JPH0756028Y2 - Blood warmer - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a blood warmer used to raise the temperature of blood that has fallen outside the body to a predetermined temperature when injecting extracorporeal blood into the body.

[Conventional technology]

When blood is circulated extracorporeally for artificial dialysis, replacement of whey, etc., the temperature of blood drops due to the outside air temperature. In addition, blood for transfusion, replacement fluid, etc. are stored in a refrigerator or other normal temperature place, and are all below the body temperature. However, during blood transfusion, if the temperature-decreased blood is sent directly into the body,
It causes symptoms such as muscle contraction and heart attack, making it a very dangerous situation.

On the other hand, due to the nature of blood, it causes hemolysis when the blood temperature rises above approximately 42 ° C, and destroys other blood when this hemolyzed blood is put into the body. Regulation is required.

Therefore, when injecting blood, a replacement fluid, or the like, the temperature of which has fallen outside the body, it is indispensable to raise the temperature to near the body temperature within the temperature increase limit without hemolysis before injecting into the body.

Here, the blood warmer conventionally used is shown in FIG.
And (b). In this apparatus, a heater 42 is provided at the bottom of a water tank 41, a temperature detector 44 is provided above the heater 42, and an overheat detector 45 is provided near the heat generating portion of the heater 42. Container 44 and overheat detector 45
Is connected to the electric controller 46.
The inside of the tube is filled with water 47 and the heater is energized, and the tube 43 wound in a coil is immersed in the water in the tank to circulate blood in the tube. When the heater 42 is heated, convection due to a temperature difference is generated in the water to circulate the water, and the temperature of the blood in the tube 43 is raised via the warm water 47 'whose temperature has risen.

[Problems to be solved by the device]

By the way, in such a conventional blood warmer,
The blood temperature in the 43 is indirectly detected by the temperature detector 44 above the heater 42 via the hot water 47 ', and the electric controller 46 controls ON / OFF of the heater 42 based on the detection result, and the heater 42 An abnormally high temperature rise is detected by the overheat detector 45 near the heat generating portion, and the heater power is cut off.

However, in the conventional use example, when heating the blood, it is not uncommon to turn on the power by mistake without putting water in the water tank 41, and in this case, the heater 42 will be heated in a few seconds because it will be empty. As a result of the abnormal temperature rise, the inside of the heater may be broken or the wire may be broken, so that the heater may be forced to be discontinued.

Further, the above blood warmer increases the water temperature in the water tank by convection generated by heating the heater 42,
In water, high temperature water tends to stay upward, so temperature differences easily occur depending on the vertical position in the water tank, and as a result, the blood in the tube cannot be heated efficiently, and the overheat detector 45 There is also the inconvenience that a detection error occurs due to the provision of hot water 47 'at the bottom of the inside.

Furthermore, even if the amount of warm water in the water tank decreases and the water level drops due to evaporation due to insufficient water injection or the use of a warmer for a long time, and the convection in the tank is stopped, the temperature balance in the tank will change There is a risk that the effect will be significantly deteriorated and that a portion that is excessively heated will cause hemolysis in a part of the blood in the tube.

In addition, when the blood flow in the tube is temporarily stopped for the convenience of medical treatment and stays in the tube, the temperature detector 44
Since the temperature is detected via the hot water 47 ', the heater control is delayed even if the blood in the tube heats up due to heat absorption while the blood flow is temporarily stopped. It may occur.

As described above, there are various problems in the conventional blood warming device, the largest of which is the heating caused by the fact that the temperature rise of the blood in the tube and the temperature detection are performed via warm water. This is because hemolysis occurs in blood in the tube due to poor correlation and delay in temperature detection.

Therefore, in view of the above-mentioned conventional circumstances, the present invention provides temperature detection and safety measures that the blood in the tube does not rise to a temperature of 42 ° C or higher where hemolysis starts, and the blood in the tube does not hemolyze efficiently within the temperature range. An object of the present invention is to provide a blood warming device that is heated.

[Means for Solving the Problems]

In order to achieve the above object, the blood warmer of the present invention is a blood warming device that warms a coiled tube through which blood flows in a water tank containing water. A heating block made of a material having excellent properties is provided, and a plurality of projecting plates for inserting the coiled tubes are formed on the outer circumference of the heating block. Further, a heater and a temperature detector are provided in the heating block. And provided.

An overheat detector is provided in the heating block, and when the overheat detector detects overheating of the heating block, the block temperature limit for completely shutting off the energization of the heater is provided. A circuit may be provided.

[Action]

In the above structure, the heating block 2 arranged in the water tank 1 is made of a material having excellent thermal conductivity, and the plurality of projecting plates 2a are formed on the outer periphery thereof, so that the contact area with water in the water tank 1 is large. Can be expanded, and the temperature of the water in the water tank can be efficiently raised.

Further, when the coiled tube 3 is inserted and attached to the outer periphery of the heating block 2 (that is, the outer periphery of the plurality of protruding plates 2a), the first
As shown in FIG. 2B, since the gap between the adjacent protruding plates 2a is closed by the coiled tube 3, when the heating block 2 raises the temperature of the surrounding water, FIG. As indicated by the arrow in), the temperature rising water rises along the gap between the closed projecting plates 2a, and the tube can be uniformly heated from the inside of the coil.

Next, when the temperature-raising water escapes above the heating block 2, the temperature-raising water moves around the coiled tube 3 as shown by the arrow in FIG. 1 (b) due to the metabolic effect with the cold water at the bottom of the water tank 1. Outside, it descends toward the bottom of the aquarium 1 and thereby the aquarium 1
The convection circulation occurs in the entire water, and the entire water in the water tank 1 is efficiently and uniformly heated, and the coiled tube 3 can be uniformly heated.

Therefore, the coiled tube 3 is provided around the heating block 2.
When the blood is circulated by inserting the blood into the tube, the blood in the tube is heated from the entire surface of the heating block 2 and is uniformly heated from the entire surface of the tube 3 by the convection circulation in the water tank 1, so that the heating efficiency is extremely high. It will be good.

Since the temperature detector 5 is provided in the heating block 2, the temperature rise of the heating block 2 can be directly detected without using the water in the tank as in the conventional case. It is possible to detect the temperature change of the heating block 2 with good reaction and accurately control the limit temperature for hemolysis.

In the present invention, the temperature of the heating block 2 can be controlled according to the detection result of the temperature detector 5 itself. However, in order to further ensure safety, the overheat detector 6 is added in addition to the temperature detector 5. The block temperature is provided in the temperature block 2, and the block temperature adjusting circuit 20 by the temperature detector 5 is arranged to completely shut off the energization of the heater 4 when the overheat detector 6 detects the excessive temperature rise. By configuring the limiting circuit 30 independently, the risk of hemolysis is completely avoided.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 (a) is a perspective view showing an embodiment of the blood warmer of the present invention, FIG. 1 (b) is a longitudinal sectional view thereof, and FIG.
Second, a perspective view of the heating block shown in FIGS.
FIG. 3B is a partially cutaway vertical sectional view thereof, and FIG. 3 is a circuit diagram relating to the electric controller of the blood warmer of the present embodiment.

In FIGS. 1 (a) and 1 (b), a heating block 2 containing a heater 4 is fixedly installed substantially in the center of a water tank 1 constituting a blood heating device, and the temperature detection is performed in the heating block 2. The device 5 and the overheat detector 6 are incorporated. The heater 4, the temperature detector 5, and the overheat detector 6 are connected to an electric controller 7 installed in the lower part of the water tank 1, and the control circuit (described later) incorporated therein turns on the electricity to the heater 2. OF
F or increase / decrease in power is controlled.

As shown in FIGS. 2 (a) and 2 (b), the heating block 2 is provided with a plurality of convex projecting plates 2a on the outer periphery thereof, and has a thermal conductivity of water (0,607 [W · m ^{− at} 30 ° C.). ¹ · K ^-1 ]) as a good conductor, for example aluminum (293 at 30 ℃
[W · m ⁻¹ · K ⁻¹ ]) is formed by integral molding.

At the time of use, the tube 3 wound in a coil shape is inserted along the outer periphery of the heating block 2 into the blood heating device configured as described above, and the coiled portion 3a of the tube 3 is sufficiently submerged. Water 8 is added to the level line 1a of the water tank 1 which is preset so that the convective water in the water tank 1 circulates smoothly. Blood to be heated flows from the inlet 3b of the tube 3 to the outlet 3c,
Heat is dissipated from the entire surface of the heating block 2 at the coiled portion 3a on the way and is heated by the hot water 8'circulating in the water tank 1.

Next, the control circuit of the electric controller 7 will be described with reference to FIG. 3. This control circuit uses the temperature detector 5 that detects the temperature rise of the heating block 2 due to the heating of the heater 4. The block temperature control circuit 20 is composed of an independent block temperature control circuit 30 with an overheat detector 6, and the double safety circuit controls temperature control and blood temperature control so that blood in the tube never exceeds 41 ° C. I am going to do it.

In FIG. 3, the temperature detector 5 and the overheat detector 6 provided in the heating block 2 are indicated by the same reference numerals 5 and 6 in each of the block temperature adjusting circuit 20 and the block temperature limiting circuit 30. Is the equivalent.

In the block temperature control circuit 20, the set temperature switching means 22 sets 37 ° C. or 41 ° C. as the temperature rising limit temperature of the heating block 2 when using the blood heating device. That is, although the ideal temperature for heating blood is a temperature equivalent to that of the human body, considering that the rate of temperature rise differs depending on the flow rate or flow rate of blood flowing through the tube 3, and also considers some loss of heat transfer. Then, the temperature set to 37 ° C. or 41 ° C., which is 1 to 2 ° C. higher than the desired temperature, is appropriately selected by the user.

Now, assuming that the set temperature is 37 ° C, the change in the resistance value of the thermistor in the temperature detector 5 is sent to the temperature control circuit 21, and until the detected temperature reaches 37 ° C, the switch of SSR24 remains ON to the heater 4. Energization is continued, and when the temperature reaches 37 ° C, the changeover switch of SSR24 is turned off and the energization to the heater 4 is cut off. The detected temperature at this time is constantly displayed on the set temperature display 25.

When the temperature detector 5 is unplugged or disconnected from the heating block 2 due to an unexpected situation during such temperature detection, the thermistor open detection circuit 23 detects it and the SSR24 is turned off. The power supply to the heater 4 is cut off.

On the other hand, in the block temperature limiting circuit 30, a change in the resistance value of the thermistor in the overheat detector 6 is sent to the 42 ° C detection circuit 31, and the detected temperature is constantly displayed on the temperature display 23, and when 42 ° C is detected. , The heating cutoff relay is operated and turned off, and the power supply to the heating heater 4 is cut off. Also, this 42 ℃
At the same time as the detection of the above, an alarm sound is emitted from the overheat alarm generation means 34.

Even if the block temperature adjusting circuit 20 raises the temperature above the set temperature by such an independent double safety circuit, the heating block 2 starts hemolysis under the control of the block temperature limiting circuit 30. When the temperature of ℃ is reached, the heater 4 is completely de-energized, so that the heating block 2 does not exceed 42 ℃, and the risk of hemolysis can be completely avoided.

[Effect of device]

As described above, according to the blood heating device of the present invention,
Unlike the conventional type that heats through water, the convection in the water tank is smoothly circulated by the heat released from the entire surface of the heating block, which has a remarkably large surface area and excellent heat transfer property. The water inside can be efficiently heated without causing a temperature difference between upper and lower positions.

Further, the temperature detector incorporated in the heating block of the present invention can detect the temperature change of the heating block itself by the temperature detector to control ON / OFF of the heater. Therefore, even if the user forgets to put water in the water tank, the dangerous heater temperature will not be reached.

Therefore, the blood in the coiled tube used by being attached to the outer periphery of the superheat block is efficiently heated without causing excessive temperature rise such as partial hemolysis.

Furthermore, in order to further ensure safety, an overheat detector is provided in addition to the temperature detector, and when the heating block is overheated to 42 ° C or more by another circuit, the heater is completely energized. By constructing the overheat limiting circuit so that it is shut off, the risk of hemolysis can be completely avoided by the overtemperature limiting circuit even if the temperature detector fails or the like.

[Brief description of drawings]

1 to 3 are views showing an embodiment of the present invention.
FIG. 1A is a perspective view showing an embodiment of the blood warmer of the present invention,
1 (b) is a longitudinal sectional view thereof, FIG. 2 (a) is a perspective view of the heating block shown in FIGS. 1 (a) and 1 (b), and FIG. 2 (b) is a partially cutaway longitudinal section thereof. Fig. 3 is a circuit diagram of an electric controller of the blood warmer according to the present embodiment, Fig. 4 (a) is a perspective view of a conventional blood warmer, and Fig. 4 (b) is a longitudinal section thereof. It is a figure. 1 ... water tank, 2 ... heating block, 2a ... protruding plate, 3 ...
… Tube, 3a …… Coil-shaped part of tube, 4 …… Heater, 5 …… Temperature detector, 6 …… Overheat detector, 7 ……
Electric controller, 20 …… Block temperature control circuit, 30 …… Block temperature control circuit.

Claims (2)

[Scope of utility model registration request] 1. A blood heating device for heating a coiled tube in which blood flows in a water tank containing water,
A heating block made of a material having excellent thermal conductivity is provided in the water tank, and an outer periphery of the heating block is formed by forming a plurality of projecting plates into which the coiled tubes are inserted, and further in the heating block. Is a blood warmer characterized by having a heater and a temperature detector. 2. An overheat detector is provided in the heating block, and when the overheat detector detects overheating of the heating block, the energization of the heater is completely cut off. The blood warmer according to claim 1, further comprising a block temperature limiting circuit.