JPH09187509A - Automatic gas supplying device for medical care - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a miniaturized and lightened automatic gas supplying device for medical care with which there is no malfunction caused by the disturbance of vibrations or external air temperature at the time of walking and further, any heavy means such as pressure reduction valve or orifice switching means is not required. SOLUTION: A pressure detecting means 5 is connected to a branch pipe 12 on the upstream side (the side of inlet 3) of automatic opening/closing valve means 6 by piping, a sonic wave/electric signal converting means 8 is connected to a branch pipe 14 on the side of outlet 4 by piping respectively, and a flow rate limiting means 7 is additionally provided on piping 13 between the branch points of both the branch pipes. On the other hand, a control part 9 with built-in arithmetic part and amplifier is connected through a signal line 18 to the automatic opening/closing valve means, and a gas quantity instructing means 10, pressure detecting means and sonic wave/ electric signal converting means are respectively connected through signal lines 19, 20 and 17 to the control part. Then, these parts are entirely housed in one casing 21, a gas supply source 1 is connected to the inlet of piping, a nose cannula 15 is connected to the outlet respectively, and gas is intermittently blown in synchronism with respiration.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oxygen supply device used by patients with chronic respiratory failure in oxygen inhalation therapy. In particular, the present invention relates to an oxygen supply device that can be used when going out from the bed to improve the QOL (also referred to as quality of life) of a patient undergoing home oxygen therapy.

[0002]

2. Description of the Related Art Conventionally, oxygen therapy for inhaling oxygen gas (including oxygen-enriched gas) supplied from an oxygen cylinder has been performed for patients with respiratory diseases (hereinafter also simply referred to as patients). . Recently, an oxygen concentrator capable of concentrating oxygen in the air to obtain an oxygen-enriched gas has been developed and put into practical use, and oxygen therapy using this has become increasingly popular. It's coming.

As such an oxygen concentrator, compressed air is introduced into an adsorbent bed filled with an adsorbent such as zeolite to adsorb nitrogen gas, water, etc. to the adsorbent, and to separate the oxygen gas that is difficult to adsorb into a product gas. As a pressure fluctuation adsorption method (hereinafter, the desorption step of desorbing nitrogen gas and water adsorbed on the adsorbent is alternately repeated, and the desorption step of depressurizing the adsorption bed to atmospheric pressure or below atmospheric pressure, (Also called PSA method)
And a membrane-type oxygen concentrator using a selective permeable membrane having a property of allowing oxygen gas to permeate better than nitrogen gas.

In addition to these, after compressing and cooling air at high pressure to form liquid air, nitrogen and oxygen are separated and purified by utilizing the difference in boiling point temperature during vaporization depending on the type of gas such as nitrogen and oxygen. A method of filling oxygen in a gas state with oxygen obtained by the cryogenic separation method and using it has been used for a long time.

As still another method, a portable liquid oxygen container has been developed and put into practical use, in which liquid oxygen is subdivided in a liquid state and placed in a small container, which is vaporized and used for oxygen inhalation.

[0006] Patients undergoing oxygen therapy obtain oxygen or oxygen-enriched gas from these oxygen sources, but the oxygen gas for inhalation usually comes to a tube (rubber or vinyl chloride resin) in the end. A flexible tube having an inner diameter of 6 to 7 mm) to the vicinity of the patient's body, and then continuously introduced into the patient's nostril as a constant flow from a nasal cannula attached to its tip.

Furthermore, as an improved oxygen supply system,
By supplying oxygen gas to the inspiratory phase or only a part of the inspiratory phase in synchronism with the respiratory phase of the patient's respiratory cycle, it is possible to prevent wasteful release of oxygen gas during periods such as the expiratory phase and to improve efficiency. Has been proposed (for example, Japanese Patent Publication No. 62-54023 and Japanese Patent Laid-Open No. 1-221).
No. 170). Further, in Japanese Patent Application Laid-Open No. 2-88079, an oxygen concentrator, an oxygen cylinder, a liquid oxygen storage means or the like is used in combination to improve the utilization efficiency of oxygen.

A combination of a so-called respiration-synchronized gas supply device for supplying oxygen gas in synchronism with respiration and an oxygen concentrator by the PSA method is disclosed in Japanese Examined Patent Publication No. 62-3.
7996 and U.S. Pat. No. 4,648,395. As a means for discriminating the inspiratory phase of the respiratory cycle, even if the nasal cannula is open, a slight difference in pressure between the expiratory phase and the inspiratory phase is used to detect the pressure change. Methods for discriminating the intake phase are disclosed in US Pat. No. 4,462,398 and JP-A-5-9203.
No. 8 discloses this. A device that detects a respiratory signal based on changes in pressure between the expiratory phase and the inspiratory phase has a problem in that when walking while using the vibration signal, vibrations of the respiratory signal enter as noise of confusing disturbances of the pressure and cause malfunctions.

Further, since the atmosphere is inhaled in the inspiratory phase, the temperature thereof is equal to the ambient temperature, but the expiratory air is warmed in the body to almost equal to the body temperature. A method of detecting with a temperature sensor such as a thermocouple is disclosed in JP-A-59-8972. In another method, Japanese Patent Laid-Open No. 59-77864 discloses a method of detecting the temperature change in the inspiratory phase and the expiratory phase by a thermistor attached to the nostril of the nasal cannula. Further, Japanese Patent Publication No. 2-12114 also discloses a method of detecting the temperature difference between the expiratory phase and the inspiratory phase using a thermocouple. The method that utilizes the temperature difference between the expiratory phase and the inspiratory phase requires a special cannula with a temperature sensor near the nostril of the cannula, which is expensive and the outside temperature rises to about the same as the body temperature during the summer. Has the drawback that it cannot be used for

The oxygen gas supply system based on these respiratory synchronisms blows oxygen gas for inhalation in pulses during the inspiratory phase or part of it. As a method of measuring the flow rate, in a float type flow meter in which a float sphere is blown up by an oxygen gas stream to measure, the weight of the float sphere and the buoyancy that the air stream lifts the float sphere and flows around the periphery of the float sphere are balanced. It can be stably measured while keeping it, but the float sphere that rebounds in a pulsed intermittent airflow rises higher than the true value due to the kinetic energy due to the mass of the sphere, and since the measurement error is large and accurate flow rate measurement is difficult, It is necessary to take measures such as switching to constant flow and measuring the average value.

On the other hand, there is a method of switching a plurality of orifices to obtain a constant desired flow rate.
It is disclosed in Japanese Patent Publication No. 88079. The method of switching these orifices to obtain a desired flow rate has the condition that a desired flow rate can be obtained by attaching an orifice having a constant pore under a constant pressure. It is smaller, lighter and easier to use than a meter, and is convenient for patients. However, in this method, a plurality of orifices, a switching mechanism therefor, and a pressure reducing valve for making the pressure functionally constant are indispensable.

[0012] On the other hand, in order to improve the QOL of patients with chronic respiratory failure, there is an increasing demand for a small oxygen source that enables the patient to go out and take a short trip, and a lightweight oxygen cylinder, a portable liquid oxygen container, or a portable oxygen container. -Type oxygen concentrators are beginning to be developed. Further, in the case of combining these with the above-mentioned respiratory tuning device, there is a demand for a device that is smaller and lighter and that allows the patient to go out in a wide range (long time).

A device that a patient with poor physical strength can use with peace of mind, such as when going out, needs to be small and lightweight without malfunction due to various disturbances. In particular, it goes without saying that in order to reduce the size and weight of the device for portable use, it is necessary to reduce the size and weight of the respiratory tuning device itself and the oxygen supply source itself. However, when using a combination of a breathing tuning device and an orifice type flow rate setter, the method of changing the amount of gas flowing is to attach a plurality of orifices with different diameters and switch between them. The conventional method of obtaining a desired flow rate while using it requires a pressure reducing valve (also referred to as a constant pressure valve or a pressure adjusting valve) for keeping the pressure of the oxygen supply source constant, a plurality of orifices and a switching mechanism thereof. Since this pressure reducing valve is generally heavy, it is not preferable to use the pressure reducing valve.

[0014]

Patients with respiratory failure have poor physical strength, and in order to increase QOL, a device that is as light as possible and does not malfunction due to various disturbances that occur when going out is needed. It Disturbances include outside temperature and vibration during walking. In the summer of our country, the days of 35 to 40 ° C. are relatively long in cities, and walking when going out is an indispensable condition, and stability against various disturbances and reduction in size and weight must be satisfied at the same time. Using a difference in breath sounds of the expiratory phase and inspiratory phase, which is not affected by the temperature of the outside air and is not affected by the vibration during walking, and is strong against disturbance, and in addition, there is a heavy pressure reducing valve or orifice switching means. There is a demand for an automatic gas supply device that is light without using a gas.

[0015]

The present invention has been completed through intensive research in order to solve the above-mentioned problems, and its constitution is roughly as follows.

(1) Pressure detecting means is connected to a branch pipe on the upstream side (inlet end side) of the automatic on-off valve means, and acoustic-electric signal converting means is connected to the branch pipe on the outlet end side. A flow rate limiting means is attached to a pipe line between the branch points, and a control section having an arithmetic section and an amplifier is connected to the automatic opening / closing means by a signal line, and the control section has a gas amount indicating means. , The pressure detecting means, and the sonic electric signal converting means are respectively connected by signal lines, and all of them are housed in one housing, and a gas supply source is provided at the inlet end of the pipe and a nose at the outlet end. An automatic gas supply device for medical use characterized in that it is configured so that cannulas are connected to each other and intermittently blows gas in synchronism with breathing.

(2) In the above automatic gas supply device,
A nasal cannula is connected to the outlet end by a pipe, and the sound waves generated at the time of exhalation and inspiration due to spontaneous breathing of the living body, which are collected at the open end of the nasal cannula that opens in the nostril, are transmitted to the sonic-electric signal converting means through the pipe, The inspiration starts by transmitting the electric signal obtained by conversion by the signal conversion means to the control section through the signal line, amplifying it by the control section, and extracting only the sound wave signal of the specific frequency due to the exhalation / inspiration by the filter section. Time is detected, and on the other hand, the gas amount instructed by the gas amount instructing means and the signal of the pressure of the gas supply source detected by the pressure detecting means are transmitted to the control section, and the automatic opening / closing valve means is opened from the start of intake. Automatic gas supply for medical use characterized by intermittently blowing gas in synchronism with breathing by calculating the time to keep and opening the automatic opening / closing valve means for that time It is the location.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The automatic gas supply apparatus for intermittently blowing in synchronism with breathing configured as described above operates as follows, so that the amount of gas supplied (breathed by the patient) per breath is reduced. , The value instructed by the gas amount instructing means 10, and this value becomes constant even if the pressure of the gas supply source 1 fluctuates within a predetermined range.

The time T for opening the automatic opening / closing means 6 from the intake start point can be calculated by the following equation. The amount of gas supplied per breath is A (mL: milliliter), the pressure of the gas supply source is Ps (kgf / cm ² · G), and the effective cross-sectional area of the flow rate limiting means (for example, orifice) is S (mm ² ). When the time for opening the automatic on-off valve means is T (ms: millisecond) and the temperature of the suction gas is t (° C), the pressure Ps of the gas supply source is 0.89 kgf.
/ Cm ² · G is smaller or larger than that, one of the following [Equation 1] and [Equation 2] is set to Ps.
The calculation unit automatically selects and calculates according to the value of. This is because the flow velocity of gas cannot exceed the speed of sound no matter how much pressure is applied, and the pressure boundary is 0.89 kgf / cm ²
-It is G.

When Ps ≦ 0.89 kgf / cm ² · G

[Equation 1]

When Ps> 0.89 kgf / cm ² · G

[Equation 2]

All numerical values in these equations are absolute values. Further, the above-mentioned flow rate limiting means can also serve as the automatic opening / closing valve means itself having a predetermined cross-sectional area of the air passage.

[0023]

EXAMPLE An automatic gas supply apparatus according to the present invention will be specifically described with reference to the example shown in FIG. The pressure detecting means 5 is connected to the branch pipe 12 on the upstream side (the inlet end 3 side) of the automatic on-off valve means 6, and the acoustic-electric signal converting means 8 is connected to the branch pipe 14 on the outlet end 4 side. A flow rate limiting means 7 is attached to the pipe 13 between the branch points. The position where the flow rate limiting means 7 is provided may be either upstream or downstream of the automatic on-off valve means 6 as long as it is between two branch points. On the other hand, the automatic on-off valve means 6 is connected to a control section 9 including a computing section and an amplifier by a signal line 18, and the control section 9 includes a gas amount instructing section 10, a pressure detecting section 5, and an acoustic-electric signal conversion. Means 8 are signal lines 1 respectively
They are connected by 9, 20, and 17. Then, all of these are housed in one housing 21, and at the same time, the housing 21
The outer surface of the pipe is provided with both ends of the pipe 13, that is, an inlet end 3 for connecting the gas supply source 1 and an outlet end 4 for connecting the nasal cannula 15.

In use, the automatic gas supply device of the present invention has a gas supply source 1 connected to the inlet end 3 and a nasal cannula 15 (gas supply means for a patient) connected to the outlet end 4.
The gas supply source 1 is a high-pressure container (cylinder) filled with gas in a gaseous state, a liquid oxygen container used while filling and vaporizing liquid oxygen, an oxygen concentrator used while concentrating oxygen in the air, and the like. Corresponds to this. 150k for cylinder
Since it is filled in a high-pressure gas state of gf / cm ² · G or more, a pressure reducing valve for reducing the pressure to a constant pressure is attached. However, the pressure varies depending on the manufacturer.

During use, sound waves generated during expiration and inspiration due to spontaneous breathing by a person are collected at the open end 16 of the nasal cannula 15 inserted into the nostril of the patient, and the tube of the nasal cannula 15 is used as a sound wave conduit. The information is transmitted to the acoustic / electrical signal converting means 8 of the body 21. Here we convert sound waves into electrical signals,
It is transmitted to the control unit 9 through the signal line 17. The control unit 9 amplifies the signal with an amplifier provided therein, and extracts only a sound wave signal having a specific frequency which differs depending on expiration and inspiration by the filter means, thereby detecting the start time of inspiration. It should be noted that using the tube of the nasal cannula 15 as a sound wave conduit and providing the sound wave / electric signal converting means 8 in the housing 21 of the automatic gas supply device is a special means for collecting sound waves generated during expiration / inhalation. Without having to make
Since a cheap and generally commercially available nasal cannula that is a consumable item can be used, it has great practical utility.

On the other hand, the signal of the gas amount instructed by the gas amount instructing means 10 and the signal of the pressure of the gas supply source 1 detected by the pressure detecting means 5 are transmitted to the control section 9, and the arithmetic section provided therein causes the intake start point. From the above, the time T for keeping the automatic opening / closing means 6 open is calculated.

In this way, exhalation and inspiration are discriminated by the breathing sound, and based on the gas pressure Ps of the gas supply source 1 detected by the pressure detecting means 5 and the gas amount instructed by the gas amount instructing means. Then, the calculation unit incorporated in the control unit 9 calculates the time width T required to supply a predetermined amount of gas by the above-mentioned calculation formula, and the automatic opening / closing valve means 6 is opened only during the time T. By doing so, the gas is supplied in a pulse form. By doing so, even if the pressure value Ps of the gas entering the inlet end 3 fluctuates within a certain range, the amount of oxygen gas inhaled by the patient can be made constant. Further, since the orifice switching type flow rate setting device used in the conventional device and the pressure reducing valve provided after the inlet end 3 can be dispensed with, the weight can be reduced by about 70 g to 200 g.

In this embodiment, the oxygen concentrator is used as the gas supply source, but the present invention is not limited to this, and oxygen in an oxygen cylinder or oxygen obtained by vaporizing liquid oxygen may be used. However,
In this case, needless to say, the pressure reducing valve for adjusting the pressure to an appropriate level is required as described above.

[0029]

EFFECTS OF THE INVENTION By adopting a breath sound type for discrimination between exhalation and inhalation, not only is it not affected by vibration during walking, and it can be used normally even when the outside temperature becomes high, and the flow rate is set. It is possible to reduce the size and weight by omitting the container and pressure reducing valve.

[Brief description of the drawings]

FIG. 1 is a flowchart showing one embodiment of the present invention.

[Explanation of symbols]

 1 Gas Supply Source 3 Inlet End 4 Outlet End 5 Pressure Detecting Means 6 Automatic Opening / Closing Means 7 Flow Limiting Means 8 Sound Wave Electric Signal Converting Means 9 Control Unit 10 Gas Amount Indicating Means 11, 13 Piping 12, 14 Branch Pipe 15 Nasal Cannula 16 Open end 17, 18, 19, 20 Signal line 21 Housing

Claims (3)

[Claims] 1. A pressure detecting means is connected to a branch pipe on the upstream side (inlet end side) of the automatic on-off valve means, and a sonic / electrical signal converting means is connected to the branch pipe on the outlet end side. A flow rate limiting means is attached to the line between the points, while a control unit having a built-in arithmetic unit and an amplifier is connected to the automatic opening / closing valve unit by a signal line, and the control unit has a gas amount indicating unit, The pressure detecting means and the sonic electric signal converting means are respectively connected by signal lines, and all of them are housed in one housing, and a gas supply source is provided at the inlet end of the pipe and a nasal cannula is provided at the outlet end. An automatic medical gas supply device, characterized in that it is configured to be connected to each other and intermittently blows gas in synchronism with breathing. 2. The automatic gas supply apparatus according to claim 1, wherein a nasal cannula is connected to an outlet end of the tubing by pipes, and the exhalation / inhalation by spontaneous breathing of the living body collected at the open end of the nasal cannula opening into the nostril. The sound wave generated at some time is transmitted to the sound wave electric signal converting means through the pipe, and the electric signal obtained by converting by the sound wave electric signal converting means is transmitted to the control portion by the signal line, is amplified by the control portion, and is filtered by the filter means. The start of inspiration is detected by extracting only the sound wave signal of a specific frequency due to expiration / inspiration, while the signal of the gas amount instructed by the gas amount instructing means and the pressure of the gas supply source detected by the pressure detecting means are detected. To the control unit,
A medical device characterized by intermittently blowing gas in synchronism with breathing by calculating the time for which the automatic opening / closing valve means is opened from the start of inspiration and opening the automatic opening / closing valve means for that time Automatic gas supply device. 3. The amount of supply gas per breath instructed by the gas amount instructing means based on the pressure of the gas supply source detected by the pressure detecting means and the effective cross-sectional area of the orifice as the flow rate limiting means. The control unit calculates the time required for flowing the gas, and the automatic opening / closing valve means is opened for a predetermined time, wherein (1) or (2)
The automatic medical gas supply device described.