JPWO2016067619A1

JPWO2016067619A1 - Ventilator

Info

Publication number: JPWO2016067619A1
Application number: JP2016556366A
Authority: JP
Inventors: 平林　剛; 剛平林; 井上　政昭; 政昭井上
Original assignee: Furrex Co Ltd
Current assignee: Furrex Co Ltd
Priority date: 2014-10-29
Filing date: 2015-10-29
Publication date: 2017-08-10
Anticipated expiration: 2035-10-29
Also published as: JP6706744B2; WO2016067619A1

Abstract

肺胞の虚脱を防ぎかつ換気効率を向上し得る人工呼吸器の提供を目的とする。人工呼吸器の制御部（１０）に、設定比率記憶手段（１４）と、呼気一回換気量決定手段（１５）と、吸気開始ポイント判断手段（１６）と、弁開閉指示手段（１７）とを有し、吸気開始ポイントを、一回の呼吸ごとに呼気一回換気量決定手段（１５）で決定された呼気一回換気量によって判断して吸気弁（４）および呼気弁（５）を駆動することにより、呼気フロー波形からｄＰＥＥＰを推定し、意図的にｄＰＥＥＰが存在するポイントで吸気を開始する。An object of the present invention is to provide a ventilator that can prevent collapse of alveoli and improve ventilation efficiency. The control unit (10) of the ventilator includes a setting ratio storage means (14), an expiration tidal volume determination means (15), an inhalation start point determination means (16), and a valve opening / closing instruction means (17). The inhalation start point is determined by the exhaled tidal volume determined by the exhaled tidal volume determining means (15) for each breath, and the inspiratory valve (4) and the exhaled valve (5) By driving, dPEEP is estimated from the expiratory flow waveform, and inspiration is started at a point where dPEEP is intentionally present.

Description

本発明は、自発呼吸が困難な場合に用いる人工呼吸器に関する。 The present invention relates to a ventilator used when spontaneous breathing is difficult.

図９は気道内圧と気流速の変化を説明するためのグラフである。
従来、吸気・呼気時間比（I：E比）は１：２と呼気時間を長く設定するのが一般的であった。呼気時間が長い場合、呼気フローは基線まで戻り、気道内圧および肺胞内圧もほぼ基線まで低下する（図９：ポイントＡ）。ポイントＡでは肺胞内圧が基線まで低下しているため、肺が虚脱することが懸念される。そこで、肺の虚脱を防ぐ目的で呼気相に一定の圧力をかけて呼気終末陽圧（ＰＥＥＰ）（ｐｏｓｉｔｉｖｅｅｎｄｅｘｈａｌａｔｉｏｎｐｒｅｓｓｕｒｅ）を設定する。これが気道内圧基線ＢＡＰ（ｂａｓｅｌｉｎｅａｉｒｗａｙｐｒｅｓｓｕｒｅ）である。すなわち、必要以上に長い呼気時間の肺胞虚脱防止手段としてＢＡＰを高く設定していた。しかし肺胞圧がある程度存在している呼気初期においては、ＢＡＰは必ずしも必要ではない。
さて、気道内圧と肺胞内圧は必ずしも一致しない。特に閉塞性疾患など、一秒率が障害された症例では、気道内圧と肺胞内圧の格差が生じる。自発呼吸のない患者の場合は、呼気終末休止法（呼吸が終わった直後に呼吸器回路を閉鎖）によりｄＰＥＥＰ（ｄｙｎａｍｉｃＰＥＥＰ）（呼気終末肺胞内圧−気道内圧格差）を測定できる。しかし、呼気終末休止法は換気を一旦停止させなければならず、また呼気終末のポイントを変えればｄＰＥＥＰは変化する。
なお、呼吸ガスが呼吸系に搬送されるときに呼吸ガスの圧力と流量を測定し、吸気時間と呼気時間の比を変化させるものがある（特許文献１）。FIG. 9 is a graph for explaining changes in airway pressure and air flow velocity.
Conventionally, inhalation / expiration time ratio (I: E ratio) is generally set to 1: 2, and the expiration time is set to be long. When the expiration time is long, the expiration flow returns to the baseline, and the airway pressure and the alveolar pressure also decrease to almost the baseline (FIG. 9: point A). At point A, the alveolar pressure is reduced to the baseline, so there is a concern that the lungs collapse. Therefore, a positive end expiratory pressure (PEEP) (positive end exhalation pressure) is set by applying a certain pressure to the expiratory phase in order to prevent collapse of the lungs. This is the airway pressure baseline BAP (baseline airway pressure). That is, BAP was set high as a means for preventing alveolar collapse with an expiration time longer than necessary. However, BAP is not always necessary in the early expiration period when alveolar pressure is present to some extent.
Now, airway pressure and alveolar pressure do not necessarily match. In cases where the rate of one second is impaired, such as obstructive disease, there is a difference between airway pressure and alveolar pressure. For patients without spontaneous breathing, dPEEP (dynamic PEEP) (end-expiratory alveolar pressure-airway pressure difference) can be measured by the end-expiratory pause method (the respiratory circuit is closed immediately after the end of breathing). However, in the end-expiration pause method, ventilation must be temporarily stopped, and dPEEP changes if the end-expiration point is changed.
In addition, there is one that measures the pressure and flow rate of the breathing gas when the breathing gas is conveyed to the breathing system, and changes the ratio of the inspiratory time to the expiratory time (Patent Document 1).

特開平９−１７３４５６号公報JP-A-9-173456

ｄＰＥＥＰの絶対値は測定できないが、呼気フロー波形からｄＰＥＥＰおよび全呼気終末肺胞内圧（ｔＰＥＥＰ）（ｔｏｔａｌＰＥＥＰ）の推移は予測できる。呼気フローが存在する時点ではｄＰＥＥＰが存在する（図９：ポイントＢ）。ポイントＢで吸気を開始させれば、ＢＡＰは最小限あるいは０ｍｍＨｇでも肺胞は虚脱せずに呼気時間を短縮できる。さらに肺胞虚脱予防効果を必要とする場合、より呼気フローが多いポイント（図９：ポイントＣ）で吸気を開始させる。この場合、肺のエアトラップによる気胸、呼吸不全の危険性は増す。
肺胞の虚脱を防ぎかつ換気効率の向上を得るには、呼気時間を最小に、十分な吸気プラトー時間が必要であると考えた。そのためには、１）呼吸モードを従圧式呼吸（Ｐｒｅｓｓｕｒｅｃｏｎｔｒｏｌｖｅｎｔｉｌａｔｉｏｎ）とする。２）呼気フローを妨げない目的でＢＡＰ（ＰＥＥＰ設定値）を最低限とする。３）たとえＢＡＰが０ｍｍＨｇでも呼気フローが存在している時点では呼気肺胞内圧が存在し（ｄｙｎａｍｉｃＰＥＥＰ）、肺胞は虚脱していない。すなわち、呼気フローを指標としながら基線にもどる以前のポイント（エアトラップを起こさずに肺胞は虚脱していないポイント）で吸気を開始させる。これによりＢＡＰがなくとも無期肺は予防され、呼気時間が最小限となり、吸気プラトー時間を最大とすることができる。
ところで、特許文献１は、コンプライアンス（呼吸系の容積導関数と圧力導関数の比）を制御パラメータとし、各患者の肺の状況に応じて圧力レベル、ＰＥＥＰ、吸気時間と呼気時間の比、および呼吸率の少なくとも１つを変化させるものである。Although the absolute value of dPEEP cannot be measured, the transition of dPEEP and total end-tidal alveolar pressure (tPEEP) can be predicted from the expiratory flow waveform. There is dPEEP at the time when the exhalation flow exists (FIG. 9: point B). If inhalation is started at point B, the expiration time can be shortened without causing the alveoli to collapse even if BAP is minimal or 0 mmHg. Further, when the effect of preventing alveolar collapse is required, inhalation is started at a point where there is more expiratory flow (FIG. 9: point C). In this case, the risk of pneumothorax and respiratory failure due to lung air traps increases.
In order to prevent the collapse of the alveoli and to improve the ventilation efficiency, it was considered that a sufficient inspiration plateau time was required to minimize the expiration time. For this purpose, 1) the breathing mode is set to pressure-controlled breathing. 2) Minimize BAP (PEEP set value) for the purpose of not hindering exhalation flow. 3) Even when BAP is 0 mmHg, when exhalation flow is present, exhalation alveolar pressure exists (dynamic PEEP), and the alveoli are not collapsed. That is, inhalation is started at a point before returning to the base line using the exhalation flow as an index (a point where the alveoli have not collapsed without causing an air trap). This prevents indefinite lungs without BAP, minimizes expiratory time, and maximizes inspiratory plateau time.
By the way, Patent Document 1 uses compliance (ratio of volume derivative and pressure derivative of the respiratory system) as a control parameter, and according to each patient's lung condition, pressure level, PEEP, ratio of inspiratory time and expiratory time, and It changes at least one of the respiration rates.

本発明は、呼気フロー波形からｄＰＥＥＰを推定し、意図的にｄＰＥＥＰが存在するポイントで吸気を開始することで、肺胞の虚脱を防ぎかつ換気効率を向上できる人工呼吸器を提供することを目的とする。 An object of the present invention is to provide a ventilator that estimates dPEEP from an expiratory flow waveform and intentionally starts inspiration at a point where dPEEP is present, thereby preventing collapse of alveoli and improving ventilation efficiency. And

請求項１記載の本発明の人工呼吸器は、使用者に装着するインターフェースと、前記インターフェースに酸素を供給する吸気経路と、前記インターフェースから二酸化炭素を排出する呼気経路と、前記呼気経路に設けた呼気弁と、前記呼気弁を開閉制御する呼気弁駆動部と、前記吸気経路からの気流速および前記呼気経路への気流速を検出する気流速検出センサと、前記吸気経路および前記呼気経路の少なくともいずれかの圧力を検出する気道内圧検出センサと、前記気流速検出センサの気流速検出値および前記気道内圧検出センサの気道内圧検出値を入力し、前記吸気弁駆動部および前記呼気弁駆動部に対して弁開閉指示を出力する制御部とを備えた人工呼吸器であって、前記制御部は、呼気終末肺胞内圧−気道内圧格差が正の値となるように呼気一回換気量を決定するための呼気一回換気量設定比率を記憶する設定比率記憶手段と、前記気流速検出センサで検出される前記気流速検出値と前記設定比率記憶手段に記憶された前記呼気一回換気量設定比率とから一回の呼吸ごとに前記呼気一回換気量を決定する呼気一回換気量決定手段と、前記呼気一回換気量決定手段で決定された前記呼気一回換気量となるタイミングを吸気開始ポイントと判断する吸気開始ポイント判断手段と、前記吸気開始ポイント判断手段で判断された前記吸気開始ポイントのタイミングで前記弁開閉指示を出力する弁開閉指示手段とを有し、前記吸気開始ポイントを、一回の前記呼吸ごとに前記呼気一回換気量決定手段で決定された前記呼気一回換気量によって判断して前記吸気弁および前記呼気弁を駆動することを特徴とする。
請求項２記載の本発明は、請求項１に記載の人工呼吸器において、前記気流速検出センサで検出される前記気流速検出値から、一回の前記呼吸ごとに呼気量を計測する呼気量計測手段と、前記気流速検出センサで検出される前記気流速検出値から、一回の前記呼吸ごとに吸気一回換気量Ｙを算出する吸気一回換気量算出手段とを有し、前記設定比率記憶手段では、前記吸気一回換気量算出手段で算出される前記吸気一回換気量Ｙを想定呼気一回換気量Ｘａと見なして、前記想定呼気一回換気量Ｘａに対する残気量Ｚａを前記呼気一回換気量設定比率として記憶し、前記呼気一回換気量決定手段では、一回の前記呼吸ごとに算出される前記吸気一回換気量Ｙと前記呼気一回換気量設定比率とから呼気一回換気量（Ｘａ−Ｚａ）を決定し、前記吸気開始ポイント判断手段では、前記呼気量計測手段で計測される前記呼気量が、前記呼気一回換気量（Ｘａ−Ｚａ）となるタイミングを前記吸気開始ポイントと判断することを特徴とする。
請求項３記載の本発明は、請求項１に記載の人工呼吸器において、前記制御部は、前記気流速検出センサで検出される前記気流速検出値から、一回の前記呼吸ごとに最大呼気値Ｘｂを検出する最大呼気値検出手段を有し、前記設定比率記憶手段では、前記最大呼気値検出手段で検出される前記最大呼気値Ｘｂに対する残気呼気値Ｚｂを前記呼気一回換気量設定比率として記憶し、前記呼気一回換気量決定手段では、一回の前記呼吸ごとに算出される前記最大呼気値Ｘｂと前記呼気一回換気量設定比率とから前記残気呼気値Ｚｂを前記呼気一回換気量として決定し、前記吸気開始ポイント判断手段では、前記気流速検出センサで検出される前記気流速検出値が前記残気呼気値Ｚｂとなるタイミングを前記吸気開始ポイントと判断することを特徴とする。
請求項４記載の本発明は、請求項１から請求項３のいずれかに記載の人工呼吸器において、前記制御部は、設定手段によってあらかじめ設定し気道内圧を記憶する気道内圧記憶手段と、前記気道内圧検出センサで検出される前記気道内圧検出値が、前記気道内圧記憶手段に記憶された前記気道内圧を越えることを監視する全呼気終末肺胞内圧監視手段と、前記弁開閉指示手段に対して呼気時間の延長を指示する呼気時間延長手段とを有し、前記全呼気終末肺胞内圧監視手段で前記気道内圧検出値が前記気道内圧を越えることを検出すると、前記呼気時間延長手段から前記弁開閉指示手段に対して前記呼気時間の延長を指示することを特徴とする。
請求項５記載の本発明は、請求項１から請求項３のいずれかに記載の人工呼吸器において、前記制御部は、前記気流速検出センサで検出される前記気流速の乱れから異常を検出する気流速異常検出手段および前記気道内圧検出センサで検出される前記圧力の乱れから異常を検出する気道内圧異常検出手段の少なくともいずれかと、前記弁開閉指示手段に対して呼気時間の延長を指示する呼気時間延長手段とを有し、前記気流速異常検出手段および前記気道内圧異常検出手段の少なくともいずれかが前記異常を検出すると、前記呼気時間延長手段から前記弁開閉指示手段に対して前記呼気時間の延長を指示することを特徴とする。
請求項６記載の本発明は、請求項１に記載の人工呼吸器において、前記制御部は、前記気流速検出センサで検出される前記気流速検出値から、吸気一回換気量を算出する吸気一回換気量算出手段と、前記気流速検出センサで検出される前記気流速検出値から、前記呼気一回換気量を算出する呼気一回換気量算出手段と、前記吸気一回換気量算出手段で算出される前記吸気一回換気量、および前記呼気一回換気量算出手段で算出される前記呼気一回換気量の少なくともいずれかが設定値を下回ると異常を検出する換気量異常検出手段と、前記弁開閉指示手段に対して呼気時間の延長を指示する呼気時間延長手段とを有し、前記換気量異常検出手段が前記異常を検出すると、前記呼気時間延長手段から前記弁開閉指示手段に対して前記呼気時間の延長を指示することを特徴とする。
請求項７記載の本発明は、請求項１から請求項６のいずれかに記載の人工呼吸器において、前記制御部は、設定手段により設定された呼吸回数を記憶する設定値記憶手段と、前記弁開閉指示手段で指示する吸気タイミングと呼気タイミングとから吸気・呼気時間比を算出する吸気・呼気時間比算出手段と、前記設定値記憶手段に記憶された前記呼吸回数と、前記吸気・呼気時間比算出手段で算出された前記吸気・呼気時間比とで決定したタイミングで前記弁開閉指示手段に指示を出力する持続強制換気指示手段とを有することを特徴とする。
請求項８記載の本発明は、請求項１から請求項６のいずれかに記載の人工呼吸器において、前記制御部は、設定手段により設定された吸気時間を記憶する設定値記憶手段と、前記弁開閉指示手段で指示する吸気タイミングと呼気タイミングとから吸気・呼気時間比を算出する吸気・呼気時間比算出手段と、前記設定値記憶手段に記憶された前記吸気時間と、前記吸気・呼気時間比算出手段で算出された前記吸気・呼気時間比とで決定したタイミングで前記弁開閉指示手段に指示を出力する持続強制換気指示手段とを有することを特徴とする。The ventilator of the present invention according to claim 1 is provided in an interface worn by a user, an inspiratory path for supplying oxygen to the interface, an expiratory path for discharging carbon dioxide from the interface, and the expiratory path. An exhalation valve, an exhalation valve drive unit that controls opening and closing of the exhalation valve, an airflow rate detection sensor that detects an airflow rate from the inhalation path and an airflow rate to the exhalation path, and at least the inhalation path and the exhalation path An airway pressure detection sensor for detecting any pressure, an airflow rate detection value of the airflow rate detection sensor and an airway pressure detection value of the airway pressure detection sensor are input to the intake valve drive unit and the exhalation valve drive unit A control unit that outputs a valve opening / closing instruction to the ventilator, wherein the control unit has a positive difference between the end-expiratory alveolar pressure and the airway pressure. Stored in the setting ratio storage means for storing the expiratory tidal volume setting ratio for determining the expiratory tidal volume, the detected air flow rate detected by the air flow rate detecting sensor, and the set ratio storing means. The expiratory tidal volume determining means for determining the expiratory tidal volume for each breath from the expiratory tidal volume setting ratio, and the expiratory tidal volume determined by the expiratory tidal volume determining means Intake start point determination means for determining the timing of the tidal volume as an intake start point; and valve opening / closing instruction means for outputting the valve opening / closing instruction at the timing of the intake start point determined by the intake start point determination means The inhalation start point is determined by the exhaled tidal volume determined by the exhaled tidal volume determining means for each breath, and the inspiratory valve and the exhaled valve are driven. Characterized in that it.
According to a second aspect of the present invention, in the ventilator according to the first aspect, an expiratory volume for measuring an expiratory volume for each breath, based on the detected value of the air flow velocity detected by the air flow velocity detection sensor. Measuring means, and an intake tidal volume calculating means for calculating an inspiratory tidal volume Y for each breath from the air flow rate detection value detected by the air flow speed detecting sensor, and the setting The ratio storage means regards the inspiratory tidal volume Y calculated by the inspiratory tidal volume calculating means as the assumed exhaled tidal volume Xa, and sets the residual air volume Za relative to the assumed exhaled tidal volume Xa. The expiratory tidal volume setting ratio is stored, and the expiratory tidal volume determining means determines from the inspiratory tidal volume Y calculated for each breath and the expiratory tidal volume setting ratio. Determine the exhaled tidal volume (Xa-Za) The starting point determining means, the amount of exhalation measured by the expiratory volume measuring means, the exhaled tidal volume and becomes a timing (Xa-Za), characterized in that it is determined that the intake starting point.
According to a third aspect of the present invention, in the ventilator according to the first aspect, the control unit is configured to perform a maximum exhalation for each breath from the air flow velocity detection value detected by the air flow velocity detection sensor. A maximum expiratory value detecting means for detecting a value Xb, and the setting ratio storage means sets a residual exhaled breath value Zb with respect to the maximum expiratory value Xb detected by the maximum expiratory value detecting means as the expiratory tidal volume setting. The expiratory tidal volume determining means stores the residual expiratory value Zb from the maximum expiratory value Xb calculated for each breath and the expiratory tidal volume setting ratio. The inhalation start point determination means determines that the timing at which the detected air flow rate value detected by the air flow rate detection sensor becomes the residual expiration value Zb is the inhalation start point. Feature To.
According to a fourth aspect of the present invention, in the ventilator according to any one of the first to third aspects, the control unit is configured to store the airway pressure in advance by setting means and store the airway pressure, An all-expiratory end-alveolar pressure monitoring means for monitoring that the airway pressure detection value detected by the airway pressure detection sensor exceeds the airway pressure stored in the airway pressure storage means; and Expiratory time extending means for instructing to extend the expiratory time, and when detecting that the airway pressure detection value exceeds the airway internal pressure by the total expiratory end alveolar pressure monitoring means, the expiratory time extending means The valve opening / closing instruction means is instructed to extend the expiration time.
According to a fifth aspect of the present invention, in the ventilator according to any one of the first to third aspects, the control unit detects an abnormality from the disturbance in the air flow velocity detected by the air flow velocity detection sensor. Instructing the valve opening / closing instruction means to extend the expiration time and at least one of the abnormal air flow velocity detecting means and the abnormal airway pressure detecting means for detecting abnormality from the pressure disturbance detected by the airway pressure detecting sensor. Expiratory time extending means, and when at least one of the air flow velocity abnormality detecting means and the airway pressure abnormality detecting means detects the abnormality, the expiratory time from the expiratory time extending means to the valve opening / closing instruction means It is characterized by instructing the extension of.
According to a sixth aspect of the present invention, in the ventilator according to the first aspect, the control unit calculates an inspiratory tidal volume from the air flow rate detection value detected by the air flow rate detection sensor. Tidal volume calculating means, expiratory tidal volume calculating means for calculating the exhaled tidal volume from the detected air flow rate detected by the air flow rate detecting sensor, and inspiratory tidal volume calculating means A ventilation amount abnormality detecting means for detecting an abnormality when at least one of the inspiratory tidal volume calculated in step 1 and the expiratory tidal volume calculating means is less than a set value; And an expiration time extension means for instructing the valve opening / closing instruction means to extend the expiration time, and when the ventilation amount abnormality detection means detects the abnormality, the expiration time extension means causes the valve opening / closing instruction means to Against the expiration time Characterized in that it indicates the length.
According to a seventh aspect of the present invention, in the ventilator according to any one of the first to sixth aspects, the control unit stores setting value storage means for storing the number of breaths set by the setting means, Inspiration / expiration time ratio calculating means for calculating an inhalation / expiration time ratio from the inspiration timing and expiration timing indicated by the valve opening / closing instruction means, the number of breaths stored in the set value storage means, and the inspiration / expiration time And a continuous forced ventilation instruction means for outputting an instruction to the valve opening / closing instruction means at a timing determined by the inhalation / expiration time ratio calculated by the ratio calculation means.
The present invention according to claim 8 is the ventilator according to any one of claims 1 to 6, wherein the control unit stores setting value storage means for storing the inspiratory time set by the setting means; Inspiration / expiration time ratio calculating means for calculating an inhalation / expiration time ratio from inspiration timing and expiration timing indicated by the valve opening / closing instruction means, the inspiration time stored in the set value storage means, and the inspiration / expiration time And a continuous forced ventilation instruction means for outputting an instruction to the valve opening / closing instruction means at a timing determined by the inhalation / expiration time ratio calculated by the ratio calculation means.

本発明によれば、一回の呼吸ごとにｄＰＥＥＰを推定し、意図的にｄＰＥＥＰが存在するポイントで吸気を開始することで、肺胞の虚脱を防ぎかつ換気効率を向上できる。 According to the present invention, dPEEP is estimated for each breath, and inspiration is started intentionally at a point where dPEEP is present, thereby preventing alveolar collapse and improving ventilation efficiency.

本発明の一実施例による人工呼吸器を機能実現手段で現したブロック図The block diagram which expressed the ventilator by one Example of this invention by the function implementation means 気道内圧と気流速の変化を示すグラフGraph showing changes in airway pressure and airflow velocity 本実施例による人工呼吸器での気道内圧と気流速の変化を示すグラフGraph showing changes in airway pressure and airflow velocity in the ventilator according to this example 本実施例による人工呼吸器での気道内圧と気流速の変化を示すグラフGraph showing changes in airway pressure and airflow velocity in the ventilator according to this example 本実施例による人工呼吸器での気道内圧と気流速の変化を示すグラフGraph showing changes in airway pressure and airflow velocity in the ventilator according to this example 本発明の他の実施例による人工呼吸器を機能実現手段で現したブロック図The block diagram which represented the ventilator by other Example of this invention with the function implementation means 本実施例による人工呼吸器での気道内圧と気流速の変化を示すグラフGraph showing changes in airway pressure and airflow velocity in the ventilator according to this example ボリュームカプノメトリを用いて換気効率を評価した結果を示す図The figure which shows the result of having evaluated the ventilation efficiency using volume capnometry 気道内圧と気流速の変化を説明するためのグラフGraph to explain changes in airway pressure and air flow velocity

本発明の第１の実施の形態による人工呼吸器は、制御部が、呼気終末肺胞内圧−気道内圧格差が正の値となるように呼気一回換気量を決定するための呼気一回換気量設定比率を記憶する設定比率記憶手段と、気流速検出センサで検出される気流速検出値と設定比率記憶手段に記憶された呼気一回換気量設定比率とから一回の呼吸ごとに呼気一回換気量を決定する呼気一回換気量決定手段と、呼気一回換気量決定手段で決定された呼気一回換気量となるタイミングを吸気開始ポイントと判断する吸気開始ポイント判断手段と、吸気開始ポイント判断手段で判断された吸気開始ポイントのタイミングで弁開閉指示を出力する弁開閉指示手段とを有し、吸気開始ポイントを、一回の呼吸ごとに呼気一回換気量決定手段で決定された呼気一回換気量によって判断して吸気弁および呼気弁を駆動するものである。本実施の形態によれば、一回の呼吸ごとにｄＰＥＥＰを推定し、意図的にｄＰＥＥＰが存在するポイントで吸気を開始することで、肺胞の虚脱を防ぎかつ換気効率を向上できる。 In the ventilator according to the first embodiment of the present invention, the control unit determines the expiration tidal volume so that the end-expiratory alveolar pressure-intra-airway pressure difference becomes a positive value. From the setting ratio storage means for storing the volume setting ratio, the air flow rate detection value detected by the air flow rate detection sensor, and the expiration tidal volume setting ratio stored in the setting ratio storage means, the expiration rate for each breath Expiratory tidal volume determining means for determining the tidal volume, inspiratory start point determining means for determining the timing at which the expiratory tidal volume determined by the expiratory tidal volume determining means is the inspiratory start point, and inhalation start Valve opening / closing instruction means for outputting a valve opening / closing instruction at the timing of the inspiration start point determined by the point determination means, and the inhalation start point is determined by the expiratory tidal volume determining means for each breath For exhaled tidal volume It is intended to drive the intake valve and the exhalation valve to determine me. According to the present embodiment, dPEEP is estimated for each breath, and inspiration is started at a point where dPEEP is intentionally present, so that collapse of the alveoli can be prevented and ventilation efficiency can be improved.

本発明の第２の実施の形態は、第１の実施の形態による人工呼吸器において、制御部が、気流速検出センサで検出される気流速検出値から、一回の呼吸ごとに呼気量を計測する呼気量計測手段と、気流速検出センサで検出される気流速検出値から、一回の呼吸ごとに吸気一回換気量Ｙを算出する吸気一回換気量算出手段とを有し、設定比率記憶手段では、吸気一回換気量算出手段で算出される吸気一回換気量Ｙを想定呼気一回換気量Ｘａと見なして、想定呼気一回換気量Ｘａに対する残気量Ｚａを呼気一回換気量設定比率として記憶し、
呼気一回換気量決定手段では、一回の呼吸ごとに算出される吸気一回換気量Ｙと呼気一回換気量設定比率とから呼気一回換気量（Ｘａ−Ｚａ）を決定し、吸気開始ポイント判断手段では、呼気量計測手段で計測される呼気量が、呼気一回換気量（Ｘａ−Ｚａ）となるタイミングを吸気開始ポイントと判断するものである。本実施の形態によれば、一回の呼吸ごとの吸気一回換気量Ｙから、吸気開始ポイントを一回の呼吸ごとに算出して吸気を実行するため、面積Ｚａにあたる換気量が残気量として残存するため、肺胞の虚脱を防ぎかつ換気効率を向上できる。According to the second embodiment of the present invention, in the ventilator according to the first embodiment, the control unit calculates the expiratory volume for each breath from the air flow velocity detection value detected by the air flow velocity detection sensor. An expiratory volume measuring means for measuring, and an inspiratory tidal volume calculating means for calculating the inspiratory tidal volume Y for each breath from the air flow rate detection value detected by the air flow rate detecting sensor, and setting In the ratio storage means, the inspiratory tidal volume Y calculated by the inspiratory tidal volume calculating means is regarded as the assumed exhaled tidal volume Xa, and the residual air volume Za with respect to the assumed exhaled tidal volume Xa is determined as the exhaled tidal volume. Store it as a ventilation rate setting ratio,
The expiratory tidal volume determining means determines the exhaled tidal volume (Xa-Za) from the inspiratory tidal volume Y calculated for each breath and the expiratory tidal volume setting ratio, and starts inhalation. The point determination means determines the timing at which the expiration amount measured by the expiration amount measurement means becomes the expiration tidal volume (Xa-Za) as the inspiration start point. According to the present embodiment, the inspiration start point is calculated for each breath from the inspiratory tidal volume Y for each breath, and the inspiration is executed. Therefore, the ventilation volume corresponding to the area Za is the residual air volume. Therefore, the alveoli can be prevented from collapsing and the ventilation efficiency can be improved.

本発明の第３の実施の形態は、第１の実施の形態による人工呼吸器において、制御部が、気流速検出センサで検出される気流速検出値から、一回の呼吸ごとに最大呼気値Ｘｂを検出する最大呼気値検出手段を有し、設定比率記憶手段では、最大呼気値検出手段で検出される最大呼気値Ｘｂに対する残気呼気値Ｚｂを呼気一回換気量設定比率として記憶し、呼気一回換気量決定手段では、一回の呼吸ごとに算出される最大呼気値Ｘｂと呼気一回換気量設定比率とから残気呼気値Ｚｂを呼気一回換気量として決定し、吸気開始ポイント判断手段では、気流速検出センサで検出される気流速検出値が残気呼気値Ｚｂとなるタイミングを吸気開始ポイントと判断するものである。本実施の形態によれば、一回の呼吸ごとの最大呼気値Ｘｂから吸気開始ポイントを一回の呼吸ごとに算出して吸気を実行するため、残気呼気値Ｚｂに対応する残気量が残存するため肺胞の虚脱を防ぎかつ換気効率を向上できる。 According to the third embodiment of the present invention, in the ventilator according to the first embodiment, the control unit detects the maximum exhalation value for each breath from the air flow rate detection value detected by the air flow rate detection sensor. A maximum expiratory value detecting means for detecting Xb, and the setting ratio storage means stores the remaining expiratory value Zb relative to the maximum expiratory value Xb detected by the maximum expiratory value detecting means as an expiratory tidal volume setting ratio; The expiratory tidal volume determining means determines the remaining exhaled breath value Zb as the expiratory tidal volume from the maximum expiratory value Xb calculated for each breath and the expiratory tidal volume setting ratio, and the inhalation start point The determination means determines the timing at which the detected air flow rate value detected by the air flow rate detection sensor becomes the remaining expiration value Zb as the inspiration start point. According to the present embodiment, since the inspiration start point is calculated for each breath from the maximum expiratory value Xb for each breath, and the inhalation is executed, the residual air amount corresponding to the residual breath value Zb is determined. Since it remains, the collapse of the alveoli can be prevented and the ventilation efficiency can be improved.

本発明の第４の実施の形態は、第１から第３のいずれかの実施の形態による人工呼吸器において、制御部が、設定手段によってあらかじめ設定した気道内圧を記憶する気道内圧記憶手段と、気道内圧検出センサで検出される気道内圧検出値が、気道内圧記憶手段に記憶された気道内圧を越えることを監視する全呼気終末肺胞内圧監視手段と、弁開閉指示手段に対して呼気時間の延長を指示する呼気時間延長手段とを有し、全呼気終末肺胞内圧監視手段で気道内圧検出値が気道内圧を越えることを検出すると、呼気時間延長手段から弁開閉指示手段に対して呼気時間の延長を指示するものである。呼気時間を短くすると呼気が十分吐ききれずに、肺にエアトラップを来たして呼吸不全の増悪や気胸の原因となることが懸念されるが、本実施の形態によれば、ｔＰＥＥＰが著しく増加している場合には、呼気時間を延長することで安全性を確保することができる。 According to a fourth embodiment of the present invention, in the ventilator according to any one of the first to third embodiments, the control unit stores an airway pressure storage unit that stores an airway pressure preset by the setting unit, The total expiration end alveolar pressure monitoring means for monitoring that the airway pressure detection value detected by the airway pressure detection sensor exceeds the airway pressure stored in the airway pressure storage means, and the expiration time of the expiration time for the valve opening / closing instruction means Expiratory time extending means for instructing an extension, and when the total expiratory end alveolar pressure monitoring means detects that the airway pressure detected value exceeds the airway pressure, the expiratory time from the expiratory time extending means to the valve opening / closing instruction means It is an instruction to extend. If the expiration time is shortened, it is feared that the expiration cannot be sufficiently exhaled and an air trap comes into the lungs, causing respiratory failure and pneumothorax. However, according to this embodiment, tPEEP increases remarkably. If so, safety can be secured by extending the expiration time.

本発明の第５の実施の形態は、第１から第３のいずれかの実施の形態による人工呼吸器において、制御部が、気流速検出センサで検出される気流速の乱れから異常を検出する気流速異常検出手段および気道内圧検出センサで検出される圧力の乱れから異常を検出する気道内圧異常検出手段の少なくともいずれかと、弁開閉指示手段に対して呼気時間の延長を指示する呼気時間延長手段とを有し、気流速異常検出手段および気道内圧異常検出手段の少なくともいずれかが異常を検出すると、呼気時間延長手段から弁開閉指示手段に対して呼気時間の延長を指示するものである。体動、術操作、咳などの影響で気流速の検出が困難となることがあるが、本実施の形態によれば、呼気時間を延長することで安全性を確保することができる。 In the fifth embodiment of the present invention, in the ventilator according to any one of the first to third embodiments, the control unit detects an abnormality from the disturbance of the air flow velocity detected by the air flow velocity detection sensor. At least one of airway pressure abnormality detecting means for detecting an abnormality from pressure disturbance detected by the air flow velocity abnormality detecting means and the airway pressure detecting sensor, and an expiration time extending means for instructing the valve opening / closing instruction means to extend the expiration time When at least one of the air flow velocity abnormality detection means and the airway pressure abnormality detection means detects an abnormality, the expiration time extension means instructs the valve opening / closing instruction means to extend the expiration time. Although detection of the air flow rate may be difficult due to the influence of body movement, surgical operation, cough, etc., according to the present embodiment, safety can be ensured by extending the expiration time.

本発明の第６の実施の形態は、第１の実施の形態による人工呼吸器において、制御部が、気流速検出センサで検出される気流速検出値から、吸気一回換気量を算出する吸気一回換気量算出手段と、気流速検出センサで検出される気流速検出値から、呼気一回換気量を算出する呼気一回換気量算出手段と、吸気一回換気量算出手段で算出される吸気一回換気量、および呼気一回換気量算出手段で算出される呼気一回換気量の少なくともいずれかが設定値を下回ると異常を検出する換気量異常検出手段と、弁開閉指示手段に対して呼気時間の延長を指示する呼気時間延長手段とを有し、換気量異常検出手段が異常を検出すると、呼気時間延長手段から弁開閉指示手段に対して呼気時間の延長を指示するものである。肺にエアトラップを来たした場合、吸気一回換気量および呼気一回換気量が著しく低下するが、本実施の形態によれば、呼気時間を延長することで安全性を確保することができる。 In the sixth embodiment of the present invention, in the ventilator according to the first embodiment, the control unit calculates the inspiratory tidal volume from the air flow rate detection value detected by the air flow rate detection sensor. Calculated by a tidal volume calculating means and a tidal volume calculating means for calculating a tidal volume and a tidal volume calculating means for calculating a tidal volume from the detected air flow rate detected by the air flow rate detecting sensor. For at least one of the inspiratory tidal volume and the exhaled tidal volume calculating means, the tidal volume abnormality detecting means for detecting an abnormality when the exhaled tidal volume falls below the set value, and the valve opening / closing instruction means Expiratory time extending means for instructing to extend the expiratory time, and when the abnormal ventilation amount detecting means detects an abnormality, the expiratory time extending means instructs the valve opening / closing instructing means to extend the expiratory time. . When an air trap comes to the lungs, the inspiratory tidal volume and exhaled tidal volume are significantly reduced, but according to the present embodiment, safety can be ensured by extending the expiration time. .

本発明の第７の実施の形態は、第１から第６のいずれかの実施の形態による人工呼吸器において、制御部が、設定手段により設定された呼吸回数を記憶する設定値記憶手段と、弁開閉指示手段で指示する吸気タイミングと呼気タイミングとから吸気・呼気時間比を算出する吸気・呼気時間比算出手段と、設定値記憶手段に記憶された呼吸回数と、吸気・呼気時間比算出手段で算出された吸気・呼気時間比とで決定したタイミングで弁開閉指示手段に指示を出力する持続強制換気指示手段とを有するものである。本実施の形態によれば、呼吸回数を固定設定した持続強制換気モードにも適用することができる。 In the ventilator according to any one of the first to sixth embodiments, the seventh embodiment of the present invention is a setting value storage means in which the control unit stores the number of breaths set by the setting means; Inhalation / expiration time ratio calculating means for calculating an inhalation / expiration time ratio from the inspiration timing and expiration timing indicated by the valve opening / closing instruction means, the number of breaths stored in the set value storage means, and the inspiration / expiration time ratio calculation means And a continuous forced ventilation instructing means for outputting an instruction to the valve opening / closing instruction means at a timing determined by the inhalation / expiration time ratio calculated in (1). According to the present embodiment, the present invention can also be applied to the continuous forced ventilation mode in which the number of breaths is fixedly set.

本発明の第８の実施の形態は、第１から第６のいずれかの実施の形態による人工呼吸器において、制御部が、設定手段により設定された吸気時間を記憶する設定値記憶手段と、弁開閉指示手段で指示する吸気タイミングと呼気タイミングとから吸気・呼気時間比を算出する吸気・呼気時間比算出手段と、設定値記憶手段に記憶された吸気時間と、吸気・呼気時間比算出手段で算出された吸気・呼気時間比とで決定したタイミングで弁開閉指示手段に指示を出力する持続強制換気指示手段とを有するものである。本実施の形態によれば、吸気時間を固定設定した持続強制換気モードにも適用することができる。 The eighth embodiment of the present invention is the ventilator according to any one of the first to sixth embodiments, wherein the control unit stores setting value storage means for storing the inspiratory time set by the setting means, Inspiration / expiration time ratio calculating means for calculating an inhalation / expiration time ratio from inspiration timing and expiration timing indicated by the valve opening / closing instruction means, inspiration time stored in the set value storage means, and inspiration / expiration time ratio calculation means And a continuous forced ventilation instructing means for outputting an instruction to the valve opening / closing instruction means at a timing determined by the inhalation / expiration time ratio calculated in (1). According to the present embodiment, the present invention can also be applied to the continuous forced ventilation mode in which the intake time is fixedly set.

以下に本発明の一実施例について説明する。
図１は本発明の一実施例による人工呼吸器を機能実現手段で現したブロック図である。
図１に示すように、本実施例による人工呼吸器は、使用者に装着するインターフェース１と、インターフェース１に酸素を供給する吸気経路２と、インターフェース１から二酸化炭素を排出する呼気経路３と、吸気経路２に設けた吸気弁４と、呼気経路３に設けた呼気弁５と、吸気弁４を開閉制御する吸気弁駆動部４ａと、呼気弁５を開閉制御する呼気弁駆動部５ａとを備えている。
インターフェース１としては、フェースマスク、鼻マスク、気管チューブ、又は気管カニューレが用いられる。
吸気経路２には、圧縮空気供給源２ａから供給される圧縮空気と、圧縮酸素供給源２ｂから供給される圧縮酸素とが混合器２ｃで混合されて供給される。
吸気弁４を設けず、呼気弁５の開度調整によって、吸気ガスの吸気流量、吸気圧、吸気時間、呼気ガスの呼気流量、呼気圧、および呼気時間を制御することができるが、さらに吸気弁４を設けることで、呼気の期間中に、吸気経路２からの吸気ガスの無駄な排出を防止できる。An embodiment of the present invention will be described below.
FIG. 1 is a block diagram showing a ventilator according to an embodiment of the present invention as function realizing means.
As shown in FIG. 1, the ventilator according to the present embodiment includes an interface 1 worn by a user, an inhalation path 2 for supplying oxygen to the interface 1, an exhalation path 3 for discharging carbon dioxide from the interface 1, An inhalation valve 4 provided in the inhalation path 2, an exhalation valve 5 provided in the exhalation path 3, an inhalation valve drive unit 4 a that controls opening and closing of the inhalation valve 4, and an exhalation valve drive unit 5 a that controls opening and closing of the exhalation valve 5 I have.
As the interface 1, a face mask, a nasal mask, a tracheal tube, or a tracheal cannula is used.
Compressed air supplied from the compressed air supply source 2a and compressed oxygen supplied from the compressed oxygen supply source 2b are mixed and supplied to the intake passage 2 by the mixer 2c.
By adjusting the opening of the exhalation valve 5 without providing the inhalation valve 4, the inspiratory gas inspiratory flow rate, inspiratory pressure, inspiratory time, expiratory gas expiratory flow rate, expiratory pressure, and expiratory time can be controlled. By providing the valve 4, it is possible to prevent wasteful discharge of the intake gas from the intake path 2 during the expiration period.

本実施例による人工呼吸器は、気流速検出センサ６と、気道内圧検出センサ７と、設定手段８と、制御部１０とを備えている。
気流速検出センサ６は、吸気経路２からの気流速および呼気経路３への気流速を検出する。従って、気流速検出センサ６を吸気経路２と呼気経路３との合流点からインターフェース１までの間に設ける場合には、一つの気流速検出センサ６によって吸気経路２からの気流速および呼気経路３への気流速を検出できるが、吸気経路２と呼気経路３とにそれぞれ気流速センサ６を設けて各気流速を検出してもよい。
気道内圧検出センサ７は、吸気経路２および呼気経路３の少なくともいずれかの圧力を検出する。設定手段８は、入力装置で構成されて各種の設定値を設定する。制御部１０は、気流速検出センサ６の気流速検出値および気道内圧検出センサ７の気道内圧検出値を入力し、吸気弁駆動部４ａおよび呼気弁駆動部５ａに対して弁開閉指示を出力する。The ventilator according to the present embodiment includes an air flow velocity detection sensor 6, an airway pressure detection sensor 7, a setting unit 8, and a control unit 10.
The air flow rate detection sensor 6 detects the air flow rate from the inspiratory path 2 and the air flow rate to the expiratory path 3. Therefore, when the air flow rate detection sensor 6 is provided between the confluence of the inhalation path 2 and the exhalation path 3 and the interface 1, the air flow rate from the inhalation path 2 and the exhalation path 3 are detected by one air flow rate detection sensor 6. However, the air flow rate sensors 6 may be provided in the inspiratory path 2 and the expiratory path 3 to detect the respective air flow speeds.
The airway pressure detection sensor 7 detects the pressure of at least one of the inspiratory path 2 and the expiratory path 3. The setting means 8 is composed of an input device and sets various setting values. The control unit 10 inputs the air flow rate detection value of the air flow rate detection sensor 6 and the airway pressure detection value of the airway pressure detection sensor 7, and outputs a valve opening / closing instruction to the intake valve drive unit 4a and the exhalation valve drive unit 5a. .

制御部１０は、呼気量計測手段１１と、吸気一回換気量算出手段１２と、呼気一回換気量算出手段１３とを有している。
呼気量計測手段１１は、気流速検出センサ６で検出される気流速検出値から、一回の呼吸ごとに呼気量を計測する。吸気一回換気量算出手段１２は、気流速検出センサ６で検出される気流速検出値から、一回の呼吸ごとに吸気一回換気量を算出する。呼気一回換気量算出手段１３は、気流速検出センサ６で検出される気流速検出値から、一回の呼吸ごとに呼気一回換気量を算出する。The control unit 10 includes expiratory volume measuring means 11, inspiratory tidal volume calculating means 12, and expiratory tidal volume calculating means 13.
The expiratory volume measuring means 11 measures the expiratory volume for each breath from the air flow velocity detection value detected by the air flow velocity detection sensor 6. The intake tidal volume calculating means 12 calculates the intake tidal volume for each breath from the detected air flow rate detected by the air flow rate detection sensor 6. The exhaled tidal volume calculating means 13 calculates the exhaled tidal volume for each breath from the detected air flow rate detected by the air flow rate detecting sensor 6.

制御部１０は、設定比率記憶手段１４と、呼気一回換気量決定手段１５と、吸気開始ポイント判断手段１６と、弁開閉指示手段１７とを有している。
設定比率記憶手段１４は、呼気一回換気量を決定するための呼気一回換気量設定比率を記憶する。設定比率記憶手段１４に記憶される呼気一回換気量設定比率は、設定手段８によって入力される。呼気一回換気量設定比率は、呼気終末肺胞内圧−気道内圧格差が正の値となるように設定される。さらに具体的には、設定比率記憶手段１４では、吸気一回換気量算出手段１２で算出される吸気一回換気量を想定呼気一回換気量と見なして、想定呼気一回換気量に対する残気量を呼気一回換気量設定比率として記憶する。
呼気一回換気量決定手段１５は、吸気一回換気量算出手段１２で算出される一回の呼吸ごとの吸気一回換気量と、設定比率記憶手段１４に記憶された呼気一回換気量設定比率とから一回の呼吸ごとに呼気一回換気量を決定する。
吸気開始ポイント判断手段１６は、呼気量計測手段１１で計測される呼気量が、呼気一回換気量決定手段１５で決定された呼気一回換気量となるタイミングを吸気開始ポイントと判断する。
弁開閉指示手段１７は、吸気開始ポイント判断手段１６で判断された吸気開始ポイントのタイミングで弁開閉指示を吸気弁駆動部４ａおよび呼気弁駆動部５ａに出力する。The control unit 10 includes setting ratio storage means 14, expiration tidal volume determination means 15, inspiration start point determination means 16, and valve opening / closing instruction means 17.
The setting ratio storage means 14 stores an expiration tidal volume setting ratio for determining the expiration tidal volume. The expiratory tidal volume setting ratio stored in the setting ratio storage means 14 is input by the setting means 8. The expiration tidal volume setting ratio is set so that the end-expiratory alveolar pressure-intra-airway pressure difference is a positive value. More specifically, the setting ratio storage means 14 regards the inspiratory tidal volume calculated by the inspiratory tidal volume calculating means 12 as the assumed exhaled tidal volume, and the residual air with respect to the assumed exhaled tidal volume. The amount is stored as a tidal volume setting ratio.
The expiratory tidal volume determining unit 15 sets the inspiratory tidal volume for each breath calculated by the inspiratory tidal volume calculating unit 12 and the expiratory tidal volume setting stored in the setting ratio storage unit 14. The exhaled tidal volume is determined for each breath from the ratio.
The inspiration start point determination unit 16 determines the timing at which the expiration amount measured by the expiration amount measurement unit 11 becomes the expiration tidal volume determined by the expiration tidal volume determination unit 15 as an inspiration start point.
The valve opening / closing instruction unit 17 outputs a valve opening / closing instruction to the intake valve driving unit 4a and the exhalation valve driving unit 5a at the timing of the inhalation start point determined by the inhalation start point determining unit 16.

制御部１０は、気道内圧記憶手段１８と、気道内圧上限記憶手段１９と、吸気終了ポイント判断手段２０とを有する。
気道内圧記憶手段１８は、設定手段８によってあらかじめ設定した気道内圧を記憶する。気道内圧上限記憶手段１９は、設定手段８によってあらかじめ設定した気道内圧上限値か、または設定された気道内圧から決定される気道内圧上限値を記憶する。吸気終了ポイント判断手段２０は、気道内圧検出センサ７で検出される気道内圧が気道内圧上限記憶手段１９に記憶されている気道内圧上限値に達したタイミングを吸気終了ポイントとして判断するか、または気道内圧検出センサ７で検出される気道内圧が気道内圧上限値に達した後に設定された吸気時間が経過した後のタイミングを吸気終了ポイントとして判断する。弁開閉指示手段１７は、吸気終了ポイント判断手段２０で判断された吸気終了ポイントのタイミングで弁開閉指示を吸気弁駆動部４ａおよび呼気弁駆動部５ａに出力する。
すなわち、本実施例は、吸気上限を気道内圧で制御する従圧式調整換気ＰＣＶ（ｐｒｅｓｓｕｒｅｃｏｎｔｒｏｌｖｅｎｔｉｌａｔｉｏｎ）モードである。The control unit 10 includes an airway internal pressure storage unit 18, an airway internal pressure upper limit storage unit 19, and an inspiration end point determination unit 20.
The airway pressure storage means 18 stores the airway pressure preset by the setting means 8. The airway pressure upper limit storage unit 19 stores the airway pressure upper limit value set in advance by the setting unit 8 or the airway pressure upper limit value determined from the set airway pressure. The intake end point determination means 20 determines the timing at which the airway pressure detected by the airway pressure detection sensor 7 reaches the airway pressure upper limit value stored in the airway pressure upper limit storage means 19 as the intake end point, or the airway The timing after the intake time set after the airway internal pressure detected by the internal pressure detection sensor 7 reaches the airway internal pressure upper limit value is determined as the intake end point. The valve opening / closing instruction unit 17 outputs a valve opening / closing instruction to the intake valve driving unit 4a and the exhalation valve driving unit 5a at the timing of the intake end point determined by the intake end point determining unit 20.
In other words, the present embodiment is a pressure control ventilation PCV (pressure control ventilation) mode in which the upper limit of intake is controlled by the airway pressure.

制御部１０は、全呼気終末肺胞内圧（ｔＰＥＥＰ）監視手段２１と、呼気時間延長手段２２とを有している。
全呼気終末肺胞内圧監視手段２１は、気道内圧検出センサ７で検出される気道内圧検出値が、気道内圧記憶手段１８に記憶された気道内圧を越えることを監視する。呼気時間延長手段２２は、弁開閉指示手段１７に対して呼気時間の延長を指示する。
そして、全呼気終末肺胞内圧監視手段２１で気道内圧検出値が気道内圧を越えることを検出すると、警報手段（図示せず）からアラームを発するとともに呼気時間延長手段２２から弁開閉指示手段１７に対して呼気時間の延長を指示する。従って、本実施例によれば、ｔＰＥＥＰが著しく増加している場合には、呼気時間を延長することで安全性を確保でき、肺にエアトラップを来たして呼吸不全の増悪や気胸の原因となることがない。The control unit 10 includes a total end expiratory alveolar pressure (tPEEP) monitoring unit 21 and an expiration time extending unit 22.
The end-expiratory alveolar pressure monitoring means 21 monitors whether the airway pressure detection value detected by the airway pressure detection sensor 7 exceeds the airway pressure stored in the airway pressure storage means 18. The expiration time extension means 22 instructs the valve opening / closing instruction means 17 to extend the expiration time.
When the total end-expiratory alveolar pressure monitoring means 21 detects that the airway pressure detection value exceeds the airway pressure, an alarm is issued from an alarm means (not shown) and the expiratory time extension means 22 sends it to the valve opening / closing instruction means 17. Instruct the patient to extend the expiration time. Therefore, according to the present embodiment, when tPEEP is remarkably increased, safety can be ensured by extending the expiration time, and an air trap is brought into the lung, which causes exacerbation of respiratory failure and pneumothorax. There is nothing.

制御部１０は、気流速検出センサ６で検出される気流速の乱れから異常を検出する気流速異常検出手段２３と、気道内圧検出センサ７で検出される圧力の乱れから異常を検出する気道内圧異常検出手段２４の少なくともいずれかを有する。
そして、気流速異常検出手段２３および気道内圧異常検出手段２４の少なくともいずれかが異常を検出すると、警報手段（図示せず）からアラームを発するとともに呼気時間延長手段２２から弁開閉指示手段１７に対して呼気時間の延長を指示する。従って、本実施例によれば、体動、術操作、咳などの影響で気流速の検出が困難となる場合には、呼気時間を延長することで安全性を確保できる。The control unit 10 includes an air flow velocity abnormality detecting means 23 that detects an abnormality from the air flow velocity disturbance detected by the air flow velocity detection sensor 6, and an airway pressure that detects an abnormality from the pressure disturbance detected by the airway pressure detection sensor 7. At least one of the abnormality detection means 24 is included.
When at least one of the air flow velocity abnormality detection means 23 and the airway pressure abnormality detection means 24 detects an abnormality, an alarm is issued from an alarm means (not shown) and the expiratory time extension means 22 notifies the valve opening / closing instruction means 17. And instruct the extension of the expiration time. Therefore, according to the present embodiment, when it is difficult to detect the air flow rate due to the influence of body movement, surgical operation, cough, etc., safety can be ensured by extending the expiration time.

制御部１０は、吸気一回換気量算出手段１２で算出される吸気一回換気量、または呼気一回換気量算出手段１３で算出される呼気一回換気量の少なくともいずれかが設定値を下回ると異常を検出する換気量異常検出手段２５を有している。
そして、換気量異常検出手段２５が異常を検出すると、警報手段（図示せず）からアラームを発するとともに呼気時間延長手段２２から弁開閉指示手段１７に対して呼気時間の延長を指示する。従って、本実施例によれば、肺にエアトラップを来たした場合に、呼気時間を延長することで吸気一回換気量および呼気一回換気量の低下を防止して、安全性を確保することができる。The control unit 10 determines that at least one of the inspiratory tidal volume calculated by the inspiratory tidal volume calculating unit 12 or the exhaled tidal volume calculated by the expiratory tidal volume calculating unit 13 is lower than the set value. And a ventilation amount abnormality detecting means 25 for detecting abnormality.
When the ventilation amount abnormality detection means 25 detects an abnormality, an alarm is issued from an alarm means (not shown) and the expiration time extension means 22 instructs the valve opening / closing instruction means 17 to extend the expiration time. Therefore, according to the present embodiment, when an air trap comes into the lung, the expiration time is extended to prevent a decrease in inspiratory tidal volume and exhaled tidal volume, thereby ensuring safety. be able to.

制御部１０は、設定値記憶手段３１と、吸気・呼気時間比算出手段３２と、持続強制換気（ＣＭＶ）（ｃｏｎｔｉｎｕｏｕｓｍａｎｄａｔｏｒｙｖｅｎｔｉｌａｔｉｏｎ）指示手段３３とを有する。
設定値記憶手段３１は、設定手段８により設定された呼吸回数または吸気時間を記憶する。吸気・呼気時間比算出手段３２は、弁開閉指示手段１７で指示する吸気タイミングと呼気タイミングとから吸気・呼気時間比を算出する。
持続強制換気指示手段３３は、呼吸回数を固定設定した持続強制換気モードでは、設定値記憶手段３１に記憶された呼吸回数と、吸気・呼気時間比算出手段３２で算出された吸気・呼気時間比とで決定したタイミングで弁開閉指示手段１７に指示を出力する。
持続強制換気指示手段３３は、吸気時間を固定設定した持続強制換気モードでは、設定値記憶手段３１に記憶された吸気時間と、吸気・呼気時間比算出手段３２で算出された吸気・呼気時間比とで決定したタイミングで弁開閉指示手段１７に指示を出力する。
なお、持続強制換気指示手段３３による持続強制換気モードは、あらかじめ吸気開始ポイント判断手段１６による換気モードを行った後に行う他、持続強制換気指示手段３３による持続強制換気モードと吸気開始ポイント判断手段１６による換気モードとを適宜切り替えて行うこともできる。The control unit 10 includes a set value storage unit 31, an inspiration / expiration time ratio calculation unit 32, and a continuous mandatory ventilation (CMV) (continuous mandatory ventilation) instruction unit 33.
The set value storage unit 31 stores the number of breaths or the inspiratory time set by the setting unit 8. The inspiration / expiration time ratio calculating means 32 calculates an inspiration / expiration time ratio from the inspiration timing and the expiration timing indicated by the valve opening / closing instruction means 17.
In the continuous forced ventilation mode in which the number of breaths is fixedly set, the continuous forced ventilation instructing means 33 and the inhalation / expiration time ratio calculated by the inspiratory / expiratory time ratio calculating means 32 and the number of breaths stored in the set value storage means 31. An instruction is output to the valve opening / closing instruction means 17 at the timing determined in the above.
In the forced forced ventilation mode in which the inspiratory time is fixedly set, the sustained forced ventilation instructing means 33 is configured to change the inspiratory time stored in the set value storage means 31 and the inspiratory / expired time ratio calculated by the inspiratory / expired time ratio calculating means 32. An instruction is output to the valve opening / closing instruction means 17 at the timing determined in the above.
The continuous forced ventilation mode by the continuous forced ventilation instructing means 33 is performed after the ventilation mode by the inhalation start point determining means 16 in advance, and the continuous forced ventilation mode by the continuous forced ventilation instructing means 33 and the inhalation start point determining means 16. It is also possible to switch between the ventilation modes according to.

図２は気道内圧と気流速の変化を示すグラフ、図３は本実施例による人工呼吸器での気道内圧と気流速の変化を示すグラフである。
図２においてＢＡＰ０ｍｍＨｇで十分呼気時間を与えた場合、呼気フローは基線まで戻り、呼気フローの積分すなわち面積Ｘが呼気一回換気量となる。また、吸気フローの積分すなわち面積Ｙが吸気一回換気量となる。呼吸器回路からのリーク、患者への吸収などの影響も受けるがおおよそＸ＝Ｙとなる。このような換気では肺胞虚脱が懸念される。
図３に示すように、本実施例では肺胞虚脱を防ぐ目的で、吸気開始をポイントＥとする。吸気開始をポイントＥとすることで、面積Ｚａにあたる換気量が残気量として増加する。吸気一回換気量算出手段１２にて一回の呼吸ごとに吸気一回換気量Ｙを算出し、吸気一回換気量算出手段１２で算出される吸気一回換気量Ｙを想定呼気一回換気量Ｘａと見なす。また、設定比率記憶手段１４では、想定呼気一回換気量Ｘａに対する残気量Ｚａを呼気一回換気量設定比率として記憶している。
そして、呼気一回換気量決定手段１５では、一回の呼吸ごとに算出される吸気一回換気量Ｙと呼気一回換気量設定比率（例えば５％Ｘａ、１０％Ｘａ）とから呼気一回換気量（Ｘａ−Ｚａ）を決定し、吸気開始ポイント判断手段１６では、呼気量計測手段１１で計測される呼気量が、呼気一回換気量（Ｘａ−Ｚａ）となるタイミングを吸気開始ポイントと判断する。従って、残気量Ｚａは想定呼気一回換気量Ｘａに対する比率で設定する。呼気フローの波形から瞬時に波形形状を予測して吸気開始のポイントＥを呼吸ごとに算出して吸気を実行する。FIG. 2 is a graph showing changes in airway pressure and air flow velocity, and FIG. 3 is a graph showing changes in airway pressure and air flow velocity in the ventilator according to this embodiment.
In FIG. 2, when a sufficient expiration time is given at BAP 0 mmHg, the expiration flow returns to the baseline, and the integration of the expiration flow, that is, the area X becomes the expiration tidal volume. Further, the integral of the intake flow, that is, the area Y becomes the intake tidal volume. Although it is affected by leaks from the respiratory circuit, absorption by the patient, etc., X = Y. Such ventilation may cause alveolar collapse.
As shown in FIG. 3, in this embodiment, the start of inspiration is set as point E for the purpose of preventing alveolar collapse. By setting the start of intake to point E, the ventilation amount corresponding to the area Za increases as the residual air amount. The inspiratory tidal volume calculating unit 12 calculates the inspiratory tidal volume Y for each breath, and the inspiratory tidal volume Y calculated by the inspiratory tidal volume calculating unit 12 is assumed as expiratory tidal ventilation. Considered as quantity Xa. In addition, the setting ratio storage means 14 stores the remaining air amount Za with respect to the assumed exhaled tidal volume Xa as an exhaled tidal volume setting ratio.
The expiratory tidal volume determining means 15 then takes an exhaled tidal volume from the inspiratory tidal volume Y calculated for each breath and the expiratory tidal volume setting ratio (for example, 5% Xa, 10% Xa). The ventilation amount (Xa-Za) is determined, and the inhalation start point determination unit 16 uses the timing at which the expiration amount measured by the expiration amount measurement unit 11 becomes the expiration tidal volume (Xa-Za) as the inspiration start point. to decide. Accordingly, the residual air amount Za is set as a ratio to the assumed exhaled tidal volume Xa. The waveform shape is instantaneously predicted from the waveform of the expiratory flow, the inspiration start point E is calculated for each breath, and the inspiration is executed.

図４は、本実施例による人工呼吸器を持続強制換気モードに用いる場合での気道内圧と気流速の変化を示すグラフである。
呼気時間を最小に、十分な吸気プラトー時間とするために、持続強制換気モードでは吸気制御方式を基本的には従圧式吸気制御（ｐｒｅｓｓｕｒｅｃｏｎｔｒｏｌ：ＰＣ）とする。従量式吸気制御（ｖｏｌｕｍｅｃｏｎｔｒｏｌ：ＶＣあるいは、ｆｌｏｗｃｏｎｔｒｏｌ：ＦＣ）では十分な吸気プラトー時間を得るのには不利である。図４では、ｄｙｎａｍｉｃ−ＰＥＥＰを意図した吸気開始機構を用いた従圧式吸気制御・持続強制換気（ｉｎｔｅｎｄｅｄｄｙｎａｍｉｃ−ＰＥＥＰ・ＰＣ・ＣＭＶ）を示す。
呼気と同様、吸気においても気道内圧と肺胞圧が解離する。健常肺胞の肺胞圧（A）は短時間で吸気気道プラトー圧に達する。しかし虚脱肺胞あるいは障害肺胞の肺胞圧（B）は吸気気道プラトー圧に達するまでにより多くの時間を要する。
ｉｎｔｅｎｄｅｄｄｙｎａｍｉｃ−ＰＥＥＰ・ＰＣ・ＣＭＶでは、１）呼吸回数を固定設定、吸気：呼吸時間比（I：E比）をｄｙｎａｍｉｃ−ＰＥＥＰを意図した吸気開始機構により自動的に随時調節する。あるいは、２）吸気時間を固定設定、呼吸回数をｄｙｎａｍｉｃ−ＰＥＥＰを意図した吸気開始機構により自動的に随時調節する。なお、ＢＡＰは最低限あるいは必要ない。
本実施例による呼吸モードは、吸気・呼気逆比呼吸（ｉｎｖｅｒｓｅｄｒａｔｉｏｖｅｎｔｉｌａｔｉｏｎ：ＩＲＶ）と、呼気時間短縮・吸気時間延長という点で類似する。しかしＩＲＶは患者状況に応じて呼気時間を安全に調節するものではない。したがって、ＩＲＶではエアトラップを来たして呼吸不全の増悪や気胸を来たす危険性がある。
本実施例では、ｄｙｎａｍｉｃ−ＰＥＥＰを意図した吸気開始機構を用いることにより、安全に呼気時間を最小限にできる。FIG. 4 is a graph showing changes in airway pressure and air flow velocity when the ventilator according to the present embodiment is used in the continuous forced ventilation mode.
In order to make the expiration time to a minimum and a sufficient intake plateau time, in the continuous forced ventilation mode, the intake control system is basically a pressure-controlled intake control (PC). The volume control (VC) or the flow control (FC) is disadvantageous for obtaining a sufficient intake plateau time. FIG. 4 shows a pressure-driven intake control / sustained forced ventilation (intended dynamic-PEEP / PC / CMV) using an intake start mechanism intended for dynamic-PEEP.
As with exhalation, airway pressure and alveolar pressure dissociate during inspiration. The alveolar pressure (A) of healthy alveoli reaches the inspiratory airway plateau pressure in a short time. However, alveolar pressure (B) in collapsed or damaged alveoli takes more time to reach the inspiratory airway plateau pressure.
Intended dynamic-PEEP / PC / CMV: 1) The number of breaths is fixedly set, and the inspiratory: breathing time ratio (I: E ratio) is automatically adjusted at any time by an inhalation start mechanism intended for dynamic-PEEP. Alternatively, 2) The inspiratory time is fixedly set, and the number of breaths is automatically adjusted at any time by an inhalation starting mechanism intended for dynamic-PEEP. Note that BAP is minimal or unnecessary.
The breathing mode according to the present embodiment is similar to the inspiratory / expiratory inverse ratio breathing (IRV) in that the expiratory time is shortened and the inspiratory time is prolonged. However, IRV does not safely adjust the expiration time according to the patient situation. Therefore, with IRV, there is a risk that an air trap will come and the respiratory failure will worsen or pneumothorax will occur.
In the present embodiment, the expiration time can be safely minimized by using an inhalation start mechanism intended for dynamic-PEEP.

自発呼吸を補助する場合、吸気制御方式を、患者の吸気・呼気を妨げない従圧式吸気制御（ｅｎｈａｎｃｅｄｐｒｅｓｓｕｒｅ−ｃｏｎｔｒｏｌ：ｅＰＣ）で行ってもよい。図５では、ｄｙｎａｍｉｃ−ＰＥＥＰを意図した吸気開始機構を用いた、患者の吸気・呼気を妨げない従圧式吸気制御・持続強制換気（ｉｎｔｅｎｄｅｄｄｙｎａｍｉｃ−ＰＥＥＰ・ｅＰＣ・ＣＭＶ）を示す。
この換気方式は気道圧開放換気（ａｉｒｗａｙｐｒｅｓｓｕｒｅｒｅｌｅａｓｅｖｅｎｔｉｌａｔｉｏｎ：ＡＰＲＶ）に類似する。ただし、ｄｙｎａｍｉｃ−ＰＥＥＰを意図した吸気開始機構を用いて、安全に呼気時間を最小限にできる。
なお、上記に加えてさらに自発呼吸をプレッシャーサポート（ＰＳ）によって補助してもよい。When assisting spontaneous breathing, the inspiration control method may be performed by a pressurized pressure-control (ePC) that does not disturb the patient's inspiration / expiration. FIG. 5 shows a pressure-controlled inspiratory control / continuous forced ventilation (intervented dynamic-PEEP / ePC / CMV) using an inhalation start mechanism intended for dynamic-PEEP, which does not interfere with the patient's inspiration / expiration.
This ventilation system is similar to airway pressure release ventilation (APRV). However, the expiration time can be safely minimized by using an inhalation start mechanism intended for dynamic-PEEP.
In addition to the above, spontaneous breathing may be further assisted by a pressure support (PS).

図６は本発明の他の実施例による人工呼吸器を機能実現手段で現したブロック図である。上記実施例と同じ手段には同一符号を付して説明を省略する。
本実施例における制御部１０は、気流速検出センサ６で検出される気流速検出値から、一回の呼吸ごとに最大呼気値を検出する最大呼気値検出手段２６を有している。
本実施例においても設定比率記憶手段１４は、呼気一回換気量を決定するための呼気一回換気量設定比率を記憶する。設定比率記憶手段１４に記憶される呼気一回換気量設定比率は、設定手段８によって入力される。呼気一回換気量設定比率は、呼気終末肺胞内圧と気道内圧との格差（呼気終末肺胞内圧−気道内圧）が正の値となるように設定される。しかし具体的には、設定比率記憶手段１４では、最大呼気値検出手段２６で検出される最大呼気値に対する残気呼気値を呼気一回換気量設定比率として記憶し、呼気一回換気量決定手段１５では、一回の呼吸ごとに算出される最大呼気値と呼気一回換気量設定比率とから残気呼気値を呼気一回換気量として決定する。
そして、吸気開始ポイント判断手段１６では、気流速検出センサ６で検出される気流速検出値が残気呼気値となるタイミングを吸気開始ポイントと判断する。FIG. 6 is a block diagram showing a ventilator according to another embodiment of the present invention as function realizing means. The same means as those in the above embodiment are denoted by the same reference numerals, and description thereof is omitted.
The control unit 10 according to the present embodiment includes a maximum expiration value detection unit 26 that detects a maximum expiration value for each breath from the detected value of the air flow rate detected by the air flow velocity detection sensor 6.
Also in the present embodiment, the setting ratio storage means 14 stores the expiration tidal volume setting ratio for determining the expiration tidal volume. The expiratory tidal volume setting ratio stored in the setting ratio storage means 14 is input by the setting means 8. The expiratory tidal volume setting ratio is set such that the difference between the end-expiratory alveolar pressure and the airway pressure (end-expiratory alveolar pressure−airway pressure) is a positive value. More specifically, however, the setting ratio storage means 14 stores the remaining expiration value for the maximum expiration value detected by the maximum expiration value detection means 26 as the expiration tidal volume setting ratio, and the expiration tidal volume determination means. In 15, the residual expiration value is determined as the expiration tidal volume from the maximum expiration value calculated for each breath and the expiration tidal volume setting ratio.
Then, the inhalation start point determination means 16 determines the timing at which the air flow rate detection value detected by the air flow rate detection sensor 6 becomes the residual exhalation value as the inspiration start point.

図７は本実施例による人工呼吸器での気道内圧と気流速の変化を示すグラフである。
図７に示すように、最大呼気値Ｘｂに対する設定比率（％）となる残気呼気値Ｚｂを吸気開始のポイントＦとする。
吸気開始をポイントＦとすることで、残気呼気値Ｚｂに対応する残気量が残存するため肺胞の虚脱を防ぎかつ換気効率を向上できる。最大呼気値検出手段２６にて一回の呼吸ごとに最大呼気値Ｘｂを検出する。また、設定比率記憶手段１４では、最大呼気値検出手段２６で検出される最大呼気値Ｘｂに対する残気呼気値Ｚｂを呼気一回換気量設定比率として記憶している。
そして、呼気一回換気量決定手段１５では、一回の呼吸ごとに算出される最大呼気値Ｘｂと呼気一回換気量設定比率とから残気呼気値Ｚｂを呼気一回換気量として決定し、吸気開始ポイント判断手段１６では、気流速検出センサ６で検出される気流速検出値が残気呼気値Ｚｂとなるタイミングを吸気開始のポイントＦと判断する。従って、呼気フローの波形から瞬時に波形形状を予測して吸気開始のポイントＦを呼吸ごとに算出して吸気を実行する。FIG. 7 is a graph showing changes in airway pressure and air flow velocity in the ventilator according to this example.
As shown in FIG. 7, a residual exhalation value Zb that is a set ratio (%) with respect to the maximum exhalation value Xb is set as a point F at the start of inspiration.
By setting the start of inspiration to the point F, the residual air amount corresponding to the residual exhalation value Zb remains, so that collapse of the alveoli can be prevented and ventilation efficiency can be improved. The maximum expiratory value detecting means 26 detects the maximum expiratory value Xb for each breath. The setting ratio storage means 14 stores the remaining expiration value Zb with respect to the maximum expiration value Xb detected by the maximum expiration value detection means 26 as an expiration tidal volume setting ratio.
The expiratory tidal volume determining means 15 determines the remaining exhaled breath value Zb as the expiratory tidal volume from the maximum expiratory value Xb calculated for each breath and the expiratory tidal volume setting ratio, The inhalation start point determination means 16 determines the timing at which the air flow rate detection value detected by the air flow rate detection sensor 6 becomes the residual exhalation value Zb as the inhalation start point F. Accordingly, the waveform shape is instantaneously predicted from the waveform of the expiratory flow, the inspiration start point F is calculated for each breath, and the inspiration is executed.

ボリュームカプノメトリを用いて換気効率を評価した結果を図８に示す。
腹腔鏡手術・同一症例において、比較例１（ＰＣV−ＶＧモード換気量設定４５０ｍｌ、I：E比１：２、呼吸回数１０回、ＢＡＰ４ｃｍＨ_２Ｏ）、比較例２（低１回換気量高ＢＡＰ）（ＰＣV−ＶＧモード換気量設定４００ｍｌ、I：E比１：２、呼吸回数１０回、ＢＡＰ１０ｃｍＨ_２Ｏ）、比較例３（ｉｎｔｅｎｄｅｄｄｙｎａｍｉｃ−ＰＥＥＰ）（ＰＣV−ＶＧモード換気量設定４５０ｍｌ、I：E比１．５：１、呼吸回数１０回、ＢＡＰ４ｃｍＨ_２Ｏ）について、それぞれ肺リクルートメントを行った後、ボリュームカプノメトリを３０分ずつ行った。なお、ｉｎｔｅｎｄｅｄｄｙｎａｍｉｃ−ＰＥＥＰｖｅｎｔｉｌａｔｉｏｎを装備した呼吸器を想定して比較例３では、呼気フローモニターを参考に随時手動でI：E比を１．５：１に設定した。
比較例１および比較例２に比べて比較例３では、換気量および気道内圧は差が認められなかった。しかし、二酸化炭素排出量が１７ｍｌから２０ｍｌに若干増加した。肺胞換気率が０．６２から０．６６に若干改善した。以上から、本実施例によれば換気効率を高めると思われる。また、吸気プラトー時間延長による肺リクルートメント様効果を期待するが、比較例３における症例は換気条件が良く、動脈血酸素濃度に大きな差を認めなかった。換気条件が良い症例では比較例３の効果は目立たない。ＡＲＤＳ、肥満症例、腹腔鏡手術など、低肺コンプライアンス症例では本実施例による高換気効率および肺虚脱予防効果が大きいと期待される。FIG. 8 shows the result of evaluating the ventilation efficiency using volume capnometry.
Laparoscopic surgery in the same case, comparative example 1 (PCV-VG mode ventilation volume setting 450 ml, I: E ratio 1: 2, breathing rate 10 times, BAP 4 cmH ₂ O), comparative example 2 (low tidal volume high BAP) (PCV-VG mode ventilation volume setting 400 ml, I: E ratio 1: 2, breathing rate 10 times, BAP 10 cmH ₂ O), comparative example 3 (intended dynamic-PEEP) (PCV-VG mode ventilation volume setting 450 ml, (I: E ratio 1.5: 1, 10 breathing times, BAP 4 cmH ₂ O), respectively, volume recruitment was performed for 30 minutes after lung recruitment. In addition, in Comparative Example 3, assuming an inspiratory dynamic-PEEP ventilation, the I: E ratio was manually set to 1.5: 1 as needed with reference to the expiratory flow monitor.
Compared to Comparative Example 1 and Comparative Example 2, Comparative Example 3 showed no difference in ventilation volume and airway pressure. However, carbon dioxide emissions increased slightly from 17 ml to 20 ml. The alveolar ventilation rate was slightly improved from 0.62 to 0.66. From the above, it is considered that the ventilation efficiency is increased according to this embodiment. Moreover, although the lung recruitment-like effect by prolonging inhalation plateau time is expected, the case in the comparative example 3 had good ventilation conditions, and did not recognize a big difference in arterial blood oxygen concentration. The effect of Comparative Example 3 is not noticeable in cases with good ventilation conditions. In cases of low lung compliance such as ARDS, obesity cases, and laparoscopic surgery, it is expected that the high ventilation efficiency and prevention of collapse of the lungs according to this example are great.

一方、現在、肺保護戦略として推奨される低１回換気量高ＢＡＰは、著しく換気効率を悪化させることがボリュームカプノメトリからわかる。肺虚脱予防を優先として換気効率を犠牲とした換気手段で、ＡＲＤＳなどの低肺コンプライアンス症例において推奨されている。高ＢＡＰを行うに当たり高気道内圧となり、肺を保護するためにも低換気にならざるをえず、高二酸化炭素血症に陥ることが問題である。
比較例３は低１回換気量高ＢＡＰよりも気道内圧が低く、さらに換気量を増加できる余力を持つ。比較例３は低い気道内圧で換気効率が高いことからより肺保護的であることが予想される。従って、肺虚脱を防ぎつつ換気効率を高める換気手段として、今後の肺保護戦略として推奨される新しい換気手段となりうる。On the other hand, volume capnometry shows that the low tidal volume high BAP currently recommended as a lung protection strategy significantly deteriorates the ventilation efficiency. Ventilation means that prioritizes prevention of lung collapse and sacrifices ventilation efficiency, and is recommended for low lung compliance cases such as ARDS. When performing high BAP, the pressure in the airway becomes high, and in order to protect the lungs, low ventilation is unavoidable, resulting in hypercapnia.
In Comparative Example 3, the airway pressure is lower than that of the low tidal volume high BAP, and further has the capacity to increase the ventilation volume. Comparative Example 3 is expected to be more pulmonary protective because of low ventilation air pressure and high ventilation efficiency. Therefore, it can be a new ventilation means recommended as a future lung protection strategy as a ventilation means for improving ventilation efficiency while preventing lung collapse.

上記実施例では、一回の呼吸ごとに呼気一回換気量決定手段１５によって呼気一回換気量を決定し、一回の呼吸ごとに吸気開始ポイント判断手段１６によって吸気開始ポイントを判断する方法を示したが、必ずしも全ての呼吸ごとに行わなくてもよい。すなわち、例えば呼気一回換気量決定手段１５での複数回による呼気一回換気量の平均値を算出し、所定回数又は所定期間この平均値を用いて、吸気開始ポイントを判断してもよい。また、呼気一回換気量決定手段１５での複数回による呼気一回換気量の平均値を用いて、吸気・呼気時間比算出手段３２において吸気・呼気時間比を算出し、算出した吸気・呼気時間比を用いて弁開閉指示手段１７から弁開閉指示を吸気弁駆動部４ａおよび呼気弁駆動部５ａに出力してもよい。 In the above-described embodiment, a method of determining the expiration tidal volume by the expiration tidal volume determination means 15 for each breath and determining the inspiration start point by the inspiration start point determination section 16 for each breath. Although shown, it need not be performed for every breath. That is, for example, the average value of the exhaled tidal volume in the exhaled tidal volume determining means 15 may be calculated, and the inspiration start point may be determined using this average value for a predetermined number of times or for a predetermined period. Further, using the average value of the exhaled tidal volume at the exhaled tidal volume determining means 15, the inspiratory / expired time ratio calculating means 32 calculates the inspiratory / expired time ratio, and the calculated inhaled / expired time A valve opening / closing instruction may be output from the valve opening / closing instruction means 17 to the intake valve driving unit 4a and the exhalation valve driving unit 5a using the time ratio.

本発明による人工呼吸器は、肺胞の虚脱を防ぎかつ換気効率を向上できる。 The ventilator according to the present invention can prevent the collapse of the alveoli and improve the ventilation efficiency.

１０制御部
１１呼気量計測手段
１２吸気一回換気量算出手段
１３呼気一回換気量算出手段
１４設定比率記憶手段
１５呼気一回換気量決定手段
１６吸気開始ポイント判断手段
１７弁開閉指示手段
１８気道内圧記憶手段
１９気道内圧上限記憶手段
２０吸気終了ポイント判断手段
２１全呼気終末肺胞内圧監視手段
２２呼気時間延長手段
２３気流速異常検出手段
２４気道内圧異常検出手段
２５換気量異常検出手段
２６最大呼気値検出手段
３１設定値記憶手段
３２吸気・呼気時間比算出手段
３３持続強制換気指示手段DESCRIPTION OF SYMBOLS 10 Control part 11 Expiratory-volume measuring means 12 Inspiratory tidal volume calculating means 13 Expiratory tidal volume calculating means 14 Setting ratio memory means 15 Expiratory tidal volume determining means 16 Inhalation start point judging means 17 Valve opening / closing instructing means 18 Airway Internal pressure storage means 19 Airway internal pressure upper limit storage means 20 Inspiratory end point determination means 21 Total expiratory end alveolar pressure monitoring means 22 Expiration time extension means 23 Air flow rate abnormality detection means 24 Airway pressure abnormality detection means 25 Ventilation volume abnormality detection means 26 Maximum expiration Value detection means 31 Set value storage means 32 Inhalation / expiration time ratio calculation means 33 Continuous forced ventilation instruction means

Claims

An interface to be worn by the user;
An intake path for supplying oxygen to the interface;
An expiratory pathway for discharging carbon dioxide from the interface;
An exhalation valve provided in the exhalation path;
An exhalation-valve driving unit that controls opening and closing of the exhalation-valve;
An air flow rate detection sensor for detecting an air flow rate from the inspiration route and an air flow rate to the expiration route;
An airway pressure detection sensor for detecting the pressure of at least one of the inspiratory path and the expiratory path;
A control unit for inputting an air flow rate detection value of the air flow rate detection sensor and an airway pressure detection value of the airway pressure detection sensor and outputting a valve opening / closing instruction to the intake valve drive unit and the exhalation valve drive unit; A respirator,
The controller is
A setting ratio storage means for storing an expiration tidal volume setting ratio for determining an expiration tidal volume so that the end-expiratory alveolar pressure-airway pressure difference is a positive value;
Expiratory tidal volume is determined for each breath based on the detected value of the air flow rate detected by the air flow velocity detection sensor and the setting ratio of expiratory tidal volume stored in the setting ratio storage means. Tidal volume determining means;
Inhalation start point determination means for determining the timing of the expiration tidal volume determined by the expiration tidal volume determination means as an inspiration start point;
Valve opening / closing instruction means for outputting the valve opening / closing instruction at the timing of the intake start point determined by the intake start point determining means;
The inhalation start point is determined based on the exhaled tidal volume determined by the exhaled tidal volume determining means for each breath, and the inhalation valve and the exhalation valve are driven. Ventilator.

The controller is
From the air flow rate detection value detected by the air flow rate detection sensor, expiratory volume measuring means for measuring the expiratory volume for each breath of one time,
An inspiratory tidal volume calculating means for calculating the inspiratory tidal volume Y for each breath from the detected air flow speed detected by the air flow speed detecting sensor;
The setting ratio storage means regards the inspiratory tidal volume Y calculated by the inspiratory tidal volume calculating means as the assumed expiratory tidal volume Xa, and the residual air volume with respect to the assumed expiratory tidal volume Xa Store Za as the exhaled tidal volume setting ratio,
The expiratory tidal volume determining means determines an expiratory tidal volume (Xa-Za) from the inspiratory tidal volume Y calculated for each breath and the expiratory tidal volume setting ratio. And
The inhalation start point determining means determines that the timing at which the expiration amount measured by the expiration amount measuring means becomes the expiration tidal volume (Xa-Za) is the inhalation start point. Item 2. The ventilator according to Item 1.

The controller has a maximum expiratory value detection means for detecting a maximum expiratory value Xb for each breath from the air flow velocity detection value detected by the air flow velocity detection sensor,
In the setting ratio storage means, a residual expiration value Zb relative to the maximum expiration value Xb detected by the maximum expiration value detection means is stored as the expiration tidal volume setting ratio,
In the expiratory tidal volume determining means, the remaining exhaled breath value Zb is used as the expiratory tidal volume based on the maximum expiratory value Xb calculated for each breath and the expiratory tidal volume setting ratio. Decide
The inhalation start point determination unit determines the timing at which the detected air flow rate value detected by the air flow rate detection sensor becomes the residual exhalation value Zb as the inhalation start point. Ventilator.

The controller is
Airway pressure storage means for storing the airway pressure preset by the setting means;
Total end-expiratory alveolar pressure monitoring means for monitoring whether the airway pressure detection value detected by the airway pressure detection sensor exceeds the airway pressure stored in the airway pressure storage means;
Expiratory time extending means for instructing the valve opening / closing instruction means to extend expiratory time,
When the total expiratory end alveolar pressure monitoring means detects that the airway pressure detection value exceeds the airway pressure, the expiratory time extending means instructs the valve opening / closing instruction means to extend the expiratory time. The ventilator according to any one of claims 1 to 3, characterized in that

The controller is
At least an air flow velocity abnormality detecting means for detecting an abnormality from the air flow velocity disturbance detected by the air flow velocity detection sensor and an airway pressure abnormality detecting means for detecting an abnormality from the pressure disturbance detected by the airway pressure detection sensor. Either
Expiratory time extending means for instructing the valve opening / closing instruction means to extend expiratory time,
When at least one of the air flow velocity abnormality detecting means and the airway pressure abnormality detecting means detects the abnormality, the expiration time extending means instructs the valve opening / closing instruction means to extend the expiration time. The ventilator according to any one of claims 1 to 3.

The controller is
An intake tidal volume calculating means for calculating an intake tidal volume from the detected value of the air flow speed detected by the air flow speed detecting sensor;
From the air flow rate detection value detected by the air flow rate detection sensor, the expiratory tidal volume calculating means for calculating the exhaled tidal volume;
An abnormality occurs when at least one of the inspiratory tidal volume calculated by the inspiratory tidal volume calculating unit and the exhaled tidal volume calculating unit calculated by the inspiratory tidal volume calculating unit falls below a set value. An abnormality detecting means for detecting a ventilation amount;
Expiratory time extending means for instructing the valve opening / closing instruction means to extend expiratory time,
2. The ventilator according to claim 1, wherein when the anomaly detecting unit detects the abnormality, the exhalation time extending unit instructs the valve opening / closing instruction unit to extend the exhalation time.

The controller is
Set value storage means for storing the number of breaths set by the setting means;
An inspiration / expiration time ratio calculating means for calculating an inspiration / expiration time ratio from an inspiration timing and an expiration timing indicated by the valve opening / closing instruction means;
Continuous forced output that outputs an instruction to the valve opening / closing instruction means at a timing determined by the number of breaths stored in the set value storage means and the inspiration / expiration time ratio calculated by the inspiration / expiration time ratio calculation means The ventilator according to any one of claims 1 to 6, further comprising a ventilation instruction unit.

The controller is
Setting value storage means for storing the intake time set by the setting means;
An inspiration / expiration time ratio calculating means for calculating an inspiration / expiration time ratio from an inspiration timing and an expiration timing indicated by the valve opening / closing instruction means;
Continuous forced output that outputs an instruction to the valve opening / closing instruction means at a timing determined by the inspiration time stored in the set value storage means and the inspiration / expiration time ratio calculated by the inspiration / expiration time ratio calculation means The ventilator according to any one of claims 1 to 6, further comprising a ventilation instruction unit.