｍｍＨｇ　）まで急速に昇圧し、続いて、後述する血圧値決定手段７２による血圧値ＢＰの決定が終了するまで、カフ圧ＰＣを２〜３ｍｍＨｇ／ｓｅｃに設定された徐速降圧速度で徐速降圧させる。そして、血圧値ＢＰの決定が終了した後にカフ圧ＰＣを大気圧まで排圧する。
【００２８】
また、脈波検出圧制御は、少なくとも一拍分以上の間、カフ圧ＰＣを脈波検出圧ＰＭ２に制御するものである。上記脈波検出圧ＰＭ２は、平均血圧値ＢＰＭＥＡＮよりも低く、好ましくは最低血圧値ＢＰＤＩＡよりも低い圧力であって、カフ脈波信号ＳＭ１の大きさが十分な大きさとなる程度に高い圧力、たとえば５０ｍｍＨｇ乃至６０ｍｍＨｇに設定される。この脈波検出圧ＰＭ２は、予め設定されていてもよいし、後述する血圧値決定手段７２により決定された血圧値ＢＰに基づいて決定されてもよい。脈波検出圧ＰＭ２がこのような圧力に設定されるのは、カフ圧ＰＣが最低血圧値ＢＰＤＩＡよりも高いと、血管が圧縮されることに起因して脈波弁別回路２４によって弁別されるカフ脈波ＣＷに歪みが生じ、特に、平均血圧値ＢＰＭＥＡＮよりも高くなると血管が圧縮される程度が大きくなることに起因してカフ脈波ＣＷの歪みが大きくなる一方で、カフ圧ＰＣが低すぎると十分な大きさの信号が得られないからである。
【００２９】
血圧値決定手段７２は、１０分乃至３０分程度に予め設定されたキャリブレーション周期Ｔｃが経過したとき、または、後述する血圧異常判定手段８２により監視血圧値ＭＢＰの異常が判定されたとき、または、後述する押圧力制御手段７６により圧脈波センサ４６の押圧力ＨＤＰが変更させられたときに実行されるものであり、カフ圧制御手段７０に指令信号を出力して、そのカフ圧制御手段７０に前記血圧測定制御を実行させ、カフ圧制御手段７０によりカフ圧ＰＣが徐速降圧させられる過程において、順次採取されるカフ脈波信号ＳＭ１が表す上腕脈波の振幅の変化および順次採取されるカフ圧信号ＳＣに基づき、良く知られたオシロメトリック法を用いて最高血圧値ＢＰＳＹＳ、最低血圧値ＢＰＤＩＡ、および平均血圧値ＢＰＭＥＡＮを決定し、その決定した最高血圧値ＢＰＳＹＳ等を表示器３４に表示する。
【００３０】
最適押圧位置制御手段７４は、圧脈波センサ４６に備えられた複数の感圧素子Ｅのうち最大圧力を検出する素子（以下、この素子を最大圧力検出素子ＥＭという）の配列位置が、配列の端を基準として、それから所定数または所定距離内側までに位置するものであることを条件とする押圧位置更新条件が成立するか否かを判断する。そして、その押圧位置更新条件が成立した場合には、以下の押圧位置更新作動を実行する。すなわち、押圧位置更新作動は、圧脈波センサ４６を体表面４２から一旦離隔させるとともに、幅方向移動装置６０により押圧装置５８および圧脈波センサ４６を所定距離移動させた後、押圧装置５８により圧脈波センサ４６を比較的小さい予め設定された第１押圧力ＨＤＰ１で押圧させ、その状態で再び上記押圧位置更新条件が成立するか否かを判断し、押圧位置更新条件が成立しなくなるまで、より好ましくは、前記最大圧力検出素子ＥＭが配列位置の略中央に位置するまで上記の作動および判断を実行する。なお、上記押圧位置更新条件における配列の端からの所定数または所定距離は、圧脈波センサ４６により押圧される動脈（本実施例では橈骨動脈５６）の直径に基づいて決定され、たとえば、その直径の１／４に設定される。
【００３１】
押圧力制御手段７６は、圧脈波センサ４６が最適押圧位置制御手段７４により最適押圧位置に位置させられた後、押圧装置５８による圧脈波センサ４６の押圧力ＨＤＰを、所定の押圧力範囲内で拍動に対応して逐次変化させ、あるいは所定の押圧力範囲内を比較的緩やかな一定速度で連続的に変化させる。そして、その押圧力ＨＤＰの変化過程で得られる圧脈波ＰＷに基づいて最適押圧力ＨＤＰＯを決定し、押圧装置５８による圧脈波センサ４６の押圧力ＨＤＰをその最適押圧力ＨＤＰＯに維持する。ここで、最適押圧力ＨＤＰＯとは、圧脈波センサ４６の押圧力ＨＤＰよって、橈骨動脈５６の血管壁の圧脈波センサ４６により押圧されている側が略平坦となる押圧力であり、たとえば図５に示すように、押圧力ＨＤＰを最適押圧力ＨＤＰＯを十分に含むような範囲で連続的に増加させる過程で、圧脈波センサ４６の最大圧力検出素子ＥＭから得られた圧脈波ＰＷの大きさと圧脈波センサ４６の押圧力ＨＤＰとを示す二次元グラフにおいて、圧脈波ＰＷの下ピーク値（立ち上がり点）ＰＷｍｉｎを結ぶ曲線（図５の破線）により形成される平坦部の中央を中心とする所定範囲内の押圧値である。
【００３２】
対応関係決定手段７８は、血圧値決定手段７２により測定された血圧値ＢＰと、その血圧値決定手段７２による血圧測定時に圧脈波センサ４６の最大圧力検出素子ＥＭにより検出された圧脈波ＰＷの大きさとの間の圧脈波血圧対応関係を、たとえば図６に示すように決定する。図６において、ＰＷｍｉｎは圧脈波ＰＷの最小値（すなわち立ち上がり点における圧脈波ＰＷの大きさ）、ＰＷｍａｘは圧脈波ＰＷの最大値（すなわちピークにおける圧脈波ＰＷの大きさ）である。なお、血圧値決定手段７２による血圧測定時とは、血圧値ＢＰを測定するためにカフ圧制御手段７０により血圧測定制御が実行されているときだけでなく、その血圧測定制御の前後の血圧値ＢＰがそれほど変動していないと見なすことができる期間も含むものとする。
【００３３】
血圧値連続決定手段８０は、上記対応関係決定手段７８で決定された圧脈波血圧対応関係を用いて、圧脈波センサ４６の最大圧力検出素子ＥＭにより逐次検出される圧脈波ＰＷの大きさから監視血圧値ＭＢＰを連続的に決定する。すなわち、上記圧脈波血圧対応関係を用いて圧脈波ＰＷの最小値ＰＷｍｉｎから監視最低血圧値ＭＢＰＤＩＡを連続的に決定し、上記圧脈波血圧対応関係を用いて圧脈波ＰＷの最大値ＰＷｍａｘから監視最高血圧値ＭＢＰＳＹＳを連続的に決定する。そして、その決定した監視最低血圧値ＭＢＰＤＩＡおよび監視最高血圧値ＭＢＰＳＹＳを表示器３４に表示する。
【００３４】
血圧異常判定手段８２は、血圧値連続決定手段８０により連続的に決定される監視最高血圧値ＭＢＰＳＹＳが予め設定された最高血圧異常判定値ＴＨＳＹＳを超えた場合、または監視最低血圧値ＭＢＰＤＩＡが予め設定された最低血圧異常判定値ＴＨＤＩＡを以下である場合に血圧異常と判定し、血圧異常であることを示す文字あるいは記号を表示器３４に表示するとともに、カフ１２による信頼性のある血圧値ＢＰを迅速に得るために、血圧値決定手段７２による血圧測定を実行させる。
【００３５】
カフ脈波検出手段８４は、血圧値決定手段７２による血圧測定時であってカフ圧ＰＣが平均血圧値ＢＰＭＥＡＮ以下とされている状態で、脈波弁別回路２４から供給されるカフ脈波ＣＷ（以下、このカフ脈波ＣＷを基準カフ脈波ＣＷｓｔという）を読み込むとともに、その血圧測定時から計測される経過時間が、キャリブレーション周期Ｔｃよりも十分に短い時間（たとえば１分乃至３分程度）に予め設定された監視精度判定周期Ｔｗを経過する毎に、カフ圧制御手段７０にカフ圧ＰＣを前記脈波検出圧ＰＭ２に制御させるための指令信号を出力し、そのカフ圧制御手段７０によりカフ圧ＰＣが脈波検出圧ＰＭ２に制御されている状態で、脈波弁別回路２４により検出されるカフ脈波ＣＷを読み込む。前述のように、血圧測定時には、カフ圧制御手段７０により血圧測定制御が実行されている時だけでなく、その血圧測定制御の前後の血圧値ＢＰがそれほど変動していないと見なすことができる期間も含まれるので、基準カフ脈波ＣＷｓｔは、カフ圧制御手段７０による血圧測定制御過程だけでなく、その血圧測定制御の前後の所定期間に読み込んだカフ脈波ＣＷであってもよい。血圧測定制御の前後に基準カフ脈波ＣＷｓｔを読み込む場合には、監視精度判定周期Ｔｗ毎にカフ脈波ＣＷを読み込む場合と同様に、カフ圧制御手段７０にカフ圧ＰＣを前記脈波検出圧ＰＭ２に制御させるための指令信号を出力して、カフ圧ＰＣを脈波検出圧ＰＭ２とした状態でカフ脈波ＣＷを読み込む。なお、本実施形態では、血圧測定制御の直後に基準カフ脈波ＣＷｓｔを読み込むものとする。
【００３６】
補正係数決定手段８６は、上記基準カフ脈波ＣＷｓｔが読み込まれた時と略同時期に圧脈波センサ４６により検出された圧脈波ＰＷ（以下、この圧脈波ＰＷを基準圧脈波ＰＷｓｔという）と、上記基準カフ脈波ＣＷｓｔとを、その大きさが同じとなるように補正するための補正係数を決定する。なお、補正係数は、カフ脈波ＣＷを補正するためのものだけを決定してもよいし、圧脈波ＰＷを補正するためのものだけを決定してもよいし、カフ脈波ＣＷおよび圧脈波ＰＷの両方を補正するために補正係数をそれぞれ決定してもよいが、本実施形態では、圧脈波ＰＷを補正するための補正係数だけを決定するものとする。図７は、基準カフ脈波ＣＷｓｔと、補正係数決定手段８６に決定された補正係数により補正された基準圧脈波ＰＷｓｔとを、立ち上がり点（最小点）を一致させた状態で示す図である。
【００３７】
比較脈波決定手段８８は、前記監視精度判定周期Ｔｗ毎に読み込まれるカフ脈波ＣＷと略同時期に圧脈波センサ４６により検出される圧脈波ＰＷを、補正係数決定手段８６により決定された補正係数により補正して比較用圧脈波ＰＷｃに決定するとともに、監視精度判定周期Ｔｗ毎に読み込まれるカフ脈波ＣＷを比較用カフ脈波ＣＷｃに決定する。ここで、カフ脈波ＣＷと略同時期に検出される圧脈波ＰＷとは、カフ脈波ＣＷに対応する圧脈波ＰＷ（すなわち同じ拍動に基づく脈波）だけでなく、カフ脈波ＣＷの検出のためにカフ圧ＰＣが脈波検出圧ＰＭ２に制御されている期間の直前や直後に検出される圧脈波ＰＷも含む意味である。
【００３８】
血圧監視精度判定手段９０は、比較脈波決定手段８８により決定された比較用圧脈波ＰＷｃと比較用カフ脈波ＣＷｃとを、それらの最小点を一致させ、比較用圧脈波ＰＷｃと比較用カフ脈波ＣＷｃのそれぞれの特徴点の大きさの差、すなわち強度差ｄを算出し、その強度差ｄが予め設定された装着異常判定値ＴＨｄを超えた場合に、圧脈波センサ４６の装着状態が不適切になったことによって血圧値連続決定手段８０により決定されている監視血圧値ＭＢＰの精度が低下したと判定し、圧脈波センサ４６の装着状態を修正するために最適押圧位置制御手段７４を再度実行させる。ここで、上記特徴点には、たとえば、ピーク、ノッチ等がある。
【００３９】
図８は、比較脈波決定手段８８により決定した比較用圧脈波ＰＷｓｔおよび比較用カフ脈波ＣＷｓｔを最小点を一致させた状態で示す図の一例であり、特徴点としてピークを選択した場合の強度差ｄが例示してある。血圧値ＢＰが変化した場合の比較用圧脈波ＰＷｃおよび比較用カフ脈波ＣＷｃのそれぞれの特徴点の大きさの変化傾向は同じであり、比較用圧脈波ＰＷｃおよび比較用カフ脈波ＣＷｃともに、血圧値ＢＰが高くなるとピークは大きくなり、逆に、血圧値ＢＰが低くなるとピークは小さくなる。また、比較用圧脈波ＰＷｃは、検出された圧脈波ＰＷが、血圧値決定手段７２による血圧測定時に基準圧脈波ＰＷｓｔの大きさを基準カフ脈波ＣＷｓｔと同じとするために決定された補正係数に基づいて補正されたものである。従って、血圧値決定手段７２による血圧測定時から血圧値ＢＰが変動していても、圧脈波センサ４６の装着状態が適切に維持され、適切な圧脈波ＰＷが検出されていれば、上記強度差ｄはそれほど大きくならないので、強度差ｄが大きくなっている場合には、圧脈波センサ４６の装着状態が不適切になったと判定できる。なお、血圧値ＢＰの変化に対する、比較圧脈波ＰＷｃの特徴点の大きさの変化傾向と比較カフ脈波ＣＷｃの特徴点の大きさの変化傾向は一致するものの、変化量までは完全には一致しないので、圧脈波センサ４６の装着状態が適切に維持されていても、強度差ｄはゼロにはならない。そのため、上記装着異常判定値ＴＨｄは、両者の変化量の違いを考慮した比較的大きな値に設定される。
【００４０】
図９乃至図１１は、図４の機能ブロック図に示したＣＰＵ３１の制御作動の要部を示すフローチャートであって、図９および図１０は圧脈波血圧対応関係を決定する対応関係決定ルーチンを示し、図１１は血圧監視ルーチンを示す。
【００４１】
まず、図９および図１０に示す対応関係決定ルーチンを説明する。図９において、ステップＳＡ１（以下、ステップを省略する。）では、圧脈波センサ４６の押圧面６２に配列された感圧素子Ｅのうち最大圧力検出素子ＥＭの配列位置が、配列の端から所定数または所定距離内側までに位置するものであるかを条件とする押圧位置更新条件（ＡＰＳ起動条件）が成立したか否かを判断する。この判断が否定された場合には、後述するＳＡ３以降を実行する。
【００４２】
一方、ＳＡ１の判断が肯定された場合、すなわち、圧脈波センサ４６の橈骨動脈５６に対する装着位置が不適切である場合には、最適押圧位置制御手段７４に相当するＳＡ２のＡＰＳ制御ルーチンを実行する。このＡＰＳ制御ル−チンでは、幅方向移動装置６０を制御することにより、圧脈波センサ４６の各圧力検出素子Ｅのうち最大振幅を検出する圧力検出素子Ｅが、圧力検出素子Ｅの配列の略中心位置になるように最適押圧位置を決定するとともに、その圧力検出素子Ｅを最大圧力検出素子ＥＭに設定する。以下の説明における圧脈波信号ＳＭ２は、このＳＡ２で決定した最大圧力検出素子ＥＭにより検出された圧脈波信号ＳＭ２を意味する。
【００４３】
前記ＳＡ１の判断が否定された場合または上記ＳＡ２を実行した場合には、続いて、押圧力制御手段７６に相当するＳＡ３のＨＤＰ制御ルーチンを実行する。すなわち、調圧弁５２を制御することにより圧脈波センサ４６の押圧力ＨＤＰを連続的に高め、その過程で前記最大圧力検出素子ＥＭによって検出される圧脈波ＰＷの振幅が最大となる押圧力を最適押圧力ＨＤＰＯに決定し、且つ、圧脈波センサ４６の押圧力ＨＤＰをその最適押圧力ＨＤＰＯに保持する。
【００４４】
続くＳＡ４では、空気ポンプ２０を起動させ、且つ、排気制御弁１６を圧力供給状態に制御することにより、カフ圧ＰＣの急速昇圧を開始する。続くＳＡ５では、カフ圧ＰＣが１８０ｍｍＨｇに設定された昇圧目標圧力値ＰＭ１を越えたか否かを判断する。この判断が否定されるうちはＳＡ５の判断を繰り返し実行し、カフ圧ＰＣの急速昇圧を継続する。一方、ＳＡ５の判断が肯定された場合には、ＳＡ６において、空気ポンプ２０を停止させ、且つ、排気制御弁１６を徐速排圧状態に切り替えることにより、カフ圧ＰＣの３ｍｍＨｇ／ｓｅｃ程度での徐速降圧を開始する。
【００４５】
続いて血圧値決定手段７２に相当するＳＡ７乃至ＳＡ９を実行する。ＳＡ７では、カフ圧ＰＣの徐速降圧過程で逐次得られるカフ脈波信号ＳＭ１が表すカフ脈波ＣＷの振幅の変化およびその振幅発生時のカフ圧ＰＣに基づいて、良く知られたオシロメトリック方式の血圧測定アルゴリズムに従って最高血圧値ＢＰＳＹＳ、平均血圧値ＢＰＭＥＡＮ、および最低血圧値ＢＰＤＩＡを決定する。続くＳＡ８では、上記ＳＡ７において血圧値ＢＰの決定が完了したか否かを判断する。このＳＡ８の判断が否定されるうちは、ＳＡ７以下を繰り返し実行し、血圧測定アルゴリズムを継続する。
【００４６】
血圧値ＢＰの決定が完了してＳＡ８の判断が肯定されると、続くＳＡ９では、ＳＡ７乃至ＳＡ８の繰り返しにより決定した最高血圧値ＢＰＳＹＳ等を表示器３４に表示する。続いて図１０に示すＳＡ１０以降を実行する。
【００４７】
ＳＡ１０では、ＳＡ７で決定した最低血圧値ＢＰＤＩＡから、１０ｍｍＨｇ程度に設定された所定値αを引くことにより脈波検出圧ＰＭ２を決定する。そして、続くＳＡ１１では、カフ圧ＰＣを上記ＳＡ１０で決定した脈波検出圧ＰＭ２に制御する。続くＳＡ１２では、その状態で、脈波弁別回路２４から供給されるカフ脈波信号ＳＭ１（すなわちカフ脈波ＣＷ）および圧脈波センサ４６から供給される圧脈波信号ＳＭ２（すなわち圧脈波ＰＷ）をそれぞれ一拍分ずつ読み込む。なお、このＳＡ１２で読み込んだカフ脈波ＣＷおよび圧脈波ＰＷが基準カフ脈波ＣＷｓｔおよび基準圧脈波ＰＷｓｔに相当する。そして、続くＳＡ１３では、排気制御弁１６を急速排圧状態に切り替えることによりカフ圧ＰＣを大気圧まで急速に排圧する。なお、図９乃至図１０のフローチャートでは、ＳＡ４乃至ＳＡ６およびこのＳＡ１３がカフ圧制御手段７０の血圧測定制御に相当する。
【００４８】
続くＳＡ１４は対応関係決定手段７８に相当し、ＳＡ７で決定した最高血圧値ＢＰＳＹＳと最低血圧値ＢＰＤＩＡ、およびＳＡ１２で読み込んだ圧脈波ＰＷの最大値ＰＷｍａｘと最小値ＰＷｍｉｎから、図６に示す圧脈波血圧対応関係を決定する。
【００４９】
そして、補正係数決定手段８６に相当するＳＡ１５では、ＳＡ１２で読み込んだ基準圧脈波ＰＷｓｔの大きさを、同じくＳＡ１２で読み込んだ基準カフ脈波ＣＷｓｔの大きさと等しくするための補正係数を決定する。
【００５０】
続いて図１１に示す血圧監視ルーチンを説明する。まず、ＳＢ１では、圧脈波センサ４６から供給される圧脈波ＰＷを一拍分読み込む。そして続くＳＢ２では、ＳＢ１で読み込んだ圧脈波ＰＷの最小値ＰＷｍｉｎおよび最大値ＰＷｍａｘから、図１０のＳＡ１４で決定した圧脈波血圧対応関係に基づいて、監視最低血圧値ＭＢＰＤＩＡおよび監視最高血圧値ＭＢＰＳＹＳを決定し、その決定した監視最低血圧値ＭＢＰＤＩＡおよび監視最高血圧値ＭＢＰＳＹＳを表示器３４に表示する。
【００５１】
続くＳＢ３では、上記ＳＢ２で決定した監視最高血圧値ＭＢＰＳＹＳが予め設定された最高血圧異常判定値ＴＨＳＹＳを超えているか否か、または上記ＳＢ２で決定した監視最低血圧値ＭＢＰＤＩＡが予め設定された最低血圧異常判定値ＴＨＤＩＡ以下であるか否かを判断する。この判断が肯定された場合には血圧が異常である可能性が高いので、カフ１０による信頼性の高い血圧値ＢＰを迅速に得るために、前述の対応関係決定ルーチンを再度実行する。
【００５２】
一方、ＳＢ３の判断が否定された場合には、続くＳＢ４において、対応関係決定ルーチンが実行されて圧脈波血圧対応関係が決定されてからの経過時間が、１０分乃至３０分程度に設定されたキャリブレーション周期Ｔｃを経過したか否かをさらに判断する。この判断が肯定された場合にも前述の対応関係決定ルーチンを再度実行する。
【００５３】
一方、ＳＢ４の判断が否定された場合には、続くＳＢ５において、後述するＳＢ６以下を実行してからの経過時間が、１分乃至３分程度に設定された監視精度判定周期Ｔｗを経過したか否かを判断する。この判断が否定された場合には、前記ＳＢ１以下を繰り返し実行して、一拍毎に監視血圧値ＭＢＰを決定する。
【００５４】
ＳＢ５の判断が肯定された場合には、ＳＢ６以下を実行して監視血圧値ＭＢＰの精度を判定する。まず、ＳＢ６では、カフ圧ＰＣをＳＡ１０で決定した脈波検出圧ＰＭ２に制御する。なお、このＳＢ６がカフ圧制御手段７０の脈波検出圧制御に相当する。
【００５５】
そして、続くＳＢ７では、カフ圧ＰＣが脈波検出圧ＰＭ２に制御されている状態で、脈波弁別回路２４から供給されるカフ脈波信号ＳＭ１すなわちカフ脈波ＣＷを一拍分読み込むとともに、圧脈波センサ４６から供給される圧脈波信号ＳＭ２すなわち圧脈波ＰＷを一拍分読み込む。なお、図９乃至図１１に示すフローチャートでは、ＳＡ１１およびＳＢ７がカフ脈波検出手段８４に相当する。
【００５６】
続くＳＢ８乃至ＳＢ９は前記ＳＢ２乃至ＳＢ３と同様の処理であり、ＳＢ８では、上記ＳＢ７で読み込んだ圧脈波ＰＷに基づいて、監視最低血圧値ＭＢＰＤＩＡおよび監視最高血圧値ＭＢＰＳＹＳを決定し、その決定した監視最低血圧値ＭＢＰＤＩＡおよび監視最高血圧値ＭＢＰＳＹＳを表示器３４に表示し、ＳＢ９では、ＳＢ８で決定した監視最高血圧値ＭＢＰＳＹＳが予め設定された最高血圧異常判定値ＴＨＳＹＳを超えているか否か、またはＳＢ８で決定した監視最低血圧値ＭＢＰＤＩＡが予め設定された最低血圧異常判定値ＴＨＤＩＡ以下であるか否かを判断する。ＳＢ９の判断が肯定された場合には、前述の対応関係決定ルーチンを再度実行する。なお、図１１では、ＳＢ２およびＳＢ８が血圧値連続決定手段８０に相当し、ＳＢ３およびＳＢ９が血圧異常判定手段８２に相当する。
【００５７】
一方、ＳＢ９の判断が否定された場合には、比較脈波決定手段８８に相当するＳＢ１０において、前記ＳＢ７で読み込んだカフ脈波ＣＷをそのまま比較用カフ脈波ＣＷｃに決定するとともに、ＳＢ７で読み込んだ圧脈波ＰＷをＳＡ１５で決定した補正係数を用いて補正して比較用圧脈波ＰＷｃを決定する。
【００５８】
続いて血圧監視精度判定手段９０に相当するＳＢ１１乃至ＳＢ１２を実行する。まず、ＳＢ１１では、ＳＢ１０で決定した比較用カフ脈波ＣＷｃと比較用圧脈波ＰＷｃとを、それらの最小点を一致させ、その状態でピーク差すなわち強度差ｄを算出する。そして、続くＳＢ１２では、ＳＢ１１で算出した強度差ｄが予め設定された装着異常判定値ＴＨｄを超えているか否かを判断する。この判断が否定された場合には、監視血圧値ＭＢＰの精度は維持されていると考えられるので、前記ＳＢ１以下を繰り返し実行することにより、監視血圧値ＭＢＰに基づく血圧監視を継続する。しかし、肯定された場合には、圧脈波センサ４６の装着状態が不適切となっている可能性が高いので、圧脈波センサ４６の装着状態を修正するために、前記対応関係決定ルーチンを再度実行する。
【００５９】
上述の実施形態によれば、血圧監視精度判定手段９０（ＳＢ１１乃至ＳＢ１２）により、圧脈波センサ４６によって検出される圧脈波ＰＷと、カフ圧ＰＣが最低血圧値ＭＢＰＤＩＡより低い圧力で検出されるカフ脈波ＣＷとが比較されて、血圧値連続決定手段８０（ＳＢ２、ＳＢ８）により連続的に決定される監視血圧値ＭＢＰの精度が判定されることから、監視血圧値ＭＢＰの精度を維持するために、カフ１０を用いた血圧測定を短い周期で行って圧脈波血圧対応関係を頻繁に更新する必要がなくなるので、患者の負担が軽減する。
【００６０】
次に、本発明の第２の実施形態を説明する。なお、以下の説明において、前述の実施形態と同一の構成を有する部分には同一の符号を付して説明を省略する。
【００６１】
第２の実施形態が前述の第１の実施形態と異なる点は、血圧監視精度判定手段における監視血圧値ＭＢＰの精度の判定の仕方のみであり、第１実施形態では、比較用圧脈波ＰＷｃの特徴点と比較用カフ脈波ＣＷｃの特徴点の大きさを比較していたいが、第２実施形態の血圧監視精度判定手段（符号を９２とする）では、比較用圧脈波ＰＷｃの形状と比較用カフ脈波ＣＷｃの形状とを比較することで、監視血圧値ＭＢＰの精度を判定する。以下、血圧監視精度判定手段９２について詳しく説明する。
【００６２】
血圧監視精度判定手段９２は、補正係数決定手段８６において補正係数の決定のために用いた基準圧脈波ＰＷｓｔと基準カフ脈波ＣＷｓｔとを、それらの最小点を一致させた状態で、図１２に示すように時間軸に垂直に複数の脈波区分Ｃ（ｎ）（ｎ＝１，２，…）に分割し（図１２では１０の区分）、それら複数の脈波区分Ｃ（ｎ）毎に基準圧脈波ＰＷｓｔと基準カフ脈波ＣＷｓｔとの基準面積差ΔＡｓｔ（ｎ）（ｎ＝１，２，…）を算出する。そして、同様にして、監視精度判定周期Ｔｗ毎に比較脈波決定手段８８により決定された比較用圧脈波ＰＷｃと比較用カフ脈波ＣＷｃについても、脈波区分Ｃ（ｎ）毎に面積差ΔＡ（ｎ）（ｎ＝１，２，…）を算出し、基準面積差ΔＡｓｔ（ｎ）に対する監視精度判定周期Ｔｗ毎に算出した面積差ΔＡ（ｎ）の変化量（以下、面積差変化量Ｑ（ｎ）（ｎ＝１，２，…）という）を算出し、その面積差変化量Ｑ（ｎ）が予め実験に基づいて設定された基準値を超えている脈波区分Ｃ（ｎ）の数を決定する。面積差変化量Ｑ（ｎ）が上記基準値を超えている脈波区分Ｃ（ｎ）の数が多い場合には、カフ脈波ＣＷの形状と圧脈波ＰＷの形状との違いが血圧測定時よりも大きくなっていることを意味するので、圧脈波センサ４６の装着状態が不適切になったことによって形状や大きさ（またはその両方）が不適切な圧脈波ＰＷが検出されていると考えられる。従って、面積差変化量Ｑ（ｎ）が上記基準値を超えている脈波区分Ｃ（ｎ）の数が予め設定された第１判定基準区分数Ｎｃ１を超えている場合には、血圧値連続決定手段８０により決定されている監視血圧値ＭＢＰの精度が低下したと判定し、圧脈波センサ４６の装着状態を修正するために最適押圧位置制御手段７４を再度実行させる。
【００６３】
また、血圧監視精度判定手段９２は、面積差ΔＡ（ｎ）の変化傾向に基づいても、監視血圧値ＭＢＰの精度を判定する。すなわち、監視精度判定周期Ｔｗ毎に算出した脈波区分Ｃ（ｎ）毎の面積差ΔＡ（ｎ）を、それぞれ基準面積差ΔＡｓｔ（ｎ）と比較して、面積差ΔＡ（ｎ）の変化傾向が増加である脈波区分Ｃ（ｎ）の数と、面積差ΔＡ（ｎ）の変化傾向が減少である脈波区分Ｃ（ｎ）の数とを決定し、面積差ΔＡ（ｎ）の変化傾向が増加である脈波区分Ｃ（ｎ）の数、または、面積差ΔＡ（ｎ）の変化傾向が減少である脈波区分Ｃ（ｎ）の数が、全脈波区分の大部分の割合（たとえば８割〜９割）に設定された第２判定基準区分数Ｎｃ２を超えているか否かを判断する。この判断は、脈波区分Ｃ（ｎ）毎に算出した面積差ΔＡ（ｎ）の変化傾向が略一致するかどうかを判断するものである。脈波区分Ｃ（ｎ）毎の面積差ΔＡ（ｎ）の変化傾向が略一致しない場合には、圧脈波センサ４６の装着状態が不適切になったことによって圧脈波ＰＷの形状に歪みが生じていることが考えられるので、上記判断が否定された場合にも、血圧値連続決定手段８０により決定されている監視血圧値ＭＢＰの精度が低下したと判定し、圧脈波センサ４６の装着状態を修正するために最適押圧位置制御手段７４を再度実行させる。
【００６４】
図１３および図１４は、第２の実施形態に係るＣＰＵ３１の制御作動の要部を示すフローチャートであって、図１３は対応関係決定ルーチンの一部を示し、図１４は血圧監視ルーチンの一部を示す。
【００６５】
まず、図１３を説明する。第２の実施形態においても、対応関係決定ルーチンは、前述の図９乃至図１０と同様に、ＳＡ１乃至ＳＡ１５を実行する。さらに、第２実施形態では、ＳＡ１５に続くＳＡ１６において、ＳＡ１２で読み込んだ基準カフ脈波ＣＷｓｔと基準圧脈波ＰＷｓｔとを、互いの最小点を一致させた状態で、複数の脈波区分Ｃ（ｎ）（たとえば図１２に示すように１０の区分）に分割し、その脈波区分Ｃ（ｎ）毎に基準圧脈波ＰＷｓｔと基準カフ脈波ＣＷｓｔとの基準面積差ΔＡｓｔ（ｎ）を算出する。
【００６６】
次に、図１４を説明する。第２の実施形態においても、血圧監視ルーチンでは、前述の図１１のＳＢ１乃至ＳＢ１０を実行する。そして、ＳＢ１０に続くＳＣ１１では、ＳＢ１０で決定した比較用カフ脈波ＣＷｃと比較用圧脈波ＰＷｃとを互いの最小点を一致させ、図１３のＳＡ１６と同様にして脈波区分Ｃ（ｎ）毎に面積差ΔＡ（ｎ）を算出する。
【００６７】
続くＳＣ１２では、脈波区分Ｃ（ｎ）毎に、上記ＳＣ１１で算出した面積差ΔＡ（ｎ）から図１３のＳＡ１６で算出した基準面積差ΔＡｓｔ（ｎ）を引くことにより、面積差変化量Ｑ（ｎ）を算出する。続くＳＣ１３では、ＳＣ１２で算出した脈波区分Ｃ（ｎ）毎に算出した面積差変化量Ｑ（ｎ）が予め設定された基準値を超えている脈波区分Ｃ（ｎ）の数を決定する。
【００６８】
そして、続くＳＣ１４では、上記ＳＣ１３で決定した脈波区分Ｃ（ｎ）の数が、予め設定された第１判定基準区分数Ｎｃ１を超えているか否かを判断する。この判断が肯定された場合には、圧脈波センサ４６の装着状態が不適切となっている可能性が高いので、圧脈波４６の装着状態を修正するために、対応関係決定ルーチンを実行する。
【００６９】
ＳＣ１４の判断が否定された場合には、続くＳＣ１５において、図１３のＳＡ１６で決定した基準面積差ΔＡｓｔ（ｎ）に対する、ＳＣ１１で決定した面積差ΔＡ（ｎ）の変化傾向を脈波区分Ｃ（ｎ）毎に決定する。
【００７０】
そして、続くＳＣ１６では、ＳＣ１５で決定した面積差ΔＡ（ｎ）の変化傾向が、増加傾向である脈波区分Ｃ（ｎ）の数および減少傾向である脈波区分Ｃ（ｎ）の数を決定し、いずれか一方の数が予め設定された第２判定基準区分数Ｎｃ２を超えているか否かを判断することにより、脈波区分Ｃ（ｎ）毎に決定した面積差ΔＡ（ｎ）の変化傾向が略一致しているか否かを判断する。この判断が否定された場合にも、圧脈波センサ４６の装着状態が不適切となっている可能性が高いので、圧脈波センサ４６の装着状態を修正するために、対応関係決定ルーチンを実行する。一方、ＳＣ１６の判断が肯定された場合には、監視血圧値ＭＢＰの精度は維持されていると考えられるので、ＳＢ１以下を繰り返し実行することにより、監視血圧値ＭＢＰに基づく血圧監視を継続する。なお、図１３および図１４に示したフローチャートでは、ＳＡ１６およびＳＣ１１乃至ＳＣ１６が血圧監視精度判定手段９２に相当する。
【００７１】
上述の第２の実施形態でも、血圧監視精度判定手段９２（ＳＡ１６、ＳＣ１１乃至ＳＣ１６）により、圧脈波センサ４６によって検出される圧脈波ＰＷと、カフ圧ＰＣが最低血圧値ＭＢＰＤＩＡより低い圧力で検出されるカフ脈波ＣＷとが比較されて、血圧値連続決定手段８０（ＳＢ２、ＳＢ８）により連続的に決定される監視血圧値ＭＢＰの精度が判定されることから、監視血圧値ＭＢＰの精度を維持するために、カフ１０を用いた血圧測定を短い周期で行って圧脈波血圧対応関係を頻繁に更新する必要がなくなるので、患者の負担が軽減する。
【００７２】
次に、本発明の第３の実施形態を説明する。第３の実施形態が第１の実施形態と異なるのは、ＣＰＵ３１の制御機能のみである。図１５は、第３の実施形態に係るＣＰＵ３１の制御機能の要部を示す機能ブロック図である。図１５に示す機能ブロック図が、第１実施形態の機能ブロック図である図４と異なるのは、補正係数決定手段８６、比較脈波決定手段８８が設けられていないこと、および、血圧監視精度判定手段９４における監視血圧値ＭＢＰの精度判定機能のみである。
【００７３】
血圧監視精度判定手段９４は、カフ脈波検出手段８４により血圧測定時に検出された基準カフ脈波ＣＷｓｔの面積、すなわち基準カフ脈波面積Ｃ＿ａｒｅａ（ｓｔ）、およびその基準カフ脈波ＣＷｓｔが検出された時と略同時期に圧脈波センサ４６により検出された圧脈波ＰＷである基準圧脈波ＰＷｓｔの面積、すなわち基準圧脈波面積Ｔ＿ａｒｅａ（ｓｔ）とを算出し、その基準カフ脈波面積Ｃ＿ａｒｅａ（ｓｔ）と基準圧脈波面積Ｔ＿ａｒｅａ（ｓｔ）との面積比すなわち基準脈波面積比ＲＡ（ｓｔ）を算出する。そして、同様にして、監視精度判定周期Ｔｗ毎に検出されるカフ脈波ＣＷおよびそのカフ脈波ＣＷに対応する圧脈波ＰＷについても、カフ脈波面積Ｃ＿ａｒｅａおよび圧脈波面積Ｔ＿ａｒｅａを算出し、そのカフ脈波面積Ｃ＿ａｒｅａと圧脈波面積Ｔ＿ａｒｅａとの脈波面積比ＲＡを算出する。さらに、基準脈波面積比ＲＡ（ｓｔ）に対する脈波面積比ＲＡの変化率（面積比変化率）δＲＡを算出する。なお、基準脈波面積比ＲＡ（ｓｔ）および脈波面積比ＲＡは、カフ脈波面積Ｃ＿ａｒｅａおよび圧脈波面積Ｔ＿ａｒｅａのいずれが分母であってもよいが、たとえば、カフ脈波面積Ｃ＿ａｒｅａを分母とすると、基準脈波面積比ＲＡ（ｓｔ）は式１で表され、脈波面積比ＲＡは式２で表され、面積比変化率δＲＡは式３で表される。
（式１）　ＲＡ（ｓｔ）＝Ｔ＿ａｒｅａ（ｓｔ）／Ｃ＿ａｒｅａ（ｓｔ）
（式２）　ＲＡ＝Ｔ＿ａｒｅａ／Ｃ＿ａｒｅａ
（式３）　δＲＡ＝（Ｔ＿ａｒｅａ／Ｃ＿ａｒｅａ）／（Ｔ＿ａｒｅａ（ｓｔ）／Ｃ＿ａｒｅａ（ｓｔ））
式３は、変形すると式４の形とすることもできる。
（式４）　δＲＡ＝（Ｔ＿ａｒｅａ／Ｔ＿ａｒｅａ（ｓｔ））／（Ｃ＿ａｒｅａ／Ｃ＿ａｒｅａ（ｓｔ））
式４は、カフ脈波面積Ｃ＿ａｒｅａの変化率に対する圧脈波面積Ｔ＿ａｒｅａの変化率を表していることから、面積比変化率δＲＡが１から大きく外れる場合には、カフ脈波面積Ｃ＿ａｒｅａと圧脈波面積Ｔ＿ａｒｅａとの違いが血圧測定時とは大きく異なっていることを意味するので、圧脈波センサ４６の装着状態が不適切になったことによって不適切な大きさの圧脈波ＰＷが検出されていると考えられる。従って、面積比変化率δＲＡが１を含む範囲に予め設定された正常範囲内の値でない場合には、血圧値連続決定手段８０により決定されている監視血圧値ＭＢＰの精度が低下したと判定し、圧脈波センサ４６の装着状態を修正するために最適押圧位置制御手段７４を再度実行する。
【００７４】
また、血圧監視精度判定手段９４は、カフ脈波面積Ｃ＿ａｒｅａおよび圧脈波面積Ｔ＿ａｒｅａの変化傾向に基づいても、監視血圧値ＭＢＰの精度を判定する。すなわち、監視精度判定周期Ｔｗ毎に算出したカフ脈波面積Ｃ＿ａｒｅａを前回の監視精度判定周期Ｔｗ経過時に算出したカフ脈波面積Ｃ＿ａｒｅａと比較してその変化傾向を決定するとともに、圧脈波面積Ｔ＿ａｒｅａについても前回の監視精度判定周期Ｔｗ時からの変化傾向を決定し、両者の変化傾向が一致するかどうかを判断する。圧脈波センサ４６の装着状態が適切な状態に維持されていれば、両者の変化傾向が一致するはずであるので、両者の変化傾向が一致しない場合にも、血圧値連続決定手段８０により決定されている監視血圧値ＭＢＰの精度が低下したと判定し、圧脈波センサ４６の装着状態を修正するために最適押圧位置制御手段７４を再度実行させる。
【００７５】
図１６および図１７は、第３の実施形態に係るＣＰＵ３１の制御作動の要部を示すフローチャートであって、図１６は対応関係決定ルーチンの一部を示し、図１７は血圧監視ルーチンの一部を示す。
【００７６】
まず、図１６を説明する。第３の実施形態においても、対応関係決定ルーチンでは、ＳＡ１乃至ＳＡ１３を実行する。そして、ＳＡ１３に続くＳＤ１４では、ＳＡ１２で読み込んだ基準カフ脈波ＣＷｓｔから基準カフ脈波面積Ｃ＿ａｒｅａ（ｓｔ）を算出し、ＳＤ１５では、ＳＡ１２で読み込んだ基準圧脈波ＰＷｓｔから基準圧脈波面積Ｔ＿ａｒｅａ（ｓｔ）を算出する。そして、続くＳＤ１６では、ＳＤ１５で算出した基準圧脈波面積Ｔ＿ａｒｅａ（ｓｔ）をＳＤ１４で算出した基準カフ脈波面積Ｃ＿ａｒｅａ（ｓｔ）で割ることにより、基準脈波面積比ＲＡ（ｓｔ）を算出する。
【００７７】
次に図１７を説明する。第３の実施形態においても、血圧監視ルーチンでは、前述の図１１のＳＢ１乃至ＳＢ９を実行する。そして、ＳＢ９に続くＳＥ１０では、ＳＢ７で読み込んだカフ脈波ＣＷの面積すなわちカフ脈波面積Ｃ＿ａｒｅａを算出し、続くＳＥ１１では、ＳＢ７で読み込んだ圧脈波ＰＷの面積すなわち圧脈波面積Ｔ＿ａｒｅａを算出する。
【００７８】
続くＳＥ１２では、ＳＥ１１で算出した圧脈波面積Ｔ＿ａｒｅａをＳＥ１０で算出したカフ脈波面積Ｃ＿ａｒｅａで割ることにより、脈波面積比ＲＡを算出する。続くＳＥ１３では、ＳＥ１２で算出した面積比ＲＡを、図１６のＳＤ１６で算出した基準面積比ＲＡ（ｓｔ）で割ることにより面積比変化率δＲＡを算出する。
【００７９】
続くＳＥ１４では、ＳＥ１３で算出した面積比変化率δＲＡが、１を含む範囲に予め設定された正常範囲内の値であるか否かを判断する。この判断が否定された場合には、圧脈波センサ４６の装着状態が不適切となっている可能性が高いので、圧脈波センサ４６の装着状態を修正するために、前述の対応関係決定ルーチンを再度実行する。
【００８０】
一方、ＳＥ１４の判断が肯定された場合には、ＳＥ１５において、前記ＳＥ１０で算出したカフ脈波面積Ｃ＿ａｒｅａの前回算出したカフ脈波面積Ｃ＿ａｒｅａに対する変化傾向と、前記ＳＥ１１で算出した圧脈波面積Ｔ＿ａｒｅａの前回算出した圧脈波面積Ｔ＿ａｒｅａに対する変化傾向とを比較して、両者の変化傾向が異なるか否かを判断する。この判断が肯定された場合、すなわち、両者の変化傾向が異なっている場合にも、圧脈波センサ４６の装着状態が不適切となっている可能性が高いので、前述の対応関係決定ルーチンを再度実行する。
【００８１】
一方、ＳＥ１５の判断が否定された場合には、監視血圧値ＭＢＰの精度は維持されていると考えられるので、ＳＢ１以下を繰り返し実行することにより、監視血圧値ＭＢＰに基づく血圧監視を継続する。なお、図１６および図１７に示したフローチャートでは、ＳＤ１４乃至ＳＤ１６およびＳＥ１０乃至ＳＥ１５が血圧監視精度判定手段９４に相当する。
【００８２】
上述の第３の実施形態でも、血圧監視精度判定手段９４（ＳＤ１４乃至ＳＤ１６、ＳＥ１０乃至ＳＥ１５）により、圧脈波センサ４６によって検出される圧脈波ＰＷと、カフ圧ＰＣが最低血圧値ＭＢＰＤＩＡより低い圧力で検出されるカフ脈波ＣＷとが比較されて、血圧値連続決定手段８０（ＳＢ２、ＳＢ８）により連続的に決定される監視血圧値ＭＢＰの精度が判定されることから、監視血圧値ＭＢＰの精度を維持するために、カフ１０を用いた血圧測定を短い周期で行って圧脈波血圧対応関係を頻繁に更新する必要がなくなるので、患者の負担が軽減する。
【００８３】
次に、本発明の第４の実施形態を説明する。第４の実施形態が前述の第３の実施形態と異なる点は、血圧監視精度判定手段における監視血圧値ＭＢＰの精度の判定の仕方のみであり、第３実施形態では、カフ脈波面積Ｔ＿ａｒｅａと圧脈波面積Ｔ＿ａｒｅａとの比較に基づいて監視血圧値ＭＢＰの精度を判定していたが、第４実施形態の血圧監視精度判定手段（符号を９６とする）では、カフ脈波ＣＷと圧脈波ＰＷとにより描かれる波形相関図形に基づいて監視血圧値ＭＢＰの精度を判定する。以下、血圧監視精度判定手段９６について詳しく説明する。
【００８４】
血圧監視精度判定手段９６は、まず、カフ脈波検出手段８４により血圧測定時に検出された基準カフ脈波ＣＷｓｔの大きさと、その基準カフ脈波ＣＷｓｔが検出された時と略同時期に圧脈波センサ４６により検出された圧脈波ＰＷである基準圧脈波ＰＷｓｔの大きさとから、図１８に例示するような基準波形相関図形を作成して、その基準波形相関図形の膨らみ長さ（以下、基準膨らみ長さという）Ｌｓｔを決定する。そして、同様にして、監視精度判定周期Ｔｗ毎に検出されるカフ脈波ＣＷおよびそのカフ脈波ＣＷに対応する圧脈波ＰＷについても、波形相関図形を作成して、その波形相関図形の膨らみ長さＬを決定する。上記波形相関図形（または基準波形相関図形）は、以下のようにして作成される。すなわち、圧脈波ＰＷおよびカフ脈波ＣＷは、所定のサンプリング周期毎に採取される圧脈波信号ＳＭ２またはカフ脈波信号ＳＭ１の集合であることから、圧脈波ＰＷとカフ脈波ＣＷとを互いの最小点を一致させ、圧脈波ＰＷの大きさを表す軸９８とカフ脈波ＣＷの大きさを表す軸１００とからなる二次元グラフ１０２に、同じ時点における圧脈波信号ＳＭ２とカフ脈波信号ＳＭ１とにより定まる位置に点を順次プロットしていくことにより作成される。また、膨らみ長さＬは、波形相関図形の最小点ａと最大点ｂとを結ぶ直線Ｓ１に垂直で、且つ、その直線Ｓ１の中点を通る直線Ｓ２が、波形相関図形と交わる２点ｄ，ｅ間の長さである。
【００８５】
さらに、血圧監視精度判定手段９６は、監視精度判定周期Ｔｗ毎に決定する膨らみ長さＬと基準膨らみ長さＬｓｔとの差ｄＬを算出する。圧脈波ＰＷの形状とカフ脈波ＣＷの形状とが似ているほど、波形相関図形の膨らみ長さＬは小さくなり、圧脈波ＰＷの形状とカフ脈波ＣＷの形状とが完全に一致する場合には、波形相関図形は直線Ｓ１となって膨らみ長さＬはゼロとなることから、膨らみ長さの差ｄＬが大きい場合には、圧脈波ＰＷとカフ脈波ＣＷとの形状の違いが血圧測定時とは大きく異なっていることを意味するので、圧脈波センサ４６の装着状態が不適切になったことによって正確な形状の圧脈波ＰＷが検出されなくなっていると考えられる。従って、血圧監視精度判定手段９６は、膨らみ長さの差ｄＬが所定の判定基準値ＴＨｄＬを超えた場合に、血圧値連続決定手段８０により決定されている監視血圧値ＭＢＰの精度が低下したと判定し、圧脈波センサ４６の装着状態を修正するために最適押圧位置制御手段７４を再度実行する。
【００８６】
図１９および図２０は、第４の実施形態に係るＣＰＵ３１の制御作動の要部を示すフローチャートであって、図１９は対応関係決定ルーチンの一部を示し、図２０は血圧監視ルーチンの一部を示す。
【００８７】
まず、図１９を説明する。第４の実施形態においても、対応関係決定ルーチンでは、ＳＡ１乃至ＳＡ１３を実行する。そして、ＳＡ１３に続くＳＦ１４では、ＳＡ１２で読み込んだ基準カフ脈波ＣＷｓｔおよび基準圧脈波ＰＷｓｔに基づいて、基準波形相関図形を決定し、続くＳＦ１５では、ＳＦ１４で決定した基準波形相関図形の膨らみ長さすなわち基準膨らみ長さＬｓｔを決定する。
【００８８】
次に図２０を説明する。第４の実施形態においても、血圧監視ルーチンでは、前述の図１１のＳＢ１乃至ＳＢ９を実行する。そして、ＳＢ９に続くＳＧ１０では、ＳＢ７で読み込んだカフ脈波ＣＷおよび圧脈波ＰＷに基づいて波形相関図形を決定し、続くＳＧ１１では、ＳＧ１０で決定した波形相関図形の膨らみ長さＬを決定する。
【００８９】
続くＳＧ１２では、ＳＧ１１で算出した膨らみ長さＬから、図１９のＳＦ１５で決定した基準膨らみ長さＬｓｔを引くことにより、膨らみ長さの差ｄＬを算出する。そして、ＳＧ１３では、その膨らみ長さの差ｄＬが予め設定された判定基準値ＴＨｄＬを超えているか否かを判断する。この判断が肯定された場合には、圧脈波センサ４６の装着状態が不適切となっている可能性が高いので、圧脈波センサ４６の装着状態を修正するために、前述の対応関係決定ルーチンを再度実行する。
【００９０】
一方、ＳＧ１３の判断が否定された場合には、監視血圧値ＭＢＰの精度は維持されていると考えられるので、ＳＢ１以下を繰り返し実行することにより、監視血圧値ＭＢＰに基づく血圧監視を継続する。なお、図１９および図２０に示したフローチャートでは、ＳＦ１４乃至ＳＦ１５およびＳＧ１０乃至ＳＧ１３が血圧監視精度判定手段９６に相当する。
【００９１】
上述の第４の実施形態でも、血圧監視精度判定手段９６（ＳＦ１４乃至ＳＦ１５、ＳＧ１０乃至ＳＧ１３）により、圧脈波センサ４６によって検出される圧脈波ＰＷと、カフ圧ＰＣが最低血圧値ＭＢＰＤＩＡより低い圧力で検出されるカフ脈波ＣＷとが比較されて、血圧値連続決定手段８０（ＳＢ２、ＳＢ８）により連続的に決定される監視血圧値ＭＢＰの精度が判定されることから、監視血圧値ＭＢＰの精度を維持するために、カフ１０を用いた血圧測定を短い周期で行って圧脈波血圧対応関係を頻繁に更新する必要がなくなるので、患者の負担が軽減する。
【００９２】
以上、本発明の実施形態を図面に基づいて詳細に説明したが、本発明はその他の態様においても適用される。
【００９３】
たとえば、前述の実施形態において、さらに、圧脈波センサ４６により連続的に検出される圧脈波ＰＷを表示器３４に表示するようになっていてもよい。なお、圧脈波検出プローブ３６がカフ１０の下流部位に装着されている場合には、カフ１０による血圧測定が実行されると圧脈波ＰＷは一時的に検出できなくなるので、圧脈波ＰＷの連続表示も一時的に途切れることになるが、前述の実施形態では、カフ１０を用いた血圧測定がそれほど頻繁に行われないことから、圧脈波ＰＷが連続的に表示される期間も長くなる。
【００９４】
また、前述の第１、第２の実施形態では、補正係数は、基準カフ脈波ＣＷｓｔの大きさと基準圧脈波ＰＷｓｔの大きさとを同じにするためのものであったが、その補正係数に加えて、基準カフ脈波ＣＷｓｔの周期と基準圧脈波ＰＷｓｔの周期とを同じにするための補正係数が決定されてもよい。
【００９５】
また、前述の第１の実施形態では、比較用カフ脈波の特徴点と比較用圧脈波の特徴点との位置の比較は、大きさ成分のみであったが、それに加えて、あるいは、それに代えて、周期成分（時間成分）を比較してもよい。
【００９６】
また、前述の第２の実施形態では、面積差変化量Ｑ（ｎ）が基準値を超えている脈波区分Ｃ（ｎ）の数に基づいて監視血圧値ＭＢＰの精度を判定するとともに、面積差ΔＡ（ｎ）の変化傾向に基づいても監視血圧値ＭＢＰの精度を判定していたが、いずれか一方のみでもよい。
【００９７】
また、前述の第３の実施形態では、カフ脈波面積Ｃ＿ａｒｅａと圧脈波面積Ｔ＿ａｒｅａとの面積比（脈波面積比）ＲＡの変化率すなわち面積比変化率δＲＡに基づいて監視血圧値ＭＢＰの精度を判定するとともに、カフ脈波面積Ｃ＿ａｒｅａの変化傾向と圧脈波面積Ｔ＿ａｒｅａの変化傾向に基づいても監視血圧値ＭＢＰの精度を判定していたが、いずれか一方のみでもよい。
【００９８】
また、前述の第２の実施形態では、カフ脈波ＣＷおよび圧脈波ＰＷを複数の脈波区分Ｃ（ｎ）に分割して、その脈波区分Ｃ（ｎ）毎に面積差ΔＡ（ｎ）を算出することにより、カフ脈波ＣＷの形状と圧脈波ＰＷの形状とを比較していたが、カフ脈波ＣＷと圧脈波ＰＷの相互相関係数を算出することによって、カフ脈波ＣＷの形状と圧脈波ＰＷの形状とを比較してもよい。
【００９９】
また、前述の第４の実施形態では、波形相関図形の膨らみ長さＬに基づいて監視血圧値ＭＢＰの精度を判定していたが、波形相関図形の面積に基づいて監視血圧値ＭＢＰの精度を判定してもよい。
【０１００】
また、第１実施形態および第２実施形態では、検出された圧脈波ＰＷを補正して一組の比較用脈波を決定し、その一組の比較用脈波に基づいて監視血圧値ＭＢＰの精度を判定する一方で、第３実施形態および第４実施形態では、検出されたカフ脈波ＣＷおよび圧脈波ＰＷをともに補正しないでそのまま用いて監視血圧値ＭＢＰの精度を判定していたが、第１実施形態および第２実施形態において、検出されたカフ脈波ＣＷおよび圧脈波ＰＷをともに補正しないでそのまま用いてもよいし、第３実施形態および第４実施形態において一組の比較用脈波を決定して、その一組の比較用脈波に基づいて監視血圧値ＭＢＰの精度を判定してもよい。
【０１０１】
なお、本発明はその主旨を逸脱しない範囲においてその他種々の変更が加えられ得るものである。
【図面の簡単な説明】
【図１】本発明が適用された非観血連続血圧監視装置の構成を説明するブロック図である。
【図２】圧脈波検出プローブの構成を詳しく説明する図である。
【図３】図２の圧脈波検出プローブに備えられた圧脈波センサの押圧面を示す図である。
【図４】図１の非観血連続血圧監視装置におけるＣＰＵの制御機能の要部を示す機能ブロック図である。
【図５】図４の押圧力制御手段において決定される最適押圧力ＨＤＰＯを説明する図である。
【図６】図４の対応関係決定手段で決定される圧脈波血圧対応関係の一例を示す図である。
【図７】基準カフ脈波ＣＷｓｔと、補正係数により補正された基準圧脈波ＰＷｓｔとを、立ち上がり点（最小点）を一致させた状態で示す図である。
【図８】図４の比較脈波決定手段により決定した比較用圧脈波ＰＷｓｔおよび比較用カフ脈波ＣＷｓｔを最小点を一致させた状態で示す図である。
【図９】図４の機能ブロック図に示したＣＰＵの制御作動の要部を示すフローチャートであって、対応関係決定ルーチンを示す図である。
【図１０】図４の機能ブロック図に示したＣＰＵの制御作動の要部を示すフローチャートであって、対応関係決定ルーチンを示す図である。
【図１１】図４の機能ブロック図に示したＣＰＵの制御作動の要部を示すフローチャートであって、血圧監視ルーチンを示す図である。
【図１２】基準圧脈波ＰＷｓｔと基準カフ脈波ＣＷｓｔとを、それらの最小点を一致させた状態で、時間軸に垂直に複数の脈波区分Ｃ（ｎ）に分割した状態を示す図である。
【図１３】第２の実施形態に係るＣＰＵの制御作動の要部を示すフローチャートであって、対応関係決定ルーチンの一部を示す図である。
【図１４】第２の実施形態に係るＣＰＵの制御作動の要部を示すフローチャートであって、血圧監視ルーチンの一部を示す図である。
【図１５】第３の実施形態に係るＣＰＵの制御機能の要部を示す機能ブロック図である。
【図１６】第３の実施形態に係るＣＰＵの制御作動の要部を示すフローチャートであって、対応関係決定ルーチンの一部を示す図である。
【図１７】第３の実施形態に係るＣＰＵの制御作動の要部を示すフローチャートであって、血圧監視ルーチンの一部を示す図である。
【図１８】第４の実施形態において作成される基準波形相関図形の一例を示す図である。
【図１９】第４の実施形態に係るＣＰＵの制御作動の要部を示すフローチャートであって、対応関係決定ルーチンの一部を示す図である。
【図２０】第４の実施形態に係るＣＰＵの制御作動の要部を示すフローチャートであって、血圧監視ルーチンの一部を示す図である。
【符号の説明】
８：非観血連続血圧監視装置
１０：カフ
７０：カフ圧制御手段
７２：血圧値決定手段
７８：対応関係決定手段
８０：血圧値連続決定手段
８４：カフ脈波検出手段
８６：補正係数決定手段
８８：比較脈波決定手段
９０：血圧監視精度判定手段
９２：血圧監視精度判定手段
９４：血圧監視精度判定手段
９６：血圧監視精度判定手段
１０２：二次元グラフ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a blood pressure monitoring device that non-invasively and continuously monitors a blood pressure value, and more particularly to a technique for reducing the burden on a patient while maintaining blood pressure monitoring accuracy in a non-invasive continuous blood pressure monitoring device. .
[0002]
[Prior art]
As a non-invasive continuous blood pressure monitoring device, a device that detects a pressure pulse wave generated from a predetermined artery of a living body and continuously monitors a blood pressure value from the pressure pulse wave, that is, a blood pressure measurement by a so-called tonometry method is used. Known devices are known. The non-invasive continuous blood pressure monitoring device of this method attaches a cuff to a part of a living body such as an upper arm, determines a blood pressure value in a process of slowly changing the compression pressure of the cuff, and determines the blood pressure value and the living body's blood pressure. From a pressure pulse wave detected using a pressure pulse wave sensor pressed toward a predetermined artery, a pressure pulse wave blood pressure correspondence between the magnitude of the pressure pulse wave and the blood pressure value is determined, and the pressure pulse The blood pressure value is continuously determined from the sequentially detected pressure pulse waves using the wave blood pressure correspondence (for example, see Patent Document 1).
[0003]
[Patent Document 1]
JP 2000-237151 A
[0004]
[Problems to be solved by the invention]
In the non-invasive continuous blood pressure monitoring device, the actual pressure pulse wave blood pressure correspondence relationship deviates from the pressure pulse wave blood pressure correspondence relationship determined by measuring the blood pressure, for example, because the mounting state of the pressure pulse wave sensor is shifted. If so, the accuracy of the monitored blood pressure value decreases. Therefore, in order to prevent the accuracy of the monitored blood pressure value from deteriorating, the pressure pulse wave blood pressure correspondence may be updated in a relatively short cycle. By updating the pressure pulse wave blood pressure correspondence relationship in a short cycle, even if the actual pressure pulse wave blood pressure correspondence relationship gradually shifts, it is possible to reduce a decrease in accuracy of the monitored blood pressure value. However, when the pressure-pulse-blood-pressure correspondence relationship is updated in a short cycle, the pressure-pulse-wave pressure correspondence relationship is updated until the pressure-pulse-wave blood-pressure correspondence relationship has not changed so much and there is no need to update. In order to update the pressure pulse wave blood pressure correspondence, blood pressure measurement using a cuff must be performed each time, and blood pressure measurement using a cuff increases the compression pressure of the cuff to a pressure higher than the systolic blood pressure value. Since the pressure is increased, the burden is placed on the patient. Therefore, it is desired that the cycle of the blood pressure measurement using the cuff be set as long as possible.
[0005]
As described above, when the accuracy of the monitored blood pressure value cannot be determined, the pressure pulse wave blood pressure correspondence must be updated relatively frequently in order to prevent the accuracy of the monitored blood pressure value from decreasing. Therefore, in Patent Document 1, when the pressure pulse wave blood pressure correspondence relationship is maintained, a part of the blood vessel wall is made substantially flat by the pressure from the pressure pulse wave sensor, and the substantially flat blood vessel is formed. The accuracy of the monitored blood pressure value is sequentially determined by utilizing the fact that the pressure pulse waves detected by the plurality of pressure detection elements located above the wall have substantially the same shape. That is, in Patent Document 1, the maximum pressure detecting element that outputs the maximum pulse wave amplitude is determined from a number of pressure detecting elements arranged on the pressing surface of the pressure pulse wave sensor, and the pressure pulse wave is determined from the maximum pressure detecting element. And the pressure pulse wave is also detected from the first pressure detection element and the second pressure detection element whose distance from the maximum pressure detection element is the first distance and the second distance, respectively, and is detected by the maximum pressure detection element. The first correlation coefficient between the detected pressure pulse wave and the pressure pulse wave detected from the first pressure detection element, and the pressure pulse wave detected by the maximum pressure detection element and detected by the second pressure detection element A second correlation coefficient with the pressure pulse wave is sequentially calculated, and the accuracy of the monitored blood pressure value is sequentially determined based on the first correlation coefficient and the second correlation coefficient.
[0006]
As described above, the cycle of blood pressure measurement using the cuff is required to be set as long as possible, but is detected by a plurality of pressure detecting elements as in the blood pressure monitoring device of Patent Document 1 described above. The technique of sequentially determining the accuracy of the monitored blood pressure value using the correlation coefficient between the pressure pulse waves is not sufficiently accurate to meet the demand, and the blood pressure measurement cycle for updating the pressure pulse wave blood pressure correspondence relationship is not sufficient. Can only be extended to some extent. Therefore, it can be used in combination with the technique of determining the accuracy of the monitoring blood pressure value described in Patent Document 1, and can be used independently of the technique to determine the accuracy of the monitoring blood pressure value. Technology development was desired.
[0007]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a non-invasive continuous blood pressure monitoring device capable of reducing a burden on a patient while maintaining high blood pressure monitoring accuracy. It is in.
[0008]
[Means for Solving the Problems]
The present inventors have conducted various studies in order to achieve the above object, and as a result, have found the following knowledge. That is, the shape of the cuff pulse wave, which is the pressure oscillation transmitted from the living body to the cuff with the compression pressure of the cuff being equal to or less than the average blood pressure value, is very similar to the shape of the pressure pulse wave detected by the tonometry method. I found something. Also, since the cuff is less likely to shift during mounting, by comparing the cuff pulse wave and the pressure pulse wave detected by the tonometry method, it is possible to determine whether the mounting state of the pressure pulse wave sensor has changed, It has been found that a decrease in the accuracy of the monitored blood pressure value can be determined. The present invention has been made based on such findings.
[0009]
That is, the present invention for achieving the above object includes (a) a cuff attached to a part of a living body, (b) a cuff pressure control means for controlling a compression pressure of the cuff, and (c) a cuff pressure. Blood pressure value determining means for determining a blood pressure value of the living body based on a signal obtained in a process in which the compression pressure of the cuff is slowly changed by the control means; and (d) pressing the blood pressure toward a predetermined artery of the living body. A pressure pulse wave detecting device for sequentially detecting a pressure pulse wave generated from the artery using a pressure pulse wave sensor to be operated; and (e) a blood pressure value determined by the blood pressure value determining means and the pressure pulse wave detecting device. (F) using the pressure pulse wave blood pressure correspondence relationship to determine the pressure pulse wave blood pressure correspondence relationship between the detected pressure pulse wave size and the pressure pulse wave blood pressure correspondence device; Monitoring blood pressure values based on the magnitude of the pressure pulse wave (G) a state in which the cuff pressure control unit sets the compression pressure of the cuff to be lower than an average blood pressure value. And (h) a cuff pulse wave detected by the cuff pulse wave detecting means and a cuff pulse wave detected by the cuff pulse wave detecting means, Blood pressure monitoring accuracy determining means for sequentially determining the accuracy of the monitored blood pressure value determined by the blood pressure value continuous determining means based on a comparison with the pressure pulse wave detected by the pressure pulse wave detecting device. It is characterized by.
[0010]
【The invention's effect】
According to this invention, the blood pressure monitoring accuracy determining means compares the pressure pulse wave detected by the pressure pulse wave detection device with the cuff pulse wave detected at a pressure at which the cuff pressure is lower than the average blood pressure value. Since the accuracy of the monitored blood pressure value continuously determined by the blood pressure value continuous determining means is determined, in order to maintain the accuracy of the monitored blood pressure value, the blood pressure measurement using the cuff is performed in a short cycle to measure the pressure pulse. Since it is not necessary to frequently update the wave blood pressure correspondence, the burden on the patient is reduced.
[0011]
Other aspects of the invention
There are various ways of comparing the pressure pulse wave and the cuff pulse wave in the blood pressure monitoring accuracy determination means. For example, it is possible to compare the positions of characteristic points of the pressure pulse wave and the cuff pulse wave. . The non-invasive continuous blood pressure monitoring device that determines the accuracy of the monitored blood pressure value in such a manner, when the blood pressure value is determined by the blood pressure value determining device, the cuff pulse wave detecting device and the pressure pulse wave detecting device respectively Correction coefficient determining means for determining a correction coefficient for correcting at least one of the cuff pulse wave and the pressure pulse wave in order to make the magnitudes of the detected cuff pulse wave and pressure pulse wave the same, and the correction coefficient determining means Using the correction coefficient determined by the above, sequentially correct at least one of the cuff pulse wave detected by the cuff pulse wave detecting means and the pressure pulse wave detected by the pressure pulse wave detection device, for comparison Comparison pulse wave determination means for determining a set of cuff pulse waves and pressure pulse waves, wherein the blood pressure monitoring accuracy determination means includes a cuff pulse wave and a pressure pulse wave determined by the comparison pulse wave determination means. One minimum point In this state, by comparing the positions of the predetermined characteristic points of the cuff pulse wave and the pressure pulse wave, the accuracy of the monitoring blood pressure value determined by the blood pressure value continuation determining means is sequentially determined. It is characterized by.
[0012]
The blood pressure monitoring accuracy determination means may compare the shape of the pressure pulse wave with the shape of the cuff pulse wave. The non-invasive continuous blood pressure monitoring device that determines the accuracy of the monitored blood pressure value in such a manner, when the blood pressure value is determined by the blood pressure value determining device, the cuff pulse wave detecting device and the pressure pulse wave detecting device respectively Correction coefficient determining means for determining a correction coefficient for correcting at least one of the cuff pulse wave and the pressure pulse wave in order to make the magnitudes of the detected cuff pulse wave and pressure pulse wave the same, and the correction coefficient determining means Using the correction coefficient determined by the above, sequentially correct at least one of the cuff pulse wave detected by the cuff pulse wave detecting means and the pressure pulse wave detected by the pressure pulse wave detection device, for comparison Comparison pulse wave determining means for determining a set of cuff pulse waves and pressure pulse waves, wherein the blood pressure monitoring accuracy determining means determines the shape of the cuff pulse waves and pressure pulse waves determined by the comparative pulse wave determining means. Based on comparison Te, sequentially, and characterized in that to determine the accuracy of monitoring the blood pressure value determined by the blood pressure values continuously determining means.
[0013]
Further, in the apparatus for comparing the shape of the pressure pulse wave and the shape of the cuff pulse wave to determine the accuracy of the monitored blood pressure value, the blood pressure monitoring accuracy determining means may include, for example, the blood pressure monitoring accuracy determining means The cuff pulse wave and the pressure pulse wave determined by the wave determining means are divided into a plurality of pulse wave segments perpendicular to the time axis in a state where the minimum points are coincident with each other, and an area is defined for each of the plurality of pulse wave segments. The difference is calculated, and based on the number of pulse wave segments in which the time change of each of the plurality of area differences exceeds a predetermined reference value, the accuracy of the monitored blood pressure value sequentially determined by the blood pressure value continuation determining means is determined. judge. Alternatively, the cuff pulse wave and the pressure pulse wave determined by the comparison pulse wave determination means are divided into a plurality of pulse wave segments perpendicular to the time axis in a state where the minimum points coincide with each other, and the plurality of pulse waves are divided. Calculating the area difference for each wave segment and sequentially determining the accuracy of the monitored blood pressure value determined by the blood pressure value continuation determining means based on whether or not the time change trends of the plurality of area differences coincide with each other. It may be.
[0014]
The blood pressure monitoring accuracy determining means may compare the area of the pressure pulse wave with the area of the cuff pulse wave. The non-invasive continuous blood pressure monitoring device that determines the accuracy of the monitored blood pressure value in such a manner is characterized in that the blood pressure monitoring accuracy determining means determines a time change of the area of the cuff pulse wave detected by the cuff pulse wave detecting means. Based on the comparison of the detection of the cuff pulse wave and the time change of the area of the pressure pulse wave detected by the pressure pulse wave detection device at the same time, the monitoring blood pressure value sequentially determined by the blood pressure value continuous determination means is sequentially determined. The accuracy is determined.
[0015]
Further, the accuracy of the monitored blood pressure value may be determined by comparing the cuff pulse wave and the pressure pulse wave as follows. That is, the blood pressure monitoring accuracy determination means converts the cuff pulse wave detected by the cuff pulse wave detection means into a two-dimensional graph including an axis representing the magnitude of the cuff pulse wave and an axis representing the magnitude of the pressure pulse wave. And the blood pressure value continuation determining unit sequentially determines the blood pressure value based on the waveform correlation graphic drawn by the pressure pulse wave corresponding to the cuff pulse wave among the pressure pulse waves detected by the pressure pulse wave detection device. The accuracy of the monitored blood pressure value may be determined.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram illustrating a configuration of a non-invasive continuous blood pressure monitoring device 8 to which the present invention is applied.
[0017]
In the figure, reference numeral 10 denotes a cuff having a rubber bag in a cloth band-shaped bag, which is wound around the upper arm 12 of the patient's right arm, for example. A pressure sensor 14 and an exhaust control valve 16 are connected to the cuff 10 via a pipe 18, and the exhaust control valve 16 is connected to an air pump 20 via a pipe 19. The exhaust control valve 16 is in a supply permitting state in which the high-pressure air generated in the air pump 20 is supplied into the cuff 10, a pressure maintaining state in which the pressure in the cuff 10 is maintained, and the inside of the cuff 10 is gradually increased. It is configured to be able to switch between four states: a slow exhaust state in which the pressure is exhausted, and a rapid exhaust state in which the cuff 10 is rapidly exhausted.
[0018]
The pressure sensor 14 detects the pressure P in the cuff 10. K And the pressure P K Is supplied to the static pressure discrimination circuit 22 and the pulse wave discrimination circuit 24, respectively. The static pressure discriminating circuit 22 includes a low-pass filter, and discriminates a cuff pressure signal SC representing a steady pressure included in the pressure signal SP, that is, a compression pressure of the cuff 10 (hereinafter, this pressure is referred to as a cuff pressure PC). The cuff pressure signal SC is supplied to the electronic control device 28 via the A / D converter 26. The pulse wave discrimination circuit 24 includes a band-pass filter, discriminates the cuff pulse wave signal SM1 which is a vibration component of the pressure signal SP, and converts the cuff pulse wave signal SM1 via the A / D converter 30 into the electronic control unit 28. Supply to This cuff pulse wave signal SM1 represents a cuff pulse wave CW because it is pressure vibration transmitted from the brachial artery (not shown) compressed by the cuff 10 to the cuff 10.
[0019]
The electronic control unit 28 includes a so-called microcomputer including a CPU 31, a ROM 32, a RAM 33, and an I / O port (not shown). The CPU 31 performs a storage function of the RAM 33 in accordance with a program stored in the ROM 32 in advance. By executing the signal processing while utilizing, the drive signal is output from the I / O port and the exhaust control valve 16 and the air pump 20 are controlled via a drive circuit (not shown) to control the pressure in the cuff 10. At the same time, based on the change in the cuff pulse wave CW represented by the cuff pulse signal SM1, the systolic blood pressure value BP is determined by the oscillometric method. SYS And diastolic blood pressure BP DIA Is determined, and the determined blood pressure value BP is displayed on the display 34.
[0020]
As shown in detail in FIG. 2, the pressure pulse wave detection probe 36 functioning as a pressure pulse wave detection device includes a container-shaped sensor housing 37, a case 38 accommodating the housing 37, and a sensor housing 37 connected to the radial artery 56. And a screw shaft 40 which is screwed to the sensor housing 37 and is rotationally driven by a motor (not shown) provided in a driving portion 39 of the case 38 to move the sensor shaft 37 in the width direction. A mounting band 41 is attached to the case 38.
[0021]
The pressure pulse wave detection probe 36 thus configured is detachably attached to the wrist 43 by the wearing band 41 with the open end of the sensor housing 37 facing the body surface 42. The wrist 43 to which the pressure pulse wave detection probe 36 is attached may be the wrist on which the cuff 10 is mounted or the wrist on the opposite side. In many cases, the cuff 10 and the pressure pulse wave detection probe 36 cannot be attached to the arm on which the infusion tube is inserted. The pressure pulse wave detection probe 36 is attached to the arm on the same side as the cuff 10.
[0022]
Inside the sensor housing 37, a pressure pulse wave sensor 46 is provided so as to be relatively movable with respect to the sensor housing 37 via the diaphragm 44 and to be able to protrude from the open end of the sensor housing 37. A pressure chamber 48 is formed by the diaphragm 44 and the like. As shown in FIG. 1, high pressure air is supplied from the air pump 50 through the pressure regulating valve 52 into the pressure chamber 48, whereby the pressure pulse wave sensor 46 is connected to the pressure chamber 48. The body surface 42 is pressed by a pressing force HDP (Hold Down Pressure) corresponding to the internal pressure.
[0023]
The sensor housing 37 and the diaphragm 44 constitute a pressing device 58 that presses the pressure pulse wave sensor 46 toward the radial artery 56. The screw shaft 40 and a motor (not shown) A width direction moving device 60 that moves a pressing position pressed toward the width direction of the radial artery 56 is configured.
[0024]
As shown in FIG. 3, a large number of semiconductor pressure-sensitive elements (hereinafter simply referred to as pressure-sensitive elements) E are arranged on the pressing surface 62 of the pressure pulse wave sensor 46 in the width direction of the radial artery 56, that is, in parallel with the screw axis 40. In the movement direction of the pressure pulse wave sensor 46, the pressure pulse wave sensors 46 are arranged so as to be longer than the diameter of the radial artery 56 and at regular intervals (for example, at intervals of 0.2 mm).
[0025]
When the thus configured pressure pulse wave detection probe 36 is pressed from above the body surface 42 of the wrist 43 toward the radial artery 56, the pressure pulse wave sensor 46 generates the pressure pulse wave from the radial artery 56 and generates the body surface 42. Is detected, and a pressure pulse wave signal SM2 representing the pressure pulse wave PW is transmitted to the electronic control unit 28 via the A / D converter 64 as shown in FIG. Supplied.
[0026]
The CPU 31 of the electronic control device 28 controls the pressure in the cuff 10 and determines the blood pressure value BP. In addition, the CPU 31 outputs a drive signal to the air pump 50 and the pressure regulating valve 52 via a drive circuit (not shown) to control the pressure. The pressure in the chamber 48 is also adjusted. Further, the electronic control device 28 is based on the pressure pulse wave PW sequentially obtained in the slow pressure change process in the pressure chamber 48, and based on the pressure pulse wave PW, a pressure pulse wave sensor for making a part of the blood vessel wall of the radial artery 56 substantially flat. The optimum pressing force HDPO of 46 is determined, and the pressure regulating valve 52 is controlled so as to maintain the optimum pressing force HDPO.
[0027]
FIG. 4 is a functional block diagram showing a main part of the control function of the CPU 31. The cuff pressure control means 70 executes the following blood pressure measurement control and pulse wave detection pressure control by controlling the exhaust control valve 16 and the air pump 20. In the blood pressure measurement control, the cuff pressure PC is changed to the systolic blood pressure value BP in the upper arm 12. SYS The pressure is rapidly increased to a preset target pressure value PM1 (for example, 180 mmHg) higher than the predetermined value, and the cuff pressure PC is maintained at 2 until the determination of the blood pressure value BP by the blood pressure value determining means 72 described later is completed. The pressure is reduced slowly at a slow pressure reduction speed set to ３3 mmHg / sec. After the determination of the blood pressure value BP is completed, the cuff pressure PC is exhausted to the atmospheric pressure.
[0028]
In the pulse wave detection pressure control, the cuff pressure PC is controlled to the pulse wave detection pressure PM2 for at least one beat or more. The pulse wave detection pressure PM2 is equal to the average blood pressure value BP Mean Lower than, preferably diastolic blood pressure BP DIA The pressure is set to be lower than the pressure and high enough to make the magnitude of the cuff pulse wave signal SM1 sufficiently large, for example, 50 mmHg to 60 mmHg. The pulse wave detection pressure PM2 may be set in advance, or may be determined based on the blood pressure value BP determined by the blood pressure value determining means 72 described later. The reason why the pulse wave detection pressure PM2 is set to such a pressure is that the cuff pressure PC is equal to the diastolic blood pressure value BP. DIA If the pressure is higher than the above, the cuff pulse wave CW discriminated by the pulse wave discrimination circuit 24 due to the compression of the blood vessel is distorted, and particularly, the average blood pressure value BP Mean If the cuff pressure PC is too low, a sufficiently large signal cannot be obtained while the distortion of the cuff pulse wave CW increases due to an increase in the degree to which the blood vessels are compressed. .
[0029]
The blood pressure value determining means 72 determines whether the monitoring blood pressure value MBP is abnormal when the preset calibration cycle Tc of about 10 to 30 minutes has elapsed, or when the blood pressure abnormality determining means 82 described later determines that the monitoring blood pressure value MBP is abnormal. This is executed when the pressing force HDP of the pressure pulse wave sensor 46 is changed by the pressing force control means 76, which will be described later, and outputs a command signal to the cuff pressure control means 70 to output the cuff pressure control means. In the process of causing the cuff pressure control means 70 to execute the blood pressure measurement control and gradually reduce the cuff pressure PC by the cuff pressure control means 70, the amplitude of the brachial pulse wave represented by the cuff pulse wave signal SM1 sequentially sampled and the sequentially collected cuff pulse wave are sequentially sampled. Systolic blood pressure value BP based on the cuff pressure signal SC using a well-known oscillometric method. SYS , Diastolic blood pressure BP DIA , And mean blood pressure BP Mean Is determined, and the determined systolic blood pressure value BP is determined. SYS Are displayed on the display 34.
[0030]
The optimal pressing position control means 74 determines that the arrangement position of the element for detecting the maximum pressure among the plurality of pressure-sensitive elements E provided in the pressure pulse wave sensor 46 (hereinafter, this element is referred to as the maximum pressure detection element EM) is arranged. It is determined whether or not a pressing position update condition that satisfies the condition that the pressing position is located within a predetermined number or a predetermined distance from the end of the reference position is satisfied. Then, when the pressing position update condition is satisfied, the following pressing position update operation is executed. That is, the pressing position updating operation is performed by temporarily separating the pressure pulse wave sensor 46 from the body surface 42, moving the pressing device 58 and the pressure pulse wave sensor 46 by the width direction moving device 60 by a predetermined distance, and then pressing the pressing device 58. The pressure pulse wave sensor 46 is pressed with a relatively small first pressing force HDP1, and it is determined whether or not the pressing position update condition is satisfied again in that state, and until the pressing position update condition is no longer satisfied. More preferably, the above operation and determination are performed until the maximum pressure detecting element EM is located substantially at the center of the arrangement position. The predetermined number or the predetermined distance from the end of the array in the pressed position update condition is determined based on the diameter of the artery (the radial artery 56 in the present embodiment) pressed by the pressure pulse wave sensor 46. It is set to 1/4 of the diameter.
[0031]
After the pressure pulse wave sensor 46 is positioned at the optimum pressing position by the optimum pressing position control means 74, the pressing force control means 76 sets the pressing force HDP of the pressure pulse wave sensor 46 by the pressing device 58 to a predetermined pressing force range. Within a predetermined range of pressing force, or continuously at a relatively slow constant speed. Then, the optimum pressing force HDPO is determined based on the pressure pulse wave PW obtained in the process of changing the pressing force HDP, and the pressing force HDP of the pressure pulse wave sensor 46 by the pressing device 58 is maintained at the optimum pressing force HDPO. Here, the optimal pressing force HDPO is a pressing force of the pressure pulse wave sensor 46 that makes the side of the blood vessel wall of the radial artery 56 pressed by the pressure pulse wave sensor 46 substantially flat by the pressing force HDP of the pressure pulse wave sensor 46. As shown in FIG. 5, in the process of continuously increasing the pressing force HDP in a range that sufficiently includes the optimum pressing force HDPO, the pressure pulse wave PW obtained from the maximum pressure detecting element EM of the pressure pulse wave sensor 46 is changed. In the two-dimensional graph showing the magnitude and the pressing force HDP of the pressure pulse wave sensor 46, the center of the flat portion formed by the curve (broken line in FIG. 5) connecting the lower peak value (rising point) PWmin of the pressure pulse wave PW is shown. This is a pressing value within a predetermined range with the center as the center.
[0032]
Correspondence determining means 78 determines the blood pressure value BP measured by blood pressure value determining means 72 and the pressure pulse wave PW detected by maximum pressure detecting element EM of pressure pulse wave sensor 46 when measuring the blood pressure by blood pressure value determining means 72. Is determined as shown in FIG. 6, for example. In FIG. 6, PW min Is the minimum value of the pressure pulse wave PW (that is, the magnitude of the pressure pulse wave PW at the rising point), PW max Is the maximum value of the pressure pulse wave PW (that is, the magnitude of the pressure pulse wave PW at the peak). The time of blood pressure measurement by the blood pressure value determining means 72 means not only the time when the blood pressure measurement control is executed by the cuff pressure control means 70 for measuring the blood pressure value BP, but also the blood pressure value before and after the blood pressure measurement control. It also includes a period during which the BP can be considered as not changing much.
[0033]
The blood pressure value continuation determining means 80 uses the pressure pulse wave blood pressure correspondence determined by the correspondence determination means 78 to determine the magnitude of the pressure pulse wave PW sequentially detected by the maximum pressure detecting element EM of the pressure pulse wave sensor 46. Thus, the monitoring blood pressure value MBP is continuously determined. That is, the minimum value PW of the pressure pulse wave PW is calculated using the pressure pulse wave blood pressure correspondence. min To monitor diastolic blood pressure MBP DIA Is continuously determined, and the maximum value PW of the pressure pulse wave PW is determined using the pressure pulse wave blood pressure correspondence relationship. max To monitor systolic blood pressure MBP SYS Is determined continuously. Then, the determined monitored diastolic blood pressure value MBP DIA And monitored systolic blood pressure MBP SYS Is displayed on the display 34.
[0034]
The blood pressure abnormality judging means 82 determines the monitored systolic blood pressure value MBP continuously determined by the blood pressure value continuous determining means 80. SYS Is a preset systolic blood pressure abnormality determination value TH SYS Is exceeded or the monitored diastolic blood pressure value MBP DIA Is a preset diastolic blood pressure abnormality determination value TH DIA Is determined to be abnormal in the following cases, a character or symbol indicating that the blood pressure is abnormal is displayed on the display 34, and the blood pressure value is determined in order to quickly obtain a reliable blood pressure value BP by the cuff 12. The blood pressure measurement by the determining means 72 is executed.
[0035]
The cuff pulse wave detecting means 84 determines that the cuff pressure PC is equal to the average blood pressure value BP when the blood pressure value determining means 72 measures the blood pressure. Mean Under the following conditions, the cuff pulse wave CW supplied from the pulse wave discrimination circuit 24 (hereinafter, this cuff pulse wave CW is referred to as a reference cuff pulse wave CWst) is read, and the time measured from the blood pressure measurement is measured. Each time the time passes a monitoring accuracy determination period Tw that is set to be sufficiently shorter than the calibration period Tc (for example, about 1 minute to 3 minutes), the cuff pressure control means 70 applies the cuff pressure PC to the pulse. A cuff pulse detected by the pulse wave discrimination circuit 24 in a state where the cuff pressure PC is controlled to the pulse wave detection pressure PM2 by outputting a command signal for controlling the pulse wave detection pressure PM2. Read the wave CW. As described above, at the time of blood pressure measurement, not only when the blood pressure measurement control is being performed by the cuff pressure control means 70, but also during the time when the blood pressure value BP before and after the blood pressure measurement control can be regarded as not changing so much Therefore, the reference cuff pulse wave CWst may be not only the blood pressure measurement control process by the cuff pressure control means 70 but also the cuff pulse wave CW read during a predetermined period before and after the blood pressure measurement control. When reading the reference cuff pulse wave CWst before and after the blood pressure measurement control, similarly to reading the cuff pulse wave CW at each monitoring accuracy determination cycle Tw, the cuff pressure control means 70 transmits the cuff pressure PC to the pulse wave detection pressure. A command signal for controlling the PM2 is output, and the cuff pulse wave CW is read with the cuff pressure PC set to the pulse wave detection pressure PM2. In the present embodiment, it is assumed that the reference cuff pulse wave CWst is read immediately after the blood pressure measurement control.
[0036]
The correction coefficient determining means 86 applies the pressure pulse wave PW detected by the pressure pulse wave sensor 46 substantially simultaneously with the reading of the reference cuff pulse wave CWst (hereinafter referred to as the reference pressure pulse wave PWst). And a correction coefficient for correcting the reference cuff pulse wave CWst to have the same magnitude. The correction coefficient may be determined only for correcting the cuff pulse wave CW, may be determined only for correcting the pressure pulse wave PW, or may be determined for the cuff pulse wave CW and the pressure. A correction coefficient may be determined for correcting both of the pulse waves PW, but in the present embodiment, only a correction coefficient for correcting the pressure pulse wave PW is determined. FIG. 7 is a diagram illustrating the reference cuff pulse wave CWst and the reference pressure pulse wave PWst corrected by the correction coefficient determined by the correction coefficient determination unit 86 in a state where the rising points (minimum points) are matched. .
[0037]
The comparison pulse wave determination means 88 determines the pressure pulse wave PW detected by the pressure pulse wave sensor 46 at substantially the same time as the cuff pulse wave CW read at each of the monitoring accuracy determination periods Tw by the correction coefficient determination means 86. The cuff pulse wave CW read at each monitoring accuracy determination period Tw is determined as the cuff pulse wave CWc for comparison, while being corrected by the correction coefficient thus determined to determine the pressure pulse wave for comparison PWc. Here, the pressure pulse wave PW detected at substantially the same time as the cuff pulse wave CW includes not only the pressure pulse wave PW corresponding to the cuff pulse wave CW (that is, a pulse wave based on the same pulsation), but also the cuff pulse wave. This includes the pressure pulse wave PW detected immediately before or immediately after the period in which the cuff pressure PC is controlled to the pulse wave detection pressure PM2 for detecting the CW.
[0038]
The blood pressure monitoring accuracy determination means 90 compares the comparison pressure pulse wave PWc and the comparison cuff pulse wave CWc determined by the comparison pulse wave determination means 88 with their minimum points and compares them with the comparison pressure pulse wave PWc. A difference between the magnitudes of the characteristic points of the cuff pulse wave CWc for use, that is, an intensity difference d is calculated, and the intensity difference d is set to a preset wearing abnormality determination value TH. d Is exceeded, it is determined that the accuracy of the monitored blood pressure value MBP determined by the blood pressure value continuous determination means 80 has decreased due to the improper mounting state of the pressure pulse wave sensor 46, and the pressure pulse wave sensor The optimal pressing position control means 74 is executed again in order to correct the mounting state of 46. Here, the characteristic points include, for example, peaks and notches.
[0039]
FIG. 8 is an example of a diagram showing the comparison pressure pulse wave PWst and the comparison cuff pulse wave CWst determined by the comparison pulse wave determination means 88 in a state where the minimum points are matched, and in the case where a peak is selected as a feature point. Is illustrated as an example. When the blood pressure value BP changes, the comparison pressure pulse wave PWc and the comparison cuff pulse wave CWc have the same tendency of change in the magnitude of each characteristic point, and the comparison pressure pulse wave PWc and the comparison cuff pulse wave CWc. In both cases, the peak increases when the blood pressure value BP increases, and conversely, the peak decreases when the blood pressure value BP decreases. Further, the comparison pressure pulse wave PWc is determined so that the detected pressure pulse wave PW has the same size as the reference cuff pulse wave CWst when the blood pressure value determination means 72 measures the blood pressure. Is corrected based on the correction coefficient. Therefore, even if the blood pressure value BP fluctuates from the time of blood pressure measurement by the blood pressure value determining means 72, if the mounting state of the pressure pulse wave sensor 46 is appropriately maintained and an appropriate pressure pulse wave PW is detected, Since the intensity difference d is not so large, when the intensity difference d is large, it can be determined that the mounting state of the pressure pulse wave sensor 46 has become inappropriate. Although the change tendency of the feature point of the comparison pressure pulse wave PWc and the change tendency of the feature point of the comparison cuff pulse wave CWc with respect to the change of the blood pressure value BP coincide, the change amount is not completely obtained. Since they do not match, the intensity difference d does not become zero even if the mounted state of the pressure pulse wave sensor 46 is properly maintained. Therefore, the above-described mounting abnormality determination value TH d Is set to a relatively large value in consideration of the difference between the two.
[0040]
FIGS. 9 to 11 are flowcharts showing the main part of the control operation of the CPU 31 shown in the functional block diagram of FIG. 4. FIGS. 9 and 10 show a correspondence determination routine for determining a pressure pulse wave blood pressure correspondence. FIG. 11 shows a blood pressure monitoring routine.
[0041]
First, the correspondence determination routine shown in FIGS. 9 and 10 will be described. In FIG. 9, in step SA1 (hereinafter, steps are omitted), the arrangement position of the maximum pressure detection element EM among the pressure-sensitive elements E arranged on the pressing surface 62 of the pressure pulse wave sensor 46 is from the end of the arrangement. It is determined whether or not a pressing position update condition (APS activation condition) that satisfies the condition of being located within a predetermined number or a predetermined distance inward is satisfied. If this determination is denied, SA3 and later described later are executed.
[0042]
On the other hand, if the determination of SA1 is affirmative, that is, if the mounting position of the pressure pulse wave sensor 46 with respect to the radial artery 56 is inappropriate, the SA2 APS control routine corresponding to the optimal pressing position control means 74 is executed. I do. In the APS control routine, by controlling the width direction moving device 60, the pressure detecting element E for detecting the maximum amplitude among the pressure detecting elements E of the pressure pulse wave sensor 46 is arranged in the array of the pressure detecting elements E. The optimum pressing position is determined so as to be substantially at the center position, and the pressure detecting element E is set as the maximum pressure detecting element EM. Pressure pulse wave signal SM in the following description 2 Is a pressure pulse wave signal SM detected by the maximum pressure detecting element EM determined in SA2. 2 Means
[0043]
When the determination of SA1 is denied or when the above SA2 is executed, subsequently, the HDP control routine of SA3 corresponding to the pressing force control means 76 is executed. That is, by controlling the pressure regulating valve 52, the pressing force HDP of the pressure pulse wave sensor 46 is continuously increased, and in the process, the pressing force at which the amplitude of the pressure pulse wave PW detected by the maximum pressure detecting element EM becomes maximum. Is determined as the optimum pressing force HDPO, and the pressing force HDP of the pressure pulse wave sensor 46 is held at the optimum pressing force HDPO.
[0044]
In subsequent SA4, the air pump 20 is started and the exhaust control valve 16 is controlled to a pressure supply state, thereby starting a rapid increase in the cuff pressure PC. In the subsequent SA5, it is determined whether or not the cuff pressure PC has exceeded the target boost pressure value PM1 set to 180 mmHg. While this determination is denied, the determination of SA5 is repeatedly performed, and the rapid increase of the cuff pressure PC is continued. On the other hand, if the determination in SA5 is affirmative, in SA6, the air pump 20 is stopped and the exhaust control valve 16 is switched to the slow exhaust pressure state, so that the cuff pressure PC at about 3 mmHg / sec. Start slow pressure reduction.
[0045]
Subsequently, SA7 to SA9 corresponding to the blood pressure value determining means 72 are executed. In SA7, a well-known oscillometric method is used on the basis of the change in the amplitude of the cuff pulse wave CW represented by the cuff pulse wave signal SM1 sequentially obtained in the step-down process of the cuff pressure PC and the cuff pressure PC when the amplitude is generated. Blood pressure value BP according to the blood pressure measurement algorithm of SYS , Mean blood pressure BP Mean , And diastolic blood pressure BP DIA To determine. In subsequent SA8, it is determined whether the determination of the blood pressure value BP in SA7 is completed. While the determination in SA8 is denied, SA7 and subsequent steps are repeatedly executed to continue the blood pressure measurement algorithm.
[0046]
When the determination of the blood pressure value BP is completed and the determination of SA8 is affirmed, in the subsequent SA9, the systolic blood pressure value BP determined by repeating SA7 to SA8. SYS Are displayed on the display 34. Subsequently, SA10 and subsequent steps shown in FIG. 10 are executed.
[0047]
In SA10, the diastolic blood pressure value BP determined in SA7 DIA Then, the pulse wave detection pressure PM2 is determined by subtracting a predetermined value α set to about 10 mmHg. Then, in SA11, the cuff pressure PC is controlled to the pulse wave detection pressure PM2 determined in SA10. In the subsequent SA12, in this state, the cuff pulse wave signal SM1 (ie, the cuff pulse wave CW) supplied from the pulse wave discrimination circuit 24 and the pressure pulse wave signal SM2 (ie, the pressure pulse wave PW) supplied from the pressure pulse wave sensor 46 in this state. ) For each beat. The cuff pulse wave CW and the pressure pulse wave PW read in SA12 correspond to the reference cuff pulse wave CWst and the reference pressure pulse wave PWst. Then, in SA13, the cuff pressure PC is rapidly exhausted to the atmospheric pressure by switching the exhaust control valve 16 to the rapid exhaust pressure state. In the flowcharts of FIGS. 9 and 10, SA4 to SA6 and SA13 correspond to the blood pressure measurement control of the cuff pressure control means 70.
[0048]
The subsequent SA14 corresponds to the correspondence determining means 78, and the systolic blood pressure value BP determined at SA7. SYS And diastolic blood pressure BP DIA , And the maximum value PW of the pressure pulse wave PW read in SA12 max And minimum value PW min Then, the pressure pulse wave blood pressure correspondence shown in FIG. 6 is determined.
[0049]
In SA15 corresponding to the correction coefficient determining means 86, a correction coefficient for determining the magnitude of the reference pressure pulse wave PWst read in SA12 to be equal to the magnitude of the reference cuff pulse wave CWst also read in SA12 is determined.
[0050]
Subsequently, the blood pressure monitoring routine shown in FIG. 11 will be described. First, at SB1, the pressure pulse wave PW supplied from the pressure pulse wave sensor 46 is read for one beat. Then, at SB2, the minimum value PW of the pressure pulse wave PW read at SB1 is set. min And maximum value PW max From the monitored diastolic blood pressure value MBP based on the pressure pulse wave blood pressure correspondence relationship determined in SA14 of FIG. DIA And monitored systolic blood pressure MBP SYS Is determined, and the determined monitored diastolic blood pressure value MBP is determined. DIA And monitored systolic blood pressure MBP SYS Is displayed on the display 34.
[0051]
In the following SB3, the monitored systolic blood pressure value MBP determined in SB2 is set. SYS Is a preset systolic blood pressure abnormality determination value TH SYS Or not, or the monitored diastolic blood pressure value MBP determined in the above SB2 DIA Is a preset diastolic blood pressure abnormality determination value TH DIA It is determined whether or not: If this determination is affirmed, there is a high possibility that the blood pressure is abnormal, so the above-described correspondence determination routine is executed again in order to quickly obtain a highly reliable blood pressure value BP by the cuff 10.
[0052]
On the other hand, if the determination in SB3 is negative, in SB4, the elapsed time from the execution of the correspondence determination routine to determine the pressure pulse wave blood pressure correspondence is set to about 10 minutes to 30 minutes. It is further determined whether the calibration period Tc has elapsed. Even when this determination is affirmed, the above-described correspondence determination routine is executed again.
[0053]
On the other hand, if the determination at SB4 is negative, then at SB5, whether the elapsed time since execution of SB6 and below, which will be described later, has passed the monitoring accuracy determination cycle Tw set to about 1 to 3 minutes. Determine whether or not. If this determination is denied, the above SB1 and subsequent steps are repeatedly executed to determine the monitor blood pressure value MBP for each beat.
[0054]
If the determination in SB5 is affirmative, SB6 and subsequent steps are executed to determine the accuracy of the monitored blood pressure value MBP. First, at SB6, the cuff pressure PC is controlled to the pulse wave detection pressure PM2 determined at SA10. This SB6 corresponds to the pulse wave detection pressure control of the cuff pressure control means 70.
[0055]
Then, in SB7, while the cuff pressure PC is controlled to the pulse wave detection pressure PM2, the cuff pulse signal SM1 supplied from the pulse wave discrimination circuit 24, that is, the cuff pulse wave CW is read for one beat, and the pressure is read. The pressure pulse wave signal SM2 supplied from the pulse wave sensor 46, that is, the pressure pulse wave PW is read for one beat. In the flowcharts shown in FIGS. 9 to 11, SA11 and SB7 correspond to the cuff pulse wave detecting means 84.
[0056]
Subsequent SB8 to SB9 are the same processing as the above SB2 to SB3. In SB8, based on the pressure pulse wave PW read in SB7, the monitored diastolic blood pressure value MBP DIA And monitored systolic blood pressure MBP SYS Is determined, and the determined monitored diastolic blood pressure value MBP is determined. DIA And monitored systolic blood pressure MBP SYS Is displayed on the display 34, and in SB9, the monitored systolic blood pressure value MBP determined in SB8 is displayed. SYS Is a preset systolic blood pressure abnormality determination value TH SYS Or not, or the monitored diastolic blood pressure value MBP determined in SB8 DIA Is a preset diastolic blood pressure abnormality determination value TH DIA It is determined whether or not: When the determination in SB9 is affirmative, the above-described correspondence determination routine is executed again. In FIG. 11, SB2 and SB8 correspond to the continuous blood pressure value determining means 80, and SB3 and SB9 correspond to the blood pressure abnormality determining means 82.
[0057]
On the other hand, if the determination in SB9 is negative, in SB10 corresponding to the comparison pulse wave determination means 88, the cuff pulse wave CW read in SB7 is determined as it is as the comparison cuff pulse wave CWc, and read in SB7. The pressure pulse wave PWc is corrected by using the correction coefficient determined in SA15 to correct the pressure pulse wave PWc.
[0058]
Subsequently, SB11 to SB12 corresponding to the blood pressure monitoring accuracy determination means 90 are executed. First, at SB11, the minimum point of the comparison cuff pulse wave CWc and the comparison pressure pulse wave PWc determined at SB10 are matched, and a peak difference, that is, an intensity difference d is calculated in that state. Then, in subsequent SB12, the intensity difference d calculated in SB11 is set to a preset mounting abnormality determination value TH. d It is determined whether or not exceeds. If this determination is denied, it is considered that the accuracy of the monitored blood pressure value MBP is maintained, and the blood pressure monitoring based on the monitored blood pressure value MBP is continued by repeatedly executing the above SB1 and below. However, if affirmed, it is highly likely that the mounting state of the pressure pulse wave sensor 46 is inappropriate. Try again.
[0059]
According to the above-described embodiment, the pressure pulse wave PW detected by the pressure pulse wave sensor 46 and the cuff pressure PC are converted to the minimum blood pressure value MBP by the blood pressure monitoring accuracy determination means 90 (SB11 to SB12). DIA The cuff pulse wave CW detected at a lower pressure is compared with the cuff pulse wave CW to determine the accuracy of the monitor blood pressure value MBP continuously determined by the blood pressure value continuous determination means 80 (SB2, SB8). In order to maintain the accuracy of the value MBP, it is not necessary to perform the blood pressure measurement using the cuff 10 in a short cycle and frequently update the pressure pulse wave blood pressure correspondence, so that the burden on the patient is reduced.
[0060]
Next, a second embodiment of the present invention will be described. In the following description, portions having the same configuration as the above-described embodiment are denoted by the same reference numerals, and description thereof will be omitted.
[0061]
The only difference between the second embodiment and the first embodiment is the method of determining the accuracy of the monitored blood pressure value MBP by the blood pressure monitoring accuracy determining means. In the first embodiment, the comparison pressure pulse wave PWc is used. It is desired to compare the size of the feature point of the comparison cuff pulse wave CWc with the size of the feature point of the comparison cuff pulse wave CWc. By comparing the shape of the comparison cuff pulse wave CWc with the shape, the accuracy of the monitored blood pressure value MBP is determined. Hereinafter, the blood pressure monitoring accuracy determination means 92 will be described in detail.
[0062]
The blood pressure monitoring accuracy determination means 92 compares the reference pressure pulse wave PWst and the reference cuff pulse wave CWst used for the determination of the correction coefficient by the correction coefficient determination means 86 with their minimum points coincident with each other. As shown in FIG. 12, the pulse wave segments are divided into a plurality of pulse wave segments C (n) (n = 1, 2,...) Perpendicularly to the time axis (ten segments in FIG. 12), and for each of the plurality of pulse wave segments C (n). Then, a reference area difference ΔAst (n) (n = 1, 2,...) Between the reference pressure pulse wave PWst and the reference cuff pulse wave CWst is calculated. Similarly, the comparison pressure pulse wave PWc and the comparison cuff pulse wave CWc determined by the comparison pulse wave determination means 88 for each monitoring accuracy determination cycle Tw also have an area difference for each pulse wave segment C (n). .., And the amount of change in the area difference ΔA (n) calculated for each monitoring accuracy determination cycle Tw with respect to the reference area difference ΔAst (n) (hereinafter, the area difference change amount) Q (n) (n = 1, 2,...)), And the pulse wave segment C (n) whose area difference change amount Q (n) exceeds a reference value set based on an experiment in advance. Determine the number of When the number of pulse wave segments C (n) in which the area difference change amount Q (n) exceeds the reference value is large, the difference between the shape of the cuff pulse wave CW and the shape of the pressure pulse wave PW is the blood pressure measurement. This means that the pressure pulse wave PW whose shape and / or size (or both) are inappropriate due to improper mounting of the pressure pulse wave sensor 46 is detected. It is thought that there is. Therefore, when the number of pulse wave segments C (n) in which the area difference change amount Q (n) exceeds the reference value exceeds the preset first determination reference segment number Nc1, the blood pressure value continuation is continued. It is determined that the accuracy of the monitoring blood pressure value MBP determined by the determining means 80 has decreased, and the optimal pressing position control means 74 is executed again to correct the mounting state of the pressure pulse wave sensor 46.
[0063]
Further, the blood pressure monitoring accuracy determination means 92 determines the accuracy of the monitored blood pressure value MBP based on the change tendency of the area difference ΔA (n). That is, the area difference ΔA (n) for each pulse wave segment C (n) calculated for each monitoring accuracy determination cycle Tw is compared with the reference area difference ΔAst (n), and the change tendency of the area difference ΔA (n) is calculated. And the number of pulse wave segments C (n) in which the change tendency of the area difference ΔA (n) is decreasing is determined, and the change in the area difference ΔA (n) is determined. The number of pulse wave segments C (n) in which the tendency is increasing or the number of pulse wave segments C (n) in which the changing tendency of the area difference ΔA (n) is decreasing is the ratio of the majority of all pulse wave segments. (For example, 80% to 90%), it is determined whether or not the number Nc2 exceeds the second determination reference section number Nc2. This judgment is for judging whether or not the changing tendency of the area difference ΔA (n) calculated for each pulse wave segment C (n) substantially coincides. If the change tendency of the area difference ΔA (n) for each pulse wave section C (n) does not substantially match, the mounting state of the pressure pulse wave sensor 46 becomes inappropriate, and the shape of the pressure pulse wave PW is distorted. Therefore, even when the above determination is denied, it is determined that the accuracy of the monitored blood pressure value MBP determined by the continuous blood pressure value determining means 80 has decreased, and the pressure pulse wave sensor 46 The optimum pressing position control means 74 is executed again to correct the mounting state.
[0064]
13 and 14 are flowcharts showing a main part of the control operation of the CPU 31 according to the second embodiment. FIG. 13 shows a part of a correspondence determination routine, and FIG. 14 shows a part of a blood pressure monitoring routine. Is shown.
[0065]
First, FIG. 13 will be described. Also in the second embodiment, the correspondence determination routine executes SA1 to SA15 in the same manner as in FIGS. 9 and 10 described above. Further, in the second embodiment, in SA16 subsequent to SA15, the reference cuff pulse wave CWst and the reference pressure pulse wave PWst read in SA12 are set to a plurality of pulse wave segments C ( n) (for example, 10 sections as shown in FIG. 12), and a reference area difference ΔAst (n) between the reference pressure pulse wave PWst and the reference cuff pulse wave CWst is calculated for each pulse wave section C (n). I do.
[0066]
Next, FIG. 14 will be described. Also in the second embodiment, in the blood pressure monitoring routine, the above-described SB1 to SB10 of FIG. 11 are executed. Then, in SC11 following SB10, the comparison cuff pulse wave CWc and the comparison pressure pulse wave PWc determined in SB10 coincide with each other at their minimum points, and the pulse wave segment C (n) is made in the same manner as SA16 in FIG. The area difference ΔA (n) is calculated every time.
[0067]
In subsequent SC12, for each pulse wave segment C (n), the area difference change amount Q is obtained by subtracting the reference area difference ΔAst (n) calculated in SA16 of FIG. 13 from the area difference ΔA (n) calculated in SC11. (N) is calculated. In subsequent SC13, the number of pulse wave sections C (n) in which the area difference change amount Q (n) calculated for each pulse wave section C (n) calculated in SC12 exceeds a preset reference value is determined. .
[0068]
Then, in SC14, it is determined whether or not the number of pulse wave segments C (n) determined in SC13 exceeds a preset first determination reference segment number Nc1. If this determination is affirmed, there is a high possibility that the state of attachment of the pressure pulse wave sensor 46 is inappropriate, and therefore, the correspondence determination routine is executed to correct the state of attachment of the pressure pulse wave 46. I do.
[0069]
If the determination in SC14 is denied, in SC15, the change tendency of the area difference ΔA (n) determined in SC11 with respect to the reference area difference ΔAst (n) determined in SA16 in FIG. n).
[0070]
Then, in SC16, the change tendency of the area difference ΔA (n) determined in SC15 determines the number of pulse wave segments C (n) that are increasing and the number of pulse wave segments C (n) that are decreasing. Then, by determining whether or not one of the numbers exceeds a preset second determination reference section number Nc2, the change in the area difference ΔA (n) determined for each pulse wave section C (n) is determined. It is determined whether or not the trends substantially match. Even if this determination is denied, there is a high possibility that the mounting state of the pressure pulse wave sensor 46 is inappropriate, so the correspondence determination routine is performed to correct the mounting state of the pressure pulse wave sensor 46. Execute. On the other hand, when the determination of SC16 is affirmative, it is considered that the accuracy of the monitored blood pressure value MBP is maintained, and thus the blood pressure monitoring based on the monitored blood pressure value MBP is continued by repeatedly executing the processing from SB1 onward. In the flowcharts shown in FIGS. 13 and 14, SA16 and SC11 to SC16 correspond to the blood pressure monitoring accuracy determination means 92.
[0071]
Also in the second embodiment described above, the pressure pulse wave PW detected by the pressure pulse wave sensor 46 and the cuff pressure PC are detected by the blood pressure monitoring accuracy determination means 92 (SA16, SC11 to SC16). DIA The cuff pulse wave CW detected at a lower pressure is compared with the cuff pulse wave CW to determine the accuracy of the monitor blood pressure value MBP continuously determined by the blood pressure value continuous determination means 80 (SB2, SB8). In order to maintain the accuracy of the value MBP, it is not necessary to perform the blood pressure measurement using the cuff 10 in a short cycle and frequently update the pressure pulse wave blood pressure correspondence, so that the burden on the patient is reduced.
[0072]
Next, a third embodiment of the present invention will be described. The third embodiment differs from the first embodiment only in the control function of the CPU 31. FIG. 15 is a functional block diagram illustrating a main part of a control function of the CPU 31 according to the third embodiment. The functional block diagram shown in FIG. 15 differs from the functional block diagram of FIG. 4 of the first embodiment in that the correction coefficient determining means 86 and the comparison pulse wave determining means 88 are not provided, and the blood pressure monitoring accuracy The determination means 94 only has a function of determining the accuracy of the monitored blood pressure value MBP.
[0073]
The blood pressure monitoring accuracy determination means 94 detects the area of the reference cuff pulse wave CWst detected at the time of blood pressure measurement by the cuff pulse wave detection means 84, that is, the reference cuff pulse wave area C_area (st), and the reference cuff pulse wave CWst. The area of the reference pressure pulse wave PWst, which is the pressure pulse wave PW detected by the pressure pulse wave sensor 46 substantially at the same time as the pressure pulse wave, that is, the reference pressure pulse wave area T_area (st) is calculated. An area ratio between the area C_area (st) and the reference pressure pulse wave area T_area (st), that is, a reference pulse wave area ratio RA (st) is calculated. Similarly, the cuff pulse wave area C_area and the pressure pulse wave area T_area are calculated for the cuff pulse wave CW detected at each monitoring accuracy determination cycle Tw and the pressure pulse wave PW corresponding to the cuff pulse wave CW. Then, a pulse wave area ratio RA between the cuff pulse wave area C_area and the pressure pulse wave area T_area is calculated. Further, the change rate (area ratio change rate) of the pulse wave area ratio RA with respect to the reference pulse wave area ratio RA (st) δ RA Is calculated. Note that the reference pulse wave area ratio RA (st) and the pulse wave area ratio RA may be any of the cuff pulse wave area C_area and the pressure pulse wave area T_area. For example, the cuff pulse wave area C_area may be denominator. Then, the reference pulse wave area ratio RA (st) is expressed by Expression 1, the pulse wave area ratio RA is expressed by Expression 2, and the area ratio change rate δ RA Is represented by Equation 3.
(Equation 1) RA (st) = T_area (st) / C_area (st)
(Equation 2) RA = T_area / C_area
(Equation 3) δ RA = (T_area / C_area) / (T_area (st) / C_area (st))
Equation 3 can be transformed into Equation 4 when transformed.
(Equation 4) δ RA = (T_area / T_area (st)) / (C_area / C_area (st))
Since Equation 4 represents the rate of change of the pressure pulse wave area T_area with respect to the rate of change of the cuff pulse wave area C_area, the area ratio change rate δ RA Greatly deviates from 1, it means that the difference between the cuff pulse wave area C_area and the pressure pulse wave area T_area is significantly different from that at the time of blood pressure measurement, and the mounting state of the pressure pulse wave sensor 46 is inappropriate. It is considered that the pressure pulse wave PW of an inappropriate size is detected due to the above. Therefore, the area ratio change rate δ RA Is not within the normal range set in advance to a range including 1, it is determined that the accuracy of the monitored blood pressure value MBP determined by the blood pressure value continuous determining means 80 has decreased, and the pressure pulse wave sensor 46 The optimal pressing position control means 74 is executed again to correct the mounting state.
[0074]
The blood pressure monitoring accuracy determining means 94 also determines the accuracy of the monitored blood pressure value MBP based on the changing tendency of the cuff pulse area C_area and the pressure pulse area T_area. That is, the cuff pulse wave area C_area calculated for each monitoring accuracy determination cycle Tw is compared with the cuff pulse wave area C_area calculated when the previous monitoring accuracy determination cycle Tw has elapsed, and the pressure pulse wave area T_area is determined. Is determined, the change tendency from the previous monitoring accuracy determination cycle Tw is determined, and it is determined whether or not the two change tendencies match. If the mounting state of the pressure pulse wave sensor 46 is maintained in an appropriate state, the change trends of the two should match. Therefore, even when the change trends do not match, the blood pressure value continuation determining means 80 determines It is determined that the accuracy of the monitored blood pressure value MBP has decreased, and the optimal pressing position control unit 74 is executed again to correct the mounting state of the pressure pulse wave sensor 46.
[0075]
16 and 17 are flowcharts showing a main part of the control operation of the CPU 31 according to the third embodiment. FIG. 16 shows a part of a correspondence determination routine, and FIG. 17 shows a part of a blood pressure monitoring routine. Is shown.
[0076]
First, FIG. 16 will be described. Also in the third embodiment, SA1 to SA13 are executed in the correspondence determination routine. Then, in SD14 following SA13, the reference cuff pulse wave area C_area (st) is calculated from the reference cuff pulse wave CWst read in SA12, and in SD15, the reference pressure pulse wave area T_area is calculated from the reference pressure pulse wave PWst read in SA12. (St) is calculated. Then, in SD16, the reference pulse wave area ratio RA (st) is calculated by dividing the reference pressure pulse wave area T_area (st) calculated in SD15 by the reference cuff pulse wave area C_area (st) calculated in SD14. .
[0077]
Next, FIG. 17 will be described. Also in the third embodiment, in the blood pressure monitoring routine, the above-described SB1 to SB9 of FIG. 11 are executed. Then, in SE10 following SB9, the area of the cuff pulse wave CW read in SB7, that is, the cuff pulse wave area C_area, is calculated, and in SE11, the area of the pressure pulse wave PW read in SB7, that is, the pressure pulse wave area T_area is calculated. I do.
[0078]
In subsequent SE12, the pulse wave area ratio RA is calculated by dividing the pressure pulse wave area T_area calculated in SE11 by the cuff pulse wave area C_area calculated in SE10. In subsequent SE13, the area ratio RA calculated in SE12 is divided by the reference area ratio RA (st) calculated in SD16 in FIG. RA Is calculated.
[0079]
In subsequent SE14, the area ratio change rate δ calculated in SE13 RA Is determined to be a value within a normal range preset in a range including 1. If this determination is denied, there is a high possibility that the mounting state of the pressure pulse wave sensor 46 is inappropriate. Therefore, in order to correct the mounting state of the pressure pulse wave sensor 46, Execute the routine again.
[0080]
On the other hand, if the determination in SE14 is affirmative, in SE15, the change tendency of the cuff pulse wave area C_area calculated in SE10 with respect to the previously calculated cuff pulse wave area C_area, and the pressure pulse wave area T_area calculated in SE11 are determined. Is compared with the previously calculated change tendency with respect to the pressure pulse wave area T_area to determine whether or not the change trends are different. If this determination is affirmative, that is, even if the two change trends are different, there is a high possibility that the mounting state of the pressure pulse wave sensor 46 is inappropriate, so the above-described correspondence determination routine is performed. Try again.
[0081]
On the other hand, if the determination in SE15 is negative, it is considered that the accuracy of the monitored blood pressure value MBP is maintained, so that the blood pressure monitoring based on the monitored blood pressure value MBP is continued by repeatedly executing the processing from SB1 onward. In the flowcharts shown in FIGS. 16 and 17, SD14 to SD16 and SE10 to SE15 correspond to the blood pressure monitoring accuracy determination means 94.
[0082]
Also in the third embodiment described above, the pressure pulse wave PW detected by the pressure pulse wave sensor 46 and the cuff pressure PC are determined by the blood pressure monitoring accuracy determination means 94 (SD14 to SD16, SE10 to SE15). DIA The cuff pulse wave CW detected at a lower pressure is compared with the cuff pulse wave CW to determine the accuracy of the monitor blood pressure value MBP continuously determined by the blood pressure value continuous determination means 80 (SB2, SB8). In order to maintain the accuracy of the value MBP, it is not necessary to perform the blood pressure measurement using the cuff 10 in a short cycle and frequently update the pressure pulse wave blood pressure correspondence, so that the burden on the patient is reduced.
[0083]
Next, a fourth embodiment of the present invention will be described. The fourth embodiment is different from the third embodiment only in the method of determining the accuracy of the monitored blood pressure value MBP by the blood pressure monitoring accuracy determining means. In the third embodiment, the cuff pulse wave area T_area and Although the accuracy of the monitored blood pressure value MBP is determined based on the comparison with the pressure pulse wave area T_area, the blood pressure monitoring accuracy determining means (reference numeral 96) of the fourth embodiment determines the cuff pulse wave CW and the pressure pulse. The accuracy of the monitored blood pressure value MBP is determined based on the waveform correlation graphic drawn by the wave PW. Hereinafter, the blood pressure monitoring accuracy determination means 96 will be described in detail.
[0084]
First, the blood pressure monitoring accuracy determining means 96 determines the magnitude of the reference cuff pulse wave CWst detected by the cuff pulse wave detecting means 84 at the time of blood pressure measurement and the pressure pulse at substantially the same time as when the reference cuff pulse wave CWst is detected. From the magnitude of the reference pressure pulse wave PWst, which is the pressure pulse wave PW detected by the wave sensor 46, a reference waveform correlation graphic as illustrated in FIG. 18 is created, and the bulging length of the reference waveform correlation graphic (hereinafter referred to as the bulge length) , Lst). Similarly, a waveform correlation pattern is created for the cuff pulse wave CW detected in each monitoring accuracy determination cycle Tw and the pressure pulse wave PW corresponding to the cuff pulse wave CW, and the swelling of the waveform correlation pattern is performed. Determine the length L. The waveform correlation graphic (or reference waveform correlation graphic) is created as follows. That is, since the pressure pulse wave PW and the cuff pulse wave CW are a set of the pressure pulse wave signal SM2 or the cuff pulse wave signal SM1 collected at each predetermined sampling period, the pressure pulse wave PW and the cuff pulse wave CW And a two-dimensional graph 102 composed of an axis 98 representing the magnitude of the pressure pulse wave PW and an axis 100 representing the magnitude of the cuff pulse wave CW. It is created by sequentially plotting points at positions determined by the cuff pulse wave signal SM1. The bulge length L is two points d perpendicular to the straight line S1 connecting the minimum point a and the maximum point b of the waveform correlation graphic and passing through the middle point of the straight line S1 at the intersection d with the waveform correlation graphic. , E.
[0085]
Further, the blood pressure monitoring accuracy determining means 96 determines the difference d between the bulging length L and the reference bulging length Lst determined for each monitoring accuracy determining cycle Tw. L Is calculated. The more similar the shape of the pressure pulse wave PW and the shape of the cuff pulse wave CW, the smaller the bulging length L of the waveform correlation graphic, and the shape of the pressure pulse wave PW and the shape of the cuff pulse wave CW completely match. In this case, since the waveform correlation graphic becomes a straight line S1 and the bulge length L becomes zero, the bulge length difference d L Is large, it means that the difference between the shape of the pressure pulse wave PW and the shape of the cuff pulse wave CW is significantly different from that at the time of measuring the blood pressure, and the mounting state of the pressure pulse wave sensor 46 has become inappropriate. Therefore, it is considered that the pressure pulse wave PW having an accurate shape is not detected. Therefore, the blood pressure monitoring accuracy determining means 96 determines the difference d in the bulging length. L Is a predetermined judgment reference value TH dL Is exceeded, it is determined that the accuracy of the monitored blood pressure value MBP determined by the blood pressure value continuation determining means 80 has decreased, and the optimal pressing position control means 74 is used to correct the mounting state of the pressure pulse wave sensor 46. Try again.
[0086]
19 and 20 are flowcharts showing a main part of the control operation of the CPU 31 according to the fourth embodiment. FIG. 19 shows a part of a correspondence determination routine, and FIG. 20 shows a part of a blood pressure monitoring routine. Is shown.
[0087]
First, FIG. 19 will be described. Also in the fourth embodiment, SA1 to SA13 are executed in the correspondence determination routine. Then, in SF14 following SA13, the reference waveform correlation graphic is determined based on the reference cuff pulse wave CWst and the reference pressure pulse wave PWst read in SA12, and in subsequent SF15, the bulging length of the reference waveform correlation graphic determined in SF14. That is, the reference bulge length Lst is determined.
[0088]
Next, FIG. 20 will be described. Also in the fourth embodiment, in the blood pressure monitoring routine, the above-described SB1 to SB9 of FIG. 11 are executed. Then, in SG10 following SB9, a waveform correlation graphic is determined based on the cuff pulse wave CW and pressure pulse wave PW read in SB7, and in SG11, the bulging length L of the waveform correlation graphic determined in SG10 is determined. .
[0089]
In the following SG12, the difference d of the bulge length is obtained by subtracting the reference bulge length Lst determined in SF15 in FIG. 19 from the bulge length L calculated in SG11. L Is calculated. And in SG13, the difference d of the bulging length L Is a predetermined reference value TH dL It is determined whether or not exceeds. If this determination is affirmed, there is a high possibility that the mounting state of the pressure pulse wave sensor 46 is inappropriate. Execute the routine again.
[0090]
On the other hand, if the determination in SG13 is negative, it is considered that the accuracy of the monitored blood pressure value MBP is maintained, so that the blood pressure monitoring based on the monitored blood pressure value MBP is continued by repeatedly executing the processing of SB1 and lower. In the flowcharts shown in FIGS. 19 and 20, SF14 to SF15 and SG10 to SG13 correspond to the blood pressure monitoring accuracy determination means 96.
[0091]
Also in the fourth embodiment, the pressure pulse wave PW detected by the pressure pulse wave sensor 46 and the cuff pressure PC are determined by the blood pressure monitoring accuracy determination means 96 (SF14 to SF15, SG10 to SG13) to the minimum blood pressure value MBP. DIA The cuff pulse wave CW detected at a lower pressure is compared with the cuff pulse wave CW to determine the accuracy of the monitor blood pressure value MBP continuously determined by the blood pressure value continuous determination means 80 (SB2, SB8). In order to maintain the accuracy of the value MBP, it is not necessary to perform the blood pressure measurement using the cuff 10 in a short cycle and frequently update the pressure pulse wave blood pressure correspondence, so that the burden on the patient is reduced.
[0092]
Although the embodiments of the present invention have been described in detail with reference to the drawings, the present invention is applicable to other aspects.
[0093]
For example, in the above-described embodiment, the pressure pulse wave PW continuously detected by the pressure pulse wave sensor 46 may be displayed on the display 34. When the pressure pulse wave detection probe 36 is attached to the downstream portion of the cuff 10, the pressure pulse wave PW cannot be detected temporarily when the blood pressure measurement is performed by the cuff 10, so that the pressure pulse wave PW Is also interrupted temporarily, but in the above-described embodiment, since the blood pressure measurement using the cuff 10 is not performed so frequently, the period during which the pressure pulse wave PW is continuously displayed is also long. Become.
[0094]
In the first and second embodiments described above, the correction coefficient is for making the size of the reference cuff pulse wave CWst and the size of the reference pressure pulse wave PWst the same. In addition, a correction coefficient for making the cycle of the reference cuff pulse wave CWst equal to the cycle of the reference pressure pulse wave PWst may be determined.
[0095]
In the first embodiment described above, the comparison of the positions of the characteristic points of the cuff pulse wave for comparison and the characteristic points of the pressure pulse wave for comparison is only the magnitude component, but in addition to that, or Instead, a periodic component (time component) may be compared.
[0096]
In the second embodiment, the accuracy of the monitored blood pressure value MBP is determined based on the number of pulse wave segments C (n) in which the area difference change amount Q (n) exceeds the reference value. Although the accuracy of the monitored blood pressure value MBP is determined based on the change tendency of the difference ΔA (n), only one of them may be determined.
[0097]
In the third embodiment, the rate of change of the area ratio (pulse wave area ratio) RA between the cuff pulse wave area C_area and the pressure pulse wave area T_area, that is, the area ratio change rate δ RA And the accuracy of the monitored blood pressure value MBP is also determined based on the changing tendency of the cuff pulse area C_area and the changing tendency of the pressure pulse wave area T_area. Only one of them may be used.
[0098]
In the above-described second embodiment, the cuff pulse wave CW and the pressure pulse wave PW are divided into a plurality of pulse wave segments C (n), and the area difference ΔA (n) for each of the pulse wave segments C (n). ), The shape of the cuff pulse wave CW is compared with the shape of the pressure pulse wave PW. However, by calculating the cross-correlation coefficient between the cuff pulse wave CW and the pressure pulse wave PW, the cuff pulse wave is calculated. The shape of the wave CW and the shape of the pressure pulse wave PW may be compared.
[0099]
In the above-described fourth embodiment, the accuracy of the monitoring blood pressure value MBP is determined based on the bulging length L of the waveform correlation graphic. However, the accuracy of the monitoring blood pressure value MBP is determined based on the area of the waveform correlation graphic. It may be determined.
[0100]
In the first and second embodiments, a set of comparison pulse waves is determined by correcting the detected pressure pulse wave PW, and the monitored blood pressure value MBP is determined based on the set of comparison pulse waves. In the third and fourth embodiments, the accuracy of the monitored blood pressure value MBP is determined by using the detected cuff pulse wave CW and the pressure pulse wave PW without correcting both of them. However, in the first embodiment and the second embodiment, the detected cuff pulse wave CW and the detected pressure pulse wave PW may be used without correction together, or may be used as a set in the third embodiment and the fourth embodiment. The comparison pulse wave may be determined, and the accuracy of the monitored blood pressure value MBP may be determined based on the set of comparison pulse waves.
[0101]
In the present invention, various other changes can be made without departing from the gist of the present invention.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a configuration of a non-invasive continuous blood pressure monitoring device to which the present invention has been applied.
FIG. 2 is a diagram illustrating the configuration of a pressure pulse wave detection probe in detail.
FIG. 3 is a diagram showing a pressing surface of a pressure pulse wave sensor provided in the pressure pulse wave detection probe of FIG. 2;
FIG. 4 is a functional block diagram showing a main part of a control function of a CPU in the non-invasive continuous blood pressure monitoring device of FIG. 1;
FIG. 5 is a diagram for explaining an optimum pressing force HDPO determined by the pressing force control means of FIG. 4;
6 is a diagram showing an example of a pressure pulse wave blood pressure correspondence determined by the correspondence determination means of FIG. 4;
FIG. 7 is a diagram illustrating a reference cuff pulse wave CWst and a reference pressure pulse wave PWst corrected by a correction coefficient in a state where rising points (minimum points) are matched.
8 is a diagram showing the comparison pressure pulse wave PWst and the comparison cuff pulse wave CWst determined by the comparison pulse wave determination means in FIG. 4 in a state where the minimum points are matched.
9 is a flowchart showing a main part of the control operation of the CPU shown in the functional block diagram of FIG. 4, and is a diagram showing a correspondence determination routine.
10 is a flowchart showing a main part of the control operation of the CPU shown in the functional block diagram of FIG. 4, and is a diagram showing a correspondence determination routine.
11 is a flowchart showing a main part of the control operation of the CPU shown in the functional block diagram of FIG. 4, and is a diagram showing a blood pressure monitoring routine.
FIG. 12 is a diagram showing a state in which a reference pressure pulse wave PWst and a reference cuff pulse wave CWst are divided into a plurality of pulse wave segments C (n) perpendicular to the time axis, with their minimum points being matched. It is.
FIG. 13 is a flowchart showing a main part of the control operation of the CPU according to the second embodiment, and is a diagram showing a part of a correspondence determination routine;
FIG. 14 is a flowchart illustrating a main part of a control operation of the CPU according to the second embodiment, and is a diagram illustrating a part of a blood pressure monitoring routine.
FIG. 15 is a functional block diagram illustrating a main part of a control function of a CPU according to a third embodiment.
FIG. 16 is a flowchart showing a main part of a control operation of the CPU according to the third embodiment, which is a diagram showing a part of a correspondence determination routine;
FIG. 17 is a flowchart showing a main part of a control operation of the CPU according to the third embodiment, and is a diagram showing a part of a blood pressure monitoring routine.
FIG. 18 is a diagram illustrating an example of a reference waveform correlation graphic created in the fourth embodiment.
FIG. 19 is a flowchart showing a main part of the control operation of the CPU according to the fourth embodiment, which is a diagram showing a part of a correspondence determination routine.
FIG. 20 is a flowchart showing a main part of a control operation of the CPU according to the fourth embodiment, and is a diagram showing a part of a blood pressure monitoring routine.
[Explanation of symbols]
8: Non-invasive continuous blood pressure monitoring device
10: Cuff
70: Cuff pressure control means
72: blood pressure value determining means
78: Correspondence determination means
80: blood pressure value continuous determination means
84: Cuff pulse wave detecting means
86: correction coefficient determining means
88: Comparative pulse wave determination means
90: blood pressure monitoring accuracy determination means
92: blood pressure monitoring accuracy determination means
94: blood pressure monitoring accuracy determination means
96: blood pressure monitoring accuracy determination means
102: Two-dimensional graph

Claims (7)

生体の一部に装着されるカフと、
該カフの圧迫圧力を制御するカフ圧制御手段と、
該カフ圧制御手段により前記カフの圧迫圧力が徐速変化させられる過程において得られる信号に基づいて、該生体の血圧値を決定する血圧値決定手段と、
該生体の所定の動脈に向かって押圧させられる圧脈波センサを用いて該動脈から発生する圧脈波を逐次検出する圧脈波検出装置と、
前記血圧値決定手段により決定された血圧値と前記圧脈波検出装置により検出された圧脈波の大きさとの間の圧脈波血圧対応関係を決定する対応関係決定手段と、
該圧脈波血圧対応関係を用い、前記圧脈波検出装置により逐次検出される圧脈波の大きさから監視血圧値を連続的に決定する血圧値連続決定手段とを備えた非観血連続血圧監視装置であって、
前記カフ圧制御手段により前記カフの圧迫圧力が平均血圧値よりも低い圧力とされた状態で、該カフ内の圧力振動であるカフ脈波を検出するカフ脈波検出手段と、
該カフ脈波検出手段により検出されたカフ脈波と、該カフ脈波の検出と同時期に前記圧脈波検出装置により検出された圧脈波との比較に基づいて、逐次、前記血圧値連続決定手段により決定された監視血圧値の精度を判定する血圧監視精度判定手段と
を含むことを特徴とする非観血連続血圧監視装置。A cuff attached to a part of a living body,
Cuff pressure control means for controlling the compression pressure of the cuff,
Blood pressure value determining means for determining a blood pressure value of the living body based on a signal obtained in a process in which the cuff pressure is gradually changed by the cuff pressure control means,
A pressure pulse wave detection device that sequentially detects pressure pulse waves generated from the artery using a pressure pulse wave sensor pressed toward a predetermined artery of the living body,
Correspondence determination means for determining a pressure pulse wave blood pressure correspondence between the blood pressure value determined by the blood pressure value determination means and the magnitude of the pressure pulse wave detected by the pressure pulse wave detection device,
A blood pressure value continuation determining means for continuously determining a monitoring blood pressure value from the magnitude of the pressure pulse wave sequentially detected by the pressure pulse wave detecting device using the pressure pulse wave blood pressure correspondence relationship; A blood pressure monitoring device,
Cuff pulse wave detecting means for detecting a cuff pulse wave, which is a pressure oscillation in the cuff, in a state where the cuff compression pressure is set to a pressure lower than an average blood pressure value by the cuff pressure control means,
Based on a comparison between the cuff pulse wave detected by the cuff pulse wave detecting means and the pressure pulse wave detected by the pressure pulse wave detection device at the same time as the detection of the cuff pulse wave, the blood pressure value is sequentially determined. A non-invasive continuous blood pressure monitoring device, comprising: a blood pressure monitoring accuracy determination unit that determines the accuracy of the monitored blood pressure value determined by the continuous determination unit. 請求項１に記載の非観血連続血圧監視装置であって、
前記血圧値決定手段により血圧値が決定されたときに前記カフ脈波検出手段および前記圧脈波検出装置によりそれぞれ検出されたカフ脈波および圧脈波の大きさを同じにするために、そのカフ脈波および圧脈波の少なくとも一方を補正する補正係数を決定する補正係数決定手段と、
該補正係数決定手段により決定された補正係数を用いて、逐次、前記カフ脈波検出手段により検出されたカフ脈波および前記圧脈波検出装置により検出された圧脈波の少なくとも一方を補正して、比較用の一組のカフ脈波および圧脈波を決定する比較脈波決定手段とを備え、
前記血圧監視精度判定手段は、該比較脈波決定手段により決定されたカフ脈波および圧脈波の互いの最小点を一致させた状態で、それらカフ脈波および圧脈波の所定の特徴点の位置を比較することによって、逐次、前記血圧値連続決定手段により決定された監視血圧値の精度を判定するものであることを特徴とする非観血連続血圧監視装置。It is a non-invasive continuous blood pressure monitoring device according to claim 1,
When the blood pressure value is determined by the blood pressure value determining means, the cuff pulse wave detecting means and the pressure pulse wave detected by the pressure pulse wave detecting device to make the same size of the cuff pulse wave and the pressure pulse wave, respectively, Correction coefficient determining means for determining a correction coefficient for correcting at least one of the cuff pulse wave and the pressure pulse wave,
Using the correction coefficient determined by the correction coefficient determination means, sequentially correcting at least one of the cuff pulse wave detected by the cuff pulse wave detection means and the pressure pulse wave detected by the pressure pulse wave detection device. A comparison pulse wave determining means for determining a set of cuff pulse waves and pressure pulse waves for comparison,
The blood pressure monitoring accuracy determining means determines a predetermined characteristic point of the cuff pulse wave and the pressure pulse wave in a state where the minimum points of the cuff pulse wave and the pressure pulse wave determined by the comparison pulse wave determining means match each other. A non-invasive continuous blood pressure monitoring device for sequentially determining the accuracy of the monitored blood pressure value determined by the blood pressure value continuous determining means by comparing the positions of the monitored blood pressure values. 請求項１に記載の非観血連続血圧監視装置であって、
前記血圧値決定手段により血圧値が決定されたときに前記カフ脈波検出手段および前記圧脈波検出装置によりそれぞれ検出されたカフ脈波および圧脈波の大きさを同じにするために、そのカフ脈波および圧脈波の少なくとも一方を補正する補正係数を決定する補正係数決定手段と、
該補正係数決定手段により決定された補正係数を用いて、逐次、前記カフ脈波検出手段により検出されたカフ脈波および前記圧脈波検出装置により検出された圧脈波の少なくとも一方を補正して、比較用の一組のカフ脈波および圧脈波を決定する比較脈波決定手段とを備え、
前記血圧監視精度判定手段は、該比較脈波決定手段により決定されたカフ脈波および圧脈波の形状の比較に基づいて、逐次、前記血圧値連続決定手段により決定された監視血圧値の精度を判定するものであることを特徴とする非観血連続血圧監視装置。It is a non-invasive continuous blood pressure monitoring device according to claim 1,
When the blood pressure value is determined by the blood pressure value determining means, the cuff pulse wave detecting means and the pressure pulse wave detected by the pressure pulse wave detecting device to make the same size of the cuff pulse wave and the pressure pulse wave, respectively, Correction coefficient determining means for determining a correction coefficient for correcting at least one of the cuff pulse wave and the pressure pulse wave,
Using the correction coefficient determined by the correction coefficient determination means, sequentially correcting at least one of the cuff pulse wave detected by the cuff pulse wave detection means and the pressure pulse wave detected by the pressure pulse wave detection device. A comparison pulse wave determining means for determining a set of cuff pulse waves and pressure pulse waves for comparison,
The blood pressure monitoring accuracy determining means determines the accuracy of the monitored blood pressure value sequentially determined by the blood pressure value continuous determining means based on the comparison of the shapes of the cuff pulse wave and the pressure pulse wave determined by the comparative pulse wave determining means. A non-invasive continuous blood pressure monitoring device characterized in that: 請求項３に記載の非観血連続血圧監視装置であって、
前記血圧監視精度判定手段は、前記比較脈波決定手段により決定されたカフ脈波および圧脈波を、互いの最小点を一致させた状態で時間軸に垂直に複数の脈波区分に分割して、該複数の脈波区分毎に面積差を算出し、該複数の面積差のそれぞれの時間変化が所定の基準値を超えた脈波区分の数に基づいて、逐次、前記血圧値連続決定手段により決定された監視血圧値の精度を判定するものであることを特徴とする非観血連続血圧監視装置。It is a non-invasive continuous blood pressure monitoring device according to claim 3,
The blood pressure monitoring accuracy determination means divides the cuff pulse wave and the pressure pulse wave determined by the comparison pulse wave determination means into a plurality of pulse wave segments perpendicular to the time axis in a state where the minimum points coincide with each other. Calculating an area difference for each of the plurality of pulse wave segments, and sequentially determining the blood pressure value based on the number of pulse wave segments in which the time change of each of the plurality of area differences exceeds a predetermined reference value. A non-invasive continuous blood pressure monitoring device for determining the accuracy of the monitored blood pressure value determined by the means. 請求項３に記載の非観血連続血圧監視装置であって、
前記血圧監視精度判定手段は、前記比較脈波決定手段により決定されたカフ脈波および圧脈波を、互いの最小点を一致させた状態で時間軸に垂直に複数の脈波区分に分割して、該複数の脈波区分毎に面積差を算出し、該複数の面積差の時間変化傾向が一致するか否かに基づいて、逐次、前記血圧値連続決定手段により決定された監視血圧値の精度を判定するものであることを特徴とする非観血連続血圧監視装置。It is a non-invasive continuous blood pressure monitoring device according to claim 3,
The blood pressure monitoring accuracy determination means divides the cuff pulse wave and the pressure pulse wave determined by the comparison pulse wave determination means into a plurality of pulse wave segments perpendicular to the time axis in a state where the minimum points coincide with each other. Calculating the area difference for each of the plurality of pulse wave segments, and based on whether or not the time-varying trends of the plurality of area differences match, the monitoring blood pressure value sequentially determined by the blood pressure value continuation determining means. Non-invasive continuous blood pressure monitoring device for determining the accuracy of blood pressure. 請求項１に記載の非観血連続血圧監視装置であって、
前記血圧監視精度判定手段は、前記カフ脈波検出手段により検出されたカフ脈波の面積の時間変化と、該カフ脈波の検出と同時期に前記圧脈波検出装置により検出された圧脈波の面積の時間変化との比較に基づいて、逐次、前記血圧値連続決定手段により決定された監視血圧値の精度を判定するものであることを特徴とする非観血連続血圧監視装置。It is a non-invasive continuous blood pressure monitoring device according to claim 1,
The blood pressure monitoring accuracy determination means includes a time change in the area of the cuff pulse wave detected by the cuff pulse wave detection means, and a pressure pulse detected by the pressure pulse wave detection device at the same time as the detection of the cuff pulse wave. A non-invasive continuous blood pressure monitoring device for sequentially determining the accuracy of a monitored blood pressure value determined by the blood pressure value continuous determining means based on a comparison with a time change of a wave area. 請求項１に記載の非観血連続血圧監視装置であって、
前記血圧監視精度判定手段は、カフ脈波の大きさを表す軸と圧脈波の大きさを表す軸とからなる二次元グラフに、前記カフ脈波検出手段により検出されたカフ脈波と、前記圧脈波検出装置により検出された圧脈波のうち該カフ脈波に対応する圧脈波とにより描かれる波形相関図形に基づいて、逐次、前記血圧値連続決定手段により決定された監視血圧値の精度を判定するものであることを特徴とする非観血連続血圧監視装置。It is a non-invasive continuous blood pressure monitoring device according to claim 1,
The blood pressure monitoring accuracy determination means, a two-dimensional graph consisting of an axis representing the magnitude of the cuff pulse wave and an axis representing the magnitude of the pressure pulse wave, cuff pulse wave detected by the cuff pulse wave detection means, Based on the waveform correlation graphic drawn by the pressure pulse wave corresponding to the cuff pulse wave among the pressure pulse waves detected by the pressure pulse wave detection device, the monitor blood pressure sequentially determined by the blood pressure value continuous determination means A non-invasive continuous blood pressure monitoring device for determining the accuracy of a value.
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