JP2879538B2 - Inhalation gas mixing device for ventilators - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ventilator which is operated by supplying oxygen and compressed air as known in the art. The present invention relates to an inhalation gas mixing device for a respirator used for mixing an inhalation gas and also administering the inhalation gas to a patient.

[0002]

2. Description of the Related Art As this type of inhalation gas mixing device for a ventilator, a device using a flow controller and a device using a mass flow controller have already been proposed.
In the case of the first conventional example, which is the former, as shown in FIG. 2, the inhalation gas mixing device 1 used for the respirator a
However, from the inhaled gas supply source 1a, the inhaled gas is sequentially supplied to the respirator circuit b in the respirator a by the inhaled gas supply pipe 1e to which the pressure regulator 1b, the on-off valve 1c, and the flow regulator 1d are connected. It mixes with the intake gas.

Here, as is known, c is a ventilator circuit b
, D is the oxygen side port, e is the compressed air side port, f is the ventilator side flow regulator, g and h are humidifiers and water traps inserted and interposed in the ventilator circuit b, i indicates an exhalation valve. Therefore, when using the suction gas mixing device 1, the regulator 1 of the flow regulator 1d is used.
By operating f, the flow rate of the inhalation gas is adjusted, and the predetermined amount of the inhalation gas is mixed into the ventilator circuit b.

At this time, when using the inhalation gas mixing device 1, the flow controller 1d is adjusted so as to obtain a predetermined inhalation gas concentration in accordance with the flow rate set value by the respirator-side flow regulator f. As a result, the inhaled gas flows into the ventilator circuit b. For this reason, according to the first conventional example of FIG. 2, in order to adjust the inhalation gas to a desired concentration, the operator grasps the inhalation gas flow rate on the respirator a side, and then adjusts the inhalation gas necessary for this. The flow rate is calculated in advance, so that the flow rate of the gas becomes the calculated value,
The flow controller 1d must be adjusted.

[0005] As a result, since it depends on an artificial operation,
If there is a risk that an unintended inhalation gas flow rate may be mixed due to an erroneous operation or a calculation error, or if the inspiration gas flow rate set value by the ventilator-side flow regulator f is changed, In each case, the flow rate of the intake gas must be calculated and readjusted, so that the operation becomes considerably complicated. Moreover, it is important that most of the currently used flow regulators 1d fluctuate the gas flow value of the inhalation gas supply pipe 1e due to the fluctuation of the outlet pressure, that is, the internal pressure in the ventilator circuit b. There is also a problem.

Therefore, in order to improve the defect of the first conventional example shown in FIG. 2, even if the internal pressure of the ventilator circuit b fluctuates as shown in FIG. Mass flow controllers 2a, 2
A suction gas mixing device 2A as a second conventional example using b and 2c has already been proposed. Basically, this type not only controls the flow rate of the inhaled gas alone as described above, but also collectively controls the oxygen introduced into the ventilator a, the compressed air and the inhaled gas to be mixed together. Therefore, the mass flow controller 2 is controlled manually or by using a central processing unit CPU.
By a, 2b, and 2c, each gas flow rate of oxygen gas, air (or nitrogen), and the suction gas supplied from the suction gas supply source 2d via the pressure regulator 2e can be electrically controlled. ing.

Here, j in FIG. 3 is a flow meter for the intake gas, and k is a device for treating the surplus gas of the intake gas discharged from the exhalation valve i. Nitrogen oxide or the like, which is used in the case where harmful nitrogen dioxide is generated as a reaction product by mixing with intake gas, is exhausted into the room after being processed in the surplus gas processing device, .

On the other hand, in the above suction gas mixing apparatus 2A, reference numerals 2f, 2g and 2h denote mixed gas (O ₂ , air and suction gas) mixed in the mixer 2i, respectively, and the total flow rate of the mixed gas. An input portion, a set value input portion for a suction gas concentration (flow rate), and a set value input portion for an oxygen concentration (flow rate) are shown. For the mixed gas, both concentration indicators for the various gases are shown.

Further, in FIG. 3, each of the mass flow controllers 2a, 2b and 2c is provided with the central processing unit CPU.
Connected to be controlled by the output of
The oxygen supply pipe 2k, the compressed air supply pipe 21 and the suction gas supply pipe 2m connected to the mixer 2i are inserted and interposed, respectively.
2 shows a safety valve connected to m.

Therefore, the suction gas mixing device 2A shown in FIG.
To illustrate the effect of
The compressed air branched from the compressed air supply pipe 21 is connected to the output side pipe line 2q of the mixer 2i to the oxygen side port d of the ventilator a and to the air side port e to which the compressed air is to be sent. The outlet pipe 2r is connected and used. Therefore, the total amount of the mixed gas and the respective concentrations of the inhaled gas and oxygen are determined by the mixed gas total flow rate set value input unit 2f.
If they are respectively set by the above-mentioned intake gas concentration set value input unit 2g and the oxygen concentration set value input unit 2h, the necessary flow rates of oxygen, air, and suction gas are automatically supplied by the central processing unit CPU. Thus, even if the total amount of the mixed gas is changed, the flow rates of the intake gas, oxygen, and air are automatically changed so that the set concentration is maintained.

For this reason, according to the second conventional example,
As described above in connection with the first conventional example, the complexity of operations involving calculations and the problem of danger due to erroneous operations can be greatly improved. However, in the case of FIG. 3, since the inhaled gas on the side of the respirator a is also to be controlled, the mixed gas is supplied to the respirator a using the inhaled gas mixing device 2A. Between the input section of the respirator a and the output section of the inhalation gas mixing device 2A, an interface 3 is often required as shown in FIG. As the interface 3, it is necessary to ensure its consistency with various models of the artificial respirator a, and it is not easy to cope with it, and an interface for each model is required.

Further, according to the second conventional example, not only the mass flow controller 2c for inhalation gas but also the mass flow controllers 2a and 2b for inspiration gas on the respirator a side are required. Not only does the entire apparatus become large, but also expensive, and the electrical control sequence for these becomes complicated. And
More importantly, as described above, since the intake gas is already mixed with oxygen or air in the mixer 2i, for example, when highly reactive nitric oxide is used as the intake gas, The problem is that the product, which is harmful nitrogen dioxide, is considerably increased.

Therefore, a third conventional example as shown in FIG. 5 has been proposed in order to solve the above-mentioned difficulties. However, when the intake gas mixing device 2B is used, the following configuration is adopted. 2A, and the same reference numerals are given to the same members in FIG. That is, unlike the former mixer 2i, the mixer 2s does not mix the oxygen, the air, and the suction gas, but mixes only the oxygen and the air. Is introduced into the ventilator circuit b of the ventilator a without being introduced into the mixer 2s via the suction gas outlet pipe 2t connected to the suction gas supply pipe 2m as in the first conventional example of FIG. , Near the patient inlet c.

Further, the output side of the mixer 2s is connected to an oxygen-side port d of the respirator a via an oxygen-air mixed gas line 2u. Therefore, according to the third conventional example, even when the highly reactive suction gas is used as a disadvantage of the second conventional example, the mixed gas output of oxygen and air is output separately. Since the inhaled gas is mixed with the inhaled gas in the vicinity of the patient in the ventilator circuit b, the effect of the reaction product can be substantially eliminated.

However, according to the third conventional example, there is little problem if the ventilator a is of a steady flow type in which a predetermined amount of inspiratory gas is always supplied, but an intermittent flow type in which the inspiratory gas is intermittently supplied. In the case of a respirator, even when the inspired gas flow in the ventilator circuit b is stopped, the inhaled gas from the inhaled gas outlet pipe 2t flows into the ventilator circuit b, and the respiratory cycle starts. Accordingly, there is a possibility that the concentration of the inhaled gas on the patient side fluctuates. Therefore, in order to solve such a problem, the inhaled gas may be intermittently flow synchronized with the respiratory cycle. For this purpose, in many cases, the respirator a and the inhaled gas mixing device are used. Both have to undergo major remodeling.

[0016]

SUMMARY OF THE INVENTION The present invention relates to the above-mentioned first aspect.
The third conventional example has been examined in view of the difficulties, and in the inhalation gas mixing device for a ventilator according to claim 1, the inspiratory gas flow rate in the respirator is constantly measured by a flow sensor. Then, the measured value electric signal is input to the central processing unit, and the measured and calculated value signal of the intake gas supply amount calculated by this input and the preset set value of the concentration of the intake gas is used to calculate the mass. Automatically controls the flow regulator. Thus, the configuration is such that the inhaled gas can be automatically mixed into the inspired gas of the ventilator circuit so that the inhaled gas always has the set concentration, and thus the complicated structure of the first conventional example is achieved. Simple operation and the risk of erroneous operation, eliminating the need for interfaces in the second and third conventional examples, reducing the number of mass flow controllers to be used, miniaturizing and reducing the cost, and simplifying the electrical control sequence. The first purpose is to realize the realization.

Further, according to the first aspect of the present invention, the flow rate sensor of the ventilator circuit constantly monitors the flow rate of the inspired gas. Is improved by improving the control sequence of the central processing unit such that
A second object is to make it possible to cope with an intermittent flow type ventilator in the conventional example and to solve the problem of the undesired fluctuation of the inhalation gas concentration.

According to a second aspect of the present invention, in addition to the configuration of the first aspect, the concentration of oxygen or inhaled gas in the ventilator circuit is measured, and if the measured concentration is abnormal. In such a case, the supply of the inhaled gas is immediately interrupted by the closing operation of the shut-off valve in response to the abnormal concentration detection signal generated by the central processing unit, so that the patient can be safely protected from the administration of the gas having the abnormal concentration.

Further, in claim 3, the above-mentioned claim 2
In addition to the above configuration, the concentration electric signal from the densitometer is compared with the concentration set value of the inhalation gas by the central processing unit, and when there is a difference between the two, the content of the concentration electric signal is changed to the concentration set value. Applying feedback control so that the intake gas flow rate of the mass flow controller can be adjusted so that the control of the intake gas concentration with high accuracy and good response can be performed. When the difference between the set value of the intake gas and the concentration of the intake gas reaches a predetermined value, the alarm device can notify the user of the difference, thereby enabling immediate response in the event of an abnormality.

[0020]

In order to achieve the above object, according to the present invention, according to the first aspect, a flow rate inserted and connected to a ventilator circuit of a ventilator to which oxygen and compressed air are supplied. A sensor and a measured value of the inspiratory gas flow rate in the ventilator circuit output from the flow sensor, and an electric signal is input, and a concentration set value of the inspired gas to be mixed with the inspired gas in the ventilator circuit. A central processing unit capable of inputting, an inhalation gas supply pipe connected to the ventilator circuit via a pressure regulator from an inhalation gas supply source, and inserted and interposed in the inhalation gas supply pipe, and In the above-mentioned central processing unit, the measured value of the intake gas flow rate is controlled by a calculated value electric signal of the intake gas supply amount calculated so as to obtain the concentration according to the concentration set value of the intake gas. Mass flow Trying to provide a ventilator suction gas mixing apparatus characterized by comprising a regulator.

Further, according to a second aspect of the present invention, in the configuration of the first aspect, there is provided a densitometer connected to the ventilator circuit for measuring an inspired gas and a required gas concentration of the inhaled gas;
A shut-off valve inserted into the suction gas supply pipe and closed by an abnormal concentration detection signal issued from the central processing unit when the concentration electric signal input to the central processing unit from the concentration meter is abnormal. What is added is the content.

According to the third aspect of the present invention, a flow sensor inserted and interposed in a ventilator circuit of a ventilator to which oxygen and compressed air are supplied, and a flow sensor in the ventilator circuit output from the flow sensor A measured value electric signal of the inspiratory gas flow rate is input, and it is possible to input a concentration set value of the inspired gas to be mixed with the inspired gas in the ventilator circuit, and connected to the ventilator circuit, A central processing unit capable of inputting a concentration electric signal from a densitometer that has detected the inspired gas and a required gas concentration of the inhaled gas, and connected to the ventilator circuit via a pressure regulator from an inhaled gas supply source. A suction gas supply pipe to be inserted and inserted into and connected to the suction gas supply pipe, and in the central processing unit, the concentration of the suction gas flow rate measured by the concentration setting value of the suction gas. Control by the calculated electric signal of the calculated intake gas supply amount to be obtained; and in the central processing unit, the concentration by the concentration set value of the suction gas is obtained with respect to the concentration electric signal of the densitometer. And a warning device that is activated by the central processing unit when the difference between the concentration electric signal and the concentration set value of the intake gas reaches a predetermined value. It is intended to provide a featured inhalation gas mixing device for ventilators.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to an embodiment of an inhalation gas mixing apparatus for a respirator shown in FIG. 1. As shown in the description of the prior art, the respirator a is again designated by the same reference numeral. The components are indicated. In the present invention, oxygen and compressed air are supplied to the oxygen side port d and the compressed air side port e of the ventilator a in the same manner as in the first conventional example of FIG. As described above, b is a ventilator circuit, c is a patient inlet, f is a ventilator side flow regulator, g and h are humidifiers and water traps respectively, i is an exhalation valve, and k is FIG. In the surplus gas processing apparatus illustrated in FIG. 4, m indicates a residual gas purging three-way valve described later.

The illustrated inhalation gas mixing device 10 for a respirator used for the respirator a is provided with the respirator a.
Is provided with a flow rate sensor 10a to be used by being inserted into and interposed with the ventilator circuit b, whereby the flow rate of the inspired gas due to oxygen and air in the ventilator circuit b is measured, and measurement electric signals S ₁ of the gas flow rate is input to the central processing unit CPU.

In the central processing unit CPU, an inhalation gas concentration set value input section 10b for setting the concentration of the inhalation gas to be mixed with the inspiration gas of the ventilator circuit b.
Is provided. Further, the above-described ventilator circuit b is supplied from the inhalation gas supply source 10c via the pressure regulator 10d.
Suction gas supply pipe 10e which will be connected at the connecting portion b ₁ is being provided and, in this, the pressure regulator 1
From the 0d side, a shutoff valve 10f and a mass flow controller 1 described later in this order.
0g is inserted and interposed, and a safety valve 10h is connected to the last stage of the suction gas supply pipe 10e in a branched state.

[0026] With the above configuration of Figure 1, the central processing unit CPU, a measured value electric signals S ₁ of the intake gas flow rate from said as flow sensors 10a, by the operation of the suction gas concentration setting input unit 10b With the input concentration setting value, how much intake gas should be mixed into the intake gas so that the concentration of the intake gas automatically becomes the concentration setting value with respect to the flow measurement value of the intake gas. The required flow rate is calculated, and the mass flow controller 10g is controlled by the calculated electric signal of the intake gas supply amount obtained thereby. As a result, even if the flow rate of the inspired gas flowing through the ventilator circuit b changes, the central processing unit CPU controls the mass flow controller 10g in accordance with the change, and the inhaled gas in the ventilator circuit b is always controlled. Is supplied to the patient after the inhalation gas is mixed into the inhalation gas so that the concentration becomes the concentration set value.

[0027] In next claim 2, densitometer 10i in addition to the above claim 1 is coupled to the ventilator circuit b, in the illustrated example, the connecting portions b ₂ is mixed in the intake gas of the connecting portion b ₁ Yes so as to be set on the downstream side, by this, not only the oxygen gas ventilator circuit b, are also available also measured the concentration of the intake gas.
Then, the density electrical signal S ₃ by the measurement is fed back to the central processing unit CPU, when there is an abnormality in the gas concentration, or closes the shutoff valve 10f in supra suction gas supply pipe 10e, sounding an alarm By
Prevents inappropriate concentrations of oxygen or inhaled gas from being administered to the patient.

Here, the safety valve 10h of the above-mentioned suction gas supply pipe 10e is attached to prevent the occurrence of an accident due to erroneous operation of the pressure regulator 10d attached to the suction gas supply source 10c. Further, the shut-off valve 10 described above is used.
f can be used not only at the time of occurrence of an abnormality as described above but also when it is desired to intentionally stop the output of the suction gas. At this time, the suction gas concentration set value input unit 10b for the mass flow controller 10g is used. Even if the concentration set value is set to zero, a slight leakage occurs, so that the presence of the shutoff valve 10f can play an extremely effective role.

Further, the three-way valve m for purging the residual gas described above.
Is adopted when the highly reactive inhalation gas is used as described above. In the operation state where the inhalation gas is mixed in the ventilator circuit b, the inhalation gas supply pipe 10e is used.
Is adjusted to be in the open state, and after the operation is completed, the residual gas remaining in each place cannot be released to the atmosphere as it is. The toxic gas is sent to the surplus gas processing device k, and is purified here and then discharged into the room or the like. Further, the valve m can be used when the inhalation gas is first administered to the patient and the dead space in each place is replaced with the inhalation gas. Therefore,
Of course, depending on the type of the intake gas, the installation of the three-way valve m for purging the residual gas becomes unnecessary.

Further, according to a third aspect, similarly to the second aspect, the density electric signal S from the densitometer 10i is provided.
_3, not only is input to the central processing unit CPU, be in the central processing unit CPU, with respect to density electrical signals,
As the concentration by the concentration setting value of the intake gas above is obtained, multiplied by the feedback control, In this way, the above concentration setting in advance desired, the difference between the density electric signal S ₃ as a result automatically It is going to disappear.

Further, in the present invention, as shown in FIG. 1, the central processing unit CPU is connected to an alarm device 10j by sound or light.
When the difference between the above-mentioned density electric signal and the density set value has reached a predetermined value or more, the central processing unit CP which made this comparison judgment
U is configured to activate the alarm 10j described above.

[0032]

According to the first aspect of the present invention, the required flow rate of the intake gas to be mixed into the intake gas is determined by the measured value of the intake gas flow sensor. The CPU automatically calculates the electric signal, so that the operator can mix the intake gas to a desired concentration by simply performing the setting of the concentration of the intake gas. At this time, even if the flow rate of the inspired gas is changed, the mixing flow rate of the inhaled gas is automatically controlled so that the concentration set value of the inspired gas is secured. It is not necessary to readjust the gas flow rate. Therefore, even if it is used for an intermittent-flow type ventilator, it can function without any trouble. And the occurrence of accidents due to erroneous operations and calculations can be suppressed.

Furthermore, in the first aspect, since the mass flow controller is used for controlling the inhaled gas, even if the internal pressure on the side of the ventilator circuit fluctuates, it is sent out from the inhaled gas supply pipe. Thus, it is possible to keep the flow rate of the suction gas constant, and to prevent undesired changes in the concentration of the suction gas. In addition, since only one mass flow controller needs to be used for controlling the intake gas, the entire apparatus can be reduced in size, the price can be reduced, and the control sequence can be greatly simplified. .

Further, since the ventilator is operated simply by supplying oxygen and compressed air by a conventional method, there is a problem that an interface is provided between the ventilator and the apparatus according to the present invention. Therefore, connection to any type of ventilator is possible, and the flow sensor can be used by simply inscribing the ventilator circuit.

According to a second aspect of the present invention, in addition to the above-described effects of the first aspect, the shutoff valve of the suction gas supply pipe is closed by the CPU due to the abnormal change in the concentration of oxygen or the suction gas. Since it is possible to control the concentration of the inhaled gas and, if necessary, the concentration of the oxygen gas, it is possible to prevent the gas having a concentration exceeding a predetermined value from being administered to the patient, thereby ensuring the safety.

In the case of the third aspect, in addition to the above-described effect of the first aspect, the mass processing by the central processing unit is performed by using the intake gas and the concentration meter for measuring the required gas concentration of the intake gas according to the second aspect. Since the feedback control of the flow controller is also performed, the correction is made so that the difference between the concentration electric signal from the concentration meter and the concentration set value is always eliminated, and the supply of the gas having the appropriate concentration value to the patient is high. It can be realized with reliability. Furthermore, the alarm is activated when the difference from the density setting value becomes somewhat large, so that a doctor or the like can quickly respond.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of piping in a use state of an inhalation gas mixing device for a ventilator according to the present invention.

FIG. 2 is a piping configuration diagram in a use state showing a first conventional example of an inhalation gas mixing device for a ventilator.

FIG. 3 is a diagram showing a pipe wiring configuration in a use state showing a second conventional example of the same suction gas mixing device.

FIG. 4 is a schematic diagram of the entire configuration showing a state in which the second conventional example of FIG. 3 is used by adopting an interface.

FIG. 5 is a piping configuration diagram in a use state showing a third conventional example of the same suction gas mixing device.

[Explanation of symbols]

10a Flow rate sensor 10b Inhalation gas concentration set value input section 10c Inhalation gas supply source 10d Pressure regulator 10e Inhalation gas supply pipe 10f Shut-off valve 10g Mass flow controller 10i Densitometer 10j Alarm device a Ventilator b Ventilator circuit S ₁ Measured value of intake gas flow rate electric signal S ₂ Calculated value of intake gas supply amount electric signal S ₃ Concentration electric signal S ₄ Abnormal concentration detection signal CPU Central processing unit

Claims (3)

(57) [Claims] 1. A flow sensor inserted into and inserted into a ventilator circuit of a ventilator to which oxygen and compressed air are supplied, and a measurement of an inspiratory gas flow output from the flow sensor in the ventilator circuit. A central processing unit that receives a value electric signal, and can input a concentration set value of the inhalation gas to be mixed with the inspiration gas in the ventilator circuit, and a pressure regulator from the inhalation gas supply source, An inhalation gas supply pipe connected to the ventilator circuit, and inserted and interposed in the inhalation gas supply pipe, and in the central processing unit, the measured value of the inspiratory gas flow rate, An inhalation gas mixing apparatus for a respirator, comprising: a mass flow controller controlled by an electric signal that is a calculated value of an inhalation gas supply amount calculated to obtain a concentration according to a concentration setting value of the inhalation gas. 2. A flow sensor inserted into and inserted into a ventilator circuit of a ventilator to which oxygen and compressed air are supplied, and measurement of an inspiratory gas flow output from the flow sensor in the ventilator circuit. A central processing unit that receives a value electric signal, and can input a concentration set value of the inhalation gas to be mixed with the inspiration gas in the ventilator circuit, and a pressure regulator from the inhalation gas supply source, An inhalation gas supply pipe connected to the ventilator circuit, and inserted and interposed in the inhalation gas supply pipe, and in the central processing unit, the measured value of the inspiratory gas flow rate, A mass flow rate regulator controlled by an electric signal, which is controlled by an electric signal, and a calculated value of an inhalation gas supply amount calculated so as to obtain a concentration according to a concentration set value of the inhalation gas; Moth A concentration meter that measures the gas concentration, is inserted from and inserted into the suction gas supply pipe, and is emitted from the central processing unit when the concentration electric signal input from the concentration meter to the central processing unit is abnormal. An inhalation gas mixing device for a ventilator, comprising: a shutoff valve that is closed by an abnormal concentration detection signal. 3. A flow sensor inserted into and inserted into a ventilator circuit of a ventilator to which oxygen and compressed air are supplied, and measuring an inspiratory gas flow rate output from the flow sensor in the ventilator circuit. A value electric signal is input, and it is possible to input a concentration set value of the inspired gas to be mixed with the inspired gas in the ventilator circuit, and the inspired gas and the inhaled gas are connected to the ventilator circuit. A central processing unit capable of inputting a concentration electric signal from a densitometer that has detected the required gas concentration, and an inhalation gas supply connected to the respirator circuit via a pressure regulator from an inhalation gas supply source Pipe, and inserted and connected to the suction gas supply pipe, and
In the above-mentioned central processing unit, the control by an electric signal, which is a calculated value of an intake gas supply amount calculated so as to obtain a concentration according to a concentration set value of the intake gas with respect to the measured value of the intake gas flow rate, In the central processing unit, for the concentration electric signal of the densitometer, mass flow controllers respectively receiving feedback control for obtaining a concentration according to the concentration set value of the suction gas, and the concentration electric signal, An inhalation gas mixing device for a respirator, comprising: an alarm that is activated by a central processing unit when a difference between the concentration setting value of the inhalation gas and a predetermined value is reached.