JPH01259871A - Transfusion solution heater equipped with flowmeter - Google Patents

Abstract

PURPOSE:To control heating temp. inclusive of a flow rate, by a method wherein a constant current is applied to a heating body to heat the same and a change in the temp. of the heating body due to a change in the flow rate of transfusion solution is detected as a change in the resistance value of the heating body to measure a flow rate. CONSTITUTION:The voltage detected by a resistance value detecting circuit 76 is converted by an A/D converter to be inputted to a multiplier 86 while the temp. signal detected by an inlet temp. sensor 72 to be subjected to A/D conversion is inputted to the multiplier 86 and a CPU 88. The definite constant determined by the inlet temp. signal is multiplied in the multiplier 86 to calculate the flow rate of a transfusion solution and the calculated data is inputted to the CPU 88 from the multiplier 86. The temp. signal detected by an outlet temp. sensor 28 is subjected to A/D conversion to be inputted to a comparator 88 and the compared value with set temp. is inputted to the CPU 88. The CPU 88 performs predetermined operation on the basis of the input signals from the multiplier 86, the inlet temp. sensor 72 and a comparator 90 to send a control signal to a heating part driving circuit 92 and, therefore, the quantity of the heat generated from a heating part 94 consisting of a rubber heater 46 and a heating plate 18 is controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a warmer for intravenous fluids, blood transfusions, etc., equipped with a flow meter.

[Prior art] Infusion fluids such as electrolyte solutions, nutrient solutions, and blood are normally stored at a temperature of 4°C, so when injecting them into a patient, the infusion fluids must be heated to a temperature close to body temperature. . Although there are methods for heating the infusion solution, such as heating the vial containing the infusion solution, the most common method is to heat the infusion fluid delivery tube.

Conventionally, infusion heaters that heat the fluid delivery tube through which the infusion fluid flows down have been used for reasons such as the small amount of fluid flowing through the narrow tube and the difficulty of measuring by directly touching the fluid for sanitary reasons. A flow meter was not installed to measure the flow rate of the infusion fluid flowing through the fluid tube.

[Problems to be Solved by the Invention] However, the rate of infusion of fluid into a patient is not constant, and depends on the state of each disease, i.e., the severity, pulse rate, blood pressure,
Taking into account the condition of the heart, for example, the time for injecting a 50C1+I vial is determined to be between 1 and 3 hours, but sometimes it may take 4 to 5 hours.

Therefore, if it is possible to accurately measure the flow rate of the transfusion fluid flowing down the fluid delivery tube, it will be possible to infuse blood transfusions, etc., at an appropriate injection rate depending on the patient's disease state, which will greatly contribute to the advancement of medical technology. In addition, in conventional infusion warmers, the heating section is controlled based on the temperature of the heated infusion, and does not respond immediately to changes in the flow rate of the infusion. If the heating temperature is controlled taking into account the flow rate of the infusion, it becomes possible to control the heating temperature of the infusion more accurately.

The present invention has been made to solve the above-mentioned problems with infusion warmers, and is capable of measuring the flow rate of a minute amount of infusion flowing through a narrow liquid delivery tube without directly touching the infusion, and also measuring the flow rate. It is an object of the present invention to provide an infusion warmer with a flow meter that can control the heating temperature.

[Means for Solving the Problems] The inventor proposed that when a heated object is brought into contact with a liquid sending pipe through which infusion fluid flows, heat is exchanged between the liquid sending pipe and the object, and the heating body is cooled. However, we focused on the fact that the cooling rate is a function of the flow rate of the infusion. Therefore, the inventor applied a constant current to the heating element to heat it.

The inventors came up with the idea of measuring the flow rate by detecting a change in the temperature of the heating element due to a change in the flow rate of the infusion as a change in the resistance value of the heating element, and completed the present invention.

In order to achieve the above object, an infusion warmer with a flow meter according to the first aspect of the present invention is capable of measuring the flow rate of an infusion.
a heating section having a liquid feeding tube housing groove for accommodating an infusion feeding tube; an infusion outlet temperature sensor that detects the temperature of the infusion in the liquid feeding tube heated by the heating section; and detection by the infusion outlet temperature sensor. In the infusion solution warmer comprising a heating section control means for controlling the heating amount of the heating section based on the temperature of the infusion solution, the infusion solution is provided in front of the heating section and accommodates the infusion solution delivery pipe before flowing into the heating section. a heat insulating section forming a liquid pipe accommodating groove; an infusion inlet temperature sensor that is attached to the entrance of the liquid pipe accommodating groove of the heat insulating section and detects the temperature of the infusion flowing into the heat insulating section;
a constant current heating plate that is attached to the liquid feeding tube housing groove of the heat insulating section and is heated with a constant current and comes into contact with the liquid feeding tube; a resistance value detection means that detects a change in resistance of the constant current heating plate; and the infusion liquid. Flow rate calculation means for calculating the flow rate of the infusion flowing through the liquid sending pipe based on the temperature of the infusion detected by the inlet temperature sensor and the resistance tXM detected by the resistance value detection means;
The gist is that the device comprises a flow rate display means for displaying the calculated flow rate of the infusion.

In addition, the infusion warmer with a flow meter according to the second aspect of the present invention is capable of controlling the amount of heating by taking into account not only the temperature of the infusion solution but also the flow rate of the infusion solution. a heating section in which a storage groove is formed; an infusion outlet temperature sensor that detects the temperature of the infusion in the liquid feeding tube heated by the heating section; and a liquid feeding solution provided in front of the heating section and before flowing into the heating section. a heat insulating part forming a liquid feeding pipe accommodation groove for accommodating the tube; an infusion inlet temperature sensor attached to the entrance of the accommodation groove of the heat insulating part to detect the temperature of the infusion flowing into the heat insulating part; and a liquid feeding part in the heat insulating part. a constant current heating plate that is attached to the tube housing groove and is heated with a constant current and contacts the liquid sending tube; a resistance value detection means that detects a change in resistance of the constant current heating plate; and a resistance value detected by the infusion inlet temperature sensor. flow rate calculation means for calculating the flow rate of the infusion flowing through the liquid delivery pipe based on the temperature of the infusion solution detected by the infusion inlet temperature sensor and the resistance value detected by the resistance value detection means; ,!
! The gist of the present invention is to include a heating section control means for controlling the heating of the heating section based on the flow rate of the infusion calculated by the calculation means and the temperature of the infusion detected by the infusion outlet temperature sensor.

[Function] The infusion tube is accommodated in the infusion tube accommodating groove of the infusion warmer. The infusion solution first flows into the heat insulating section through the liquid feeding pipe, and the temperature of the infusion solution is detected by the infusion inlet temperature sensor. Next, the infusion flowing down the liquid delivery tube passes through the area where the constant current heating plate is in contact with the infusion, but at that time, heat is exchanged between the constant current heating plate and the infusion, and the constant current heating plate Although the constant current heating plate is cooled, a change in the temperature of the constant current heating plate due to a change in the flow rate of the infusion or the like is detected by the resistance value detection means as a change in the resistance value of the constant current heating plate, and is inputted to the flow rate calculation means.

Since the cooling rate of the constant current heating plate is a function of the flow rate of the infusion liquid, etc., if the inlet temperature is known, the flow rate of the infusion liquid etc. can be calculated by detecting the resistance value of the constant current heating plate. Based on this principle, the flow 1 calculation means calculates the flow rate of the infusion flowing through the liquid sending pipe based on the temperature of the infusion detected by the infusion inlet temperature sensor and the resistance value detected by the resistance value detection means. The calculated flow rate of the infusion fluid is displayed by the flow rate display means.

In addition, the heating section is heated based on the temperature of the infusion, etc. detected by the inlet temperature sensor, the flow rate of the infusion, etc. calculated by the flow rate calculation means, and the temperature of the infusion, etc. detected by the outlet temperature sensor. If configured to control the amount, the heating section control means will control the amount of heating of the heating section in response to changes in the temperature and flow rate of the infusion immediately.

[Embodiment] A preferred embodiment of the present invention will be described below with reference to the drawings.

Fig. 1 is a perspective view of one embodiment of the infusion warmer of the present invention;
The figure is a longitudinal sectional view taken along line 1'' in FIG. 1, and FIG. 3 is a plan view of the embodiment shown in FIG. 1. In FIG. , a heater housing chamber 14 and a circuit element chamber 16. A heating plate 18 constituting the heating section 94 is fitted into the opening 12a on the heater storage chamber 14 side, and a power lamp 54 and a digital flow rate display are mounted on the surface of the opening 12b on the circuit element storage chamber 16 side. Cover 22 with flow rate indicator 20 attached
is fitted. The surface of the heating plate 18 accommodates a liquid feeding tube with a zero-shaped cross section into which the infusion liquid feeding tube can just fit./II24
is provided, and this liquid feeding tube housing groove 24 is provided with a heating plate 18.
An inlet straight section 2 that traverses the heating plate 18 straight from a corner of
4m, a meandering part 24b that meanders in a figure 8 pattern at the center of the heating plate 18, and a meandering part 24b that meanders in a figure 8 pattern at the center of the heating plate 18, and a heating plate 18 that extends straight from the end of the meandering part 24b.
It consists of an exit straight section 24c that traverses vertically. This outlet straight portion 24e is extended as it is and connected to a liquid feeding tube housing groove 24d on the surface of the cover 22.

The corner of the heating plate 18 where the starting end of the liquid feeding tube accommodating groove 24 is cut out into a square is fitted with a heat insulating part 70 made of a heat insulating material. A groove 24e is provided.

An infusion inlet temperature sensor 72 is attached to the side of the heat insulating section 70 near the entrance of the liquid feeding pipe housing groove 24e. The constant current heating plate 74 is a metal plate processed into a semi-cylindrical shape having the same cross section as the liquid feeding tube housing groove 24.
1!24 It is fitted in the center of e.

An infusion outlet temperature sensor 28 is attached to the liquid feeding tube housing groove 24d of the cover 22 to measure the temperature of the infusion in the liquid feeding tube heated by the heating plate 18.

Furthermore, a recess 30 in a portion of the heating plate 18 surrounded by the liquid feeding tube housing groove 24 is filled with silicone rubber 32 . On the front side of the case body 10, there is a lid body 34 that can be opened and closed.
6, a locking protrusion 38 is protruded on the other side, and a key portion 40 formed on one side of the lid 34 can be locked. An aluminum pressing plate 44 is fixed to the tube through a heat insulating material 42, and prevents the liquid feeding tube accommodated in the liquid feeding tube housing groove 24 from detaching, and also presses the liquid feeding tube to prevent the tube from moving. The outer peripheral portion is brought into close contact with the liquid feeding tube housing groove 24.

As shown in the sectional view of FIG. 2, a rubber heater 46 constituting a heating section 94 is attached to the back surface of the heating plate 18 that covers the heater housing chamber 14.

A heat insulating material 50 is attached to the bottom of the heater storage chamber 14.A circuit board element chamber 16 houses an electric circuit element group 52 wired to a printed circuit board.A power lamp is provided in the display section 20. 54 is attached, and this display section 20
When the lid 34 is closed, it is exposed through a through hole 56 provided in the lid 34 so that the TI lamp 54 and the flow rate display can be visually recognized. A hanging ring 58 is attached to the upper side surface of the case body 10, and a hanging band 60 is hung on this hanging ring, so that the case body 10 can be suspended at any location. The power cord 62 is wired to the printed circuit board via a bushing 64 fitted into the lower side wall of the case body 10.

The resistance value detection circuit 76 of the constant current heating plate 74 is as shown in FIG. 4, and the constant current heating plate 74 is connected to one side of a resistance bridge 78 to apply a constant current.

When the infusion fluid flows through the liquid sending pipe that the constant current heating plate 74 contacts, heat is removed from the constant current heating plate 74, the temperature changes, and the resistance value changes, so an unbalanced voltage is generated in the bridge 78. This unbalanced voltage is amplified and outputted by an amplifier 80, and is indicated on the flow rate indicator 20 via a compensation circuit 82.

The configuration block diagram for controlling the temperature of the infusion is shown in FIG. 5. The voltage detected by the resistance value detection circuit 76 is A/D converted and input to the multiplier 86. On the other hand, the inlet temperature sensor 72
The temperature signal detected and A/D converted by the multiplier 86 and C
It is input to PU88.

The multiplier 86 multiplies a constant constant determined by the inlet temperature signal to calculate the flow rate of the infusion, and the data is sent to the multiplier 86.
is input to the CPU 88 from.

Further, the temperature signal detected by the outlet temperature sensor 28 is
It is converted into D and inputted to the comparator 88, and the comparison value with the set temperature is inputted to cpuss. CP (J88 is multiplier 86
, performs predetermined calculations based on the inputs from the inlet temperature sensor 72 and the comparator 90, and then sends a control signal to the heating section drive circuit 92. Control takes place.

[Effects of the Invention] As explained above, the infusion warmer with a flow meter of the present invention has the following advantages:
This method uses the fact that there is a certain functional relationship between the cooling rate of the constant current heating plate that contacts the liquid sending tube and the flow rate of the infusion solution, and calculates the flow rate of the infusion solution from the change in the resistance value of the constant current heating plate. Therefore, it is possible to measure the flow rate of a small amount of infusion flowing through a thin tube without directly contacting the 1llI solution, and it is possible to infuse transfused blood, etc. at an appropriate injection rate depending on the patient's disease state. It has excellent effects. Furthermore, since the amount of heat generated by the heating plate can be controlled based on the temperature of the infusion before heating and the flow rate of the infusion, it is possible to control the heating amount of the heating section in response to changes in the temperature and flow rate of the infusion, etc. Become.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of an embodiment of the present invention, Fig. 2 is a sectional view taken along the line ■-■ in Fig. 1, Fig. 3 is a plan view of Fig. 1, and Fig. 4 is a constant current heating plate. FIG. 5 is a block diagram showing the configuration of an embodiment of the control means of the present invention. 18... Heating plate, 20... Flow rate indicator, 24...
Liquid feeding tube accommodation groove, 28... Infusion outlet temperature sensor, 70...
...Insulation section, 72...Infusion inlet temperature sensor, 74...
・Constant current heating plate, 76...Resistance value detection means, 86...
- Multiplier, 88...CPU, 90...Comparator. Figure 2 Figure 3 Figure 4 Figure 5

Claims (2)

[Claims] (1) A heating section having a liquid feeding tube housing groove for accommodating an infusion feeding tube, an infusion outlet temperature sensor that detects the temperature of the infusion inside the liquid feeding tube heated by the heating section, and the infusion outlet temperature. In an infusion warmer comprising a heating part control means that controls the heating amount of the heating part based on the temperature of the infusion detected by a sensor, an infusion liquid feeding pipe provided in front of the heating part and before flowing into the heating part is provided. an infusion inlet temperature sensor that is attached to the inlet of the liquid feeding tube accommodating groove of the heat insulating part and detects the temperature of the infusion flowing into the heat insulating part; A constant current heating plate that is attached to the liquid tube storage groove and is heated with a constant current and contacts the liquid sending tube, a resistance value detection means that detects a change in the resistance value of the constant current heating plate, and a temperature sensor that detects the temperature at the infusion inlet. and a flow rate display means for displaying the calculated flow rate of the infusion. Infusion warmer with a flow meter. (2) a heating section in which a liquid feeding tube housing groove is formed for accommodating an infusion feeding tube; an infusion outlet temperature sensor that detects the temperature of the infusion in the liquid feeding tube heated by the heating section; A heat insulating part is provided at the front and forms a liquid feeding pipe housing groove for accommodating the liquid feeding pipe before flowing into the heating part, and a heat insulating part is attached to the entrance of the housing groove of the heat insulating part to control the temperature of the infusion fluid flowing into the heat insulating part. An infusion inlet temperature sensor for detecting, a constant current heating plate attached to the liquid feeding tube housing groove of the heat insulating section and being heated with a constant current and in contact with the liquid feeding tube, and detecting a change in resistance of the constant current heating plate. resistance value detection means; flow rate calculation means for calculating the flow rate of the infusion flowing through the liquid delivery pipe based on the temperature of the infusion detected by the infusion inlet temperature sensor and the resistance value detected by the resistance value detection means; and the infusion solution heating unit control means for controlling the heating amount of the heating unit based on the temperature of the infusion detected by the inlet temperature sensor, the flow rate of the infusion calculated by the flow rate calculation unit, and the temperature of the infusion detected by the infusion outlet temperature sensor; An infusion warmer with a flow meter.