JPS6159144B2 - - Google Patents

Description

Detailed Description of the Invention Background of the Invention (Technical Field) The present invention relates to a moist heat exchanger for breathing to maintain the temperature and humidity of breathing gas in a suitable state when using an anesthesia machine, a ventilator, etc. on a patient. It is related to vessels.

(Prior art and its problems) This type of moist heat exchanger has, for example,
-3911, JP-A-53-126796 and JP-A-55-
Many things are known below No. 73268. These conventional heat-and-moisture exchangers are typically shown schematically in FIGS. 1, 2, and 3. The one shown in FIG. 1 has an exchanger body made of paper or aluminum foil in a housing 1, which is made by stacking a corrugated molded body and a flat plate and winding them in a spiral shape.
The device shown in Fig. 2 is described in Utility Model Publication No. 52-3911, and has an exchanger body built in a housing 1 in which a porous material 4 such as non-woven fabric is sandwiched between aluminum nets 3. It is. The device shown in FIG. 3 is described in Japanese Patent Application Laid-open No. 55-73268, and is a device in which a fiber floc 5 and a cellulose foam 6 are combined in a housing 1 and an exchanger is built in. .

In the case shown in Figures 1 and 2, as will be explained in detail later, the exhaled air is cooled when passing through the exchanger, and the water vapor contained in the exhaled air condenses and becomes water droplets that adhere to the exchanger. , which provided latent heat and moisture to the exchanger. Therefore, the difference between the amount of saturated water vapor at the initial exhalation temperature and the amount of saturated water vapor at the exhalation temperature after passing through the exchanger is only accumulated as moisture, and there is a drawback that the moisture exchange performance is generally low. In the case shown in FIG. 3, in addition to the condensation of water vapor due to the cooling of exhaled air, water is sorbed onto the exchanger by passing through fine passages. Therefore, water accumulation is high. However, because the heat exchange efficiency of the exchanger itself is low and the pressure loss is high, it is necessary to have a large exchanger capacity and a wide gas passage area, which increases the internal volume of the housing and ultimately improves ventilation efficiency. This has caused problems such as a decrease in patient performance and an increase in the burden on patients.

Purpose of the Invention Therefore, the present invention provides a method for applying an inhaled air to a state close to natural breathing when an endotracheal tube or tracheostomy tube is intubated into a patient's trachea and connected to an anesthesia machine or a ventilator. The object of the present invention is to provide a heat and humidity exchanger for breathing that can stably provide warmth and humidification, has a small dead space volume, is lightweight, inexpensive, and easily manufactured.

Specific Structure of the Invention According to the present invention, in the respiratory moisture heat exchanger, the housing has an open end for connecting to an endotracheal tube or a tracheostomy tube and an open end for connecting to a tube for introducing breathing air or anesthetic air. The housing includes a breathable moisture exchange layer that mainly performs a moisture exchange function and a breathable heat exchange layer that mainly performs a heat exchange function, and further, the heat exchange layer has high thermal conductivity. A strip-shaped foil body of material is spirally wound, the axial direction of the spiral body is parallel to the respiratory airflow direction, and the moisture exchanger layer and the heat exchanger layer are arranged in series in the respiratory airflow direction. By arranging it, the above object can be achieved. Although the breathable moisture exchanger layer and the heat exchanger layer may be arranged in any order, it is particularly preferable that the heat exchanger layer be located on the open end side for connecting the breathing air insertion tube. In addition, the number of alternate layers of the breathable heat exchanger layer and the breathable moisture exchanger layer is n+
It is preferable that the first layer be one layer (n is an integer) and the latter be n layers.
The breathable heat exchanger layer is a spirally wound laminate of a corrugated foil strip made of a material with high thermal conductivity and a strip with good hygroscopicity. It is preferably made of a sponge made of good material, particularly the foil is corrugated aluminum foil and the sponge is preferably made of cellulose sponge.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The respiratory moisture heat exchanger of the present invention will be described in detail below with reference to preferred embodiments shown in the accompanying drawings.

As shown in FIG. 4, the respiratory moist heat exchanger 10 is connected to a connector 14 attached to the proximal end of an endotracheal tube 13 inserted into the trachea 12 of a patient 11, and an anesthesia machine, a respirator, etc. It is used by being inserted between the flexible tube 15 and the flexible tube 15, and has the effect of creating a state close to natural breathing.

In the present invention, in order to be able to create a state closer to nature than the conventional breathing heat and humidity exchanger typically shown in FIGS. do.

FIG. 5 shows a first embodiment of the respiratory moisture heat exchanger 10 of the present invention. In this example, a heat exchanger is mainly provided in a housing 18 provided with sockets 16 and 17 at both ends for joining an endotracheal tube or a tracheostomy tube and a flexible tube connected to an anesthesia machine, a ventilator, etc., respectively. It houses a breathable heat exchange layer 19 that performs a function and a breathable moisture exchange layer 20 that mainly performs a moisture exchange function. As shown in FIG. 6, which is a cross-sectional view taken along the - line in FIG. It is constructed by spirally winding a laminate of good band-shaped porous members 22. On the other hand, the moisture exchanger layer 20 is made of a sponge 20 with good hygroscopicity and a large effective area, as shown in FIG. 7, which is a cross-sectional view taken along the - line in FIG.

The heat exchanger layer 19 and the moisture exchanger layer 20 may be arranged in any order as long as they are arranged alternately, but it is preferable to arrange the moisture exchanger layer 20 on the side of the endotracheal tube connection socket 16. is particularly suitable. Furthermore, the number of layers of the heat exchanger layer 19 and the moisture exchanger layer 20 may be an even number or an odd number of layers as long as they are arranged alternately, but in the case of an odd number of layers, the former is replaced with n+1 (n is an integer) layers, It is preferable that the latter be an n layer.

The strip-shaped foil 21 constituting the heat exchanger layer 19 may be any material as long as it has high thermal conductivity, and aluminum foil is particularly suitable, but is not limited to this, and may include aluminum mesh, copper foil, copper mesh, steel wool, Metal foam or the like can be used. Porous member 2 with good hygroscopicity of heat exchanger layer 19
For material 2, in addition to cloth or nonwoven fabric, paper or the like can be used, but materials that generate fine particles are unsuitable. Note that the laminated spiral body of the heat exchanger layer includes not only a layered structure in which both of the above materials are layered, but also a layered structure in which a water-absorbing material is previously coated on a foil.

As mentioned above, the moisture exchanger layer 20 is preferably made of a sponge with good hygroscopicity. However, in the present invention, the term "sponge" should be understood in a broad sense, and includes not only so-called porous materials in general but also cotton lumps. This includes the following. A typical example is cellulose sponge, but other materials include felt, rayon cotton, polyvinyl alcohol foam, urethane foam, and sintered polymer porous materials (nylon,
PMMA, acrylonitrile), etc., but it is necessary to process them so as not to generate small free substances.

The internal volume of the housing of the respiratory moist heat exchanger of the present invention is 50 to 100 ml for adults and 10 to 100 ml for children.
Approximately 50 ml is appropriate, and the amount of dead space can be reduced compared to conventional ones.

Other embodiments of the respiratory moisture heat exchanger 10 of the present invention will be shown below. What is shown in FIG. 8 is a heat exchanger layer 19
housing 18 with two layers and one layer with moisture exchanger layer 20.
This is an example of storing it inside.

The one shown in FIG. 9 has three heat exchanger layers 19,
This is an example in which the moisture exchanger layer 20 is housed within the two-layer housing 18. The number of layers of the heat exchanger layer 19 and the moisture exchanger layer 20 may be an even number or an odd number as long as they are arranged alternately, but in the case of an odd number of layers, the former is n
+1 (n is an integer) layer, and the latter is preferably an n layer.

What is shown in FIG. 10 is a two-layer heat exchanger layer 19.
This is an example in which a moisture exchange layer 20 is provided in between, which is made of cotton-like fibers with excellent hygroscopicity and whose surface is treated to prevent foreign matter from being released. In the case shown in FIG. 11, a moisture exchange layer made of cellulose sponge is inserted into a heat exchange layer 19 made of a porous material made of continuously foamed metal having excellent thermal conductivity.

Specific Functions of the Invention Next, the functions and effects of the respiratory moisture heat exchanger of the present invention will be specifically explained in comparison with conventional ones. In the graphs showing the performance of each example, for convenience, the endotracheal tube side of the moist heat exchanger is abbreviated as the lung, and the side of the anesthesia machine, respirator, etc. is abbreviated as the machine.

Conventional heat and humidity exchangers typically have a first
As mentioned at the beginning of the specification, there are the types shown in FIGS. 2 and 3. The performance of the type shown in FIG. 1 using paper as an exchanger is shown in FIG. 12a (temperature change) and FIG. 12b (moisture content change). Air at 32℃ and 33.8mg/(saturated water vapor content) is cooled as it passes through the exchanger, and some of the water vapor it contains condenses into water droplets.
It adheres to the exchanger and imparts latent heat and moisture to the exchanger.
Therefore, normally only the difference between the moisture content of the exhaled breath at the beginning and the saturated water vapor content of the exhaled breath after passing through the exchanger is accumulated as moisture, but in reality, some absorption and adsorption by the exchanger itself occurs. , the accumulation due to this is added. However, they generally have the disadvantage of low moisture accumulation.

The performance of the product shown in FIG. 2 is shown in FIG. 13a (temperature change) and FIG. 13b (moisture content change). This is also based on almost the same principle as the one shown in FIG. 1, and the amount of moisture accumulated is low.

The performance of the product shown in FIG. 3 is shown in FIG. 14a (temperature change) and FIG. 14b (moisture content change). This mainly involves passing exhaled air through fine passages made of hygroscopic material to absorb and adsorb the water vapor in the exhaled air.Although the amount of water accumulated is relatively large, in order to achieve the full effect, This requires a large contact area, resulting in a large volume.

Performance tests similar to those of conventional products were conducted on the respiratory moisture heat exchanger of the present invention having the configuration shown in FIG.
The characteristics of the product used are as follows, and the performance results are shown in Figure 15a (temperature change) and Figure 15b (moisture content change). The exhaled air passes through the moisture exchanger layer 2
The water vapor is cooled as it passes through the heat exchanger 19 arranged in series in the direction of the respiratory airflow, and the water vapor condenses and adheres to the surface of the aluminum foil 21 as fine water droplets, and the latent heat is mainly transferred to the aluminum foil 21. give to Furthermore, the porous member 22 absorbs water condensed on the surface of the aluminum foil 21, and at the same time absorbs, adsorbs, and accumulates a portion of the steam in the exhaled breath. Intake air is mainly heated by the aluminum foil and humidified mainly by the porous member. By performing such heat exchange and moisture exchange individually and continuously, the performance of the product of the present invention shown in Fig. 15 is superior to that of conventional similar products (Figs. 12 and 13).
(See Figure 14), the heat exchange performance and moisture exchange performance have been greatly improved, and a state closer to natural breathing than the conventional system has been realized, which not only relieves pain for the patient but also helps the therapist can be easily cared for. Generally, when exhaled air leaves the alveoli, the temperature is 37℃.
It is in a state of 100% RH, and the temperature near the patient's mouth is 32~
34℃, change from 80 to 100%RH. According to actual measurements,
When the ventilation volume is about 850 ml and the exhaled air is about 32°C and 100% RH, the intake air of about 20°C and 20 to 40% RH will be about 30°C and 90% RH after passing through the moist heat exchanger of the present invention. That's all. Furthermore, the product of the present invention has a small volume and is easy to manufacture. Note that the air resistance of the moist heat exchanger was about 3 cmH ₂ O//S or less, which caused no practical problems. The characteristics of the product of the present invention used are as follows.

(i) Housing (1) Capacity 70ml, (2) Inner dimension 50mmφ×29mm (ii) Aluminum foil (1) Thickness 25-30μm, (2) Width 20mm (3) Total length 3.7m (4) Wave shape Wave Pitch 3.3~3.5mm Mountain height 0.30~0.35mm Radius of curvature 1.0~1.5mm (iii) Porous member (cloth) (1) Material cotton, (2) Thickness 180~200μm, (3) Width 20mm, (4) Total length 3.5-3.7m (iv) Cellulose sponge (1) Thickness 9-10mm, (2) Diameter 50-52mmφ, (3) Weight 1.5-1.5g (30-50% water absorption state) (4) Density 1.5 to 1.8 g/cm ³ (5) Porosity 97 to 99% Next, a performance test similar to that of a conventional product was conducted on the breathing moisture heat exchanger of the present invention having the configuration shown in FIG. The characteristics of the product used are as follows, and the performance results are shown in Figure 16a (temperature change) and Figure 16.
Figure b (moisture content change) is shown. When exhaled air leaves the alveoli
The temperature is 37°C and 100% RH, which changes to 32 to 34°C and 80 to 100% RH near the patient's mouth, but as it passes through the heat exchanger 19, it is cooled and the water vapor condenses and passes through the aluminum foil 21. The aluminum foil 21 adheres to the surface of the aluminum foil 21 as fine water droplets, and mainly gives latent heat to the aluminum foil 21. Further, the porous member 22 absorbs condensed water on the surface of the aluminum foil 21, and at the same time absorbs, adsorbs, and accumulates a portion of the water vapor in exhaled breath. Next, the exhaled air enters the moisture exchanger layer 20, and as it passes through the fine net-like passages, the water vapor in the exhaled air is absorbed or adsorbed, giving sensible heat and moisture. Moisture and heat are then applied to the next heat exchanger 19. Intake air is mainly heated by the aluminum foil and humidified by the porous member. By performing such heat exchange and moisture exchange individually and continuously, the performance of the three-layer structure product of the present invention shown in FIG. (Reference), the heat exchange performance and moisture exchange performance are significantly improved, and it is also superior to the two-layer structure of the present invention, and a state closer to natural breathing than the conventional one is realized. This not only alleviates the pain for the patient, but also facilitates the care of the therapist. According to actual measurements, the ventilation volume is approximately 850ml, and the exhalation volume is approximately 850ml.
In the case of 32° C. and 100% RH, the intake air of about 20 to 40% RH became about 30° C. and 97% RH or more after passing through the moist heat exchanger of the present invention. Furthermore, the product of the present invention has a small volume and is easy to manufacture. Note that the air resistance of the moist heat exchanger was about 3 cmH ₂ O//S or less, which caused no practical problems. The characteristics of the product of the present invention used are as follows.

(i) Housing (1) Capacity 70ml, (2) Inner dimension 50mmφ×29mm (ii) Aluminum foil (1) Thickness 25-30μm, (2) Width 10mm (3) Total length 3.7m (4) Wave shape Wave Pitch 3.3~3.5mm Height of peak 0.30~0.35mm Radius of curvature 1.0~1.5mm (iii) Porous member (1) Material cotton, (2) Thickness 180~200μm (3) Width 10mm, (4) Overall length 3.5-3.7m (iv) Cellulose sponge (1) Thickness 9-10mm, (2) Diameter 50-52mmφ, (3) Weight 1.5-1.8g (30-50% water absorption state) (4) Density 1.5-1.8g /cm ³ (5) Porosity: 97-99% Specific Effects of the Invention The respiratory moisture heat exchanger according to the present invention has many advantages over conventional ones as described below.

(1) In the present invention, the layer that mainly performs heat exchange function and the layer that mainly performs moisture exchange function are arranged in series in the breathing airflow direction, so that the temperature and moisture of the intake air are sufficiently transferred to the exchanger. By transferring this temperature and moisture to the inhaled air and recovering it from the exchanger, conditions closer to natural breathing can be achieved than in the prior art.

(2) Moisture in exhaled breath does not accumulate as dew water, and stable heating and humidification performance can be obtained over a long period of time.

(3) The exchange efficiency of temperature and moisture is very high, and the capacity of the exchanger can be made small and lightweight.

(4) Since the dead space capacity is small, there is little CO ₂ accumulation, and gas compression is also small, making it possible to obtain accurate ventilation volume.

(5) The structure is simple because it is only necessary to house the laminate spiral body and the sponge in the housing.
There is almost no need for maintenance, no upkeep costs are required, treatment costs can be reduced, and it is easy to manufacture and can be supplied at low cost.

(6) It is better to add the heat of the heat exchanger layer to the intake air first, and then add moisture after that, as the hygroscopicity is better, resulting in better performance.

(7) If there is a moisture exchanger layer after the heat of the intake air is absorbed by the heat exchanger layer, moisture absorption will be easy in relation to the saturated water vapor amount, and in addition, if there is a moisture exchanger layer after the heat of the intake air is absorbed by the The above (6) also has a heat exchanger layer.
It also has the effect of

(8) By making the laminate into a spiral shape, it has air permeability and can perform sufficient heat exchange and moisture exchange functions.

(9) If the moisture exchanger layer is made of a sponge, especially a cellulose sponge, it has excellent hygroscopicity and good air permeability.

(10) If corrugated aluminum foil is used as the corrugated foil, breathability will be better than in (8), and breathing resistance will be reduced.

[Brief explanation of the drawing]

Figures 1, 2, and 3 are schematic vertical cross-sectional views of typical conventional respiratory moisture heat exchangers, Figure 4 is a diagram showing the actual usage state of the respiratory moisture heat exchanger, and Figure 5
The figure is a longitudinal cross-sectional view of the breathing moisture heat exchanger of the present invention, No. 6
The figure is a sectional view taken along the - line in Figure 5, and Figure 7 is a sectional view taken along the - line in Figure 5.
Cross-sectional view taken along the - line in the figure, Figure 8, Figure 9, Figure 1
0 and 11 are longitudinal cross-sectional views of other configuration examples of the breathing moisture heat exchanger of the present invention, FIG. 12 is a diagram showing the performance of the conventional moisture heat exchanger shown in FIG. 1, and FIG. A diagram showing the performance of the conventional moist heat exchanger shown in Figure 2,
FIG. 14 is a diagram showing the performance of the conventional moisture heat exchanger shown in FIG. 3, FIG. 15 is a diagram showing the performance of the breathing moisture heat exchanger of the present invention shown in FIG. FIG. 3 is a diagram showing the performance of the respiratory moist heat exchanger of the present invention shown in FIG. Explanation of symbols, 1... Housing, 2... Spiral body such as paper, 3... Aluminum mesh, 4... Porous material, 5... Fluffy mass, 6... Foam, 10... Present invention Humid heat exchanger for breathing, 11... patient, 12...
Trachea, 13... endotracheal tube, 14... connector, 15... snake tube, 16, 17... socket, 18...
... Housing, 19 ... Heat exchange layer, 20 ... Moisture exchange layer, 21 ... Waved strip foil, 22 ... Porous member.

Claims (1)

[Scope of Claims] 1. A respiratory moist heat exchanger having a housing having an open end for connecting to an endotracheal tube or a tracheostomy tube and an open end for connecting to a tube for introducing breathing air or anesthesia air, wherein the housing includes: It has a breathable moisture exchange layer that primarily performs a moisture exchange function and a gas permeable heat exchange layer that primarily performs a heat exchange function, and further, the heat exchange layer is made of a band-shaped material having high thermal conductivity. A foil body is spirally wound, the axial direction of the spiral body is parallel to the respiratory airflow direction, and the moisture exchanger layer and the heat exchanger layer are provided in series in the respiratory airflow direction. A breathing moisture heat exchanger characterized by: 2. The respiratory moist heat exchanger according to claim 1, wherein the breathable heat exchange layer is on the open end side for connection to the tube for introducing breathing air or anesthetic air. 3. The respiratory moist heat exchanger according to claim 1, wherein (n+1) breathable heat exchanger layers and n breathable moisture exchanger layers (n is an integer) are alternately provided in the housing. vessel. 4. The breathable heat exchange layer is a spirally wound laminate of a band-shaped corrugated foil made of a material with high thermal conductivity and a band-shaped body made of a porous material with good hygroscopicity. The breathing moisture heat exchanger according to any one of Item 1 and Item 3. 5. The respiratory moisture heat exchanger according to any one of claims 1 to 4, wherein the breathable moisture exchanger layer is a sponge made of a material with good hygroscopicity. 6. The respiratory moist heat exchanger according to claim 4, wherein the band-shaped corrugated foil of a material with high thermal conductivity is a band-shaped corrugated aluminum foil. 7. The respiratory moisture heat exchanger according to claim 5, wherein the sponge made of a material with good hygroscopicity is a cellulose sponge.