JPH0543388B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a blood sampling device for collecting blood into a blood container.

[Prior Art] Conventionally, a blood sampling device as described in Japanese Patent Publication No. 51-3153 has been proposed.

The blood collection device needs to include a measurement sensor for measuring the amount of blood collected into a blood container.

Further, in a blood sampling device that collects blood into a blood container using negative pressure generated by a vacuum pump, it is necessary to include a pressure sensor for measuring the pressure of the vacuum blood sampling chamber in which the blood container is set.

[Problems to be Solved by the Invention] A measurement sensor or a pressure sensor can be treated as if the output of the sensor constitutes a constant function with respect to the measured amount (blood sampling amount or pressure). Therefore, the blood sampling device is equipped with a control means that calculates a desired measurement amount (blood sampling amount or pressure) assuming that the output of the measurement sensor constitutes the above-mentioned specific function.

Now, let us consider the sensor for measuring the blood sampling amount as a representative, and the output y of the measurement sensor is a linear function y with respect to the measured blood sampling amount w.
= aw + b (a: gain (sensitivity), b: offset value) When handling it as a component, the offset value b may drift over time due to heat generation and stress changes as a general characteristic of sensors ( (See Figure 7).

Therefore, the offset value b01 of the linear function initially set in the control means is changed to b02, b03 during use.
In the case of drift as in..., error values (b02-b01), (b03-b01), etc. will occur unless this is corrected.

SUMMARY OF THE INVENTION An object of the present invention is to always automatically correct changes due to drift in the offset value of the output of a blood sampling amount measuring sensor, and to ensure accuracy in measuring the amount of blood sampling.

An object of the present invention is to always automatically correct changes due to drift in the offset value of the output of a pressure sensor, and also to ensure accuracy in measuring the pressure generated in the vacuum blood collection chamber.

[Means for Solving the Problems] The present invention as set forth in claim 1 includes a blood collection amount measuring means equipped with a measurement sensor for measuring the amount of blood collected when blood is collected into a blood container, and an output of the measurement sensor. A blood sampling device comprising a control means that calculates the amount of blood to be collected on the assumption that y constitutes a function of y=f(w) with respect to the measured amount of blood to be collected, and the control means is configured to operate when the measured amount of blood to be collected w is zero. Automatically captures the output y0 of the measurement sensor under certain conditions at regular intervals,
The offset value of y=f(w) is corrected based on this y0.

According to a second aspect of the present invention, the measurement sensor is a weight sensor for measuring the weight of blood sample.

The present invention according to claim 3 is a blood collection device that sets the blood container in a vacuum blood collection chamber and collects blood into the blood container using negative pressure generated in the vacuum blood collection chamber, and detects the pressure in the vacuum blood collection chamber. The control means further includes a pressure measuring means equipped with a pressure sensor for controlling the output z of the pressure sensor relative to the measured pressure p.
The pressure is calculated as a function that constitutes the function = f(p), and furthermore, the output z0 of the pressure sensor under the condition where the measured pressure p is zero is automatically taken in at regular intervals, and this z0 The offset value of z=f(p) is corrected based on .

[Operation] According to the present invention as set forth in claims 1 and 2, the control means is adapted to a function y=f(w) that is established between the output y of the measurement sensor and the measured blood sampling amount (volume or weight) w. Based on this, the blood sampling amount w is calculated from the output y of the measurement sensor. At this time, the control means automatically takes in the output y0 of the measurement sensor under the condition where the measured blood sampling amount w is zero at regular intervals, and calculates the offset of y=f(p) above based on this y0. Correct the value. That is, it is possible to always automatically correct changes due to drift in the offset value of the output of the blood sampling amount measurement sensor, and to ensure the measurement accuracy of the blood sampling amount.

According to the present invention as set forth in claim 3, in addition to calculating the blood sampling amount w, the control means calculates a function z=f that is established between the output z of the pressure sensor and the measured pressure p.
Based on (w), the pressure p in the vacuum blood collection chamber is calculated from the output z of the pressure sensor. At this time, similarly to the correction of the offset value of y=f(w) above, the control means automatically imports the output z0 of the pressure sensor under the condition where the measured pressure p is zero at regular intervals. , the offset value of z=f(p) is corrected based on this z0.
In other words, changes due to drift in the offset value of the output of the pressure sensor can be automatically corrected at all times, and accuracy in measuring the pressure generated in the vacuum blood collection chamber can be ensured.

[Example] Fig. 1 is a front view showing a blood sampling device according to an embodiment of the present invention, Fig. 2 is a side view showing a main part of Fig. 1 cut away, and Fig. 3 is a plan view of Fig. 1. Figure 4 is the first
FIG. 5 is a vacuum circuit diagram, FIG. 6 is a control block diagram, and FIG. 7 is a diagram showing the drift state of the offset value of the sensor.

The blood sampling device 10, as shown in FIGS. 1 to 4,
A display panel 12 is provided on the front of the housing 11,
A vacuum blood collection chamber 13 is formed inside the housing 11. 14 is the opening/closing lid of the blood collection chamber 13, 15 is the lid 1
Hinge 4 and 16 are sealing rubber for sealing the blood collection chamber 13. 14A is a handle of the lid 14.
Further, the blood sampling device 10 includes a vacuum pump 17 and a control device 18 in the lower part of the housing 11.

The vacuum blood collection chamber 13 of the blood collection device 10 is communicated with the inlet port 17A of the vacuum pump 17 so as to be able to reduce the pressure, and is equipped with a bag tray 19 that supports a blood bag (blood container) 1 made of polyvinyl chloride or the like. There is. The blood sampling device 10 applies a predetermined negative pressure to the blood bag 1 supported by the bag receiving tray 19 to collect blood while reducing the pressure in the vacuum blood sampling chamber 13 . At this time, the blood collecting device 10 shakes the bag tray 19 to stir the blood and an anticoagulant such as heparin that has been loaded in the blood bag 1 in advance, and also measures the weight of the blood bag 1 to collect blood. measure quantity.

The structure for swinging the bag receiving tray 19 and the structure for measuring the weight of the blood bag 1 in the blood collecting device 10 are as follows.

First, a pedestal 20 is installed at the bottom of the vacuum blood collection chamber 13, and a swing frame 22 that is rotatable via a support shaft 21 is supported on the pedestal 20.
Further, a swing motor 23 is fixed to the pedestal 20,
and a driving shaft 24 driven by a swing motor 23
is supported. 25 and 26 are toothed pulleys,
27 is a toothed belt. A crank wheel 28 is fixed to one end of the driving shaft 24.
One end of the link 29 is connected to the rotation radius of the
The other end of the link 29 is connected to a connecting piece 30 that is integral with the swing frame 22.

On the other hand, a pair of scale mounting blocks 31 are fixed to the upper surface of the swing frame 22, and both mounting blocks 31
A scale (blood sampling amount measuring means) 33 is supported in a cantilever manner by a support plate 32 that spans the end of the blood sample. Scale 3
3 includes strain gauges 34 as weight sensors attached to two positions on the top surface and two positions on the bottom surface to form a Wheatstone bridge circuit,
The bag receiving tray 19 described above is fixed to the tip of the scale 33 via a weighing table 35 and a receiving plate 36. 37
38 is a stopper that prevents the balance 33 from swinging from side to side.
is a weight sensor amplification unit.

That is, the blood sampling device 10 rotates the driving shaft 24 and the crank wheel 28 by the operation of the swing motor 23, thereby swinging the swing frame 22, and is supported by the swing frame 22 via the scale 33. This means that the bag receiving tray 19 that is in place will be rocked. In addition, the blood sampling device 10 supports a bag tray 19 on a scale 33 that is cantilever-supported on the swing frame 22 via a mounting block 31 and a support plate 32, and a strain gauge based on the deflection deformation of the scale 33. The weight of the blood bag 1 is measured based on the change in the output of 34, and thus the amount of blood collected is measured.

Note that the blood sampling device 10 detects the rotational position of the detection cam 39 provided at the other end of the driving shaft 24 using an optical sensor 40.
Under the condition that the bag receiving tray 19 is temporarily stopped at the lowest point (bottom dead center) and held under a constant posture condition, the swing motor 23 is driven and controlled thereby. The weight of the blood bag 1 is measured as described above.

As shown in FIG. 5, the blood collection device 10 connects the inlet port 17A of the vacuum pump 17 and the vacuum blood collection chamber 13 with a vacuum pipe 41, and connects the vacuum pipe 41 with a
The exhaust valve 43 is closed when the exhaust solenoid 42 is turned on and opened by gravity when the exhaust solenoid 42 is turned off. The blood collection device 10 creates a constant negative pressure (degree of vacuum) in the vacuum blood collection chamber 13 by on/off control of the vacuum pump 17, and opens the exhaust valve 43 at the end of blood collection to close the vacuum blood collection chamber 1.
3 is released to the atmosphere.

The blood collection device 10 includes a tube holder 44 in the upper part of the front side of the housing 11 adjacent to the vacuum blood collection chamber 13, so that the blood collection tube 2 connected to the blood bag 1 housed in the vacuum blood collection chamber 13 can be pulled out. The tube holder 44 includes a tube clamp (blood collection stopping means) 46 driven by a tube clamp solenoid 45, and the tube clamp 46 clamps and closes the blood collection tube 2 to stop the blood collection operation of the blood bag 1. 4
7 is a clamp release button for the tube clamp 46, and 48 is a clamp button for operating the tube clamp 46 in an emergency.

The display panel 12 of the blood sampling device 10 includes a blood sampling amount/vacuum degree switching indicator lamp 49, a blood sampling amount/vacuum degree switching switch 50, a 400ml/200ml switching indicator lamp 51,
400ml/200ml changeover switch 52, stop switch 5
3. Start switch 54, usage bug indicator lamp 5
5, a use bag changeover switch 56 and a blood sampling amount/vacuum degree display section 57 are provided. Note that the blood sampling device 10 is
A power switch 58 is located at the lower front of the housing 11.
A tube holder 59 is provided, and a power connector 60 is provided at the lower rear of the housing 11.

Next, the control device 18 of the blood sampling device 10 will be explained. The control device 18 mainly includes a main control circuit 61, a drive circuit 62, and a display circuit 63, as shown in FIG. Note that 64 is a power supply unit.

The main control circuit 61 includes a CPU (central processing unit) 65 [including a memory in which a control program for a series of operations of the device 10 is written], a memory (storage means) 66, an input/output control unit 67, an LED ( It has a light emitting diode) drive circuit 68, a buzzer 69, and a failsafe circuit 70. The input/output control unit 67 is configured to transfer detection signals from the aforementioned optical sensor 40 that detects the swinging position of the bag receiving tray 19 and the blood leakage sensor 71 that detects blood leakage from the blood bag 1. It's summery.

The memory 66 is composed of a nonvolatile memory such as EA-ROM or EEP-ROM, and can read and rewrite stored data, and can hold stored data even without application of a power supply voltage. The data stored in the memory 66 includes the negative pressure generated in the vacuum blood collection chamber 13, the set amount of blood to be collected into the blood bag 1, the extended period of swinging of the bag tray 19 after blood collection is completed, and the like.

The buzzer 69 indicates the completion of blood collection, vacuum blood collection chamber 1
Error of negative pressure formed in 3, swing motor 2
3, the detection of blood leakage by the blood leakage sensor 71, etc., the sounds are made in different ways.

The failsafe circuit 70 monitors the occurrence of runaway in the CPU 65 and safely stops the device when the runaway occurs.

The drive circuit 62 is connected to the main control circuit 61 and includes an A/D conversion circuit 72. The A/D conversion circuit 72 is connected to the weight sensor amplification unit 38 in which the strain gauge 34 described above is connected, and the pressure sensor 73 provided in the vacuum piping 41 to detect the negative pressure in the vacuum blood collection chamber 13 is connected to the pressure sensor 73 that is connected to the vacuum piping 41 described above. It is connected via a sensor amplification circuit 74.

At this time, the CPU 65 of the control device 18 determines that the output y of the strain gauge 34 is y=aw for the measured blood sampling weight w.
The weight of blood collected is calculated assuming that it constitutes a linear function +b. In addition, the CPU 65 also controls the pressure sensor 7.
The pressure is calculated on the assumption that the output z of No. 3 constitutes a linear function of z=cp+d with respect to the measured pressure p.

The drive circuit 62 also includes a solenoid drive circuit 75 that controls the tube clamp solenoid 45, a solenoid drive circuit 76 that controls the exhaust solenoid 42, a pump drive circuit 78 that turns on/off the power supply switch 77 of the vacuum pump 17, and a swing motor. A motor drive circuit 80 is provided to turn on/off the power supply switch 79 of 23.

The CPU 65 of the control device 18 obtains the detected pressure of the pressure sensor 73 and the set pressure of the vacuum blood collection chamber 13, which is data stored in the memory 66, and adjusts the vacuum so that the detected pressure matches the set pressure. The power supply switch 77 of the pump 17 is controlled on/off as described above. As a result, vacuum blood collection chamber 1
The negative pressure in step 3 changes minutely within a certain range of the set pressure,
The result is a constant pressure state.

Next, a blood sampling operation procedure using the blood sampling apparatus 10 will be described.

Turn on the power switch 58.

The amount of blood to be collected is selected using the 400ml/200ml changeover switch 52. This selection result is shown in the switching display lamp 5.
1 is displayed.

The bag to be used is selected by the bag to be used switch 56. This selection result is displayed on the display lamp 55.
will be displayed. The types of bags used include single (S), which includes only a parent bag, double (D), which also includes one or more small bags, triple (T), and quadruple (Q).

A blood collection needle provided at the end of the blood collection tube 2 is inserted into a blood donor, and a certain amount of blood is collected.

Blood bag 1 is placed in vacuum blood collection chamber 13 and placed on bag receiving tray 19, and blood collection tube 2 is set in tube holder 44.

Turn on the start switch 54. Control device 18
drives and controls the vacuum pump 17 and swing motor 23 to collect blood by reducing the pressure in the vacuum blood collection chamber 13 and swing the bag tray 19. In addition, the control device 1
8 is the timing when the bag tray 19 temporarily stops at the lowest point, and the weight sensor amplification unit 38
, the measured blood collection amount of blood bag 1 is detected, and using the set blood collection amount written in the memory 66, blood specific gravity, and pre-registered weight of blood bag 1, the following formula (1) is calculated. Calculate the remaining blood collection amount (volume).

Remaining blood sample amount (ml) = [contact blood sample amount (g) + pre-registered weight (g) - measured blood sample amount (g)]/specific gravity (g/ml)...(1) The control device 18 uses the above calculation result to On the condition that a certain amount of remaining blood to be collected reaches zero, the tube clamp 46 closes the blood collection tube 2 and stops the operation of collecting blood into the blood bag 1. At this time, the control device 18 stops the vacuum pump 17 and opens the exhaust valve 43 to release the vacuum blood collection chamber 13 to the atmosphere.

After the blood collection is completed, the control device 18 extends and drives the swing motor 23 for a predetermined period of time to swing the bag tray 19. After that, a buzzer notifies you that blood collection is complete.

The clamp release button 47 is turned on, the blood collection tube 2 is removed from the tube holder 44, and the blood bag 1 is taken out from the vacuum blood collection chamber 13.

In the case of the CPU 65 of the control device 18, the power switch 58 is turned on and the following ( In A) and (B), the offset value b of the strain gauge 34 and the offset value d of the pressure sensor 73 are corrected.

(A) As mentioned above, the CPU 65 automatically captures the output y0 of the strain gauge 34 under the condition that the measured blood sample weight w is zero at regular intervals, and calculates b of y=aw+b mentioned above based on this y0. to correct. Specifically, using the offset value b01 already written in the memory 66 in the previous correction stage as a reference, if the above y0 in the current correction stage is y0≦b01+m (for example, m=3g), the above y0 is used as the new offset value. is adopted and stored in the memory within the CPU 65, and if y0>b01+m, it is determined that an object has been loaded into the sensor, and the previous b01 is adopted this time as well.

(B) As mentioned above, the CPU 65 automatically captures the output z0 of the pressure sensor 73 under the condition where the negative pressure p of the vacuum blood collection chamber 13 is zero at regular intervals, and
Based on z0, d in the above-mentioned z=cp+d is corrected. Specifically, using the offset value d01 already written in the memory 66 in the previous correction stage as a reference, the above z0 in the current correction stage satisfies z0≦d01+
If r (for example, r = 3 mmHg), the above z0 is adopted as a new offset value and stored in the memory in the CPU 65, and if z0 > d01 + r, it is determined that a pressure change due to the start of blood collection has already occurred. The previous d01 will be maintained this time as well.

Next, the operation of the above embodiment will be explained.

According to the above embodiment, the offset value b of the function y=aw+b formed by the output y of the strain gauge 34 with respect to the measured blood sample weight w is automatically corrected at regular intervals according to (A) above. Therefore, the strain gauge 34
It is possible to always automatically correct changes due to drift in the offset value b of the output of the blood sample, thereby ensuring accuracy in measuring the weight of blood sample.

Furthermore, the offset value d of the function z=cp+d formed by the output z of the pressure sensor 73 with respect to the measured pressure p is also
According to (B) above, it is automatically corrected at regular intervals. Therefore, changes due to drift in the offset value d of the output of the pressure sensor 73 are always automatically corrected, and the measurement accuracy of the pressure generated in the vacuum blood collection chamber 13 can also be ensured.

In addition, in the present invention, the above-mentioned y=f(w) and z=f(p) are not linear functions, but quadratic functions, exponential functions,
Basically, the same can be applied to the case of logarithms.

[Effects of the Invention] According to the present invention as set forth in claims 1 and 2, it is possible to always automatically correct changes due to drift in the offset value of the output of the blood sampling amount measurement sensor, and to ensure the measurement accuracy of the blood sampling amount. can.

According to the third aspect of the present invention, changes due to drift in the offset value of the output of the pressure sensor are always automatically corrected, and accuracy in measuring the pressure generated in the vacuum blood collection chamber can also be ensured.

[Brief explanation of drawings]

FIG. 1 is a front view showing a blood sampling device according to an embodiment of the present invention, FIG. 2 is a side view showing a main part of FIG. 1 broken away, FIG. The figure is the first
FIG. 5 is a vacuum circuit diagram, FIG. 6 is a control block diagram, and FIG. 7 is a diagram showing the drift state of the offset value of the sensor. 1...Blood bag (blood container), 10...Blood sampling device,
13...Vacuum blood collection chamber, 34...Strain gauge (measurement sensor), 65...CPU (control means), 73...Pressure sensor.

Claims (1)

[Scope of Claims] 1. When blood is collected into a blood container, it has a blood collection amount measuring means equipped with a measurement sensor for measuring the blood collection amount, and the output y of the measurement sensor is expressed as y=f( w), the control means is configured to keep the output y0 of the measurement sensor constant under a state where the measured blood collection amount w is zero. is automatically captured every cycle, and based on this y0 the above y=
A blood sampling device equipped with an automatic sensor correction function, characterized in that the offset value of f(w) is corrected. 2. The blood sampling device with an automatic sensor correction function according to claim 1, wherein the measurement sensor is a weight sensor for measuring the weight of blood sampled. 3 A blood collection device that sets the blood container in a vacuum blood collection chamber and collects blood into the blood container using negative pressure generated in the vacuum blood collection chamber, and is equipped with a pressure sensor for detecting the pressure of the vacuum blood collection chamber. The control means further comprises measuring means, and the control means is configured to measure the output z of the pressure sensor.
The pressure is calculated as a function of z=f(p) for the measured pressure p, and the output of the pressure sensor under the condition where the measured pressure p is zero.
3. A blood sampling device equipped with an automatic sensor correction function according to claim 1 or 2, wherein zo is automatically taken in at regular intervals and the offset value of z=f(p) is corrected based on this z0. .