JP4212778B2 - Positive pressure ventilator - Google Patents
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【０００１】
【発明の属する技術分野】
本発明は医療用人工呼吸補助装置に関する。さらに詳細には、高炭酸ガス血症のような換気不全患者の治療に適する陽圧換気療法（IPPV：Intermittent Positive Pressure Ventilation）に使用する陽圧式人工呼吸補助装置に関する。
【０００２】
【従来の技術】
医療用陽圧式人工呼吸補助装置は、肺結核後遺症や慢性閉塞性肺疾患（COPD）、肺気腫など自発呼吸だけでは十分に換気することができない換気不全使用者の呼吸をサポートするために使用される。
【０００３】
陽圧式人工呼吸補助装置の中でも最も一般的な鼻マスクを用いるタイプを、図１を用いて説明する。本体１は２〜３０cmH2O程度の陽圧ガスを間欠的に発生し、導管２に送る。中でも、使用者７の吸気と呼気に合わせて２レベルの圧力、例えば図２に示すように、吸気時陽圧（IPAP：Inspiration Positive Airway Pressure）：１２〜１５cmH2O、呼気時陽圧（EPAP：Expiration Positive Airway Pressure）：２〜４cmH2Oの設定圧力で陽圧ガスを使用者に供給するタイプが主流である。導管２は、マスククッション６を固定するマスクフレーム５に繋がり、マスククッション６を通して、陽圧ガスを使用者７の鼻腔へ送る。呼気排出孔３は使用者７の呼気ガスを呼吸回路外へ排出するために設けてあり、また、酸素など治療用ガスの混入を必要とする場合には、治療用ガス混入ポート４より治療用ガスを混入して使用する。特に、呼吸インターフェースが鼻マスクであるものは扱いも簡単なため、近年では在宅医療用機器としても使用者が急激に増加している。
【０００４】
治療効果としては、次のようなことが国内外で報告されている。すなわち、▲１▼使用者の肺胞換気量を増大させることによって血中二酸化炭素濃度を減少させる、▲２▼圧力補助によって呼吸筋疲労が減少する、▲３▼呼気時供給圧力（PEEP：Positive End Expiratory Pressure）によって気道閉塞や肺胞の虚脱を防ぐ、などである。
【０００５】
【発明が解決しようとする課題】
ところが、ある種の疾患では上述したような陽圧換気療法を施しても思うような治療効果が得られないケースや、使用者が呼吸し難さを訴えて治療を断念せざるを得ないケースも報告されている。
【０００６】
一般に換気障害は、肺結核後遺症などを含む拘束性換気障害と肺気腫などを含む閉塞性換気障害に大別される。拘束性換気障害は、肺実質の変化、あるいは胸膜、胸壁、および神経、筋組織の病変のために肺の拡張が制限されるような病態である。この病態は、安静時一回換気量の減少で特徴付けられるが、陽圧換気療法のサポートによって一回換気量を増やしてやれば正常な換気に近づき、陽圧式人工呼吸補助装置による治療効果は高い。
【０００７】
一方の閉塞性換気障害は、呼気時気道閉塞によって気道抵抗が増大するため呼出障害を呈することで特徴付けられる。特に、呼気後半部分でのみ呼出障害が起こり、呼気の前半部分では正常に吐きだせるものがほとんどである。また、高い肺気量位で気道閉塞が起こるために、残気量は増大し呼吸困難感を感じる。このような病態に対して、従来のIPAPとEPAPの圧力を供給するような陽圧式人工呼吸補助装置を用いても、効果的に換気補助ができないケースがある。例えば、一般的によく用いられる４cmH2Oの呼気時設定圧力を供給したとしても、呼気時圧力が低いために気道閉塞を消し去ることができないことがある。この場合、呼出障害に加え、気道閉塞が起きたまま吸気に移るため努力吸気となり、吸気筋疲労も併発してしまう。また、気道閉塞を消し去るために呼気時圧力を高くする方法が考えられるが、呼気時にあまり高い圧力をかけると、かえって患者は吐きだし難さを感じてしまう。
【０００８】
特開平８−３２２９３６号公報には、気道挿管などにより肺内圧力を過度に低下させることなく、肺に多量の新鮮空気を供給する人工呼吸器が記載されている。かかる装置では、呼気前半は呼気圧力を設定値よりも低くなるように制御し、その後呼気流量が減少するに従って、呼気圧力を設定値に向かって上昇させる制御を行う装置である。
【０００９】
かかる人工呼吸器は、呼気前半でよりたくさんの換気をさせるように呼気前半圧力を低くするもので、拘束性換気障害に対しては適するものの、呼気後半で気道閉塞を起す閉塞性換気障害の患者には適用することができない。
【００１０】
更にかかる人工呼吸器の様に、圧力調整に呼気弁を用いると呼吸回路が複雑になり、特に呼吸用マスク（鼻マスク、鼻口マスク）を用いるような場合にはマスク周りが重くなってしまい、患者への負担となる。また、呼吸用インターフェースに治療用ガスを混入して用いる場合には、呼気弁を開放している期間に呼気弁から投入された治療用ガスが逃げてしまい、治療用ガスの無駄になる問題も存在する。
【００１１】
本発明は、陽圧換気療法において、呼気後半部分に気道閉塞を呈するような使用者に対して、気道閉塞を消し去り、かつ、吸気に移りやすくなるような陽圧式人工呼吸補助装置を提供することを課題とする。
【００１２】
【課題を解決するための手段】
かかる課題を達成するため、本発明者は鋭意検討した結果、使用者の呼気期間中に呼気時陽圧を段階的に下げるような陽圧式人工呼吸補助装置を提供することによって課題を解決できることを見出した。
【００１３】
即ち本発明は、使用者に陽圧ガスを供給する陽圧ガス発生手段、使用者の呼吸に対応して吸気時に吸気時圧力（IPAP）及び呼気時にそれよりも低い呼気時圧力（EPAP）の陽圧ガスを供給する該陽圧ガス発生手段の制御手段、使用者に該陽圧ガスを供給するための呼吸用インターフェース、および該陽圧ガス発生手段と該呼吸用インターフェースを繋ぐ導管手段を備えた陽圧式人工呼吸補助装置において、該制御手段が、使用者の呼気時に該呼気時圧力を呼気後半の圧力が呼気前半の圧力より低くなるように段階的に下げる制御を行う手段であることを特徴とする陽圧式人工呼吸補助装置を提供するものである。
【００１４】
また本発明は、かかる制御手段が、呼気前半時に該吸気時圧力よりも低い呼気前半時設定圧力、および呼気後半時に該呼気前半時設定圧力よりも低い呼気後半時設定圧力で陽圧ガスを発生する制御手段であることを特徴とする陽圧式人工呼吸補助装置を提供するものである。
【００１５】
また本発明は、かかる陽圧式人工呼吸補助装置の呼吸回路中に使用者の呼吸流量を測定する手段を備え、該制御手段が、呼気期間中の呼気流量が最大値を示した後に変曲点をとった時点で、該呼気前半時設定圧力から該呼気後半時設定圧力に切り替える制御を行う手段であることを特徴とする陽圧式人工呼吸補助装置を提供するものである。
【００１６】
また本発明は、かかる陽圧式人工呼吸補助装置の呼吸回路中に使用者の呼吸流量を測定する手段を備え、該制御手段が、該呼吸流量を時間積分して換気量を演算する手段を備え、呼気時の換気量が直前の吸気時に吸入した量に対して予め設定した割合だけ呼出した時点で、該呼気前半時設定圧力から該呼気後半時設定圧力に切り替える制御を行う手段であることを特徴とする陽圧式人工呼吸補助装置を提供するものである。
【００１７】
また本発明は、かかる陽圧式人工呼吸補助装置に使用者の呼気開始点を検出する手段を備え、該制御手段が、呼気開始点から予め設定された時間が経過した時点で、該呼気前半時設定圧力から該呼気後半時設定圧力に切り替えるような制御を行う手段であることを特徴とする陽圧式人工呼吸補助装置を提供するものである。
【００１８】
また本発明は、かかる陽圧式人工呼吸補助装置の呼吸回路中に使用者の呼吸流量を測定する手段を備え、該制御手段が、呼気期間中の呼気流量が最大値を示した時点で、該呼気前半時設定圧力から該呼気後半時設定圧力に切り替える制御を行う手段であるを特徴とする陽圧式人工呼吸補助装置を提供するものである。
【００１９】
更に本発明は、かかる陽圧ガス発生手段が、回転数を制御することによって所定圧力の陽圧ガスを発生させるブロア手段であり、該呼吸用インターフェースが呼吸用マスク手段であることを特徴とする陽圧式人工呼吸補助装置を提供するものである。
【００２０】
【発明の実施の形態】
本発明者は、健常人、拘束性肺疾患患者、閉塞性肺疾患患者における、従来の陽圧式人工呼吸補助装置（IPAPとEPAPを間欠的に供給）使用時、および自発呼吸時の呼吸パターンを調査した結果、図３に示すように、健常人、拘束性肺疾患患者では呼気時の呼吸パターン（流量ｖｓ時間）が、比較的単純な下に凸形状を示すのに対して、閉塞性肺疾患患者では、呼気流量が最大値を示した後に上に凸形状を示し、呼気時呼吸パターンに気道閉塞に基づく変曲点が存在し、変曲点以降に気道閉塞が発生していることを見出した。
また、閉塞性肺疾患患者の呼気時気道閉塞は、自発呼吸時より陽圧式人工呼吸補助装置使用時の方がより顕著であり、EPAPを一定とした場合には、患者へのサポート圧（＝IPAP−EPAP）が大きいほど、気道閉塞の度合いがより大きくなる傾向があることを見出した。このことは、サポート圧が大きい場合、即ち一回換気量が大きく呼気流速が速いほど気道内圧が低下し、気道閉塞が発生しやすいことを示している。更に、呼気流速の速い呼気前半部分で一旦気道閉塞が発生すると、呼気期間の最後まで気道閉塞が続いてしまうため、呼気前半部分での気道閉塞を防ぐことが本治療の鍵となる。
本発明者は、呼気流速の速い呼気前半部分に比較的高い圧力を供給することによって呼気流速の上昇を防止し、さらに呼気後半部分で圧力を下げることによって、患者に不必要に負担をかけることなく気道閉塞を防止することができることを見出した。
本発明の陽圧式人工呼吸補助装置は、使用者の呼吸に対応して陽圧ガスを発生する陽圧ガス発生手段、使用者に該陽圧ガスを供給するための呼吸用インターフェース、および該陽圧ガス発生装置と該呼吸用インターフェースを繋ぐ導管手段から構成される。
【００２１】
かかる陽圧ガス発生手段は、空気を加圧して陽圧ガスを発生する手段であり、ブロアが用いられる。陽圧ガス供給の制御は、使用者の医師の処方圧力に合わせて吸気時間に吸気時陽圧を供給し、呼気時に段階的に圧力を下げるように制御するものである。好ましくは、使用者の吸気時に吸気時陽圧、呼気前半時に呼気前半時陽圧、および呼気後半時に呼気後半時陽圧のガスを供給するように、陽圧ガス発生手段の発生を制御するものであり、陽圧ガス発生手段出口から導管手段、呼吸用インターフェース内の呼吸回路に圧力センサー、流量センサー等を設けることにより患者の吸気開始点、呼気前半開始点、および呼気後半開始点を検出し、これに応じて陽圧ガス発生手段の供給圧力を切り替え制御する方法や、吸気時間、呼気前半時間、および呼気後半時間を予め設定しておき、それに従って陽圧ガス発生手段の供給圧力を切り替え制御し、使用者がそれに呼吸を合わせる方法が使用される。
【００２２】
呼気前半時から呼気後半時への圧力切り替えポイントは、呼気期間中の呼気流量が最大値を示した後に変曲点をとった時点とすれば良い。かかる変曲点は、呼吸回路中に使用者の呼吸流量を測定する手段を備え、呼気流量が最大値を示した時点以降で、測定値を２回微分した値が初めてゼロになる点を演算することにより求めることが出来る。具体的には、まず、測定したデジタル呼吸流量値において、前後する２つのデータの差を取ることで微分値（呼吸流量の加速度）を導く。さらに前後する微分値の差を取った値が２回微分値である。デジタル呼吸流量値は、使用者の呼吸に短時間で応答するために、１〜１０msec.のサンプリングレートで測定した値を用いるのが望ましい。呼吸流量の最大値は、微分値がマイナス側からプラス側に変わる点を演算することによって、求めることができる。
【００２３】
呼吸流量を測定する手段としては、差圧式流量センサー、熱線式流量センサー等を用いることができるが、使用者に十分な圧力を供給するために、圧損の少ない流量計を使用する必要がある。また、流量センサーは、陽圧ガス発生装置から呼吸用インターフェースまでの呼吸回路中に設置することができる。特に、正確な値を測定するために、使用者と流量センサーとの間に漏れが無いことが望ましい。また、呼気排出孔よりも上流側に流量センサーを設ける場合には、測定したガス流量の一部が、呼気排出孔から排出される分を含むため、呼気排出孔からの流出流量を算出し、これを差し引くことにより流量データを補正することができる。呼吸用マスク等からの漏れがある場合には、その分も同様に補正する必要がある。また、測定値は、ノイズ除去のために移動平均を取るのが望ましい。
【００２４】
また別の方法として、本発明は、かかる陽圧式人工呼吸補助装置の呼吸回路中に使用者の呼吸流量を測定する手段、および呼吸流量を時間積分して換気量を演算する手段を備え、呼気時の換気量が直前の吸気時に吸入した量に対して予め設定した割合だけ呼出した時点を呼気後半開始点とし、これに応じて供給圧力を制御する方法を用いることができる。
【００２５】
吸気時に吸入した量、および換気量は、各吸気および呼気において、Σ（呼吸流量値×サンプリングレート）で求めることができる。呼気時の換気量が直前の吸気時に吸入した量に対して１０〜３０％だけ呼出した時点で呼気後半圧力へ切り替えることが望ましい。
【００２６】
また別の方法として、かかる陽圧式人工呼吸補助装置に使用者の呼気前半開始点を検出する手段を備え、呼気前半開始点から予め設定された時間が経過した時点を呼気後半開始点とし、呼気後半時圧力へ切り替える制御を行う方法を用いることが出来る。呼気前半開始点から呼気後半圧力への切り替えは、呼気期間中であればいくらにでも設定できるが、望ましくは呼気前半開始後0.1〜1秒後である。
【００２７】
さらに別の方法として、かかる陽圧式人工呼吸補助装置の呼吸回路中に使用者の呼吸流量を測定する手段を備え、呼気期間中の呼気流量が最大値を示した時点を呼気後半開始点とし、呼気後半時設定圧力へ切り替えるように制御する方法を用いることができる。
【００２８】
呼気前半時圧力および呼気後半時圧力は、使用する患者の気道閉塞状態によって設定する圧力が異なるが、呼気前半時圧力が６〜１０cmH2O、呼気後半時圧力が２〜６cmH2Oの圧力値に制御し用いることが出来る。
【００２９】
【実施例】
本発明の陽圧式人工呼吸補助装置の実施例を、図４を用いて更に詳細に説明する。陽圧ガス発生装置出口端部に差圧式流量計を備え、差圧式流量計によって測定した流量値を演算手段に送る。演算手段では、呼気排出孔からのガス排出量および鼻マスクからの漏れを補正する。また演算手段は、上述してきた方法によって、吸気開始点、呼気前半開始点、および呼気後半開始点を演算し、ブロア回転数制御手段へ入力する。ブロア回転制御手段は、ブロア回転数を制御するものであり、入力されてきた各圧力供給期間に応じて、予め決められた吸気時圧力、呼気前半時設定圧力、および呼気後半時設定圧力に相当する電圧を陽圧ガス発生手段に入力する。陽圧ガス発生手段は入力された電圧に応じた陽圧ガスを発生し、導管へ送る。また、設定値入力用手段は、吸気時圧力、呼気前半時設定圧力、および呼気後半時設定圧力等、医師が設定すべき項目を入力することができ、演算手段、またはブロア回転数制御手段に送る。
【００３０】
図５は、本発明の好適な供給圧力パターンである。呼気時の段階的な圧力低下は、本発明のように前半/後半の２段階だけでなく、より細かく区切って圧力を下げていくことや、スロープ状に圧力を下げることも可能である。
【００３１】
こうして呼気前半時に呼気後半時圧力よりも高い圧力を供給することにより、呼気時気道閉塞を呈する使用者の気道を広げ、呼気を出し易くすることによって、治療効果が向上する。また、気道を広げることによって、使用者が努力吸気することなく吸気に移ることが可能となり、患者の治療コンプライアンスも向上する。
【図面の簡単な説明】
【図１】鼻マスク式の陽圧式人工呼吸補助装置。
【図２】一般的な陽圧式人工呼吸補助装置における供給圧力パターン。
【図３】各疾患別呼吸パターン。
【図４】本発明の陽圧式人工呼吸補助装置の好適な実施例。
【図５】本発明の好適な供給圧力パターン。
【符号の説明】
１．人工呼吸器本体
２．導管
３．呼気排出孔
４．治療用ガス混入ポート
５．マスクフレーム
６．鼻マスク
７．使用者
８．差圧式流量計[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a medical artificial respiration assist apparatus. More specifically, the present invention relates to a positive pressure type artificial respiration assisting device used for positive pressure ventilation therapy (IPPV) suitable for the treatment of ventilatory insufficiency patients such as hypercapnia.
[0002]
[Prior art]
The positive pressure artificial respiration assist device for medical use is used to support the respiration of a ventilation failure user who cannot sufficiently ventilate by spontaneous breathing alone such as pulmonary tuberculosis sequelae, chronic obstructive pulmonary disease (COPD), and emphysema.
[0003]
The most common type using a nasal mask among positive pressure artificial respiration assisting devices will be described with reference to FIG. The main body 1 intermittently generates a positive pressure gas of about 2 to 30 cmH 2 O and sends it to the
[0004]
The following has been reported at home and abroad as therapeutic effects. That is, (1) Decrease blood carbon dioxide concentration by increasing the alveolar ventilation of the user, (2) Respiratory muscle fatigue is reduced by pressure assistance, (3) Supply pressure at expiration (PEEP: Positive End Expiratory Pressure) prevents airway obstruction and alveolar collapse.
[0005]
[Problems to be solved by the invention]
However, in some diseases, the positive therapeutic effects of the positive pressure ventilation as described above cannot be obtained, or the user is forced to give up treatment due to difficulty in breathing. Has also been reported.
[0006]
Ventilation disorders are generally classified into restrictive ventilation disorders including pulmonary tuberculosis sequelae and obstructive ventilation disorders including emphysema. Restrained ventilatory impairment is a condition in which pulmonary dilation is restricted due to changes in the lung parenchyma or lesions of the pleura, chest wall, and nerves, muscle tissue. This condition is characterized by a decrease in the tidal volume at rest, but if the tidal volume is increased with the support of positive pressure ventilation therapy, it approaches normal ventilation, and the therapeutic effect of the positive pressure ventilator is not high.
[0007]
One obstructive ventilatory disorder is characterized by a call disorder due to increased airway resistance due to airway obstruction during expiration. In particular, in most cases, a call failure occurs only in the second half of exhalation, and the first half of exhalation can be discharged normally. In addition, since airway obstruction occurs at a high lung volume level, the residual air volume increases and a feeling of difficulty in breathing is felt. For such pathological conditions, there are cases in which ventilation assistance cannot be effectively performed even if a positive pressure type artificial respiration assisting device that supplies pressure of conventional IPAP and EPAP is used. For example, even if a commonly used expiratory pressure of 4 cmH 2 O is supplied, the airway obstruction may not be eliminated because the expiratory pressure is low. In this case, in addition to the call failure, the intake air is moved while the airway obstruction occurs, so that the intake becomes forced inspiration, and the intake muscle fatigue also occurs. In order to eliminate the airway obstruction, a method of increasing the pressure during expiration may be considered. However, if a high pressure is applied during expiration, the patient may feel difficulty in exhaling.
[0008]
Japanese Patent Application Laid-Open No. 8-322936 describes a ventilator that supplies a large amount of fresh air to the lung without excessively reducing the intrapulmonary pressure by airway intubation or the like. In such a device, the first half of exhalation is a device that controls the exhalation pressure to be lower than the set value, and thereafter performs control to increase the exhalation pressure toward the set value as the exhalation flow rate decreases.
[0009]
This ventilator lowers the first half-expiratory pressure to allow more ventilation in the first half of exhalation and is suitable for restrictive ventilatory disturbances, but patients with obstructive ventilatory disturbances that cause airway obstruction in the second half of exhalation It cannot be applied to.
[0010]
Furthermore, if an exhalation valve is used for pressure adjustment like this ventilator, the breathing circuit becomes complicated, especially when a respirator (nasal mask, nostril mask) is used, the area around the mask becomes heavy. , It will be a burden on the patient. In addition, when a therapeutic gas is mixed in the respiratory interface, the therapeutic gas input from the exhalation valve escapes during the period when the exhalation valve is open, and the therapeutic gas is wasted. Exists.
[0011]
The present invention provides a positive pressure artificial respiration assisting device that eliminates airway obstruction and makes it easier to move to inhalation for a user who exhibits airway obstruction in the second half of exhalation in positive pressure ventilation therapy. This is the issue.
[0012]
[Means for Solving the Problems]
In order to achieve such a problem, the present inventor has intensively studied and found that the problem can be solved by providing a positive pressure type artificial respiration assisting device that gradually lowers the positive pressure during expiration during the expiration period of the user. I found it.
[0013]
That is, the present invention provides a positive pressure gas generating means for supplying a positive pressure gas to a user, an inspiratory pressure (IPAP) corresponding to the user's breathing and an expiratory pressure (EPAP) lower than that during exhalation. Control means for the positive pressure gas generating means for supplying the positive pressure gas, a breathing interface for supplying the positive pressure gas to the user, and a conduit means for connecting the positive pressure gas generating means and the breathing interface In the positive pressure artificial respiration assist device, the control means is a means for performing a control to lower the exhalation pressure step by step so that the exhalation pressure becomes lower than the first exhalation pressure when the user exhales. A positive pressure type artificial respiration assisting device is provided.
[0014]
Further, according to the present invention, the control means generates a positive pressure gas at a first half-expired set pressure lower than the inspiratory pressure at the first half of exhalation and at a second half-expired set pressure lower than the first half-expired set pressure at the second half of exhalation. The present invention provides a positive pressure artificial respiration assisting device characterized by being a control means.
[0015]
The present invention further includes means for measuring a user's respiratory flow in the breathing circuit of the positive pressure artificial respiration assist device, and the control means has an inflection point after the expiratory flow during the expiration period shows a maximum value. The present invention provides a positive pressure artificial respiration assisting device that is a means for performing control to switch from the first half-expired set pressure to the second half-expired set pressure at the time of taking.
[0016]
The present invention further includes means for measuring the respiratory flow rate of the user in the breathing circuit of the positive pressure artificial respiration assisting device, and the control means includes means for calculating the ventilation volume by time-integrating the respiratory flow rate. The means for performing control to switch from the first half-expired set pressure to the second half-expired set pressure when the exhaled ventilation volume is called by a preset ratio with respect to the amount inhaled during the previous inspiration. A positive pressure type artificial respiration assisting device is provided.
[0017]
The present invention also includes means for detecting a user's expiration start point in such a positive-pressure artificial respiration assist device, and the control means is configured to detect the first half of the expiration when a preset time has elapsed from the expiration start point. The present invention provides a positive pressure type artificial respiration assisting device which is a means for performing control to switch from a set pressure to a set pressure in the latter half of expiration.
[0018]
The present invention further includes means for measuring the respiratory flow rate of the user in the breathing circuit of the positive pressure type artificial respiration assisting device, and the control means has the maximum value when the exhalation flow rate during the expiration period shows the maximum value. The present invention provides a positive pressure artificial respiration assisting device that is a means for performing control to switch from the first half-expired set pressure to the second half-expired set pressure.
[0019]
Further, according to the present invention, the positive pressure gas generating means is a blower means for generating a positive pressure gas of a predetermined pressure by controlling the rotation speed, and the breathing interface is a breathing mask means. A positive pressure artificial respiration assistance device is provided.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
The present inventor has shown the breathing pattern when using a conventional positive pressure artificial respiration assist device (intermittently supplying IPAP and EPAP) and during spontaneous breathing in healthy individuals, patients with restrictive lung disease, and patients with obstructive lung disease. As a result of the investigation, as shown in FIG. 3, the breathing pattern (flow rate vs time) at the time of exhalation in a healthy person and a patient with restrictive lung disease shows a relatively simple downward convex shape, whereas the obstructive lung In patients with illness, the expiratory flow shows a convex shape after reaching the maximum value, and there is an inflection point based on airway obstruction in the breathing pattern during exhalation, and airway obstruction has occurred after the inflection point. I found it.
In addition, airway obstruction during exhalation in patients with obstructive pulmonary disease is more conspicuous when using a positive pressure artificial respiration assist device than during spontaneous breathing. When EPAP is constant, the support pressure (= We found that the greater the IPAP-EPAP), the greater the degree of airway obstruction. This indicates that when the support pressure is large, that is, as the tidal volume is large and the expiratory flow rate is fast, the airway pressure decreases and airway obstruction tends to occur. Furthermore, once airway obstruction occurs once in the first half of the expiratory period where the expiratory flow rate is fast, airway obstruction continues until the end of the expiratory period, so preventing airway obstruction in the first half of exhalation is the key to this treatment.
The present inventor prevents an increase in the expiratory flow rate by supplying a relatively high pressure to the first half of the expiratory flow where the expiratory flow rate is fast, and further imposes an unnecessary burden on the patient by lowering the pressure in the second half of the expiratory flow. And found that airway obstruction can be prevented.
The positive-pressure artificial respiration assist apparatus of the present invention includes a positive-pressure gas generating means for generating a positive-pressure gas corresponding to a user's respiration, a breathing interface for supplying the positive-pressure gas to the user, and the positive-pressure gas generating means. Consists of conduit means connecting the pressurized gas generator and the breathing interface.
[0021]
Such positive pressure gas generating means is means for generating positive pressure gas by pressurizing air, and a blower is used. The control of the positive pressure gas supply is performed so that the positive pressure during inspiration is supplied during the inspiration time in accordance with the prescription pressure of the user's doctor and the pressure is gradually reduced during expiration. Preferably, the generation of the positive pressure gas generating means is controlled so as to supply a positive pressure during inspiration, a positive pressure during the first half of the expiration, and a positive pressure during the second half of the expiration. By installing a pressure sensor, a flow sensor, etc. in the breathing circuit in the breathing interface in the conduit means from the outlet of the positive pressure gas generating means, the patient's inhalation start point, early exhalation start point, and late exhalation start point are detected. According to this, the method of switching the supply pressure of the positive pressure gas generating means and the inhalation time, the first half time of exhalation, and the second half time of exhalation are set in advance, and the supply pressure of the positive pressure gas generating means is switched accordingly. A method is used to control and adjust the user's breath to it.
[0022]
The pressure switching point from the first half of the exhalation to the second half of the exhalation may be a point at which the inflection point is taken after the exhalation flow rate during the exhalation period shows the maximum value. This inflection point is equipped with a means for measuring the user's respiratory flow in the breathing circuit and calculates the point where the value obtained by differentiating the measured value twice is zero for the first time after the expiratory flow shows the maximum value. It can be obtained by doing. Specifically, first, in the measured digital respiratory flow value, a differential value (acceleration of the respiratory flow) is derived by taking a difference between two preceding and following data. Further, the value obtained by taking the difference between the differential values before and after is the differential value twice. The digital respiratory flow rate value is preferably a value measured at a sampling rate of 1 to 10 msec. In order to respond to the user's breathing in a short time. The maximum value of the respiratory flow rate can be obtained by calculating the point at which the differential value changes from the minus side to the plus side.
[0023]
As a means for measuring the respiratory flow rate, a differential pressure type flow rate sensor, a hot wire type flow rate sensor, or the like can be used. However, in order to supply a sufficient pressure to the user, it is necessary to use a flow meter with little pressure loss. The flow sensor can be installed in the breathing circuit from the positive pressure gas generator to the breathing interface. In particular, in order to measure an accurate value, it is desirable that there is no leakage between the user and the flow sensor. In addition, when providing a flow sensor upstream of the exhalation exhaust hole, since a part of the measured gas flow rate includes the amount discharged from the exhalation exhaust hole, the outflow flow rate from the exhalation exhaust hole is calculated, By subtracting this, the flow rate data can be corrected. If there is a leak from the breathing mask or the like, it is necessary to correct that amount as well. In addition, it is desirable that the measured value is a moving average in order to remove noise.
[0024]
As another method, the present invention includes means for measuring the respiratory flow rate of the user in the breathing circuit of the positive pressure artificial respiration assist device, and means for calculating the ventilation volume by integrating the respiratory flow time over time. A method of controlling the supply pressure in accordance with the point in time when the ventilation volume at the time of calling up a predetermined ratio with respect to the volume inhaled at the time of the previous inspiration is set as the second half of the exhalation start point can be used.
[0025]
The amount inhaled and the amount of ventilation during inspiration can be obtained by Σ (respiration flow value × sampling rate) in each inspiration and expiration. It is desirable to switch to the exhalation latter half pressure when the exhaled ventilation volume is called 10-30% of the amount inhaled during the previous inspiration.
[0026]
As another method, the positive pressure type artificial respiration assisting device is provided with means for detecting the user's first half-expiration start point, and a point in time set in advance from the first half-expiration start point is used as the second half-expiration start point. A method of performing control to switch to the latter half pressure can be used. Switching from the first exhalation start point to the second exhalation pressure can be set any number of times during the exhalation period, but is preferably 0.1 to 1 second after the first exhalation start.
[0027]
As another method, the breathing circuit of such a positive pressure type artificial respiration assisting device is provided with means for measuring the user's breathing flow, and the point in time when the expiratory flow during the expiration period shows the maximum value is set as the starting point of the second half of the expiration. A method of controlling to switch to the set pressure at the end of exhalation can be used.
[0028]
The pressure set for the first half-expiratory pressure and the second half-expired pressure varies depending on the airway obstruction state of the patient to be used, but the first half-expired pressure is 6 to 10 cmH 2 O and the second half-expired pressure is 2 to 6 cmH 2 O. Can be controlled and used.
[0029]
【Example】
An embodiment of the positive pressure artificial respiration assistance apparatus of the present invention will be described in more detail with reference to FIG. A differential pressure type flow meter is provided at the outlet end of the positive pressure gas generator, and the flow rate value measured by the differential pressure type flow meter is sent to the calculation means. The calculation means corrects the gas discharge amount from the exhalation discharge hole and the leak from the nasal mask. The calculating means calculates the inhalation start point, the first half-expiration start point, and the second half-expiration start point by the method described above, and inputs them to the blower rotation speed control means. The blower rotation control means controls the number of blower rotations, and corresponds to a predetermined pressure at the time of inhalation, a setting pressure at the first half of expiration, and a setting pressure at the second half of expiration according to each input pressure supply period. The voltage to be input is input to the positive pressure gas generating means. The positive pressure gas generating means generates a positive pressure gas corresponding to the input voltage and sends it to the conduit. Further, the setting value input means can input items to be set by the doctor, such as the pressure during inhalation, the setting pressure during the first half of expiration, and the setting pressure during the second half of expiration, and can be input to the calculation means or the blower rotation speed control means. send.
[0030]
FIG. 5 is a preferred supply pressure pattern of the present invention. The stepwise pressure drop during exhalation is not limited to the first half / second half as in the present invention, but can be divided more finely or the pressure can be lowered in a slope shape.
[0031]
Thus, by supplying a pressure higher than the pressure in the first half of the exhalation during the first half of the exhalation, the airway of the user exhibiting the airway obstruction during the exhalation is widened and the exhalation is facilitated, thereby improving the therapeutic effect. In addition, widening the airway allows the user to move to inspiration without effort inspiration, improving patient treatment compliance.
[Brief description of the drawings]
FIG. 1 is a nasal mask type positive pressure artificial respiration assist device.
FIG. 2 shows a supply pressure pattern in a general positive pressure type artificial respiration assist device.
FIG. 3 shows respiratory patterns for each disease.
FIG. 4 shows a preferred embodiment of the positive pressure artificial respiration assist apparatus according to the present invention.
FIG. 5 is a preferred supply pressure pattern of the present invention.
[Explanation of symbols]
1. 1.
Claims (3)
該制御手段は、使用者の呼気前半時には該吸気時圧力よりも低い呼気前半時設定圧力に設定し、使用者の呼気後半時には該呼気前半時設定圧力よりも低い呼気後半時設定圧力に設定して、使用者の呼気時における該呼気時圧力を段階的に下げるように陽圧ガスを発生させる制御を行い、
該陽圧式人工呼吸補助装置の呼吸回路中には使用者の呼吸流量を測定する手段が設けられており、該制御手段は、呼気期間中の呼気流量が最大値を示した後に変曲点をとった時点で、該呼気前半時設定圧力から該呼気後半時設定圧力に切り替える制御を行うことを特徴とする陽圧式人工呼吸補助装置。Positive pressure gas generating means for supplying positive pressure gas to the user, supplying positive pressure gas at the time of inspiration (IPAP) and lower pressure at expiration (EPAP) at the time of expiration corresponding to the user's breathing Positive pressure artificial respiration comprising control means for the positive pressure gas generating means, a respiration interface for supplying the positive pressure gas to a user, and a conduit means for connecting the positive pressure gas generation means and the respiration interface In the auxiliary device,
The control means sets the first half-expired set pressure lower than the inspiratory pressure during the first half of the user's exhalation, and sets the second exhalation set pressure lower than the first half-expired set pressure during the second half of the user's exhalation. And performing control to generate positive pressure gas so as to lower the exhalation pressure at the time of exhalation of the user stepwise,
Means for measuring the respiratory flow rate of the user is provided in the breathing circuit of the positive pressure artificial respiration assisting device, and the control means sets the inflection point after the expiratory flow rate during the expiration period shows the maximum value. A positive pressure type artificial respiration assisting device that performs control to switch from the first half-expired pressure setting to the second expiratory pressure setting when taken.
該制御手段は、使用者の呼気前半時には該吸気時圧力よりも低い呼気前半時設定圧力に設定し、使用者の呼気後半時には該呼気前半時設定圧力よりも低い呼気後半時設定圧力に設定して、使用者の呼気時における該呼気時圧力を段階的に下げるように陽圧ガスを発生させる制御を行い、
該陽圧式人工呼吸補助装置の呼吸回路中には使用者の呼吸流量を測定する手段が設けられており、該制御手段は、該呼吸流量を時間積分して換気量を演算する手段を備え、呼気時の換気量が直前の吸気時に吸入した量に対して予め設定した割合だけ呼出した時点で、該呼気前半時設定圧力から該呼気後半時設定圧力に切り替える制御を行うことを特徴とする陽圧式人工呼吸補助装置。Positive pressure gas generating means for supplying positive pressure gas to the user, supplying positive pressure gas at the time of inspiration (IPAP) and lower pressure at expiration (EPAP) at the time of expiration corresponding to the user's breathing Positive pressure artificial respiration comprising control means for the positive pressure gas generating means, a respiration interface for supplying the positive pressure gas to a user, and a conduit means for connecting the positive pressure gas generation means and the respiration interface In the auxiliary device,
The control means sets the first half-expired set pressure lower than the inspiratory pressure during the first half of the user's exhalation, and sets the second exhalation set pressure lower than the first half-expired set pressure during the second half of the user's exhalation. And performing control to generate positive pressure gas so as to lower the exhalation pressure at the time of exhalation of the user stepwise,
Means for measuring the respiratory flow of the user is provided in the breathing circuit of the positive pressure artificial respiration assist device, and the control means includes means for calculating the ventilation volume by integrating the respiratory flow over time, A control is performed to switch from the first half-expired set pressure to the second half-expired set pressure when the exhaled ventilation volume is called by a preset ratio with respect to the amount inhaled during the previous inspiration. Pressure ventilator assist device.
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| US20060011195A1 (en) * | 2004-07-14 | 2006-01-19 | Ric Investments, Llc. | Method and apparatus for non-rebreathing positive airway pressure ventilation |
| CA2623756A1 (en) | 2005-09-20 | 2007-03-29 | Lutz Freitag | Systems, methods and apparatus for respiratory support of a patient |
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| WO2008144589A1 (en) | 2007-05-18 | 2008-11-27 | Breathe Technologies, Inc. | Methods and devices for sensing respiration and providing ventilation therapy |
| CA2700878C (en) | 2007-09-26 | 2018-07-24 | Breathe Technologies, Inc. | Methods and devices for providing inspiratory and expiratory flow relief during ventilation therapy |
| JP5513392B2 (en) | 2007-09-26 | 2014-06-04 | ブリーズ・テクノロジーズ・インコーポレーテッド | Method and apparatus for treating sleep apnea |
| WO2009151791A2 (en) | 2008-04-18 | 2009-12-17 | Breathe Technologies, Inc. | Methods and devices for sensing respiration and controlling ventilator functions |
| US8770193B2 (en) | 2008-04-18 | 2014-07-08 | Breathe Technologies, Inc. | Methods and devices for sensing respiration and controlling ventilator functions |
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| US9132250B2 (en) | 2009-09-03 | 2015-09-15 | Breathe Technologies, Inc. | Methods, systems and devices for non-invasive ventilation including a non-sealing ventilation interface with an entrainment port and/or pressure feature |
| CA2757588C (en) | 2009-04-02 | 2017-01-03 | Breathe Technologies, Inc. | Methods, systems and devices for non-invasive open ventilation with gas delivery nozzles in free space |
| US9962512B2 (en) | 2009-04-02 | 2018-05-08 | Breathe Technologies, Inc. | Methods, systems and devices for non-invasive ventilation including a non-sealing ventilation interface with a free space nozzle feature |
| CN102762250B (en) | 2009-09-03 | 2017-09-26 | 呼吸科技公司 | Mthods, systems and devices for including the invasive ventilation with entrainment port and/or the non-tight vented interface of pressure characteristic |
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| WO2012045051A1 (en) | 2010-09-30 | 2012-04-05 | Breathe Technologies, Inc. | Methods, systems and devices for humidifying a respiratory tract |
| CN107308530A (en) * | 2012-05-02 | 2017-11-03 | 瑞思迈有限公司 | The equipment adjusted for pressure therapy |
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