JPH03231681A - Method and apparatus for detecting amount of transfusion in transfusion apparatus - Google Patents

Abstract

PURPOSE:To detect accurately the amt. of transfusion without any influence of fluctuation of thicknesses of a transfusion tube and a drip needle and deviation of a blood pressure of a patient by irradiating a light to a liq. drop, receiving the projected light changed by this liq. drop and detecting the peak value of the amt. of light attenuation of the received irradiation light. CONSTITUTION:When a belt-like irradiation light 7 passes through a drip tube 1 and is received on a light receiving part 9 as a passing light 3, the light receiving part 9 feeds an electric signal corresponding to the passing light 8 to an amplifier 12. This electric signal is changed by crossing the irradiation light 7 with a liq. drop 4. Then, when the lower end of the liq. drop 4 reaches the irradiation light 7 at a time t1, amt. of light attenuation L is increased. The amt. of the light attenuation L changes by drawing approximately a wave shape of a half of a sin curve and when the upper end of the liq. drop 4 passes at a time t2, the amt. of attenuation L returns to the same level as that at the time t1. In this case, the peak value R of the sinusoidal wave shape corresponds to the max. dimension of the expanded part of the liq. drop 4. Then, the vol. of the liq. drop can be obtd. as a vol. of a rotating body obtd. by rotation of 2pi times by using a horizontal axis which is a reference line of the sinusoidal curve as a center.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method and device for detecting the amount of infusion in an infusion device used in the medical field.

[Conventional technology]

In infusion devices used in the medical field, conventional methods for measuring the amount of liquid injected into the human body include counting the number of infusions in an infusion set, and mechanical displacement applied to the tube. Methods such as calculating the number of times as a coefficient are used.

In this method of counting the number of infusions, a nurse or the like generally counts the number visually. In addition, in the method of counting the number of mechanical displacements described above, the amount of infusion is mechanically measured by detecting the number of brushing movements of the fingers in the spiral movement mechanism, the number of rotations of the roller in the cola drive mechanism, etc. I try to do that.

Furthermore, JP-A-59-166816 discloses that the droplet is assumed to be spherical and the volume of the droplet is calculated according to ■=4πr3/3.

[Problems to be Solved by the Invention] The above prior art has the following problems.

That is, in the method using the number of infusions described above, firstly, the infusion set used to determine the setting values of the infusion device may not correspond accurately to the infusion set actually used, and this mismatch may occur. This causes an error in the amount of infusion. Second, the difference in droplet size due to the difference in the viscosity of the liquid causes an error in the amount of infusion. Thirdly,
Errors in the amount of infusion occur due to differences in the size of droplets due to variations in the thickness of the infusion needle of the infusion cent and variations in the thickness of the infusion tube. Fourth, errors in the amount of infusion occur due to fluctuations in the patient's blood pressure, dislocation of the injection needle, and the like. Fifth
As a result, errors in the amount of infusion occur due to attenuation or changes in the restoring force of the infusion tube due to long-term use or the temperature of the environment in which it is used.

In addition, in the method of counting the number of mechanical displacements described above, although a dedicated infusion tube is attached to the infusion device, it is difficult to maintain a large number of infusion tubes in a homogeneous state for a long period of time. , even with a dedicated infusion tube,
Currently, there is an error in the amount of infusion of approximately ±10%.

Note that in this type of infusion device, the amount of infusion per hour is usually set, but depending on the type of drug solution, it is desirable to set it in units of minutes or seconds.

The purpose of the present invention is to make it possible to use an inexpensive infusion set, and to reduce the viscosity of the liquid, the variation in the thickness of the infusion tube and the thickness of the IV needle, and the loss of restoring force of the infusion tube due to long-term use. It is an object of the present invention to provide a method and device for detecting the amount of infusion in an infusion device, which can accurately detect the amount of infusion without being affected by changes in blood pressure, dislodgement of an injection needle, etc.

[Means to solve the problem]

In order to achieve the above object, the infusion amount detection method according to the present invention is implemented in an infusion device that supplies droplets from an intravenous needle to a predetermined supply point, by irradiating the droplets with light to detect the droplets. , and detects the peak value R of the amount of optical attenuation of the received irradiated light, and also detects the attenuation start time t1 and the attenuation end time t of this optical attenuation amount.
Detect the time tw of the difference from 2, and calculate the half wave of the sine curve (
However, the peak value R is expressed as a formula that substantially represents the volume of the rotating body obtained by rotating the wave height (the wave height is the peak value R and the waveform width is the time tw) about the reference line. The volume (2) of the droplet is calculated by substantially substituting the detected values of (1) and (2) for the time.

In addition, the infusion amount detection device according to the present invention for achieving the above object is provided in an infusion device configured to supply droplets from an intravenous needle to a predetermined supply location, in which the droplets are irradiated and the droplets are A droplet sensor unit that receives irradiated light that has changed due to the presence of the irradiated light and outputs an electrical signal according to this irradiated light, and a droplet sensor unit that detects the peak value of the output signal of this droplet sensor unit and generates a peak value that corresponds to this peak value. peak detection means for outputting a detection signal vi; time width detection means for detecting the waveform width of the output signal of the droplet sensor section and outputting a time width detection signal vw according to this waveform width; Substantially, the volume of the rotating body obtained by rotating the wave component (the wave height is the above-mentioned peak detection signal V and its waveform width is the above-mentioned time width detection signal V) around its reference line is and calculation means for calculating the volume of the droplet by substantially substituting each detected value of the peak detection signal V and the time width detection signal vw into the equations represented by the formula. It is something to do.

〔Example〕

Hereinafter, one embodiment of the infusion device according to the present invention will be described in detail using the drawings.

FIG. 1 is a diagram showing a droplet sensor section (optical system) of an infusion amount detection device using the above-mentioned infusion device, FIG. 1(a) is a front view thereof, and FIG. 1(b) is a plan view thereof. The figure shows.

1 is the drip tube of the I#i liquid set. Infusion bottle 10 (
The liquid flowing out from the infusion tube (see Figure 4) passes through the infusion tube 3 and reaches the infusion tube 1, and from the lower end of the infusion needle 2 protruding into the inside of the infusion tube 1, it becomes a droplet 4 and flows into the lower part of the infusion tube 1. Drip towards. The liquid accumulated in the lower part of the drip tube 1 is supplied to the patient side through the infusion tube 5.

On the other hand, the light emitting unit 6 irradiates the dropping droplet 4 with irradiation light 7 from a direction substantially perpendicular to the dropping direction. The irradiation light 7 has a vertical cross section in a direction substantially perpendicular to the traveling direction, which is substantially line-shaped or slit-shaped, and is generally perpendicular to the above-mentioned dropping direction (i.e., extends almost horizontally). A strip-shaped laser beam (for example, thickness 1-1 width 10M) can be used. This band-shaped irradiation light 7 passes through the drip tube 1 and is received by the light receiving section 9 as passing light 8. The light receiving section 9 has a slit-shaped window and receives the band-shaped passing light 8. The light receiving section 9 then supplies an electrical signal corresponding to the received passing light 8 to the amplifying section 12 (see FIG. 4).

The electrical signal supplied to this amplifier 12 changes as the droplet 4 traverses the strip of illumination light 7 that extends approximately horizontally. This is because the irradiation light 7 is temporarily blocked by the droplet 4 in the drip tube 1. In addition, in FIG. 1(b), the irradiation light 7 in the drip tube 1 is indicated by a broken arrow in order to show the state of light shielding.

FIG. 2 is a curve diagram showing the optical attenuation (blocking) of the passing light 8 caused by being blocked by the droplet 4. In the second time, the vertical axis shows the optical attenuation of the irradiation light 7, and the horizontal axis shows the time. As can be seen from FIG. 2, when the lower end of the droplet 4 reaches the time t1 in the band-shaped irradiation light 7 made of laser light and extending substantially horizontally, the optical attenuation increases. Then, the optical attenuation meter changes approximately in a waveform corresponding to a half wave of the sine curve, and when the upper end of the droplet 4 passes at time L2, the attenuation meter returns to the same level as at time t1. In this case, the peak value R of the sine waveform corresponds to the maximum dimension of the swollen portion of the droplet 4.

Note that the mark in FIG. 2 indicates the time difference between time t2 and time t.

Here, a method for calculating the droplet volume (method for detecting the amount of infusion) in the droplet sensor section shown in FIG. 1 will be described.

According to experiments conducted by the present inventors, the actual outer shape of the droplet 4 is almost the same as the amount of light attenuation shown in FIG.

That is, as shown in FIG. 3, a half-wave waveform of a sine curve is approximately drawn, which represents the bulge of the actual outer shape of the droplet 4 from the vertical center line. In FIG. 3, the vertical axis shows the value of the waveform function f(to), and the horizontal axis shows the position X in the vertical direction.

Therefore, the general formula for determining the droplet volume is to divide the curve shown in Figure 3 by 2
As the volume of the rotating body obtained by rotating π,
You can ask for it. That is, the waveform function f in FIG.
. Let the starting point of f (X) be Xl, the end point of f (X) be X2, and furthermore, let dx be the minute value from a certain value X on the horizontal axis,
The volume ■ is expressed by the following formula.

Since the waveform function f, ゎ depicts a habosine waveform, it can be expressed by the following equation.

f (X) −kRsin x −−−−−−−−
--1--(2) Here, k is a constant determined by the measurement system (that is, various states of the infusion device).

In addition, the dropping speed (droplet speed) of droplet 4 is
At the lower end position, V=O. Then, if the distance from the lower end position of the drip needle 2 to the irradiation position of the irradiation light 7 (the point where the amount of light attenuation by the laser is detected) is h, then the droplet velocity V at the detection point is v-1 1l--- −−−−−−−−−−−−−−−−
----------(3) Here, g is gravitational acceleration.

Now, when the general formula (1) for calculating the droplet volume is applied to the optical attenuation meter shown in FIG. 2, the time t of the output waveform of the light receiving section 9. (=tz t+), using an arbitrary time t and minute time dt, and using the above equations (2), (3) and x=
By substituting vt, the volume ■ is expressed by the following formula.

In addition, in (4) 2 above, π and g are constants, and h
Since and k are constants determined by the measurement system, the droplet volume (2) can be found by detecting the peak value R of the optical attenuation measurement and the time tw. Then, the peak value R is determined by the light receiving section 9
By processing the output signal of V by an electronic circuit, the voltage V can be easily changed.

can be obtained as Therefore, R in formula (4) can be replaced with V. Also, time t. is a counter that starts at time t1 and stops at time 2 (
It can be easily obtained as an electrical signal (data) using a timer or the like.

Next, an infusion device to which the infusion amount detection method according to (4) 2 is applied will be described.

FIG. 4 is a block diagram showing the overall configuration of an infusion device in an embodiment of the present invention. In Figure 4,
Components that are the same as in FIG. 1 are given the same reference numerals.

In FIG. 4, the infusion set includes an infusion bottle 10 containing a liquid 11, an infusion tube 3 connected to the infusion bottle 1o, an infusion tube 1 having an infusion needle 2 connected to the infusion tube 3, and an infusion tube. 5.5′ (actually,
These tubes 5 and 5' may consist of a single tube as a whole. Note that the infusion tube 5' is connected to the patient side. Furthermore, the light emitting section 6 and the light receiving section 9 constitute a part of the drip sensor, as explained based on FIG. The light emitting section 6 is
It is driven by the arithmetic control unit 16 to emit a band-shaped irradiation light 7. The light receiving section 9 supplies an electric signal corresponding to the received passing light 8 to the amplifying section 12 .

The amplification unit 12 amplifies the electrical signal supplied from the light receiving unit 9 and outputs an output signal having a voltage proportional to the optical attenuation scale as shown in FIG. 2 to the voltage peak detection unit 13 and the voltage waveform width detection unit 18. supply to. Note that the voltage gain of the amplifier section 12 is adjusted by a gain signal supplied from the arithmetic control section 16. The reason for adjusting the voltage gain in this way is to compensate for the overall attenuation of the amount of light, since when the drip tube 1 becomes cloudy due to temperature, the irradiated light 7 reaches the light receiving section 9 with attenuation as a whole. It is.

The voltage peak detection section 13 may include a peak hold circuit and a clock generation circuit that generates a clock when the peak hold circuit holds the peak value. Then, the voltage peak detection section 13 supplies the peak voltage V of the output signal of the amplification section 12 (voltage corresponding to R in FIG. 2) to the analog-to-digital (A/D) conversion section 14, and latches the clock. 15 (signal lines are omitted from illustration).

The A/D converter 14 converts the peak voltage vi supplied from the voltage peak detector 13 into a digital signal and supplies it to the launch 15. The latch 15 is connected to the voltage peak detection section 13
The output signal of the A/D converter 14 is latched in accordance with the clock supplied from the A/D converter 14. The latch 15 then supplies a digital signal corresponding to the peak voltage V to the arithmetic control section 16.

On the other hand, the voltage waveform width detection unit 18 includes a comparator, a counter that counts predetermined pulses supplied from the pulse oscillator 17 according to the output of the comparator, and a clock and an interrupt when the counter finishes counting. It may consist of a digital circuit that sequentially generates signals. Then, when the output voltage from the amplifying section 12 becomes zero or more at time L1 in FIG. 2, the voltage waveform width detecting section 18 starts counting the pulses supplied from the pulse oscillator 17. Furthermore, when the output signal from the amplification section 12 returns to zero at time t2, the count is stopped and the count value (the value corresponding to t in FIG. 2) and the clock are supplied to the latch 19.

The latch 19 latches the count value (time width detection signal v,) supplied from the voltage waveform width detection section 18 using the clock supplied in the same manner.

The latch 19 then supplies this latched count value to the calculation control section 16. After that, the voltage waveform width detection section 1
8 supplies an interrupt signal to the calculation control section 16. Arithmetic system:
'I11 section 16, when supplied with an interrupt signal from voltage waveform width detection section 18, reads data V corresponding to R in the above equation (4) from latch 15, and
The data V corresponding to the request in the equation (4) is read from 9.

Thereafter, the calculation control section 16 almost simultaneously operates the voltage peak detection section 13, latch 15, voltage waveform width detection section 18, and latch 1.
9 (signal lines are omitted from illustration).

The arithmetic control unit 16 may consist of a microcomputer or the like, and the data Vi obtained from the latches 15, 19,
The volume V of the droplet 4 is calculated by calculating VW based on the above equation (4). And the volume of droplet 4 per unit time■
The infusion flow rate per unit time is calculated from the summation of , and the cumulative amount of infusion is calculated based on the time from the start of the infusion. The calculation control unit 16 also compares the calculated value of the infusion flow rate with the set value of the infusion flow rate supplied from the infusion flow rate setting unit 20 (a value related to the reference value of the volume of the droplet 4 and the period of the droplet). do.

Furthermore, the calculated value of the cumulative amount of infusion and the cumulative amount of infusion setting section 21
Compare the set value of the cumulative amount of infusion supplied from

If no abnormality is found in these comparison results, the arithmetic control section 16 supplies the motor drive control section 25 with a speed control signal set to a predetermined value based on the above calculated value. The motor drive control section 25 controls the infusion drive section 26 based on the supplied speed control signal. Infusion drive unit 26
In this embodiment, the ring motion mechanism is a wheel movement mechanism, and is composed of a motor (not shown) and three or more fingers (not shown) that are caused to move in a helical manner as a whole by the motor. These fingers selectively clamp the portion of the infusion tube between the infusion tubes 5 and 5' (in fact, these tubes 5 and 5' may consist of one tube as a whole). It is configured to move the clamping position sequentially.

In other words, the motor drive control unit 25 controls the motor of the infusion drive unit 26 to adjust the infusion flow rate. And, depending on the operating state of the infusion drive unit 26? f
The volume of f1M4 changes. For this reason, the infusion control system in this infusion device achieves closed-loop control, making it possible to achieve accurate control of the amount of infusion.

Next, a case will be described in which an abnormality is recognized in the comparison result in the arithmetic control section 16. A case where an abnormality is recognized is a case where the calculated value of the volume V is zero even though the droplet 4 has been formed, or a case where the calculated value of the droplet is determined depending on the calculated value of the obtained volume ■. period (this droplet period is
There may be a case where the actually detected droplet 4 dropping cycle (calculated by the arithmetic control unit 16 based on the set value supplied from the infusion flow rate setting unit 20) and the actually detected dropping cycle may be significantly different.

If such an abnormality is recognized, the arithmetic control unit 16
supplies a signal indicating the occurrence of an abnormality to the droplet cycle abnormality alarm section 27. In response to this signal, the droplet cycle abnormality alarm unit 27 lights up a lamp (not shown) and sounds a buzzer (not shown) to generate an alarm sound. Further, a stop signal, which is part of the signal supplied to the droplet cycle abnormality alarm section 27, is supplied to the motor drive control section 25. When supplied with this stop signal, the motor drive control section 25 stops the motor of the infusion drive section 26 . Therefore, the fingers of the infusion drive unit 26 stop their spiral movement, and the infusion ends.

Note that the infusion start switch 22 is a switch that supplies a signal instructing the start of infusion to the calculation control unit 16. When the infusion start switch 22 is turned on, the arithmetic control section 16 supplies the motor drive control section 25 with a speed control signal set to a set value of zero or more. In addition, the infusion stop switch 23 sends a signal instructing to stop the infusion to the calculation control unit 1.
This is a switch that supplies power to 6. Then, when this infusion stop switch 23 is set to on, the calculation control unit 16
A zero speed control signal is supplied to the motor drive control section 25 (substantially a signal equal to a stop signal).

In addition, the infusion flow rate/cumulative amount display section 24 is connected to the calculation control section 16.
Displays data on the actual infusion flow rate and integrated infusion volume supplied by the system. This actual I#I liquid flow rate is expressed by the sum of the volumes of droplets 4 dropped per unit time. Further, the actual integrated amount of infusion is expressed by the sum of the volumes of the droplets 4 that have been dropped since the start of infusion.

Next, an outline of the operation of the infusion device shown in FIG. 4 will be explained based on FIG. 5.

FIG. 5 is a general flowchart showing the operation of the infusion device. In FIG. 5, when the power is turned on to the infusion device shown in FIG.
performs initialization (initialization settings). By this initialization, the calculation control section 16 drives the light emitting section 6. For this reason, the light emitting unit 6 has a band-shaped irradiation light (laser light) 7.
emits light. Further, the arithmetic control unit 16 maintains the infusion stop state by setting the speed control signal to zero and supplying it to the motor drive control unit 25, and also resets the infusion flow rate/integrated amount display unit 24 and the like.

Next, in step S2, the calculation control unit 16 reads the set value of the infusion flow rate set in the infusion flow rate setting unit 20 and the set value of the integrated infusion amount set in the integrated infusion amount setting unit 21. The arithmetic and control unit 6 then enters a standby state waiting for an on signal from the infusion start switch 22.

Next, in step S3, when the infusion start switch 22 is turned on and an on signal is supplied to the calculation control section 16, the calculation control section 16 sets the speed control signal to a predetermined value and controls the motor drive control section. 25. Therefore, the motor drive control unit 25 drives the motor of the infusion drive unit 26,
By driving this motor, the finger starts a spiral movement, so that infusion is performed.

Next, since the light emitting section 6 emits the irradiation light 7 when the power is turned on (at the time of initialization), the light receiving section 9 generates a signal corresponding to the dropping of the droplet 4 in step S4. That is, droplet detection is performed.

Then, since the output signal of the light receiving section 9 is supplied to the amplifying section 12, in step S5, the latch 15 is
A digital signal corresponding to the peak voltage V (corresponding to R in FIG. 2) is supplied from the latch 19 to the arithmetic control unit 16, and a count value corresponding to the time width detection signal v5 (corresponding to R in FIG. 2) is supplied from the latch 19. (corresponding to the current value) is supplied to the arithmetic control section 16.

That is, the voltage waveform width and peak voltage of the output voltage of the amplifying section 12 are detected.

Next, in step S6, the arithmetic control unit 16 calculates the volume ■ of the droplet 4 based on the above equation (4), calculates the sum of the volume ■ per unit time, and calculates the actual infusion flow rate. The actual integrated amount of infusion is calculated by calculating the volume of the droplet 4 from the time of starting the infusion.

Then, in step S7, the calculated actual infusion flow rate is compared with its set value, and the calculated actual integrated infusion amount is compared with its set value.

Next, in step S8, the calculation control unit 16 determines whether there is an abnormality in the droplet period based on the comparison result in step S7. If there is no abnormality, the process moves to step S9, and if there is an abnormality, the process moves to step S312. In step S9, the actual wheel W1. calculated in step S6. Data on the flow rate and the integrated amount of transfusion are supplied from the calculation control section 16 to the infusion flow rate/integrated amount display section 24 . As a result, the infusion flow rate/integrated amount display section 24 displays the infusion flow rate and the integrated infusion amount.

Next, in step SIO, the calculation control unit 16 supplies the motor drive control unit 25 with a speed control signal whose value is set based on the calculated infusion flow rate and integrated amount of infusion.

The motor drive control section 25 drives and controls the infusion drive section 26 .

Next, in step 311, the calculation control unit 16 determines the signal supplied from the infusion stop switch 23. Then, if the signal of the infusion stop switch 23 is in the OFF state,
Returning to step S4, the series of processes is repeated again. Further, if the signal of the infusion stop switch 24 is in the ON state, the arithmetic control unit 16 supplies a speed control signal whose value is set to zero to the motor drive control unit 25, and after the infusion stops, the process returns to step S2 again. .

On the other hand, if it is determined in step S8 that there is an abnormality, the process moves to step S12 as described above. and,
In this step 31.2, the calculation control section 16 supplies a signal indicating the occurrence of an abnormality to the droplet cycle abnormality alarm section 27. Therefore, the droplet cycle abnormality alarm unit 27 lights up the lamp and sounds the buzzer to generate an alarm sound. Then, in step S13, a stop signal is supplied to the motor drive control section 25. As a result, the motor drive control section 25 stops the motor of the infusion drive section 26, so that the infusion is stopped. After the processing in step S13, the process moves to the next processing routine, but its explanation will be omitted.

Next, the characteristics of the volume of a single droplet produced by the infusion control system of the above-mentioned infusion device will be explained using FIG. 6.

In Figure 6, the horizontal axis is the flow rate of infusion (rr+F!/h)
, and the vertical axis is the droplet volume [ml] of one drop.

A high viscosity liquid is used as the infusion solution, and the infusion set is a commonly used 15-drop infusion set (configured to produce about 15 droplets per minute). The dashed-dotted line in the figure shows the actual measurement data (true value), and the solid line shows the above (
4) The calculated value of the volume of droplet 4 by 2 is shown, and the dashed line is liquid?
The calculated values are shown in the case of a conventional example (Japanese Unexamined Patent Publication No. 166816/1983) in which the volume was calculated assuming Wi4 as a sphere.

As can be seen from Figure 6, calculating the volume of the droplet 4 based on (4) 2 is better than calculating the volume assuming the droplet 4 as spherical, based on the actual measured data. close.

Furthermore, the characteristics of the difference between the measured value (data) and the calculated value of the droplet volume provided by the infusion control system of the above-mentioned infusion device will be explained using FIG.

In Fig. 7, the horizontal axis is the flow rate of the infusion (m!!, /h), and the vertical axis is the difference [mβ] between the measured value and the calculated droplet volume per drop. Physiological saline was used, and the infusion set was for 15 drops, the same as that used in the case of FIG.

The solid line in the figure is the volume value of the droplet 4 according to (4) 2, and the broken line is the calculated value in the conventional example in which the volume was calculated assuming the droplet 4 was spherical.

As can be seen from FIG. 7, when the volume of the droplet 4 is calculated based on equation (4), the difference from the actual measurement data is smaller.

In the above-described embodiment, the light emitting unit 6 emits laser light as the irradiation light 7, but it does not need to be a laser light as long as a band-shaped light beam can be similarly obtained. In addition, in order to obtain a band-shaped light beam, the light emitting section 6
It is also possible to guide the irradiated light 7 from the drip tube 1 to the drip tube 1.

Further, in the above embodiment, the light receiving section 9 has a slit-shaped window, but instead of having such a slit-shaped window, a line-shaped optical sensor (line sensor) may be used to receive light. .

Further, in the above-described embodiment, the infusion drive unit 26 is composed of a spiral movement mechanism, but it may also be a drive mechanism using a roller or simply a plunger and an anvil (
The clamping mechanism may be a clamping mechanism consisting of a bulging portion). In addition, although the infusion drive unit 26 is installed at the rear of the IV tube 1 (between the IV tube 1 and the patient), the infusion drive unit 26 is installed at the front of the IV tube 1 (U).
The infusion drive unit 26 can also be installed between the liquid bottle IO and the drip tube 1.

〔Effect of the invention〕

According to the present invention described in detail above, it is possible to use an inexpensive infusion set, and the viscosity of the liquid, the variation in the thickness of the infusion tube and the thickness of the drip needle, and the recovery of the infusion tube due to long-term use. The annulus and fluid volume can be accurately detected without being affected by force attenuation, fluctuations in patient blood pressure, or dislodgement of the injection needle.

[Brief explanation of drawings]

The drawings show an embodiment of an infusion device according to the present invention, and FIGS. 1(a) and 1(c) are schematic diagrams of a droplet sensor section of an infusion amount detection device used in the above-mentioned infusion device. FIG. 2 is a curve diagram showing the amount of optical attenuation of passing light in the droplet sensor section of FIG. 1, and FIG. 3 is a front view and a plan view.
Fig. 1 is a curve diagram showing the actual outline of the droplet in the droplet sensor section, Fig. 4 is a block diagram of the entire infusion device, and Fig. 5 is a general flowchart showing the operation of the infusion device in Fig. 4. , FIG. 6 is a curve diagram showing the measured value and calculated value of the droplet volume of one drop, and FIG. 7 is a curve diagram showing the difference between the measured value and the calculated value of the droplet volume per drop. . In addition, in the symbols used in the drawings, 1----- ---One drip needle 4
−・−・−・・−・・・・・−・Droplet 6−−−−−−
−−−−−−−−−−−−Light emitting part 7・・−・−・・
・・・・・・−Irradiation light 8−・−−−−−−−・・・・−
- Passing light 9 - - - - - - - Light receiving section 13 - - - Voltage peak detection section (peak detection means ) 26. Calculation control section (calculation means) Voltage waveform width detection section (time width detection means) Infusion drive section embedded shed (a) Front view Figure 1 Figure 4 Flow rate -1- Figure 6 (-〃] Figure 7

Claims (1)

[Claims] 1. In an infusion device configured to supply droplets from an intravenous needle to a predetermined supply location, the droplets are irradiated with light and the irradiated light is changed due to the presence of the droplets. The peak value R of the optical attenuation of the received irradiation light is detected, and the time t_w of the difference between the attenuation start time t_1 and the attenuation end time t_2 of this optical attenuation is detected, and the half wave of the sine curve is detected. (However, let the wave height be the above peak value R and the waveform width be the above time t_w).The above peak value R and the above time t
A method for detecting an infusion amount, characterized in that the volume V of the droplet is calculated by substituting each detected value of _w. 2. As a formula that substantially represents the volume of the rotating body, V = 1/
2(k・R/2)^2π√(2gh)・t_w (where, k is a constant determined by the state of the infusion device, g is the gravitational acceleration, and h is from the lower end of the IV needle to the point where the optical attenuation of the droplet is detected. The infusion amount detection method according to claim 1, characterized in that the method uses: (distance). 3. The amount of infusion according to claim 1 or 2, characterized in that the driving state of the infusion driving means for controlling the dripping state of the droplet dropped from the infusion needle is controlled in accordance with the calculation result of the volume V of the droplet. Detection method. 4. In an infusion device configured to supply droplets from an intravenous needle to a predetermined supply point, the device receives irradiation light that is irradiated onto the droplet and has changed due to the presence of the droplet, and responds to this irradiation light. a droplet sensor unit that outputs an electrical signal from the droplet sensor unit; a peak detection unit that detects a peak value of the output signal of the droplet sensor unit and outputs a peak detection signal v_i according to the peak value; and the droplet sensor unit a time width detection means for detecting the waveform width of the output signal of the output signal and outputting a time width detection signal v_w according to the waveform width; The peak detection signal v_i and the time width detection signal v_w are expressed as a formula that substantially represents the volume of the rotating body obtained by rotating the waveform width of the time width detection signal v_w about its reference line. An infusion amount detection device comprising: calculation means for calculating the volume V of the droplet by substantially substituting each detected value. 5. The formula that practically represents the volume of the rotating body is: V=1/2(k・v_i/2)^2π√(2gh)・v
_w (where k is a constant determined by the state of the infusion device,
5. The infusion amount detection device according to claim 4, wherein g is gravitational acceleration and h is a distance from the lower end of the infusion needle to a point at which optical attenuation of the droplet is detected. 6. The infusion device is equipped with an infusion driving means for controlling the dripping state of droplets dripped from the infusion needle, and the calculation means controls the driving state of the infusion driving means according to the calculation result of the volume V of the droplet. The infusion amount detection device according to claim 4 or 5, characterized in that: