JPH019577Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to an infusion remaining amount detection device for detecting the remaining amount of infusion (including blood transfusion).

(Prior Art) In hospitals and the like, infusions in which large amounts of fluid are administered into blood vessels, subcutaneously, or intraperitoneally, or blood transfusions in which blood is injected into blood vessels are performed. If the transfusion container becomes empty during such transfusion, air may enter the living body, and in some cases, bodily fluids may flow back from the human body, which is extremely dangerous. To avoid such risks, patients monitor the amount of fluid left in their infusion and contact a nurse or doctor when the amount is low, but this is cumbersome and lacks safety. . Therefore, the following devices have been proposed that automatically detect when an infusion container runs out of infusion fluid.

(1) Insert two syringe needles into the rubber stopper that closes the opening at the bottom of the infusion container, apply voltage between the two syringe needles, and check whether current flows between the two syringe needles. Detects infusion shortage. (Since infusion fluid is a conductor, current will flow if there is an infusion in the infusion container, and no current will flow if the infusion is cut off.) (2) Continuously measure the weight of the infusion container, and adjust the infusion based on the measured value. Detect breaks.

(3) A photoelectric switch attached to the bottom of the infusion container is used to detect an infusion shortage based on changes in the amount of transmitted light.

(Problem to be solved by the invention) However, in the detection method based on the presence or absence of current conduction in (1) above, the other end of the infusion tube connected to the infusion container is inserted into the patient's blood vessel. There is a risk of electric current flowing inside your body. In detection method (2), which measures the weight of the infusion container, the specific gravity of the patient and the infusion differs depending on the type of infusion, so the weight must be adjusted depending on the type of infusion used, making handling complicated. Malfunctions are also likely to occur. It also detects infusion shortages based on changes in the amount of transmitted light (3)
In this method, the color of the infusion varies depending on the type,
The light transmission coefficient also varies, making it difficult to adjust. Furthermore, if the infusion remains attached to the detection tube of the photoelectric switch, it may cause malfunction.

(Means for Solving the Problems) The inventors of the present invention solved the problems of the conventional device for detecting the shortage of infusion fluid stored in the infusion container, and developed a device that is highly reliable, easy to handle, and safe. The present invention was arrived at as a result of intensive study to provide a device for detecting the remaining amount of infusion fluid that is sufficiently secured. In other words, the present invention connects a thin pipe that communicates with the inside of the container, which prevents infusion from entering by surface tension, to the lower end of an infusion container whose interior is maintained at atmospheric pressure, and connects it to the other end of the thin pipe. The pressure sensor detects changes in the water column pressure due to changes in the surface of the infusion in the infusion container as changes in the pressure of the air sealed in the thin pipe, and the signal sent from the pressure sensor is sent to the pressure setting circuit. This infusion fluid remaining amount detection device is characterized in that it is configured to compare with a set value of the water column pressure and issue an alarm when the signal from the pressure sensor reaches the set value.

(Example) Next, an example of the infusion remaining amount detection device of the present invention will be described with reference to the drawings. In FIG. 1, an infusion container 5 filled with a predetermined infusion solution is suspended from a stand 4. A rubber stopper 8 is attached to the opening at the lower end of the infusion container 5, and the tip of the rubber stopper 8 opens into the space provided in the upper part of the infusion container, communicating the inside and outside of the infusion container, thereby greatly expanding the inside of the container. An air needle 6b that is held at atmospheric pressure and a container needle 6a that is connected to an infusion tube 7 that is injected into a patient are punctured.

A thin pipe 9 for pressure detection communicating with the inside of the infusion container is further connected to the rubber stopper 8. The thin pipe 9 may be connected to the rubber stopper in any way, but usually, for example, as shown in FIG. Preferably connected.

The thin pipe 9 for pressure detection is one that prevents infusion liquid from entering the pipe due to surface tension, and when using a flexible PVC pipe used for medical purposes, the inner diameter is usually 1 mm or less, preferably. is 0.8mm
The following pipes are used. A pressure sensor 10 is attached to the end of the pipe. A diaphragm type pressure transducer is usually used as this pressure sensor. The air A injected into the thin pipe 9 has a water column pressure corresponding to the head pressure of the infusion stored in the infusion container 5, that is, the height from the opening end of the thin pipe into the infusion container to the liquid level of the infusion. (h mm Aq) is given. Therefore, when the liquid level in the infusion container changes, the water column pressure is immediately and reliably applied to the air A sealed in the thin pipe 9, and can be converted into a change in air pressure. Infusion fluid must never enter the thin pipe 9. When the infusion enters the pipe, the height H between the upper end of the air sealed in the pipe and the level of the infusion stored in the container, as shown in Figure 4.
is displayed by adding the penetration height h' of the infusion into the pipe to the actual liquid level height h. Therefore, even if the infusion container is empty, it appears that the infusion remains by an amount equivalent to the height h' of the infusion into the pipe. The pressure change of the air A causes a displacement to the diaphragm of the pressure sensor 10 attached to the tip of a thin pipe, and the minute displacement of this diaphragm is detected by a metal wire strain gauge, semiconductor strain gauge, etc., and the detection signal is sent to the control device. Send to 20. In the control device, this signal is amplified by an amplification circuit 11 and the liquid level is displayed on a display 12. This signal is also sent to the comparison circuit 13. Setting circuit 1 in the comparison circuit
It is compared with the water column pressure (liquid level) set in step 4. When the liquid level decreases and the signal from the pressure sensor 10 reaches a set value, a signal is sent to the alarm 15.

FIG. 2 shows an example in which a large amount of infusion is performed, and three infusion containers 5 each made of a flexible bag are used.
Injection needles 6d punctured at the lower ends of a, 5b, and 5c are connected by a connecting tube 18, and a valve 16 is provided in each connecting tube. Further, an infusion tube 7 whose tip is connected to a catheter or the like inserted into a patient's blood vessel is connected to the injection needle 6a inserted into the infusion container 5a. A valve 17 and a constant flow pump 19 such as a roller pump are installed in the middle of the infusion tube 7, and the liquid level in the infusion container 5a is detected by a thin pipe 9 filled with air attached to the infusion container 5a. do. The infusion container 5a
When the liquid level falls below the set value, the valve 16 installed in the connecting pipe 18 is opened, and at the same time, the rotation speed of the pump 19 installed in the infusion circuit 7 is controlled to completely drain the infusion in all the infusion containers. Can be transfused. In addition, when using a sufficiently soft plastic bag such as PVC as the infusion container 5,
Since the inside of the bag is maintained at atmospheric pressure, an air needle as shown in FIG. 1 is not required.

(Effects of the invention) This invention converts the liquid level of the infusion in the infusion container into pressure, and detects this pressure with a pressure sensor, thereby providing accurate information regardless of the shape, color, etc. of the container containing the infusion. The residual infusion amount can be detected. Moreover, since the detection point can be detected continuously instead of just one point, if you need to replace the infusion container, you can set the alarm point with a margin in advance for the amount of remaining fluid, so that the infusion circuit will not be affected. It is possible to prevent air from entering and eliminate the complexity of replacing infusion containers.

[Brief explanation of the drawing]

Fig. 1 is a flowchart of the infusion remaining amount detection device of the present invention, Fig. 2 is a flowchart when a plurality of infusion containers are used, and Figs. 3 and 4 explain the lower structure of the infusion container. FIG. 5... Infusion container, 6a... Container needle, 6b... Air needle, 7... Infusion tube, 8... Rubber stopper, 9...
... Pipe, 10 ... Pressure sensor, 12 ... Display, 13 ... Comparison circuit, 14 ... Setting circuit, 15
...Alarm.

Claims (1)

[Scope of utility model registration request] A thin pipe that prevents infusion from entering the container due to surface tension and communicates with the inside of the container is connected to the lower end of the infusion container whose interior is kept at atmospheric pressure, and a pressure sensor connected to the other end of the thin pipe. The system detects changes in the water column pressure due to changes in the liquid level of the infusion in the infusion container as changes in the pressure of the air sealed in the thin pipe, and also transmits the signal sent from the pressure sensor to the pressure set by the pressure setting circuit. 1. An infusion fluid remaining amount detection device, characterized in that the device is configured to compare a water column pressure with a set value and issue an alarm when a signal from the pressure sensor reaches a set value.