JPH04303456A - Method and device for respiration-synchronized gas supply control - Google Patents

Abstract

PURPOSE:To provide a method of using no electricity at all in a gas flow control system, in the case of the respiration-synchronized gas supply control method. CONSTITUTION:A pressure in a gas supply line to a user, changing according to respiration of this user, is detected by a diaphragm-type pressure detecting means 18 as a mechanical signal 16 corresponding to respiration of this user, and by opening/closing a gas flow control valve 14 in the gas supply line with this mechanical signal 16, an intermittent gas flow, synchronized with the respiration, is obtained. Since no electricity is used at all a rate of trouble is also reduced by also decreasing a number of part items with no work required for replacement, charge, etc., of a battery.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] When supplying a gas such as oxygen to a patient or other recipient, the present invention synchronizes the gas flow with the recipient's breathing and supplies only the period of inspiration or a portion thereof. This relates to a so-called breathing synchronized oxygen supply device, and more specifically, the means for controlling the flow of gas such as oxygen uses mechanical pressure detection means to detect pressure changes in the gas supply path as the recipient breathes. It is characterized by being a mechanical element.

0002

[Background Art] When supplying a gas such as oxygen to a recipient, a so-called breathing synchronized oxygen supply is used in which a signal corresponding to the respiratory phase of the recipient is used to intermittently supply only the inhalation period or a portion thereof. It is well known that the method of gas supply using a device is superior to the constant flow method of continuously supplying gas even during the exhalation phase in terms of saving consumption of gases such as oxygen.

[0003] As an example of this prior art,
-54023, and as another example,
There is a publication No. 63-49512.

[0004] In these known examples, ingenuity is mainly recognized in the means for detecting the respiratory phase, and the former detects temperature changes in exhaled and inhaled air as electrical signals from a thermocouple sensor attached to a nasal cannula.

[0005] The latter also detects temperature changes in exhaled and inhaled air as changes in the electrical resistance of a thermistor attached to the nasal cannula.

[0006]Respiration phase detection using these conventional techniques is as follows:
It was designed to detect temperature changes associated with breathing as electrical signals.

[0007] There are also devices that detect pressure changes associated with breathing in the gas supply path, but these use a pressure switch that converts the pressure change into an electrical signal, or a diaphragm gap that changes due to pressure changes, and which detects pressure changes between the gaps. These devices detect changes in capacitance as electrical signals.

[0008]

[Problems to be Solved by the Invention] All of the breathing signals in the prior art described above are electrical signals, and in order to control the flow of gas such as oxygen using the breathing signals, an electrical signal amplifier and a solenoid valve are required. A power source such as a battery or a rectifier is always required, and if the battery is rechargeable, there is a problem that if the battery is exhausted, it may become unusable while being charged.

[0009]

[Means for Solving the Problems] In order to solve these problems, the present invention provides a method for supplying gas such as oxygen to a person to whom the gas is supplied using an open gas supply device (for example, a nasal cannula). The diaphragm pressure detection means detects changes in the pressure in the passage as the person breathes as a mechanical signal. By mechanically connecting this mechanical signal to a gas flow control valve attached to the gas supply path that is operated by the same mechanical signal, the gas flow control valve is activated in synchronization with the breathing of the recipient. Gas is supplied intermittently by opening and closing.

0010

[Operation] The present invention operates as follows. There are two main methods for supplying gas such as oxygen to a recipient: The first method is by using a closed mask or the like, which is the so-called closed method supply. The second one is to open the supply end to the atmosphere.
That is, it is a so-called open method of supply using a nasal cannula or the like attached to the nostril.

Of these, the present invention attempts to improve the latter open type supply, but it goes without saying that the same principle can easily be applied to the former closed type supply.

[0012] The pressure change due to breathing in the gas supply path in such an open system supply is relatively small because the supply end is open to the atmosphere, and the height of the water column is about 5 to 15 mm (hereinafter referred to as mmAq).

Therefore, the sensitivity of the diaphragm type pressure detection means described above must be such that it can detect such small pressure changes.

[0014] In order to control the gas flow as an intermittent flow synchronized with respiration, signals corresponding to the inhalation phase and/or expiration phase of the recipient are obtained, and these signals are used to control the gas flow control valve. need to be opened and closed.

[0015] It is known that normally there is a breathing pause period of at least about 0.1 seconds or more when the inspiratory phase and expiratory phase change, and the signals corresponding to the inspiratory and expiratory phases and the inspiratory For signals corresponding to one of the exhalation phases, one breathing cycle is about 3 to 5 seconds, although there are slight differences over time, so it is difficult to treat these two as almost the same signals in practice. There isn't.

In the embodiment of the present invention, the gas flow is stopped only during the exhalation period of the person to be supplied, and the gas flow is stopped by the mechanical signal 16 of the pressure detection means 18 so as to supply gas during the inhalation period including the period of stopping breathing. The flow control valve 14 is opened and closed.

As mentioned above, the pressure change associated with breathing in the gas supply path is relatively small, so when the gas flow control valve 14 operates, the pressure on the inlet side of the gas flow control valve 14, that is, the pressure of the pressure regulating valve 12, increases. Pressure detection means 1 at the outlet side pressure
8 must be prevented from malfunctioning.

However, this is not necessary if the pressure change associated with breathing in the gas supply path and the pressure on the gas inlet side or the pressure on the outlet side of the pressure regulating valve can be clearly distinguished.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of the present invention will be explained below with reference to the drawings. FIG. 1 shows an overview of the configuration of an embodiment of the present invention.
After the gas such as oxygen supplied to the gas inlet 10 is adjusted to a desired pressure by a pressure regulating valve 12, an intermittent gas flow is controlled by a gas flow control valve 14 that operates in synchronization with the breathing of the person being supplied. The gas is supplied from the gas outlet 20 to the recipient via a nasal cannula (not shown).

This gas flow control valve 14 detects pressure changes due to countercurrent airflow during exhalation as a mechanical signal using the diaphragm of the pressure detection means 18 connected to the gas outlet 20, and uses the mechanical signal to detect pressure changes caused by countercurrent airflow during exhalation. The gas flow control valve 14 described above is opened and closed.

The flow rate adjustment valve 22 attached to the inlet side of the gas flow control valve 14 is for setting the flow rate of gas such as oxygen to a desired amount.

Although the flow rate regulating valve 22 is attached to the inlet side of the gas flow control valve 14, this position may also be on the outlet side of the gas flow control valve 14, or the pressure regulating valve 12 may be omitted. By changing the pressure of the supplied gas such as oxygen, it is also possible to substantially change the flow rate of the supplied gas.

The pressure detection means 18 of this embodiment has a diameter of 1.
0cm diameter supported by 0.08mm thick rubber
An aluminum plate with a thickness of 0.1 mm was used. In this example, the mechanical signal 16 connecting the pressure detection means 18 and the gas flow control valve 14 was a liquid contained in a tube with an inner diameter of 2.0 mm. With this configuration, when the pressure detecting means 18 is pressurized due to exhalation, the cross-sectional area of the diaphragm of the pressure detecting means (approximately 80 mm2) and the cross-sectional area of the orifice of the gas flow control valve 14 (approximately 2. 5mm2) is about 32, so even if the minimum pressurization associated with normal exhalation is about 5mmAq, the gas flow will be reduced even when the gas flow control valve 14 is closed and the pressure on the inlet side of the valve is 70mmAq. It is possible to block the Further, in this embodiment, the mechanical signal 16 is a liquid contained in a tube, but
This may be another fluid or gas, or depending on the size of the diaphragm, it may be driven directly by mechanical force.

With the above configuration, the pressure on the outlet side of the pressure regulating valve 12 is reduced to 4 mmAq when the gas flow control valve 14 is open and a nasal cannula with a 1.8 m supply tube is connected to the gas outlet 20. It was adjusted so that Note that when the gas flow control valve 14 was closed, the amount was 70 mmAq.

Further, the gas flow control valve 14 uses a control valve with an orifice diameter of 1.8 mm, and the flow rate control valve 2
2 is set to the maximum opening, the flow rate of the gas outlet 20 is 4.5
It was liter/min.

[0026] Furthermore, during exhalation, the gas supply is stopped,
Gas was supplied when switching to intake air, but a slight peak flow was observed at the beginning of supply.

[0027] Sources of supply of gas such as oxygen include oxygen cylinders, liquid oxygen cylinders, wall piping in hospitals, oxygen concentrators, etc., but since these supply pressures vary and are not unified, it is difficult to control the gas flow. A pressure regulating valve 12 is installed on the inlet side of the valve 14.
By adding an oxygen supply source, it is possible to always supply a constant flow rate of gas using any of these types of oxygen supply sources.

Furthermore, in this embodiment, this pressure regulating valve 12
However, if the device of the present invention is used in combination only with a device with a constant discharge pressure, such as an oxygen concentrator, this pressure regulating valve can be omitted.

As explained above, in this embodiment, the gas flow control valve 14 is controlled to be opened and closed directly by the mechanical signal 16 detected by the diaphragm of the pressure detection means 18 as shown in FIG. As shown in Fig. 2, the first gas flow control valve attached to another gas flow path branched from the gas supply path is operated, and the gas flow controlled by this first gas flow control valve is used to supply gas. It is also possible to use a so-called pilot control method that indirectly controls a second gas flow control valve installed in the passage, and in this case, the mechanical signal that is the output of the pressure detection means may be even smaller. , it is possible to make the pressure detection means more compact.

In addition, in this embodiment, the pressure change on the outlet side of the gas flow control valve 14 was detected as a breathing signal, but in addition to this example, one side of the nasal cannula attached to the two nostrils was used for pressure detection. It is also possible to connect it to a pressure detection means and use the other side to supply a gas such as oxygen.

[0031] Although this configuration requires a special nasal cannula and cannot be used when one nostril does not function due to nasal congestion, etc.,
It is now possible to clearly distinguish between the pressure detection system and the gas supply pipe system, and there is almost no risk that the pressure detection means will malfunction due to the pressure on the outlet side of the pressure regulating valve, making it possible to supply a larger gas flow rate. .

[0032]

Effects of the Invention: When supplying gas such as oxygen to a recipient, the present invention does not use electricity at all as a control means for intermittent insufflation in synchronization with the recipient's breathing. In addition to eliminating the hassle of replacement, power outage accidents, and charging work, there is no complicated electronic circuit for control, and the number of parts is small, which reduces the chance of failure.

In addition, since the gas flow control valve is closed by the countercurrent pressure caused by the exhaled air in the cannula supply tube only in the case of exhalation, for example, when expiration is exhausted or the respiratory force is weakened, continuous constant flow is maintained. This can also be expected to improve safety when supplying oxygen.

Furthermore, since the gas supply equipment such as the nasal cannula used in the breathing synchronized gas supply device of the present invention does not need to be equipped with a sensor, there is an advantage that a commercially available general-purpose product can be used.

It has been known for a long time that the breathing synchronized gas supply method is superior to the constant flow method of continuously supplying gas in terms of saving consumption of gases such as oxygen. This is similar to the conventional technology.

[Brief explanation of drawings]

FIG. 1 is a system diagram showing an overview of the configuration of the present invention.

FIG. 2 is a system diagram showing an outline of the configuration when the present invention is a pilot control system.

FIG. 3 is a diagram comparing a continuous constant flow and a flow rate waveform of a gas flow resulting from a breath synchronized gas supply.

[Explanation of symbols]

10 Gas inlet 12 Pressure regulating valve 14 Gas flow control valve 16 Mechanical signal 18 Pressure detection means 20 Gas outlet 22 Flow rate adjustment valve

Claims (4)

[Claims] Claim 1: In a method for supplying a gas such as oxygen to a person to be supplied, it is determined that the pressure within the gas supply path to the person to be supplied changes with the breathing of the person to be supplied by mechanical pressure. The detection means detects a mechanical signal corresponding to the inhalation phase and/or exhalation phase of the person to be supplied, and the gas flow control valve provided in the gas supply path is opened or closed using this mechanical signal. Breath synchronized gas supply control method. 2. A breathing synchronized gas supply control device using the control method according to claim 1. 3. A first gas flow control valve attached to another gas flow path branched from the gas supply path is actuated by a mechanical signal from the mechanical pressure detection means to control the flow of the first gas. 3. The breathing synchronized gas supply control device according to claim 2, wherein a second gas flow control valve attached within the gas supply path is controlled by the gas flow controlled by the flow control valve. 4. The breathing synchronized gas supply control device according to claim 2, further comprising a pressure regulating valve and/or a flow regulating valve attached to the inlet side of the gas supply path for supplying gas such as oxygen.