JP3978924B2 - Continuous blood pressure monitoring device - Google Patents

Description

【００２６】
第２相関係数算出手段８２は、前記最大圧力検出素子から出力された圧脈波形と、その最大圧力検出素子からの距離が第１距離Ｌ₁ よりも小さい距離に設定された第２距離Ｌ₂ である第２圧力検出素子Ｅ₂ から出力された圧脈波形との第２相関係数ｒ₂ を算出する。すなわち、上記第１相関係数算出手段８０と同様に、所定区間（たとえば１拍分）の、最大圧力検出素子から出力される光電脈波信号ＳＭ₂ と第２圧力検出素子Ｅ₂ から出力される光電脈波信号ＳＭ₂ とに基づいて、上記数式２に示す関係から第２相関係数ｒ₂ を逐次算出する。ここで、上記第２距離Ｌ₂ は、一般的な血管内径に基づいて決定される値であり、たとえば第１距離Ｌ₁ の１／５倍に設定される。なお、第２圧力検出素子Ｅ₂ も第１圧力検出素子Ｅ₁ と同様に２つ存在し、第２相関係数ｒ₂ も逐次２つの値が算出される。
【００２７】
最適押圧力決定手段８４は、押圧位置制御手段７８により幅方向移動装置６４が移動させられた場合、押圧位置制御手段７８により押圧位置が制御された圧脈波センサ４６から逐次出力される圧脈波信号ＳＭ₂ に基づいて、最適押圧力Ｐ_HDPOを決定する。すなわち、図６の圧力検出素子の位置と相関係数との関係を示す図にも示されるように、第１相関係数算出手段８０により算出された２つの第１相関係数ｒ₁ が、最適押圧力Ｐ_HDPOとして許容される押圧力の上限値を判断するために予め実験により決定された第１基準値ＴＨ₁ （たとえば０．９）以上となるように、且つ第２相関係数算出手段８２により算出された２つの第２相関係数ｒ₂ が、最適押圧力Ｐ_HDPOとして許容される押圧力の下限値を判断するために予め実験により決定された第２基準値ＴＨ₂ （たとえば０．９５）以上となるように圧脈波センサ４６の押圧力を制御し、第１相関係数ｒ₁ が第１基準値ＴＨ₁ 以上となり、第２相関係数ｒ₂ が第２基準値ＴＨ₂ 以上となったときの押圧力を最適押圧力Ｐ_HDPOに決定する。
【００２８】
すなわち、最適押圧力を決定する条件が満たされた場合には、まず押圧装置６２による圧脈波センサ４６の押圧力が予め設定された初期値、たとえば５０ｍｍＨｇとされ、その状態で第１相関係数ｒ₁ および第２相関係数ｒ₂ が算出され、第１相関係数ｒ₁ が第１基準値ＴＨ₁ 以下である場合は、押圧力が所定値（たとえば２０ｍｍＨｇ）だけ強められ、第２相関係数ｒ₂ が第２基準値ＴＨ₂ 以下である場合は、押圧力が所定値（たとえば２０ｍｍＨｇ）だけ弱められ、再び第１相関係数ｒ₁ および第２相関係数ｒ₂ が算出される。上記作動が第１相関係数ｒ₁ が第１基準値ＴＨ₁ 以上となり且つ第２相関係数ｒ₂ が第２基準値ＴＨ₂ 以上となるまで繰り返され、その条件を満たした時点の押圧力が最適押圧力Ｐ_HDPOに決定される。
【００２９】
第１相関係数ｒ₁ が第１基準値ＴＨ₁ 以下である場合は、押圧力が不足している場合である。すなわち、撓骨動脈５６の血管壁の一部が略平坦となるほどには押圧されないため、最大圧力検出素子から出力される圧脈波に比べ、その最大圧力検出素子から第１距離Ｌ₁ 離れた第１圧力検出素子Ｅ₁ から出力される圧脈波の強度が弱いので、第１相関係数ｒ₁ が低くなるのである。また、第２相関係数ｒ₂ が第２基準値ＴＨ₂ 以下である場合は、押圧力が強すぎる場合である。すなわち、押圧力が強すぎるために、第１圧力検出素子Ｅ₁ よりも最大圧力検出素子に近い側に位置する第２圧力検出素子Ｅ₂ により検出された圧脈波でさえも歪んでしまい第２相関係数ｒ₂ が低下するのである。従って、第１相関係数ｒ₁ が第１基準値ＴＨ₁ 以下である場合は押圧力を強める方向に圧脈波センサ４６の押圧力を制御し、第２相関係数ｒ₂ が第２基準値ＴＨ₂ 以下である場合は、押圧力を弱める方向に圧脈波センサ４６の押圧力を制御する。
【００３０】
さらに詳細に上記最適押圧力決定手段８４を説明すると、アクティブエレメントＥ₀ の両側において、第１相関係数ｒ₁ および第２相関係数ｒ₂ がそれぞれ一つづつ、合計４つの相関係数ｒ₁ ・ｒ₂ が算出されるので、第１相関係数ｒ₁ が第１基準値ＴＨ₁ より上か下か、および第２相関係数ｒ₂ が第２基準値ＴＨ₂ より上か下かにより分類すると、図７に示すように１６パターンが考えられる。なお、図７の「○」は、第１相関係数ｒ₁ および第２相関係数ｒ₂ がそれぞれ第１基準値ＴＨ₁ または第２基準値ＴＨ₂ 以上であることを示し、「×」は、それぞれ基準値ＴＨ₁ ・ＴＨ₂ よりも下であることを示している。
【００３１】
図７において、パターン１の場合は、押圧力は変更されない。従って、その時点の押圧力が最適押圧力とされる。パターン２の状態の場合、第１相関係数ｒ₁ および第２相関係数ｒ₂ が共に基準値以下であるので、最初は押圧力が増加させられ、第１相関係数ｒ₁ が増加しなければ、逆に押圧力が減少させられる。または、最初は押圧力が減少させられ、第２相関係数ｒ₂ が減少しなければ、逆に押圧力が増加させられる。
【００３２】
パターン３〜５は、第２相関係数ｒ₂ はどちらも第２基準値ＴＨ₂ 以上であるが、少なくとも一方の第１相関係数ｒ₁ が第１基準値ＴＨ₁ よりも小さい場合であるので、押圧力が強められる。パターン６〜８は、第１相関係数ｒ₁ はどちらも第１基準値ＴＨ₁ 以上であるが、少なくとも一方の第２相関係数ｒ₂ が第２基準値ＴＨ₂ よりも小さい場合であるので、押圧力が弱められる。
【００３３】
そして、パターン９〜１６の場合は、押圧位置制御起動手段８６により、押圧位置制御手段７８が起動させられる。すなわち、押圧位置制御起動手段８６は、第１相関係数ｒ₁ および第２相関係数ｒ₂ がパターン９〜１６に示す押圧位置変更範囲内にある場合、押圧位置が不適切であると考えられるので、押圧位置制御手段７８による幅方向移動装置の制御を起動させ、圧脈波センサ４６の押圧位置を変更する。
【００３４】
押圧力修正手段８８は、最適押圧力決定手段８４により決定された最適押圧力Ｐ_HDPOを逐次修正する。すなわち、最適押圧力決定手段８４により最適押圧力Ｐ_HDPOが決定され、推定血圧値決定手段７６により、アクティブエレメントＥ₀ から出力される圧脈波信号ＳＭ₂ に基づいて推定血圧値ＭＢＰが逐次決定されている状態において、第１相関係数算出手段８０により逐次算出される第１相関係数ｒ₁ が第１基準値ＴＨ₁ 以下である場合は、押圧装置６２による圧脈波センサ４６の押圧力を所定値増加させ、第２相関係数算出手段８２により逐次算出される第２相関係数ｒ₂ が第２基準値ＴＨ₂ 以下である場合、押圧装置６２による圧脈波センサ４６の押圧力を所定値減少させる。
【００３５】
図８乃至図９は、上記演算制御装置２８の制御作動の要部を説明するフローチャートであって、図８はメインルーチンを示し、図９はメインルーチンにおいて最適押圧力を決定する必要があると判断された場合に実行される最適押圧力決定ルーチンを示している。
【００３６】
図８のステップＳＡ１（以下、ステップを省略する。）では、初回のＳＡ１の実行であるか否か、および前回に対応関係が更新されてからの経過時間が十数分乃至数十分程度に予め設定されたキャリブレーション周期を超えたか否かが判断される。通常はそのＳＡ１の判断が否定されるので、ＳＡ２において所定の押圧位置更新条件（ＡＰＳ起動条件）が成立したか否か、たとえば、圧脈波センサ４６の押圧面５４に配列された圧力検出素子のうちの最大振幅を検出するものが配列位置のうちの端部に位置する状態となったか否かなどが判断される。
【００３７】
初回の装着時など、圧脈波センサ４６の撓骨動脈５６に対する押圧位置がずれ、所定の押圧位置変更条件（ＡＰＳ起動条件）が成立する場合には、上記ＳＡ２の判断が肯定されるので、前記押圧位置制御手段７８に対応するＳＡ３のＡＰＳ制御ルーチンが実行される。このＡＰＳ制御ル−チンは、圧脈波センサ４６の各圧力検出素子によりそれぞれ検出された圧脈波信号ＳＭ₂ の振幅分布曲線の最大振幅を検出する素子が、圧力検出素子の略中心位置になるような最適押圧位置が決定されるとともに、そのときの最大振幅を検出する素子を中心位置圧力検出素子すなわちアクティブエレメントＥ₀ として設定する。従って、上記ＳＡ３は最大圧力検出素子決定手段７２にも対応する。
【００３８】
上記ＳＡ３のＡＰＳ制御ルーチンが実行されると、次に、前記最適押圧力決定手段８４に対応するＳＡ４のＨＤＰ制御ルーチンすなわち図９に詳しく示す最適押圧力決定ルーチンが実行される。
【００３９】
図９において、まずＳＢ１では、押圧装置６２による圧脈波センサ４６の押圧力が予め初期値として設定された５０ｍｍＨｇとされ、続くＳＢ２では、１つの圧脈波が発生し、上記アクティブエレメントＥ₀ 、そのアクティブエレメントＥ₀ の配列方向両側においてアクティブエレメントＥ₀ から５つ隣に位置する２つの第１圧力検出素子Ｅ₁ 、およびアクティブエレメントＥ₀ の両隣に位置する２つの第２圧力検出素子Ｅ₂ から、それぞれ一脈波分の圧脈波信号ＳＭ₂ が入力されたか否かが判断される。
【００４０】
上記ＳＢ２の判断が否定された場合は、ＳＢ２が繰り返し実行されることにより待機させられるが、肯定された場合は、続く第１相関係数算出手段８０に対応するＳＢ３において、上記ＳＢ２においてアクティブエレメントＥ₀ から入力された一拍分の圧脈波と、第１圧力検出素子Ｅ₁ から入力された一拍分の圧脈波との第１相関係数ｒ₁ が、前記数式２に基づいて算出される。
【００４１】
続く第２相関係数算出手段８２に対応するＳＢ４では、上記ＳＢ２においてアクティブエレメントＥ₀ から入力された一拍分の圧脈波と、第２圧力検出素子Ｅ₂ から入力された一拍分の圧脈波との第２相関係数ｒ₂ が、前記数式２に基づいて算出される。
【００４２】
続くＳＢ５では、上記ＳＢ３で算出された２つの第１相関係数ｒ₁ が、両方とも第１基準値ＴＨ₁ として予め決定されている０．９以上であり、且つ、上記ＳＢ４で算出された２つの第２相関係数ｒ₂ が、両方とも第２基準値ＴＨ₂ として予め決定されている０．９５以上であるか否か、すなわち、図７のパターン１の状態であるか否かが判断される。このＳＢ５の判断が肯定された場合は、押圧装置６２による圧脈波センサ４６の押圧力は最適であると判断され、その押圧力が最適押圧力Ｐ_HDPOに決定されて本ルーチンは終了させられ、図８のメインルーチンに戻って、ＳＡ５以降が実行される。
【００４３】
しかし、上記ＳＢ５の判断が否定された場合は、続くＳＢ６において、前記２つの第１相関係数ｒ₁ が両方とも０．９より小さく、且つ、前記２つの第２相関係数ｒ₂ が両方とも０．９５より小さいか否か、すなわち、図７のパターン２の状態であるか否かが判断される。この判断が肯定されると、続くＳＢ７では、今回の最適押圧力決定ルーチンの実行において、上記ＳＢ６の判断が肯定されたのは最初であるか否かが判断される。
【００４４】
上記ＳＢ７の判断が肯定された場合は、続くＳＢ８において、押圧装置６２による圧脈波センサ４６の押圧力が予め設定された所定値（たとえば２０ｍｍＨｇ）だけ増加させられて、前記ＳＢ２以降が繰り返される。一方、上記ＳＢ７の判断が否定された場合、すなわち、図７のパターン２の状態であると判断され、押圧力が所定値だけ増加させられたが、依然として図７のパターン２の状態であり、再び前記ＳＢ６の判断が肯定された場合は、ＳＢ９の判断が実行される。
【００４５】
ＳＢ９では、直前に前記ＳＢ３で算出された第１相関係数ｒ₁ が、その一回前に前記ＳＢ３で算出された第１相関係数ｒ₁ よりも大きいか否かが判断される。すなわち、前記ＳＢ８により押圧力が所定値増加させられたことにより、第１相関係数ｒ₁ が第１基準値ＴＨ₁ に近くなったか否かが判断される。このＳＢ９の判断が肯定された場合は、さらに押圧力を増加させるため、前記ＳＢ８が実行される。
【００４６】
しかし、上記ＳＢ９の判断が否定された場合、すなわち、押圧力を増加させたことにより、第１相関係数ｒ₁ が一層小さい値になってしまった場合は、押圧力の増減方向が逆であったと判断されて、続くＳＢ１０において、押圧装置６２による圧脈波センサ４６の押圧力が予め設定された所定値（たとえば２０ｍｍＨｇ）だけ減少させられた後、前記ＳＢ２以降が繰り返される。
【００４７】
前記ＳＢ６の判断が否定された場合、さらに続くＳＢ１１において、前記２つの第２相関係数ｒ₂ は両方とも０．９５以上であり、且つ、前記２つの第１相関係数ｒ₁ のうち少なくとも一方が０．９０より小さいか否か、すなわち、図７のパターン３〜５の状態であるか否かが判断される。
【００４８】
このＳＢ１１の判断が肯定された場合は、前記ＳＢ８が実行されて、押圧力が所定値だけ増加させられる。一方、ＳＢ１１の判断が否定された場合は、さらに続くＳＢ１２において、前記２つの第１相関係数ｒ₁ は両方とも０．９０以上であり、且つ、前記２つの第２相関係数ｒ₂ のうち少なくとも一方が０．９５より小さいか否か、すなわち、図７のパターン６〜８の状態であるか否かが判断される。この判断が肯定された場合は、前記ＳＢ１０が実行されて、押圧力が所定値だけ減少させられる。
【００４９】
しかし、上記ＳＢ１２の判断も否定された場合、すなわち、上記ＳＢ５、ＳＢ６、ＳＢ１１、およびＳＢ１２の判断が全て否定された場合は、図７のパターン９〜１６のいずれかに該当する押圧位置が不適切な場合であるので、図８のＳＡ３のＡＰＳ制御ルーチンが実行される。従って、上記ＳＢ５、ＳＢ６、ＳＢ１１、ＳＢ１２が押圧位置制御起動手段８６に対応する。図９の最適押圧力決定ルーチンは、ＡＰＳ制御ルーチン（図８のＳＡ３）により圧脈波センサ４６の押圧位置が最適押圧位置に制御された直後に実行されることから、通常は、押圧位置を変更する必要はない。すなわち、図７のパターン１〜８のいずれかに該当するため、上記ＳＢ１２の判断が否定されることはないのであるが、押圧力の決定作動中に体動等により圧脈波センサ４６の押圧位置がずれた場合は、上記ＳＢ１２の判断が否定される。
【００５０】
図８に戻って、上記ＳＡ４のＨＤＰ制御ルーチンが終了した後、または、前回対応関係が決定されてからの経過時間が予め設定されたキャリブレーション周期を超え、前記ＳＡ１の判断が肯定された場合、ＳＡ５においてカフ１０を用いた血圧測定が実行された後、ＳＡ６において対応関係が更新され、その後、ＳＡ７以下が実行される。すなわち、先ず、前記血圧値決定手段７０に対応するＳＡ５では、排気制御弁１６を圧力供給状態に切り換え且つ空気ポンプ１８を作動させてカフ１０内の圧力を患者の予想される最高血圧値よりも高い目標圧力（たとえば１８０mmHg）まで昇圧した後、空気ポンプ１８を停止させ且つ排気制御弁１６を徐速排圧状態に切り換えてカフ１０内の圧力を３mmHg/sec程度に予め定められた徐速降圧速度で下降させることにより、この徐速降圧過程で逐次得られる脈波信号ＳＭ₁ が表す圧脈波の振幅の変化に基づいて、良く知られたオシロメトリック方式の血圧値決定アルゴリズムに従って最高血圧値ＢＰ_SYS 、平均血圧値ＢＰ_MEAN、および最低血圧値ＢＰ_DIA （基準血圧値）が測定されるとともに、脈波間隔に基づいて脈拍数などが決定される。そして、その測定された血圧値および脈拍数などが表示器３２に表示されるとともに、排気制御弁１６が急速排圧状態に切り換えられてカフ１０内が急速に排圧される。
【００５１】
次に、前記関係決定手段７４に対応するＳＡ６では、圧脈波センサ４６のアクティブエレメントＥ₀ からの圧脈波の大きさ（絶対値すなわち圧脈波信号ＳＭ₂ の大きさ）と上記ＳＡ５において測定されたカフ１０による血圧値ＢＰ_SYS 、ＢＰ_DIA との間の対応関係が求められ、更新される。すなわち、圧脈波センサ４６のアクティブエレメントＥ₀ からの圧脈波が１拍読み込まれ且つその圧脈波の最高値Ｐ_Mmaxおよび最低値Ｐ_Mminが決定されるとともに、それら圧脈波の最高値Ｐ_Mmaxおよび最低値Ｐ_MminとＳＡ５にてカフ１０により測定された最高血圧値ＢＰ_SYS および最低血圧値ＢＰ_DIA とに基づいて、図４に示す圧脈波の大きさと血圧値との間の対応関係が決定されるのである。
【００５２】
上記ＳＡ６において対応関係が決定された場合、または、撓骨動脈５６に対する圧脈波センサ４６の押圧位置が正常範囲であり、前記ＳＡ２の判断が否定された場合、続くＳＡ７において１つの圧脈波が発生し、前記アクティブエレメントＥ₀ 、２つの第１圧力検出素子Ｅ₁ 、および２つの第２圧力検出素子Ｅ₂ から、それぞれ一脈波分の圧脈波信号ＳＭ₂ が入力されたか否かが判断される。このＳＡ７の判断が否定された場合はＳＡ１、ＳＡ２、ＳＡ７が繰り返し実行させられることにより待機させられる。しかし、１つの圧脈波が発生し、ＳＡ７の判断が肯定されると、前記推定血圧値決定手段７６に対応するＳＡ８において、最適押圧力Ｐ_HDPOにて押圧されている圧脈波センサ４６のアクティブエレメントＥ₀ からの圧脈波信号ＳＭ₂ から、その波動の最高値Ｐ_Mmaxおよび最低値Ｐ_Mminが決定され、図４の対応関係からその圧脈波の最高値Ｐ_Mmaxおよび最低値Ｐ_Mminに基づいて推定最高血圧値ＭＢＰ_SYS および推定最低血圧値ＭＢＰ_DIA が決定され、表示器３２に一拍毎に逐次表示されるとともに、図４の対応関係と圧脈波信号ＳＭ₂ から決定された推定血圧値の連続波形が表示器３２に表示される。
【００５３】
次に、押圧力修正手段８８に対応するＳＡ９の押圧力修正ルーチンが実行される。この押圧力修正ルーチンは、圧脈波センサ４６の押圧力が前記ＳＡ４で決定された最適押圧力Ｐ_HDPOである以外は、前述の図９に示した最適押圧力決定ルーチンと同様である。すなわち、押圧力修正ルーチンは、図９のＳＢ３以降と同様である。このＳＡ９が実行されることにより、前記ＳＡ４で決定された最適押圧力Ｐ_HDPOが一拍毎に修正されるので、前記ＳＡ７では、歪みのない、正確な圧脈波が逐次入力される。
【００５４】
上述のように、本実施例によれば、幅方向移動装置６４が押圧位置制御手段７８（ＳＡ３）により制御されて、最大圧力検出素子決定手段７２（ＳＡ３）により決定されたアクティブエレメントＥ₀ が両端の圧力検出素子から予め設定された第１距離Ｌ₁ 以上中央側に位置する圧力検出素子となるように、圧脈波センサ４６の押圧位置が撓骨動脈５６の幅方向に移動させられた状態で、第１相関係数算出手段８０（ＳＢ３）により、アクティブエレメントＥ₀ から出力された圧脈波形と、第１圧力検出素子Ｅ₁ から出力された圧脈波形との第１相関係数ｒ₁ が算出され、第２相関係数算出手段８２（ＳＢ４）により、アクティブエレメントＥ₀ から出力された圧脈波形と、第２圧力検出素子Ｅ₂ から出力された圧脈波形との第２相関係数ｒ₂ が算出され、最適押圧力決定手段８４（ＳＡ４）により、押圧装置６２が圧脈波センサ４６を押圧する押圧力が変化させられて、第１相関係数ｒ₁ が最適押圧力Ｐ_HDPOとして許容される押圧力の上限値を判断するために予め設定された第１基準値ＴＨ₁ （０．９）以上となるように、且つ第２相関係数ｒ₂ が最適押圧力Ｐ_HDPOとして許容される押圧力の下限値を判断するために予め設定された第２基準値ＴＨ₂ （０．９５）以上となるように、最適押圧力Ｐ_HDPOが決定されるので、最適押圧力Ｐ_HDPOの決定が短時間で終了し、推定血圧値決定手段７６（ＳＡ８）による血圧監視が中断される時間を短くすることができる。
【００５５】
また、本実施例によれば、幅方向移動装置６４が押圧位置制御手段７８（ＳＡ３）により制御されて、最大圧力検出素子決定手段７２（ＳＡ３）により決定されたアクティブエレメントＥ₀ が両端の圧力検出素子から予め設定された第１距離Ｌ₁ 以上中央側に位置する圧力検出素子となるように、圧脈波センサ４６の押圧位置が撓骨動脈５６の幅方向に移動させられた状態で、第１相関係数算出手段８０（ＳＢ３）により、アクティブエレメントＥ₀ から出力された圧脈波形と、第１圧力検出素子Ｅ₁ から出力された圧脈波形との第１相関係数ｒ₁ が算出され、第２相関係数算出手段８２（ＳＢ４）により、アクティブエレメントＥ₀ から出力された圧脈波形と、第２圧力検出素子Ｅ₂ から出力された圧脈波形との第２相関係数ｒ₂ が算出され、押圧力修正手段８８（ＳＡ９）により、第１相関係数ｒ₁ が予め設定された第１基準値ＴＨ₁ （０．９）以上となるように、且つ第２相関係数ｒ₂ が予め設定された第２基準値ＴＨ₂ （０．９５）以上となるように、最適押圧力決定手段８４（ＳＡ４）により決定された最適押圧力Ｐ_HDPOが逐次修正されるので、推定血圧値決定手段７６（ＳＡ８）により決定される推定血圧値ＭＢＰの精度が高い状態に維持できる。
【００５６】
また、本実施例によれば、押圧位置制御手段７８（ＳＡ３）は、最大圧力検出素子決定手段７２（ＳＡ３）により決定されたアクティブエレメントＥ₀ が、複数の圧力検出素子の配列方向において予め設定された略中央部に位置する圧力検出素子となるように幅方向移動装置６４を制御するものであることから、圧脈波センサ４６の押圧位置がずれた場合でも、アクティブエレメントＥ₀ が押圧面５４の端部に位置することが少なくなるので、圧脈波センサ４６の押圧位置を再決定する必要が少なくなる利点がある。
【００５７】
以上、本発明の一実施例を図面に基づいて説明したが、本発明はその他の態様においても適用される。
【００５８】
たとえば、前述の実施例では、カフ１０が上腕に装着され且つ圧脈波センサ４６が撓骨動脈の圧脈波を検出するために手首に装着されていたが、カフ１０が大腿部に巻回され且つ圧脈波センサ４６がそのカフ１０が巻回されていない側の脚部の足背動脈の圧脈波を検出するために足に装着されていてもよいのである。
【００５９】
また、前述の実施例では、押圧力修正手段８８（ＳＡ９）により、一拍毎に押圧力が修正されたいたが、２拍以上または予め設定された所定時間毎に押圧力が修正されるものであってもよい。
【００６０】
また、前述の実施例では、最適押圧力決定手段８４は、第１相関係数ｒ₁ および第２相関係数ｒ₂ が基準値ＴＨ₁ 、ＴＨ₂ 以上となるように押圧力が調整されて、最適押圧力Ｐ_HDPOが決定されていたが、従来のように、押圧力を連続的に変化させ、その変化過程で得た圧脈波に基づいて最適押圧力Ｐ_HDPOを決定するものであってもよい。
【００６１】
また、前述の実施例では、アクティブエレメントＥ₀ から５つ隣に位置する素子が第１圧力検出素子Ｅ₁ に決定されていたが、これは押圧面５４の半導体感圧素子の間隔によって変わり得る。たとえば、押圧面に配列された半導体感圧素子の間隔が前述の実施例よりも広い場合は、アクティブエレメンＥ₀ から２つ隣の素子が第１圧力検出素子Ｅ₁ に決定されてもよい。
【００６２】
その他、本発明はその主旨を逸脱しない範囲において種々変更が加えられ得るものである。
【図面の簡単な説明】
【図１】本発明の一実施例である連続血圧監視装置の構成を示すブロック図である。
【図２】図１の実施例の圧脈波検出プローブを一部を切り欠いて説明する拡大図である。
【図３】図１の実施例の圧脈波センサにより検出される圧脈波を例示する図である。
【図４】図１の実施例において用いられる対応関係を例示する図である。
【図５】図１の実施例の演算制御装置の制御機能の要部を説明する機能ブロック線図である。
【図６】圧力検出素子の位置と相関係数ｒ₁ 、ｒ₂ との関係を示す図である。
【図７】第１相関係数ｒ₁ および第２相関係数ｒ₂ とそれぞれの基準値との関係を列挙した図である。
【図８】図１の実施例の演算制御装置の制御作動の要部を説明するフローチャートであって、メインルーチンを示している。
【図９】図１の実施例の演算制御装置の制御作動の要部を説明するフローチャートであって、最適押圧力決定ルーチンを示している。
【符合の説明】
４６：圧脈波センサ
６２：押圧装置
６４：幅方向移動装置
７２：最大圧力検出素子決定手段
７６：推定血圧値決定手段
７８：押圧位置制御手段
８０：第１相関係数算出手段
８２：第２相関係数算出手段
８４：最適押圧力決定手段
８６：押圧力修正手段[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a continuous blood pressure monitoring apparatus that quickly determines an optimal pressing force for an artery and successively corrects the pressing force for the artery in a state where the blood pressure value of a living body is continuously monitored.
[0002]
[Prior art]
A pressure pulse wave sensor having a plurality of pressure detection elements arranged in the width direction of the artery to detect a pressure pulse wave generated from a living artery, and the pressure pulse wave sensor from above the skin of the living body Based on the magnitude of the pressure pulse wave detected by the pressure detecting element of the pressure pulse wave sensor from the preset relationship between the pressure pulse wave and the estimated blood pressure value, the pressing device pressing toward the artery, the living body There is known a continuous blood pressure monitoring device that includes estimated blood pressure value determining means for sequentially determining the estimated blood pressure value, and continuously monitoring the blood pressure value of the living body using the estimated blood pressure value. For example, this is a continuous blood pressure monitoring apparatus described in Japanese Patent Application Laid-Open No. 8-187230.
[0003]
[Problems to be solved by the invention]
By the way, within the continuous blood pressure monitoring period of the continuous blood pressure monitoring device as described above, the mounting belt that is mounting the pressure pulse wave sensor on the living body is loosened, and the pressure site where the pressure pulse wave sensor is continuously pressed Due to the familiar deformation or dent of the skin and the tissue directly under the skin, the pressure may be deviated from the optimal pressing state while being pressed by the optimal pressing force that was initially determined, and as a result, the accuracy of the monitored blood pressure is reduced. was there.
[0004]
Furthermore, when a body motion that changes a preset relationship between the pressure pulse wave and the estimated blood pressure value is detected, or when the estimated blood pressure value that is sequentially determined changes significantly, the predetermined optimal pressing When the pressure determination activation condition is satisfied, in order to redetermine the optimum pressing force, the pressing force of the pressure pulse wave sensor is continuously changed to the pressing force that collapses the blood vessel pressed by the pressure pulse wave sensor. In the meantime, since the estimated blood pressure value cannot be determined, monitoring of the blood pressure value of the living body by the estimated blood pressure value is interrupted for a relatively long time.
[0005]
The present invention has been made in the background of the above circumstances, and an object thereof is to provide a continuous blood pressure monitoring apparatus capable of continuously monitoring blood pressure with high accuracy and having a short interruption time of blood pressure monitoring. There is.
[0006]
[First Means for Solving the Problems]
The gist of the first invention for achieving this object is to have a plurality of pressure detecting elements arranged in the width direction of the artery on the pressing surface in order to detect pressure pulse waves generated from the artery of the living body. A pressure pulse wave sensor, a pressure device that presses the pressure pulse wave sensor toward the artery from the skin of the living body, and a preset optimum based on a preset relationship between the pressure pulse wave and the estimated blood pressure value An estimated blood pressure value determining means for sequentially determining an estimated blood pressure value of the living body from the magnitude of the pressure pulse wave detected by the pressure detecting element of the pressure pulse wave sensor pressed by the pressing device with a pressing force; A continuous blood pressure monitoring device that continuously monitors the blood pressure value of the living body based on the estimated blood pressure value, (a) a width direction moving device that moves the pressing position of the pressure pulse wave sensor in the width direction of the artery; b) The plurality of pressure sensing elements Maximum pressure detection element determination means for determining the maximum pressure detection element that outputs the maximum pulse wave amplitude, and (c) the maximum pressure detection element determined by the maximum pressure detection element determination means is preset from the pressure detection elements at both ends. A pressing position control means for controlling the width direction moving device so that the pressure detecting element is located on the center side more than the first distance, and (d) the pressing position of the pressure pulse wave sensor is controlled by the pressing position control means. In this state, the pressure pulse waveform output from the maximum pressure detection element and the pressure pulse waveform output from the pressure detection element whose distance from the maximum pressure detection element is the preset first distance. A first correlation coefficient calculating means for calculating a first correlation coefficient; and (e) a pressure output from the maximum pressure detecting element in a state where the pressing position of the pressure pulse wave sensor is controlled by the pressing position control means. Pulse waveform and its peak A second correlation coefficient for calculating a second correlation coefficient with the pressure pulse waveform output from the pressure detection element that is a second distance set at a distance smaller than the first distance from the large pressure detection element A first correlation coefficient calculated by the calculating means and (f) the first correlation coefficient calculating means is set in advance to determine an upper limit value of the pressing force allowed as the optimum pressing force. The second correlation coefficient calculated by the second correlation coefficient calculation means is set in advance so as to be equal to or higher than the reference value and to determine the lower limit value of the pressing force allowed as the optimum pressing force. And an optimum pressing force determining means for determining the optimum pressing force so as to be equal to or greater than the second reference value.
[0007]
[Effect of the first invention]
In this case, the width direction moving device is controlled by the pressing position control means, and the maximum pressure detection element determined by the maximum pressure detection element determination means is centered by a predetermined distance from the pressure detection elements at both ends. Output from the maximum pressure detecting element by the first correlation coefficient calculating means in a state in which the pressure pulse wave sensor is moved in the width direction of the artery so that the pressure detecting element is located on the side. The first correlation coefficient between the pressure pulse waveform and the pressure pulse waveform output from the first pressure detection element is calculated, and the pressure pulse waveform output from the maximum pressure detection element by the second correlation coefficient calculation means And the second correlation coefficient with the pressure pulse waveform output from the second pressure detecting element is calculated, and the pressing force by which the pressing device presses the pressure pulse wave sensor is changed by the optimum pressing force determining means. The first correlation coefficient is The lower limit of the pressing force permitted as the optimum pressing force so that the upper limit value of the pressing force allowed as the optimum pressing force is equal to or higher than a first reference value set in advance. Since the optimum pressing force is determined so as to be equal to or greater than a second reference value set in advance to determine the value, determination of the optimum pressing force is completed in a short time, and blood pressure monitoring by the estimated blood pressure value determining means Can be shortened.
[0008]
[Second means for solving the problem]
The gist of the second invention for achieving this object is to have a plurality of pressure detection elements arranged in the width direction of the artery on the pressing surface in order to detect a pressure pulse wave generated from the artery of the living body. A pressure pulse wave sensor, a pressing device that presses the pressure pulse wave sensor toward the artery from the skin of the living body, and the pressing device is configured to press the pressure pulse so that a part of a blood vessel wall of the artery is substantially flat. Pressure pulse wave detected by the pressure detection element of the pressure pulse wave sensor based on a preset relationship between the pressure pulse wave and the estimated blood pressure value, and the optimum pressure determining means for determining the optimum pressure force for pressing the wave sensor An estimated blood pressure value determining means for sequentially determining the estimated blood pressure value of the living body based on the magnitude of the blood pressure, and continuously monitoring the blood pressure value of the living body by the estimated blood pressure value, a) The pressing position of the pressure pulse wave sensor A width direction moving device for moving in the width direction of the artery; (b) a maximum pressure detecting element determining means for determining a maximum pressure detecting element that outputs a maximum pulse wave amplitude among the plurality of pressure detecting elements; The width direction moving device is controlled so that the maximum pressure detection element determined by the maximum pressure detection element determination means is a pressure detection element located on the center side at least a preset first distance from the pressure detection elements at both ends. (D) the pressure pulse waveform output from the maximum pressure detecting element in a state where the pressing position of the pressure pulse wave sensor is controlled by the pressing position control means, and from the maximum pressure detecting element A first correlation coefficient calculating means for calculating a first correlation coefficient with a pressure pulse waveform output from the pressure detecting element whose distance is the preset first distance; and (e) a pressing position control means. Pressing position of pressure pulse wave sensor The pressure pulse waveform output from the maximum pressure detection element and the pressure detection element that is a second distance in which the distance from the maximum pressure detection element is set to be smaller than the first distance A second correlation coefficient calculating means for calculating a second correlation coefficient with the pressure pulse waveform outputted from the first correlation coefficient, and (f) the first correlation coefficient calculated by the first correlation coefficient calculating means The second correlation coefficient calculated by the second correlation coefficient calculation means so as to be equal to or higher than a first reference value set in advance to determine the upper limit value of the pressing force allowed as the pressure is the optimum A pressing force correcting means for sequentially correcting the optimum pressing force determined by the optimum pressing force determining means so as to be equal to or greater than a second reference value set in advance to determine the lower limit value of the pressing force. It is in.
[0009]
[Effect of the second invention]
In this case, the width direction moving device is controlled by the pressing position control means, and the maximum pressure detection element determined by the maximum pressure detection element determination means is centered by a predetermined distance from the pressure detection elements at both ends. Output from the maximum pressure detecting element by the first correlation coefficient calculating means in a state in which the pressure pulse wave sensor is moved in the width direction of the artery so that the pressure detecting element is located on the side. The first correlation coefficient between the pressure pulse waveform and the pressure pulse waveform output from the first pressure detection element is calculated, and the pressure pulse waveform output from the maximum pressure detection element by the second correlation coefficient calculation means And a second correlation coefficient between the pressure pulse waveform output from the second pressure detecting element and the first correlation coefficient is equal to or higher than a first reference value set in advance by the pressing force correcting means. And the second correlation coefficient is preset. Since the optimum pressing force determined by the optimum pressing force determining means is successively corrected so as to be equal to or higher than the second reference value, the accuracy of the estimated blood pressure value determined by the estimated blood pressure value determining means is maintained at a high level. it can.
[0010]
Other aspects of the invention
Here, preferably, in the pressing position control means, the maximum pressure detection element determined by the maximum pressure detection element determination means is located at a substantially central portion preset in the arrangement direction of the plurality of pressure detection elements. The width direction moving device is controlled to be a pressure detecting element. In this way, even when the pressure pulse wave sensor pressing position is deviated, the maximum pressure detecting element is less likely to be located at the end of the pressing surface, so the pressure pulse wave sensor pressing position is determined again. There is an advantage that there is less need to do.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
[0012]
FIG. 1 is a diagram showing a configuration example of a continuous blood pressure monitoring apparatus according to the present invention, and is used for monitoring the condition of a patient during and after surgery, a living body during an exercise load test, and the like. In the figure, reference numeral 10 denotes a cuff having a rubber bag in a cloth belt-like bag, which is mounted in a state of being wound around the upper arm 12 of a patient, for example. A pressure sensor 14, an exhaust control valve 16, and an air pump 18 are connected to the cuff 10 via a pipe 20. The exhaust control valve 16 includes a pressure supply state that allows supply of pressure into the cuff 10, a slow exhaust pressure state that gradually exhausts the inside of the cuff 10, and a rapid exhaust pressure state that rapidly exhausts the inside of the cuff 10. It is configured to be switched to one state.
[0013]
The pressure sensor 14 detects the pressure in the cuff 10 and supplies a pressure signal SP representing the pressure 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, discriminates the cuff pressure signal SK representing the steady pressure included in the pressure signal SP, and calculates the cuff pressure signal SK via the A / D converter 26. 28. The pulse wave discrimination circuit 24 includes a bandpass filter, and a pulse wave signal SM that is a vibration component of the pressure signal SP. ₁ And the pulse wave signal SM ₁ Is supplied to the arithmetic and control unit 28 via the A / D converter 30. This pulse wave signal SM ₁ The cuff pulse wave represented by is a pressure vibration wave generated from a brachial artery (not shown) and transmitted to the cuff 10 in synchronization with the heartbeat of the patient, and the pulse wave discrimination circuit 24 functions as a cuff pulse wave detection means. Yes.
[0014]
The arithmetic control unit 28 includes a CPU 29, a ROM 31, a RAM 33, and a so-called microcomputer having an I / O port (not shown). The CPU 29 has a storage function of the RAM 33 according to a program stored in advance in the ROM 31. By executing the signal processing while using it, a drive signal is output from the I / O port to control the exhaust control valve 16 and the air pump 18 via a drive circuit (not shown). When measuring blood pressure using the cuff 10, for example, the pressure in the cuff 10 is rapidly increased to a predetermined target pressure, then gradually decreased at a rate of about 3 mmHg / sec, and pulses sequentially collected in the process of gradually decreasing the pressure. Wave signal SM ₁ The blood pressure values (reference blood pressure values) such as the maximum blood pressure value and the minimum blood pressure value are determined by the oscillometric method based on the change of the pulse wave represented by the above, and the determined blood pressure value is displayed on the display 32.
[0015]
As shown in detail in FIG. 2, the pressure pulse wave detection probe 34 includes a case 37 that houses a container-like sensor housing 36, and a sensor housing 36 for moving the sensor housing 36 in the width direction of the radial artery 56. And a screw shaft 41 that is screwed to 36 and is rotationally driven by a motor (not shown) provided in a drive unit 39 of the case 37. A mounting band 40 is attached to the case 37, and the side where the cuff 10 is not wound by the mounting band 40 in a state where the open end of the container-shaped sensor housing 36 faces the body surface 38 of the human body. The left wrist 42 is detachably attached. A pressure pulse wave sensor 46 is provided inside the sensor housing 36 through a diaphragm 44 so as to be relatively movable and projectable from the opening end of the sensor housing 36. The pressure is applied by the sensor housing 36, the diaphragm 44, and the like. A chamber 48 is formed. Pressure air is supplied from the air pump 50 through the pressure regulating valve 52 into the pressure chamber 48, so that the pressure pulse wave sensor 46 has a pressing force corresponding to the pressure in the pressure chamber 48. Pressed against the body surface 38. In this embodiment, the pressing force of the pressure pulse wave sensor 46 is indicated by the pressure in the pressure chamber 48 (unit: mmHg).
[0016]
The sensor housing 36 and the diaphragm 44 constitute a pressing device 62 that presses the pressure pulse wave sensor 46 toward the radial artery 56. The pressing device 62 is an optimum pressing force P described later. _HDPO Then, the pressure pulse wave sensor 46 is pressed. The screw shaft 41 and the motor (not shown) constitute a pressing position changing device that changes the pressing position where the pressure pulse wave sensor 46 is pressed in the width direction of the radial artery 56, that is, a width direction moving device 64. is doing.
[0017]
In the pressure pulse wave sensor 46, for example, a large number of semiconductor pressure sensitive elements (not shown) are parallel to the radial direction of the radial artery 56, that is, the screw shaft 41, on the pressing surface 54 made of a semiconductor chip made of single crystal silicon or the like. The pressure pulse wave sensor 46 is arranged at a constant interval of about 0.2 mm in the moving direction of the pressure pulse wave sensor 46, and is pressed onto the radial artery 56 on the body surface 38 of the wrist 42. A pressure oscillation wave, that is, a pressure pulse wave generated and transmitted to the body surface 38 is detected, and a pressure pulse wave signal SM representing the pressure pulse wave is detected. ₂ Is supplied to the arithmetic and control unit 28 via the A / D converter 58. FIG. 3 shows a pressure pulse wave signal SM detected by the pressure pulse wave sensor 46. ₂ An example is shown.
[0018]
The CPU 29 of the arithmetic control device 28 executes signal processing using the storage function of the RAM 33 in accordance with a program stored in the ROM 31 in advance, and outputs a drive signal to the air pump 50 and the pressure regulating valve 52 via a drive circuit (not shown). The pressure in the pressure chamber 48 is adjusted. For example, when monitoring the continuous blood pressure, the arithmetic and control unit 28 makes a part of the vascular wall of the radial artery 56 substantially flat based on the pressure pulse wave successively obtained in the slow pressure change process in the pressure chamber 48. Optimal pressing force P of the pressure pulse wave sensor 46 _HDPO And the optimum pressing force P is determined. _HDPO The pressure regulating valve 52 is controlled so as to maintain the above. Further, the arithmetic and control unit 28 uses the cuff 10 to measure the systolic blood pressure value BP. _SYS And minimum blood pressure BP _DIA And the above optimum pressing force P _HDPO The central position pressure detecting element (active element E) located directly above the radial artery 56 among the semiconductor pressure sensitive elements of the pressure pulse wave sensor 46 in a state where the pressure is maintained. ₀ ) The maximum value P of the pressure pulse wave detected by _Mmax And minimum value P _Mmin Based on the measured blood pressure value BP and the pressure pulse wave magnitude P _M A correspondence relationship between the absolute value and the magnitude P of the pressure pulse wave successively detected by the pressure pulse wave sensor 46 is obtained from the correspondence relationship. _M (MmHg), that is, maximum value (upper peak value) P _Mmax And lowest value (lower peak value) P _Mmin Blood pressure MBP based on _SYS And minimum blood pressure MBP _DIA (Estimated blood pressure value, ie, monitored blood pressure value) is sequentially determined, and the determined maximum blood pressure value MBP is displayed on the display 32. _SYS And minimum blood pressure MBP _DIA Is displayed numerically for each beat, and a waveform indicating the estimated blood pressure value MBP is continuously displayed.
[0019]
For example, the correspondence relationship is shown in FIG. In Equation 1, A is a constant indicating the slope, and B is a constant indicating the intercept.
[0020]
[Expression 1]
MBP = AP _M + B
[0021]
FIG. 5 is a functional block diagram illustrating a main part of the control function of the arithmetic control device 28 in the continuous blood pressure monitoring device configured as described above. In the figure, when the blood pressure is measured, the pressure sensor 14 detects the compression pressure of the cuff 10 that is changed by the cuff pressure control means 68. The blood pressure value measuring means 70 is based on an oscillometric method or a pulse synchronization signal obtained in the process of gradually changing the pressure applied by the cuff 10 at a speed of about 2 to 3 mmHg / sec, for example, based on a change in pulse wave amplitude or Korotkoff sound. Maximum blood pressure BP of living body according to Korotkoff sound method _SYS , Mean blood pressure BP _MEAN , And diastolic blood pressure BP _DIA (Reference blood pressure value) is measured.
[0022]
The maximum pressure detecting element determining means 72 is located directly above the radial artery 56 among the plurality of pressure detecting elements arranged on the pressing surface 54 of the pressure pulse wave sensor 46, and the maximum pulse wave amplitude, that is, the maximum pulse wave intensity. Pressure detector element (active element E ₀ ). The relationship determining unit 74 includes a maximum pressure detecting element (active element E) determined by the maximum pressure detecting element determining unit 72. ₀ ) Of the pressure pulse wave detected by _M And the blood pressure value BP measured by the blood pressure value measuring means 70 are determined in advance as shown in FIG. From the correspondence relationship, the estimated blood pressure value determining means 76 is, for example, the active element E among the plurality of pressure detection elements arranged on the pressing surface 54 of the pressure pulse wave sensor 46. ₀ The estimated blood pressure value MBP of the living body is continuously determined based on the magnitude of the pressure pulse wave detected by.
[0023]
The pressing position control means 78 detects the maximum amplitude of the pressure detecting elements arranged on the pressing surface 54 at the time of initial mounting (ie, the maximum pressure detecting element) at the end of the arrangement position. Or a first correlation coefficient r described later. ₁ And the second correlation coefficient r ₂ When a predetermined pressing position update condition is satisfied, such as when the pressure pulse wave sensor 46 is within a predetermined pressing position change range, the pressure pulse wave sensor 46 is moved by the pressing device 62 to an optimum pressing force P described later. _HDPO A relatively small first pressing value P set in advance that is sufficiently smaller than ₁ In this state, the width direction moving device 64 is controlled so that the maximum pressure detecting element is positioned at a substantially central portion preset in the arrangement direction of the pressure detecting elements. That is, when a predetermined pressing position update condition is satisfied, the pressure pulse wave sensor 46 is once separated from the body surface 38, and the pressing device 62 and the pressure pulse wave sensor 46 are moved by the width direction moving device 64, and again. By repeating the operation of determining whether or not the maximum pressure detection element is positioned at substantially the center in the arrangement direction, the maximum pressure detection element is set to a first distance L set in advance from the pressure detection elements at both ends. ₁ More preferably, the maximum pressure detection element is positioned at the substantially central portion in the arrangement direction. In addition, when the maximum pressure detection element is located at a substantially central portion in the arrangement direction, the maximum pressure detection element is also referred to as a center position pressure detection element. In this way, the first pressure L that is set in advance from the pressure detection elements at both ends of the maximum pressure detection element ₁ The first correlation coefficient r is set by the first correlation coefficient calculation means 80 described below to be positioned at the center side. ₁ Because the first distance L is calculated. ₁ Will be described in the description of the first correlation coefficient calculating means 80.
[0024]
The first correlation coefficient calculating means 80 is output from the maximum pressure detecting element determined by the maximum pressure detecting element determining means 72 in a state where the pressing position of the pressure pulse wave sensor 46 is controlled by the pressing position control means 78. The first distance L in which the pressure pulse waveform and the distance from the maximum pressure detecting element are set in advance ₁ The first pressure detecting element E ₁ Correlation coefficient r with the pressure pulse waveform output from ₁ Are calculated sequentially. That is, the pressure pulse wave signal SM ₂ As shown in FIG. 3, the pressure pulse waveform represented by is represented by a photoelectric pulse wave signal SM input every sampling period of several milliseconds or tens of milliseconds. ₂ The photoelectric pulse wave signal SM output from the maximum pressure detecting element in a predetermined section (for example, for one beat) ₂ And first pressure detecting element E ₁ Photoelectric pulse wave signal SM output from ₂ Based on the above, the first correlation coefficient r is obtained from the relationship shown in Formula 2. ₁ Are calculated sequentially. Here, the preset first distance L ₁ Is determined based on a general blood vessel outer diameter, and is, for example, about 1 mm. The first distance L from the maximum pressure detecting element ₁ Since the separated positions exist on both sides in the arrangement direction of the pressure detection elements, the first pressure detection element E ₁ Exists, and the first correlation coefficient r ₁ Also, two values are calculated sequentially.
[0025]
[Expression 2]

[0026]
The second correlation coefficient calculating means 82 is configured such that the pressure pulse waveform output from the maximum pressure detecting element and the distance from the maximum pressure detecting element are the first distance L. ₁ The second distance L set to a smaller distance than ₂ The second pressure detecting element E ₂ Correlation coefficient r with the pressure pulse waveform output from ₂ Is calculated. That is, similar to the first correlation coefficient calculating means 80, the photoelectric pulse wave signal SM output from the maximum pressure detecting element in a predetermined section (for example, for one beat). ₂ And the second pressure detecting element E ₂ Photoelectric pulse wave signal SM output from ₂ Based on the above, the second correlation coefficient r ₂ Are calculated sequentially. Here, the second distance L ₂ Is a value determined based on a general blood vessel inner diameter, for example, the first distance L ₁ Is set to 1/5. The second pressure detection element E ₂ The first pressure detection element E ₁ There are two as well as the second correlation coefficient r ₂ Also, two values are calculated sequentially.
[0027]
When the width direction moving device 64 is moved by the pressing position control means 78, the optimum pressing force determination means 84 is a pressure pulse sequentially output from the pressure pulse wave sensor 46 whose pressing position is controlled by the pressing position control means 78. Wave signal SM ₂ Based on the optimum pressing force P _HDPO To decide. That is, the two first correlation coefficients r calculated by the first correlation coefficient calculating means 80 are also shown in the diagram showing the relationship between the position of the pressure detecting element and the correlation coefficient in FIG. ₁ Is the optimum pressing force P _HDPO As a first reference value TH determined in advance in order to determine an upper limit value of the pressing force allowed as ₁ Two second correlation coefficients r calculated by the second correlation coefficient calculation means 82 so as to be (for example, 0.9) or more. ₂ Is the optimum pressing force P _HDPO To determine a lower limit value of the allowable pressing force as a second reference value TH determined in advance by experiment ₂ The pressing force of the pressure pulse wave sensor 46 is controlled to be equal to or greater than (for example, 0.95), and the first correlation coefficient r ₁ Is the first reference value TH ₁ Thus, the second correlation coefficient r ₂ Is the second reference value TH ₂ The optimum pressing force P is the pressing force when _HDPO To decide.
[0028]
That is, when the condition for determining the optimum pressing force is satisfied, first, the pressing force of the pressure pulse wave sensor 46 by the pressing device 62 is set to a preset initial value, for example, 50 mmHg. Number r ₁ And the second correlation coefficient r ₂ Is calculated, and the first correlation coefficient r ₁ Is the first reference value TH ₁ In the case of the following, the pressing force is increased by a predetermined value (for example, 20 mmHg), and the second correlation coefficient r ₂ Is the second reference value TH ₂ In the case of the following, the pressing force is weakened by a predetermined value (for example, 20 mmHg), and the first correlation coefficient r is again obtained. ₁ And the second correlation coefficient r ₂ Is calculated. The above operation is the first correlation coefficient r ₁ Is the first reference value TH ₁ And the second correlation coefficient r ₂ Is the second reference value TH ₂ It repeats until it becomes above, and the pressing force at the time of satisfying the condition is the optimal pressing force P _HDPO To be determined.
[0029]
First correlation coefficient r ₁ Is the first reference value TH ₁ In the following cases, the pressing force is insufficient. That is, since a part of the vascular wall of the radial artery 56 is not pressed so much as to be substantially flat, the first distance L from the maximum pressure detecting element is compared with the pressure pulse wave output from the maximum pressure detecting element. ₁ The separated first pressure sensing element E ₁ Since the intensity of the pressure pulse wave output from the first correlation coefficient r ₁ Is lowered. The second correlation coefficient r ₂ Is the second reference value TH ₂ The following is a case where the pressing force is too strong. That is, since the pressing force is too strong, the first pressure detection element E ₁ The second pressure detection element E located closer to the maximum pressure detection element than ₂ Even the pressure pulse wave detected by distorts the second correlation coefficient r ₂ Will fall. Therefore, the first correlation coefficient r ₁ Is the first reference value TH ₁ In the case of the following, the pressing force of the pressure pulse wave sensor 46 is controlled in the direction of increasing the pressing force, and the second correlation coefficient r ₂ Is the second reference value TH ₂ In the case of the following, the pressing force of the pressure pulse wave sensor 46 is controlled in the direction of decreasing the pressing force.
[0030]
The optimum pressing force determining means 84 will be described in more detail. The active element E ₀ On both sides of the first correlation coefficient r ₁ And the second correlation coefficient r ₂ 4 correlation coefficients r, one each ₁ ・ R ₂ Is calculated, the first correlation coefficient r ₁ Is the first reference value TH ₁ Above or below and the second correlation coefficient r ₂ Is the second reference value TH ₂ If classified according to whether it is above or below, 16 patterns can be considered as shown in FIG. Note that “◯” in FIG. 7 indicates the first correlation coefficient r. ₁ And the second correlation coefficient r ₂ Are the first reference values TH ₁ Or second reference value TH ₂ “×” indicates the reference value TH ₁ ・ TH ₂ It shows below.
[0031]
In FIG. 7, in the case of pattern 1, the pressing force is not changed. Therefore, the pressing force at that time is set as the optimum pressing force. In the case of pattern 2, the first correlation coefficient r ₁ And the second correlation coefficient r ₂ Are both less than or equal to the reference value, the pressing force is initially increased and the first correlation coefficient r ₁ If the pressure does not increase, the pressing force is decreased. Alternatively, first, the pressing force is decreased, and the second correlation coefficient r ₂ If the pressure does not decrease, the pressing force is increased.
[0032]
Patterns 3 to 5 show the second correlation coefficient r ₂ Are both the second reference value TH ₂ As described above, at least one first correlation coefficient r ₁ Is the first reference value TH ₁ Therefore, the pressing force is increased. Patterns 6-8 are the first correlation coefficient r ₁ Are both the first reference value TH ₁ Above, but at least one second correlation coefficient r ₂ Is the second reference value TH ₂ Is smaller, the pressing force is weakened.
[0033]
In the case of the patterns 9 to 16, the pressing position control starting unit 86 starts the pressing position control unit 78. In other words, the pressing position control starting means 86 has the first correlation coefficient r. ₁ And the second correlation coefficient r ₂ Is within the pressing position change range shown in the patterns 9 to 16, the pressing position is considered to be inappropriate. Therefore, the control of the width direction moving device by the pressing position control means 78 is activated, and the pressure pulse wave sensor 46 Change the pressing position.
[0034]
The pressing force correcting means 88 is an optimum pressing force P determined by the optimum pressing force determining means 84. _HDPO Are corrected sequentially. That is, the optimum pressing force P is determined by the optimum pressing force determining means 84. _HDPO Is determined by the estimated blood pressure value determining means 76 and the active element E ₀ Pressure pulse wave signal SM output from ₂ The first correlation coefficient r sequentially calculated by the first correlation coefficient calculation means 80 in the state where the estimated blood pressure value MBP is sequentially determined based on ₁ Is the first reference value TH ₁ In the following case, the pressing force of the pressure pulse wave sensor 46 by the pressing device 62 is increased by a predetermined value, and the second correlation coefficient r sequentially calculated by the second correlation coefficient calculating means 82 ₂ Is the second reference value TH ₂ When it is below, the pressing force of the pressure pulse wave sensor 46 by the pressing device 62 is decreased by a predetermined value.
[0035]
8 to 9 are flowcharts for explaining the main part of the control operation of the arithmetic and control unit 28. FIG. 8 shows a main routine, and FIG. 9 shows that the optimum pressing force needs to be determined in the main routine. An optimal pressing force determination routine executed when it is determined is shown.
[0036]
In step SA1 in FIG. 8 (hereinafter, steps are omitted), it is determined whether or not the first SA1 is executed, and the elapsed time since the correspondence was updated last time is about ten minutes to several tens of minutes. It is determined whether or not a preset calibration cycle has been exceeded. Normally, the determination of SA1 is negative, so whether or not a predetermined pressing position update condition (APS activation condition) is satisfied in SA2, for example, a pressure detection element arranged on the pressing surface 54 of the pressure pulse wave sensor 46 It is determined whether or not the one that detects the maximum amplitude is positioned at the end of the array position.
[0037]
Since the pressing position of the pressure pulse wave sensor 46 with respect to the radial artery 56 is deviated and the predetermined pressing position changing condition (APS activation condition) is satisfied, such as at the first mounting, the determination of SA2 is affirmed. A SA3 APS control routine corresponding to the pressing position control means 78 is executed. This APS control routine is the pressure pulse wave signal SM detected by each pressure detecting element of the pressure pulse wave sensor 46. ₂ The optimum pressing position is determined so that the element that detects the maximum amplitude of the amplitude distribution curve of the sensor is approximately the center position of the pressure detection element. Element E ₀ Set as. Therefore, SA3 also corresponds to the maximum pressure detecting element determining means 72.
[0038]
When the SA3 APS control routine is executed, the SA4 HDP control routine corresponding to the optimum pressing force determining means 84, that is, the optimum pressing force determining routine shown in detail in FIG.
[0039]
In FIG. 9, first, in SB1, the pressing force of the pressure pulse wave sensor 46 by the pressing device 62 is set to 50 mmHg set as an initial value in advance, and in the subsequent SB2, one pressure pulse wave is generated, and the active element E ₀ , Its active element E ₀ Active element E on both sides ₀ Two first pressure sensing elements E located next to ₁ , And active element E ₀ Two second pressure detecting elements E located on both sides of ₂ From, each one pulse wave pressure pulse wave signal SM ₂ Whether or not is input is determined.
[0040]
When the determination of SB2 is negative, the process is made to stand by by repeatedly executing SB2. However, when the determination is positive, in SB3 corresponding to the subsequent first correlation coefficient calculating means 80, the active element in SB2 E ₀ Pressure pulse wave input from 1 and the first pressure detecting element E ₁ The first correlation coefficient r with the pressure pulse wave for one beat input from ₁ Is calculated based on Equation 2.
[0041]
In SB4 corresponding to the subsequent second correlation coefficient calculating means 82, the active element E in SB2 above. ₀ Pressure pulse wave input from 1 and the second pressure detecting element E ₂ Second correlation coefficient r with a pressure pulse wave of one beat input from ₂ Is calculated based on Equation 2.
[0042]
In the subsequent SB5, the two first correlation coefficients r calculated in the above SB3. ₁ Are both the first reference value TH ₁ As two second correlation coefficients r that are not less than 0.9 and are calculated in SB4. ₂ Are both the second reference value TH ₂ It is determined whether it is 0.95 or more determined in advance, that is, whether it is the state of the pattern 1 in FIG. When the determination of SB5 is affirmed, it is determined that the pressing force of the pressure pulse wave sensor 46 by the pressing device 62 is optimal, and the pressing force is the optimal pressing force P. _HDPO This routine is terminated and the routine returns to the main routine of FIG. 8 to execute SA5 and subsequent steps.
[0043]
However, if the determination in SB5 is negative, in the subsequent SB6, the two first correlation coefficients r ₁ Are both less than 0.9 and the two second correlation coefficients r ₂ Are both smaller than 0.95, that is, whether or not the state of the pattern 2 in FIG. If this determination is affirmed, in the subsequent SB7, it is determined whether or not it is the first time that the determination of SB6 is affirmed in the execution of the present optimum pressing force determination routine.
[0044]
If the determination of SB7 is affirmed, in the following SB8, the pressing force of the pressure pulse wave sensor 46 by the pressing device 62 is increased by a predetermined value (for example, 20 mmHg), and the above SB2 and subsequent steps are repeated. . On the other hand, when the determination of SB7 is negative, that is, it is determined that the state is the state of pattern 2 in FIG. 7, and the pressing force is increased by a predetermined value, but is still in the state of pattern 2 in FIG. If the determination at SB6 is affirmed again, the determination at SB9 is executed.
[0045]
In SB9, the first correlation coefficient r calculated in SB3 immediately before is calculated. ₁ Is the first correlation coefficient r calculated in SB3 one time before ₁ It is judged whether it is larger. That is, when the pressing force is increased by a predetermined value by the SB8, the first correlation coefficient r ₁ Is the first reference value TH ₁ It is determined whether or not it is close to. When the determination of SB9 is affirmed, the SB8 is executed to further increase the pressing force.
[0046]
However, if the determination of SB9 is negative, that is, by increasing the pressing force, the first correlation coefficient r ₁ Has become smaller, it is determined that the increasing / decreasing direction of the pressing force is reversed, and in subsequent SB10, the pressing force of the pressure pulse wave sensor 46 by the pressing device 62 is set to a predetermined value ( After being reduced by, for example, 20 mmHg), the SB2 and subsequent steps are repeated.
[0047]
If the determination in SB6 is negative, in the subsequent SB11, the two second correlation coefficients r ₂ Are both 0.95 or more and the two first correlation coefficients r ₁ It is determined whether or not at least one of them is smaller than 0.90, that is, whether or not the state is the pattern 3 to 5 in FIG.
[0048]
If the determination at SB11 is affirmative, SB8 is executed, and the pressing force is increased by a predetermined value. On the other hand, if the determination in SB11 is negative, in the subsequent SB12, the two first correlation coefficients r ₁ Are both 0.90 or more and the two second correlation coefficients r ₂ It is determined whether or not at least one of them is smaller than 0.95, that is, whether or not the patterns 6 to 8 in FIG. If this determination is affirmed, the SB10 is executed, and the pressing force is decreased by a predetermined value.
[0049]
However, when the determination at SB12 is also denied, that is, when all the determinations at SB5, SB6, SB11, and SB12 are denied, the pressing position corresponding to any of patterns 9 to 16 in FIG. Since it is appropriate, the APS control routine of SA3 in FIG. 8 is executed. Therefore, SB5, SB6, SB11, and SB12 correspond to the pressed position control starting means 86. The optimum pressing force determination routine in FIG. 9 is executed immediately after the pressing position of the pressure pulse wave sensor 46 is controlled to the optimum pressing position by the APS control routine (SA3 in FIG. 8). There is no need to change. That is, since it corresponds to any one of patterns 1 to 8 in FIG. 7, the determination of SB12 is not denied, but the pressure pulse wave sensor 46 is pressed by body movement or the like during the pressing force determination operation. When the position is shifted, the determination of SB12 is denied.
[0050]
Returning to FIG. 8, after the HDP control routine of SA4 is completed, or when the elapsed time since the previous correspondence was determined exceeds a preset calibration cycle, the determination of SA1 is affirmed After the blood pressure measurement using the cuff 10 is executed in SA5, the correspondence is updated in SA6, and thereafter, SA7 and subsequent steps are executed. That is, first, in SA5 corresponding to the blood pressure value determining means 70, the exhaust control valve 16 is switched to the pressure supply state and the air pump 18 is operated to set the pressure in the cuff 10 to be higher than the expected maximum blood pressure value of the patient. After increasing the pressure to a high target pressure (for example, 180 mmHg), the air pump 18 is stopped and the exhaust control valve 16 is switched to the slow exhaust pressure state, so that the pressure in the cuff 10 is reduced to a predetermined speed of about 3 mmHg / sec. Pulse wave signal SM obtained sequentially in this slow-down process by descending at speed ₁ Based on the change in the amplitude of the pressure pulse wave represented by the maximum blood pressure value BP according to the well-known oscillometric blood pressure value determination algorithm _SYS , Mean blood pressure BP _MEAN , And diastolic blood pressure BP _DIA (Reference blood pressure value) is measured, and the pulse rate and the like are determined based on the pulse wave interval. Then, the measured blood pressure value and pulse rate are displayed on the display 32, and the exhaust control valve 16 is switched to the rapid exhaust pressure state so that the inside of the cuff 10 is rapidly exhausted.
[0051]
Next, in SA6 corresponding to the relationship determining means 74, the active element E of the pressure pulse wave sensor 46 is displayed. ₀ Pressure pulse wave magnitude (absolute value, ie, pressure pulse wave signal SM) ₂ ) And blood pressure value BP by the cuff 10 measured in SA5 _SYS , BP _DIA Correspondence between and is determined and updated. That is, the active element E of the pressure pulse wave sensor 46 ₀ 1 pulse is read and the maximum value P of the pressure pulse is read _Mmax And minimum value P _Mmin Is determined, and the maximum value P of these pressure pulse waves is _Mmax And minimum value P _Mmin And BP measured by cuff 10 at SA5 _SYS And minimum blood pressure BP _DIA Based on the above, the correspondence between the magnitude of the pressure pulse wave and the blood pressure value shown in FIG. 4 is determined.
[0052]
When the correspondence is determined in SA6, or when the pressure pulse wave sensor 46 is pressed in the normal range with respect to the radial artery 56 and the determination in SA2 is negative, one pressure pulse wave is continued in SA7. Occurs and the active element E ₀ Two first pressure sensing elements E ₁ , And two second pressure sensing elements E ₂ From, each one pulse wave pressure pulse wave signal SM ₂ Whether or not is input is determined. If the determination of SA7 is negative, SA1, SA2, and SA7 are repeatedly executed to be put on standby. However, when one pressure pulse wave is generated and the determination in SA7 is affirmed, the optimum pressure P is determined in SA8 corresponding to the estimated blood pressure value determining means 76. _HDPO The active element E of the pressure pulse wave sensor 46 pressed by ₀ Pressure pulse wave signal SM from ₂ From the highest value P of the wave _Mmax And minimum value P _Mmin Is determined, and the maximum value P of the pressure pulse wave is determined from the correspondence in FIG. _Mmax And minimum value P _Mmin Estimated systolic blood pressure value MBP based on _SYS And estimated diastolic blood pressure MBP _DIA 4 is sequentially displayed for each beat on the display 32, and the correspondence relationship and the pressure pulse wave signal SM in FIG. ₂ A continuous waveform of the estimated blood pressure value determined from the above is displayed on the display 32.
[0053]
Next, the SA9 pressing force correction routine corresponding to the pressing force correction means 88 is executed. In this pressing force correction routine, the pressing force of the pressure pulse wave sensor 46 is determined as the optimum pressing force P determined in SA4. _HDPO Except for this, it is the same as the optimum pressing force determination routine shown in FIG. That is, the pressing force correction routine is the same as that after SB3 in FIG. By executing SA9, the optimum pressing force P determined in SA4 is obtained. _HDPO Is corrected for each beat, and in SA7, an accurate pressure pulse wave without distortion is sequentially input.
[0054]
As described above, according to the present embodiment, the width direction moving device 64 is controlled by the pressing position control means 78 (SA3), and the active element E determined by the maximum pressure detecting element determination means 72 (SA3). ₀ Is a preset first distance L from the pressure detecting elements at both ends. ₁ The first correlation coefficient calculating means 80 (SB3) with the pressing position of the pressure pulse wave sensor 46 moved in the width direction of the radial artery 56 so as to be the pressure detecting element located on the center side. , Active element E ₀ And the first pressure detecting element E ₁ Correlation coefficient r with the pressure pulse waveform output from ₁ Is calculated by the second correlation coefficient calculating means 82 (SB4). ₀ And the second pressure detecting element E ₂ Correlation coefficient r with the pressure pulse waveform output from ₂ Is calculated, and the pressing force by which the pressing device 62 presses the pressure pulse wave sensor 46 is changed by the optimum pressing force determining means 84 (SA4), and the first correlation coefficient r is calculated. ₁ Is the optimum pressing force P _HDPO As a first reference value TH set in advance to determine the upper limit value of the pressing force allowed as ₁ (0.9) or more and the second correlation coefficient r ₂ Is the optimum pressing force P _HDPO As a second reference value TH set in advance to determine the lower limit value of the pressing force allowed as ₂ (0.95) Optimum pressing force P _HDPO Is determined, the optimum pressing force P _HDPO Is completed in a short time, and the time during which the blood pressure monitoring by the estimated blood pressure value determining means 76 (SA8) is interrupted can be shortened.
[0055]
Further, according to the present embodiment, the width direction moving device 64 is controlled by the pressing position control means 78 (SA3), and the active element E determined by the maximum pressure detecting element determination means 72 (SA3). ₀ Is a preset first distance L from the pressure detecting elements at both ends. ₁ The first correlation coefficient calculating means 80 (SB3) with the pressing position of the pressure pulse wave sensor 46 moved in the width direction of the radial artery 56 so as to be the pressure detecting element located on the center side. , Active element E ₀ And the first pressure detecting element E ₁ Correlation coefficient r with the pressure pulse waveform output from ₁ Is calculated by the second correlation coefficient calculating means 82 (SB4). ₀ And the second pressure detecting element E ₂ Correlation coefficient r with the pressure pulse waveform output from ₂ Is calculated by the pressing force correcting means 88 (SA9). ₁ Is a preset first reference value TH ₁ (0.9) or more and the second correlation coefficient r ₂ Is a preset second reference value TH ₂ (0.95) The optimum pressing force P determined by the optimum pressing force determining means 84 (SA4) so as to be greater than or equal to (0.95). _HDPO Are sequentially corrected, so that the accuracy of the estimated blood pressure value MBP determined by the estimated blood pressure value determining means 76 (SA8) can be maintained at a high level.
[0056]
Further, according to the present embodiment, the pressing position control means 78 (SA3) is the active element E determined by the maximum pressure detection element determination means 72 (SA3). ₀ Is the pressure direction of the pressure pulse wave sensor 46 because the width direction moving device 64 is controlled so as to be a pressure detection element located at a substantially central portion preset in the arrangement direction of the plurality of pressure detection elements. Active element E even if ₀ Is less likely to be located at the end of the pressing surface 54, and there is an advantage that it is less necessary to re-determine the pressing position of the pressure pulse wave sensor 46.
[0057]
As mentioned above, although one Example of this invention was described based on drawing, this invention is applied also in another aspect.
[0058]
For example, in the embodiment described above, the cuff 10 is attached to the upper arm and the pressure pulse wave sensor 46 is attached to the wrist to detect the pressure pulse wave of the radial artery, but the cuff 10 is wound around the thigh. The pressure pulse wave sensor 46 may be attached to the foot in order to detect the pressure pulse wave of the foot dorsal artery of the leg on the side where the cuff 10 is not wound.
[0059]
In the above-described embodiment, the pressing force is corrected every beat by the pressing force correcting means 88 (SA9). However, the pressing force is corrected every two beats or every predetermined time set in advance. It may be.
[0060]
Further, in the above-described embodiment, the optimum pressing force determining means 84 has the first correlation coefficient r. ₁ And the second correlation coefficient r ₂ Is the reference value TH ₁ , TH ₂ The pressing force is adjusted so that the optimum pressing force P is obtained. _HDPO However, as in the prior art, the pressing force is continuously changed, and the optimum pressing force P is determined based on the pressure pulse wave obtained in the changing process. _HDPO May be determined.
[0061]
In the above-described embodiment, the active element E ₀ 5 elements next to the first pressure detecting element E ₁ However, this may vary depending on the distance between the semiconductor pressure-sensitive elements on the pressing surface 54. For example, when the interval between the semiconductor pressure-sensitive elements arranged on the pressing surface is wider than that of the above-described embodiment, the active element E ₀ The two elements next to the first pressure detecting element E ₁ May be determined.
[0062]
In addition, the present invention can be variously modified without departing from the gist of the present invention.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a continuous blood pressure monitoring apparatus according to an embodiment of the present invention.
FIG. 2 is an enlarged view illustrating a pressure pulse wave detection probe of the embodiment of FIG. 1 with a part cut away.
FIG. 3 is a diagram illustrating a pressure pulse wave detected by the pressure pulse wave sensor of the embodiment of FIG. 1;
FIG. 4 is a diagram illustrating correspondence relationships used in the embodiment of FIG. 1;
FIG. 5 is a functional block diagram illustrating a main part of a control function of the arithmetic and control unit of the embodiment of FIG. 1;
FIG. 6 shows the position of the pressure detection element and the correlation coefficient r. ₁ , R ₂ It is a figure which shows the relationship.
FIG. 7 shows a first correlation coefficient r ₁ And the second correlation coefficient r ₂ FIG. 6 is a table listing the relationships between the reference values and the reference values.
FIG. 8 is a flowchart for explaining a main part of the control operation of the arithmetic and control unit of the embodiment of FIG. 1, and shows a main routine.
FIG. 9 is a flowchart for explaining a main part of the control operation of the arithmetic and control unit of the embodiment of FIG. 1, and shows an optimum pressing force determination routine.
[Explanation of sign]
46: Pressure pulse wave sensor
62: Pressing device
64: Width direction moving device
72: Maximum pressure detecting element determining means
76: Estimated blood pressure value determining means
78: Pressing position control means
80: First correlation coefficient calculating means
82: Second correlation coefficient calculating means
84: Optimal pressing force determining means
86: Pressing force correction means

Claims (2)

A pressure pulse wave sensor having a plurality of pressure detection elements arranged in the width direction of the artery on the pressing surface to detect a pressure pulse wave generated from the artery of the living body, and the pressure pulse wave sensor from above the skin of the living body Pressure of the pressure pulse wave sensor pressed by the pressing device with a preset optimum pressing force based on a preset relationship between the pressing device pressing toward the artery and the pressure pulse wave and the estimated blood pressure value Continuous blood pressure, comprising: estimated blood pressure value determining means for sequentially determining an estimated blood pressure value of the living body from the magnitude of the pressure pulse wave detected by the detection element, and continuously monitoring the blood pressure value of the living body using the estimated blood pressure value A monitoring device,
A width direction moving device for moving the pressing position of the pressure pulse wave sensor in the width direction of the artery;
A maximum pressure detecting element determining means for determining a maximum pressure detecting element that outputs a maximum pulse wave amplitude among the plurality of pressure detecting elements;
The width direction moving device is controlled so that the maximum pressure detecting element determined by the maximum pressure detecting element determining means is a pressure detecting element located on the central side more than a preset first distance from the pressure detecting elements at both ends. Pressing position control means,
The pressure pulse waveform output from the maximum pressure detecting element and the distance from the maximum pressure detecting element in the state where the pressing position of the pressure pulse wave sensor is controlled by the pressing position control means are the first preset. First correlation coefficient calculating means for calculating a first correlation coefficient with the pressure pulse waveform output from the first pressure detection element that is a distance;
The pressure pulse waveform output from the maximum pressure detecting element and the distance from the maximum pressure detecting element are smaller than the first distance in a state where the pressing position of the pressure pulse wave sensor is controlled by the pressing position control means. Second correlation coefficient calculating means for calculating a second correlation coefficient with the pressure pulse waveform output from the second pressure detection element that is the second distance set to the distance;
The first correlation coefficient calculated by the first correlation coefficient calculating means is equal to or greater than a first reference value set in advance for determining an upper limit value of the pressing force allowed as the optimum pressing force. In addition, the second correlation coefficient calculated by the second correlation coefficient calculating means is equal to or greater than a second reference value set in advance for determining the lower limit value of the pressing force allowed as the optimum pressing force. A continuous blood pressure monitoring apparatus comprising: an optimum pressing force determining means for determining the optimum pressing force. A pressure pulse wave sensor having a plurality of pressure detection elements arranged in the width direction of the artery on the pressing surface to detect a pressure pulse wave generated from the artery of the living body, and the pressure pulse wave sensor from above the skin of the living body A pressing device that presses toward the artery, and an optimal pressing force determination unit that determines an optimal pressing force by which the pressing device presses the pressure pulse wave sensor so that a part of the blood vessel wall of the artery becomes substantially flat. In addition, from the preset relationship between the pressure pulse wave and the estimated blood pressure value, the estimated blood pressure value of the living body is sequentially determined based on the magnitude of the pressure pulse wave detected by the pressure detection element of the pressure pulse wave sensor A continuous blood pressure monitoring device that continuously monitors the blood pressure value of the living body using the estimated blood pressure value,
A width direction moving device for moving the pressing position of the pressure pulse wave sensor in the width direction of the artery;
A maximum pressure detecting element determining means for determining a maximum pressure detecting element that outputs a maximum pulse wave amplitude among the plurality of pressure detecting elements;
The width direction moving device is controlled so that the maximum pressure detecting element determined by the maximum pressure detecting element determining means is a pressure detecting element located on the central side more than a preset first distance from the pressure detecting elements at both ends. Pressing position control means,
The pressure pulse waveform output from the maximum pressure detecting element and the distance from the maximum pressure detecting element in the state where the pressing position of the pressure pulse wave sensor is controlled by the pressing position control means are the first preset. First correlation coefficient calculating means for calculating a first correlation coefficient with the pressure pulse waveform output from the first pressure detection element that is a distance;
The pressure pulse waveform output from the maximum pressure detecting element and the distance from the maximum pressure detecting element are smaller than the first distance in a state where the pressing position of the pressure pulse wave sensor is controlled by the pressing position control means. Second correlation coefficient calculating means for calculating a second correlation coefficient with the pressure pulse waveform output from the second pressure detection element that is the second distance set to the distance;
The first correlation coefficient calculated by the first correlation coefficient calculating means is equal to or greater than a first reference value set in advance for determining an upper limit value of the pressing force allowed as the optimum pressing force. In addition, the second correlation coefficient calculated by the second correlation coefficient calculating means is equal to or greater than a second reference value set in advance for determining the lower limit value of the pressing force allowed as the optimum pressing force. A continuous blood pressure monitoring apparatus comprising: a pressing force correction unit that sequentially corrects the optimal pressing force determined by the optimal pressing force determination unit.

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