JPH08243166A - Respiration tuning type respiration assisting device - Google Patents

Abstract

PURPOSE: To rapidly drop the pressure of a supply gas in the initial period of an exhalation phase to facilitate the discharge of the patient's exhalation gas by releasing a pressure reducing means at the time of starting a shift from an inhalation phase to the exhalation phase and lowering supply gas flow in the period until the pressure value of the gas coincides with the PEEP set in the exhalation phase. CONSTITUTION: Gaseous flow is supplied from a fan 21 through a conduit means 22 to a patient 34 and the pressure of this gaseous flow is detected by a pressure detecting means 30. The gas in the conduit means is released to the atm. atmosphere by using pressure type valves 25, 29 when the inhalation phase is detected. The pressure drop is adjusted to rapidly drop the supply pressure by changing the opening degree of a small-sized butterfly valve 23 so as to hinder the flow of the air flow generated from the fan 21 in the period until the pressure value nearly coincides with the PEEP, i.e., in the initial period of the shift to the exhalation phase. The exhalation gas is pushed out into the ambient atmosphere by the exhalation effort of the patient from the opening parts of the pressure type valves 25, 29 opened to the ambient atmosphere in the initial period of the shift to the exhalation phase.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a breathing-synchronized positive airway pressure type respiratory assist device for supplying pressurized gas for breathing to the respiratory tract.

[0002]

2. Description of the Related Art A breathing assistance device applied to a patient who can breathe spontaneously is required to have sufficient ventilation capacity and not cause discomfort or pain to the patient. Therefore, it is desirable to provide respiratory assistance in synchronization with the patient's spontaneous breathing.

From this viewpoint, as a conventional technique, there is a biphasic positive pressure system, for example. In this case, the pressure control unit of the artificial respiration device is required to have the following two characteristics. That is, when the expiratory phase shifts to the inspiratory phase, and when the inspiratory phase shifts to the expiratory phase, it is desired to greatly change the pressure value within a short time. On the other hand, during the inspiratory phase and the expiratory phase, it is necessary to perform fine control so as to maintain a constant pressure value regardless of changes in the respiratory state of the patient.

Further, when the proportional assist type artificial respiration method (Japanese Patent Laid-Open No. 5-115554) is used for the purpose of not giving discomfort or pain to the patient, finer pressure control is required during the inspiration phase. A specific device configuration of the biphasic positive pressure system is described in, for example, Japanese Patent Laid-Open No. 3-222963. According to the description, the pressure control unit "is preferably in the form of a movable valve that provides an open flow path to the atmosphere through a restricted opening". That is, it is a method of controlling the pressure by changing the opening amount of the flow path opened to the atmosphere.

The inventors of the present invention, in Japanese Patent Application No. 6-154761, provide decompression means between the pressure control means and the patient so that the patient's exhaled gas is supplied to the patient again during the next inspiration phase. We proposed a breathing assistance device that reduces the phenomenon (hereinafter called rebreathing).

[0006]

In the conventional method, a positive end-expiratory pressure (hereinafter referred to as PEEP) pressure gas is supplied to a patient during the expiratory phase, particularly at the moment when the inspiratory phase starts so that the airway is not blocked. However, the conventional method has the following problems. In a respiratory assistance device, one device configuration cannot supply gas from a high PEEP to a low PEEP to a patient selectively and reduce rebreathing to reduce dead space.

When the PEEP is large, for example, when the PEEP prescribed to the patient is 5 cmH ₂ O or more, the gas flow from the breathing assistance device is caused by a small opening provided in the nasal mask attached to the patient or in the vicinity thereof. The exhalation of the patient's exhaled gas into the ambient atmosphere primarily exchanges gas in the conduit to reduce dead space. However, when the PEEP is low, for example, about 1 cmH ₂ O, there is a problem that the exhaled gas of the patient is difficult to be pushed out into the surrounding atmosphere, the dead space becomes large, and the gas exchange efficiency deteriorates.

The present invention solves the above problems by
In a breathing assistance device applied to a patient who can spontaneously breathe, the exhalation gas of the patient is easily exhaled by decreasing the pressure of the supply gas within a short time at the beginning of the expiratory phase, and the supply gas of The purpose of the present invention is to obtain a respiratory assistance device capable of performing pressure control, reducing the dead space as much as possible regardless of the level of PEEP immediately before the start of the inspiration phase, reducing discomfort and pain of the patient, and obtaining a high therapeutic effect. There is.

[0009]

SUMMARY OF THE INVENTION The present invention is a positive airway pressure breathing entrainment type breathing assistance device, and a gas flow generating means for generating a breathing gas flow and a supplying means for supplying the breathing gas to a patient. A conduit means for connecting the gas flow generating means and the supplying means to the gas means by adjusting the pressure of the gas flow without releasing the gas in the conduit means to the atmosphere. Is arranged in the vicinity of the pressure adjusting means in the conduit means and on the side of the supplying means, and releases the gas in the conduit means to an atmosphere having a pressure equal to or lower than atmospheric pressure. A first decompression means and a second decompression means disposed in the conduit means in the vicinity of the supply means for releasing the gas in the conduit means to an atmosphere of atmospheric pressure or less, and a normal expiratory phase of the patient. At the time of transition The first and second decompression means are opened to release the gas in the conduit means to an atmosphere having a pressure equal to or lower than atmospheric pressure, and the first and second decompression means are opened during the normal inspiratory phase of the patient. (EN) Provided is a breathing assist type breathing assistance device, which is provided with a control means for closing both together.

Such a device of the present invention includes a respiratory assistance device having a respiratory phase detecting means for detecting the means phase of the patient.

Further, in the apparatus of the present invention, the control means is
A breathing assistance device having a function of maximizing the pressure loss of the pressure adjusting means to extremely reduce the supply gas flow for a certain period in the early phase of the expiratory phase after the transition from the inspiratory phase to the expiratory phase is included.

Further, the apparatus of the present invention comprises pressure detection means for detecting the gas pressure in the supply means or the conduit means, and the control means controls the gas pressure value in the conduit means after the start of the expiratory phase. After the pressure detected by the pressure detecting means has dropped to reach a desired pressure value, the second pressure reducing means is fully closed, and in the latter half of the expiratory phase, the pressure loss of the pressure adjusting means is adjusted to end the end exhalation. A breathing assistance device is included which has the function of controlling the positive pressure value to provide a breathing gas stream.

The device of the present invention further includes a breathing assistance device in which the desired pressure value is set to a value linked to the value of positive end expiratory pressure.

As described above, the device of the present invention is, in a respiratory tuned breathing assist device of positive airway pressure, a gas flow generating means for generating a respiratory gas flow, a conduit means and a supply means for guiding the gas flow to a patient, It is arranged in series between the gas flow generating means and the patient, and the pressure is adjusted by utilizing the pressure loss of the gas flow without being released to the atmosphere to supply the gas flow to the conduit means and to the airway at a variable pressure. A pressure adjusting means, a first depressurizing means arranged in the vicinity of the downstream of the pressure adjusting means and released to an atmosphere having a pressure of at least atmospheric pressure or less, and an atmosphere of at least an atmospheric pressure or less placed in the vicinity of the patient; PEEP has a function of controlling the pressure value of the supply gas flow by appropriately adjusting the pressure loss of the pressure adjusting means at the start of the transition from the inspiratory phase to the expiratory phase.
Is low, during the transition from the inspiratory phase to the expiratory phase, the first and second depressurizing means are opened during the period until the pressure value of the supply gas flow substantially matches PEEP during the expiratory phase. After being released into an atmosphere having a pressure lower than atmospheric pressure, the pressure value of the gas flow in the conduit means drops and reaches PEEP, and then the second pressure reducing means is closed, and the control means is preset to PEEP. It has the function of supplying breathing gas to the patient.

In the device of the present invention, the control means has a function of maximizing the pressure loss of the pressure adjusting means and extremely reducing the supply gas flow for a certain period in the initial phase of the expiratory phase after the transition from the inspiratory phase to the expiratory phase. It also comprises a pressure detecting means for detecting the gas pressure in the system, and after the start of the expiratory phase, the gas pressure value in the conduit means drops and the pressure detected by the pressure detecting means is the desired pressure value. After that, the second pressure reducing means is fully closed, and in the latter half of the expiratory phase, the pressure loss of the pressure regulating means is adjusted to control the positive end expiratory pressure to supply the respiratory gas flow. The breathing assistance device having a function of controlling the pressure value, the desired pressure value being preset as PEEP in the control means, and the pressure adjusting means being controlled so that the system internal pressure does not fall below the desired pressure. Is included

In the device of the present invention, the gas generated from the gas flow generating means is supplied to the airway of the patient through the conduit means. The first and second decompression means are not released during the patient's normal inspiration phase, and both the first and second decompression means are fully opened during the patient's normal expiratory phase transition. The gas in the conduit means is released to a pressure atmosphere below atmospheric pressure. Further, the apparatus of the present invention preferably comprises a flow meter for detecting the gas flow rate in the conduit means.

In the latter half of the expiratory phase, the second pressure reducing means is fully closed, the first pressure reducing means is opened, and the pressure adjusting means is adjusted based on the characteristics of the flow rate and pressure in the conduit means,
The pressure in the supply means is controlled to be a preset pressure. The pressure control during the inspiration phase and the expiration phase is performed by operating the pressure adjusting means. The control means controls the operations of the pressure reducing means and the pressure adjusting means, and is, for example, a microcomputer unit (MP
Computer means including U) are used.

However, even during the expiratory phase, if it is necessary to rapidly increase the pressure for some reason, such as when the patient's spontaneous breathing is stopped and the expiratory phase continues for a long time, the above-mentioned first , And the second depressurizing means are both fully closed, and it is desirable that the control means be provided with a function of increasing the pressure. Further, even during the inspiratory phase, if it is necessary to drastically reduce the pressure for some reason, for example, if the patient feels strong discomfort or distress because the supply pressure is too high, the first and second It is desirable that the second depressurizing means is released so that the pressure can be reduced. As the decompression means, it is desirable that the opening area for releasing the gas in the conduit means to the surrounding atmosphere rapidly change within a short time. This can be realized, for example, by using a commercially available solenoid valve or the like.

[0019]

[Operation] At the start of transition from the inspiratory phase to the expiratory phase, the first,
And the second depressurizing means is released, until the pressure value of the gas actually supplied to the preset PEEP during the expiratory phase approximately agrees, or an appropriately determined constant period,
The pressure loss of the pressure adjusting means is appropriately adjusted to extremely reduce the supply gas flow. By these operations, the supply pressure can be decreased within a short time, and the exhaled gas of the patient is discharged from the opening portion of the first and second depressurizing means released to the ambient atmosphere at the beginning of the expiratory phase transition. Extruded into the atmosphere around the mask.

For example, the set PEEP is low and about 1 cmH ₂ O
In some cases, exhaled gas from the patient is easily pushed through a small opening in or near the nasal mask. This can significantly reduce the patient's dyspnea and the amount of dead space associated with rebreathing.

Thus, the pressure in the conduit means can be largely reduced within a short period of time at the beginning of the expiratory phase transition, and the pressure of the supply gas can be controlled to a preset pressure value in the latter half of the expiratory phase.

[0022]

EXAMPLES The apparatus of the present invention will be described in more detail below with reference to embodiments. However, the present invention is not limited to these examples.

FIG. 1 is a schematic block diagram of a breathing assistance device according to an embodiment of the present invention. In FIG. 1, 1 is a fan of the gas flow generation unit, and 2 is an inner diameter of 20 mm which is a conduit means.
Of the artificial respirator tube, 3 is a small butterfly valve as a pressure adjusting unit, 4 is a first pressure reducing unit, 5 is a flow rate detecting means for continuously detecting the gas flow rate in the conduit, and 6 is a second pressure reducing unit. Reference numeral 7 is composed of a commercially available semiconductor pressure sensor which is a pressure detecting means.

FIG. 2 is a block diagram showing the embodiment of FIG. 1 more specifically. In the figure, reference numeral 21 denotes a gas flow generation unit having a variable rotation speed fan, and the rotation speed is several thousand to one.
The fan output pressure is adjusted to approximately 30 cmH ₂ O between ten thousand rpm. Reference numeral 22 is a ventilator tube having an inner diameter of 20 mm which is a conduit means and has a length of about 3 m. Reference numeral 23 is a small butterfly valve having an outer diameter of 20 mm, which is a pressure adjusting unit that adjusts the supply pressure by utilizing the pressure loss of the gas flow without being released to the atmosphere. The first pressure reducing unit for releasing the inside of the conduit to the atmospheric pressure atmosphere is composed of a three-way solenoid valve 24 and a pneumatic valve 25. Reference numeral 26 is a flow rate detecting means for continuously detecting the gas flow rate in the conduit, and a commercially available mass flow type flow meter with a small pressure loss is used.

Reference numeral 27 is a bacterial filter, and a three-way solenoid valve 28 and a pneumatic valve 2 are provided in the vicinity of the patient as a second pressure reducing unit for releasing the inside of the conduit to the atmosphere.
It is composed of nine. Reference numeral 30 is a commercially available semiconductor pressure sensor which is a pressure detecting means for continuously detecting the gas pressure in the conduit, and 31 is a gas pressure conducting tube connecting them. Reference numeral 32 is a supply means for supplying breathing gas, and is constituted by a nasal mask worn by the patient here. 12
Shows the internal structure of the apparatus, and 13 shows the patient circuit outside the apparatus. Reference numeral 33 denotes a microcomputer unit (MPU) which is a control means for grasping the respiratory phase of the patient from the result detected by the pressure detection means 30 and controlling the pressure adjusting unit 23 and the like connected based on the breathing phase. Represent.

In FIG. 2, the patient 34 is supplied with gas flow from fan 21 via conduit means 22. The pressure of the gas flow is detected by the pressure detecting means 30.

When the patient's expiratory phase is detected, pressure valves 25 and 29 are used to release the gas in the conduit means to atmospheric pressure. In particular, by releasing the second depressurizing units 28 and 29, the small butterfly valve 23 during a period until it substantially coincides with PEEP, that is, at the beginning of the expiratory phase transition.
The pressure loss is adjusted by changing the opening degree of the so as to block the flow of the air flow generated from the fan 21. By these operations, the supply pressure can be reduced within a short time. Then, in the initial stage of the expiratory phase transition, the expiratory gas is pushed out to the ambient atmosphere by the patient's expiratory effort through the opening portions of the pressure type valves 25 and 29 which are opened to the ambient atmosphere. Furthermore, by adjusting the opening of the small butterfly valve 23,
The gas flow from the fan 21 forces the patient exhaled gas that has accumulated in the conduit through the opening of the pneumatic valve 29 into the ambient atmosphere.

Thereafter, the gas pressure in the conduit means drops and P
The second decompression unit 2 at the time when it almost matches the EEP
8 and 29 are closed. The first decompression units 24 and 25 are continuously released, the opening amount of the small butterfly valve 23 is changed to finely adjust the pressure loss amount, and a preset PEEP gas flow is supplied to the patient. That is, when it is desired to lower the supply pressure a little, the small butterfly valve 23
The opening degree of is appropriately changed in the direction of impeding the gas flow generated from the fan 21. On the contrary, when it is desired to increase the supply pressure a little, the opening degree of the small butterfly valve 23 is changed in the direction in which the gas flow generated from the fan 21 flows.

In the present embodiment, the gas pressure for closing the second depressurizing unit is set to PEEP, but 50% of PEEP or PEEP-0.5 cmH ₂ O may be used as this set value.

Then, when the inspiratory phase of the patient is detected, the first decompression units 24 and 25 are closed, and the opening of the small butterfly valve 23 is changed so as not to disturb the flow of the air flow generated from the fan 21. The pressure loss due to the small butterfly valve 23 is reduced. By these operations, the supply pressure of the gas flow to the patient is increased within a short time.

FIGS. 3 (a) and 3 (b) are various signal outputs for respiratory assistance according to one embodiment of the present invention, and FIG. 3 (a) is PEE.
P = 1 cm H ₂ O is set and the gas pressure value is 1 cm during the expiratory phase.
This is a case where the gas does not fall to H ₂ O and the first and second depressurizing units are both fully opened and the phase shifts to the intake phase. See also FIG.
(b) When PEEP = 3 cmH ₂ O is set, the gas pressure value drops to 3 cmH ₂ O in the middle of the expiratory phase, and the second decompression unit closes in the latter half of the expiratory phase to perform PEEP control. Is. FIG. 4 shows various signal outputs of breathing assistance according to the prior art, and is a case where PEEP = 1 cmH ₂ O is set.

The symbols in FIGS. 3A, 3B and 4 are as follows. The horizontal axis is the time axis and one scale is 100 ms.
The inspiration phase and the expiration phase are shown. 40 is a flow rate detecting means 26
Gas flow rate output signal by the vertical axis 1 scale 7.2L / min, 41
Is a gas pressure output signal in the vicinity of the patient by the pressure detecting means 30, 1 axis of the vertical axis is 1 cmH2O, and 42 is an opening / closing signal of the three-way solenoid valve 28 constituting the second pressure reducing unit, which is opened by the HI signal. Reference numeral 43 denotes an opening / closing signal of the three-way solenoid valve 24 which constitutes the first pressure reducing unit, which is opened by the HI signal.

In both FIGS. 3 (a) and 4, PEEP is 1 cmH ₂
When set to O, the shaded portion in the figure is the flow of the exhaled gas from the patient toward the fan 21 of the apparatus, and if the flow from the fan 21 to the patient is positive, the flow rate is the reverse flow rate. As is clear from a comparison between the two figures, the shaded area in FIG. 3 (a) is smaller than that in FIG. Therefore, as a function of the present invention, the reverse flow rate of the exhaled gas is reduced, and the flow rate immediately before inhalation is positively inverted, which means that the gas in the conduit escapes from the small opening near the nasal mask. Therefore, the expired gas of the patient is almost completely extruded into the atmospheric pressure atmosphere, and the dead space is reduced.

[0034]

INDUSTRIAL APPLICABILITY As described in detail above, the present invention reduces the discomfort and pain of the patient, reduces the dead space due to rebreathing regardless of the level of PEEP, and obtains a high therapeutic effect. Can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic illustration of an example of an embodiment of a breathing-type breathing assistance device of the present invention.

FIG. 2 shows an embodiment of a breathing assist type breathing assistance device of the present invention.

FIG. 3 is an illustration of various breathing assistance signal outputs for the embodiment of FIG. 2 of the present invention. (a) is the setting PEEP = 1 cmH ₂ O,
In the latter half of the expiratory phase, this is an example of the case where the second depressurization units 28 and 29 are opened and transition to the inspiratory phase. (b) is the setting P
This is an example of the case where the second decompression unit 28, 29 is closed in the latter half of the expiratory phase with EEP = 3 cmH ₂ O and PEEP control is performed.

FIG. 4 is an illustration of various breathing assistance signal outputs according to the prior art.

[Explanation of symbols]

 1: Gas flow generating unit 2: Conduit means 3: Pressure adjusting unit 4: Pressure reducing unit 1 5: Flow rate detecting means 6: Depressurizing unit 2 7: Pressure detecting means 12: Inside device 13: Outside device circuit 21: Gas flow Generating unit 22: Conduit means 23: Pressure adjusting unit 24: Three-way solenoid valve 1 25: Air pressure type valve 1 26: Flow rate detecting means 27: Bacteria filter 28: Three way solenoid valve 2 29: Air pressure type valve 2 30: Pressure detection Means 31: Pressure conduction tube 32: Nasal mask 40: Gas flow rate output signal in conduit 41: Gas pressure output signal in the vicinity of the patient 42: Pressure reducing unit solenoid valve 28 opening / closing signal 43: Pressure reducing unit solenoid valve 24 opening / closing signal

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takaki Nakagawa 3-4-1 Mihara, Ibaraki City, Osaka Prefecture Teijin Limited Osaka Research Center

Claims (5)

[Claims] 1. A positive airway pressure breathing tuned breathing assistance device, wherein gas flow generating means for generating a breathing gas stream, supply means for supplying breathing gas to a patient, and conduit means for connection. And adjusting the pressure of the gas flow to the supply means side of the conduit means at a variable pressure by adjusting the pressure of the gas flow without releasing the gas in the conduit means to the atmosphere through the gas flow generation means and the supply means. Means and first decompression means arranged near the pressure adjusting means in the conduit means and on the side of the supply means for releasing the gas in the conduit means to an atmosphere having a pressure equal to or lower than atmospheric pressure, A second decompression means disposed in the conduit means in the vicinity of the supply means for releasing the gas in the conduit means to an atmosphere below atmospheric pressure, the first and the second during the normal expiratory phase transition of the patient. Second decompression means Is opened to release the gas in the conduit means to an atmosphere having a pressure equal to or lower than atmospheric pressure, and to close both the first and second depressurizing means during the normal inspiratory phase of the patient. A breathing assist type breathing assisting device, characterized in that. 2. The breathing assistance apparatus of claim 1 including breathing phase detection means for detecting the means phase of the patient. 3. The control means has a function of maximizing the pressure loss of the pressure adjusting means for a certain period of time in the early phase of the expiratory phase after the transition from the inspiratory phase to the expiratory phase to extremely reduce the supply gas flow. The respiratory assistance device according to claim 1. 4. A pressure detecting means for detecting a gas pressure in the supply means or in the conduit means, wherein the control means decreases the gas pressure value in the conduit means after the start of the expiratory phase to detect the pressure. After the pressure detected by reaches the desired pressure value, the second decompression means is fully closed, and in the latter half of the expiratory phase, the pressure loss of the pressure adjusting means is adjusted to control the value of the positive end expiratory pressure. The breathing assistance apparatus according to claim 1, further comprising a function for supplying a breathing gas flow. 5. The respiratory assistance apparatus according to claim 4, wherein the desired pressure value is set to a value that is linked to a value of positive end expiratory pressure.