JPH0433231B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Technical Field> The present invention relates to a tube occlusion monitoring device for an infusion pump, and more particularly to a device for monitoring tube occlusion between a drug solution bag and a pump head.

<Prior Art> Medical infusion pumps are required to have high reliability in their operation. For this purpose, many self-monitoring functions are required, one of which is a function to detect the blockage state of a tube used for infusion.

The blockage of the tube between the pump and the drug solution (infusion) bag containing the drug solution is called upstream blockage.The causes of this upstream blockage are (a) forgetting to open the upstream clamp, and (b) closing the upstream filter. There is a blockage, etc.

Even if the pump continues to operate without these causes being detected, the chemical solution will not flow as long as the tube remains blocked. Therefore, no fluid is injected into the human body (patient).

<Objective of the invention> The present invention provides a function to monitor upstream blockage of an infusion pump, prevents the supply of drug solution from stopping due to upstream blockage, and improves the reliability of the infusion pump. .

<Example> Hereinafter, the configuration of the present invention will be described with reference to the drawings.

FIG. 1 shows the configuration of a tube occlusion monitoring device for an infusion pump according to an embodiment of the present invention.

In the figure, 1 is a drug solution bag (medicine solution storage section) in which a drug solution (infusion) is stored, and the drug solution bag 1
The chemical solution inside is set into the pump system 3 through a tube 2 connected to the drug solution bag 1.

The pump system 3 has a pump head 4 inside. The pump head portion 4 has a rotatable structure, and its tip portion is designed to squeeze the tube 2. Then, the control of the pump head section 4, that is, the control of the pump head section 4,
By rotating the tube 2 and exerting a peristaltic action on the tube 2, a prescribed flow rate of the medicinal solution is injected (infusion) into the human body (patient) 5. Note that a needle portion 6 that is pierced into the human body 5 is attached to the tip of the tube 2.

The pump system 3 is also provided with a sensor 7. The sensor 7 detects the degree of swelling of the tube 2 between the drug solution bag 1 and the pump head section 4 by an active or passive method.

The detection methods of the sensor 7 include (a) pressure sensor, (b) strain gauge sensor, (c) ultrasonic sensor, and (d)
The upstream portion of the tube 2 is detected by the sensor 7 continuously monitoring the swelling of the tube 2 based on a predetermined detection method.
That is, the closed state of the tube in the range indicated by 8 in the figure can be monitored.

Next, a monitoring method of the upstream monitoring device will be explained.

In this embodiment, the above-mentioned (a) pressure sensor method is adopted as the detection method of the sensor 7.

Due to the properties of the tube 2, such as its material, after the sensor 7 starts contacting the tube 2,
It operates to continue the contact state. That is, as long as pressure is continued to be applied, the tube 2 will work in a direction to reduce the swelling over time even if there is no upstream blockage. This phenomenon is called a creeping phenomenon.

The creeping phenomenon is shown in FIGS. 2a, b, and c. In the figure, 2 corresponds to the tube (upstream side), and 7 corresponds to the sensor 7.

The sensor 7 is adapted to move in conjunction with a door (not shown) of the pump head section 4. That is, in FIG. 1A, the door of the pump head section 4 is still open, and the tube 2 and the sensor 7 are not yet in contact with each other.

When the door of the pump head section 4 is closed, the sensor 7 presses the tube 2, as shown in FIG.

After that, as time passes, the tube 2
is gradually contracted by being pressed by the sensor 7. As shown in figure c.

The speed of contraction of the tube 2 due to this creeping phenomenon shows a shape close to a logarithmic curve.

When the contraction of the tube 2 is graphed based on the pressure value detected by the sensor 7 and time, the third
As shown in the diagram.

In the figure, the vertical axis indicates the pressure P in the tube 2 detected by the sensor 7, and it is assumed that the smaller the value of this pressure P, the more the tube 2 is contracted. Also, the horizontal axis represents time H.

Time H ₀ is the time when the door of the pump head section 4 is closed, and time H ₁ is the time when the pump starts operation (start).
represents the point in time.

Therefore, the area indicated by A in the graph shows the state from when the tube 2 is set in the pump head section 4 and the door of the pump head section 4 is closed until the motor starts rotating. At this time (time width T _A ), regardless of the presence or absence of upstream occlusion, the infusion itself is not being performed, so there is no large difference in the swelling of the tube 2, and the swelling of the tube 2 is large. It does not change.

On the other hand, when entering the region indicated by B in the same graph, that is, after the pump is started, the change in pressure P becomes as shown by curve I when there is no upstream blockage. However, if there is an upstream blockage in the same area,
Since the chemical liquid is not supplied from the chemical liquid bag 1, the chemical liquid in the tube 2 rapidly decreases, and the change in the pressure P becomes as shown by the curve J.

Since the change curves I and J are close to logarithmic curves, the sampling interval of the pressure P value needs to be gradually widened from a short time interval to a long time interval. This is because when the time T _A from closing the door of the pump head section 4 to starting the pump becomes longer, the tube 2 has already shrunk sufficiently due to the creeping phenomenon described above.
This is because the speed of contraction of the bulge in the tube 2 decreases, and even if an upstream blockage occurs due to this, it becomes difficult to determine unless a long time difference is observed.

Therefore, in this example, the sample interval was set as shown by T. On the same graph, x ₁ is the sample value at time T ₁ , x ₂ is the sample value at time T ₂ , and x ₃ , x ₄ , x ₅ are the times T ₃ , T when the pressure P shows the change of curve I. ₄ , sample value at T ₅ , x′ ₃ ,
x' ₄ and x' ₅ are sample values at times T ₃ , T ₄ , and T ₅ when the pressure P shows a change according to the curve J.

Here, the criteria for determining upstream blockage will be explained using the graph of FIG. 4.

In the graph, the vertical axis indicates the pressure P of the tube 2 detected by the sensor 7, and it is assumed that the smaller the value of this pressure P, the more the tube 2 is contracted. The direction of contraction is indicated by an arrow Q. Also, the horizontal axis represents time H.

Time H ₀ is the time when the door of the pump head section 4 is closed, and time H ₁ is the time when the pump starts operation (start).
represents the point in time.

Furthermore, T indicates the sample interval.

As shown in the figure, when T ₄ is the latest sample timing and the pressure value sampled at the sample timing T _A is x ₄ , it is determined that there is no upstream blockage _;
In order to determine that there is an upstream blockage when the sampled pressure value is x′ ₄ , the following criteria can be considered.

(b) The pressure value sampled at time T ₄ (i.e., x ₄ for curve I and x' ₄ for curve J) is a constant value that is greater than the pressure values x ₁ , x ₂ , x ₃ sampled in the past. or lower.

(b) The pressure values sampled at time T ₄ are x ₁ , x ₂ ,
x ₃ e% value (100>e) or less (prescribed percentage or less)
To be.

(c) Judgment is made from the sampled pressure value. That is, D ₂ ′≧D ₁ as D ₁ =x ₁ −x ₃ D _′ 2 =x ₂ −x′ ₄ .

When it is determined that an upstream blockage has occurred according to the above-mentioned criteria, the pump system 3 is provided with a device that notifies the outside of this fact. The notification is made by generating a visual or audible alarm. Furthermore, when it is determined that an upstream blockage has occurred, the pump operation is stopped to prevent the pump from being in an abnormal state any longer.

FIG. 5 shows a block diagram of the pump system 3.

In the figure, reference numeral 7 corresponds to the sensor, and the tube pressure value detected by the sensor 7 is sampled by a device 9 having a sampling function and stored in the memory 10.

The memory 10 has a memory x _o that stores the most recently sampled data and a memory x _{o-1 .} . . x _ol that stores past sample data. Therefore, the oldest data is stored in the memory x _ol .

The sample timing of the device 9 is determined by a sample timing generator 11. That is, the sample timing generator 11 includes a memory 1 that stores timing intervals t ₁ , t ₂ . . . t _n in advance.
It is equipped with 2. Based on the timing intervals t ₁ , t ₂ . . . t _o stored in the memory 12, the sample timing generator 11 sequentially performs the following steps:
generating a pulse signal, thereby causing said device 9 to
is activated.

In the figure, reference numeral 13 denotes a determination unit that determines whether an upstream blockage has occurred based on the pressure value stored in the memory 10.

The determination process of the determination unit 13 is based on the above-mentioned criteria.
(a), (b) or (c) shall be accomplished accordingly.

When determining that an upstream blockage has occurred, the determination unit 13 drives the alarm 14 to notify the outside of the event. Specifically, the alarm device 14 includes a buzzer, a voice synthesizer output device, a liquid crystal display device, a light emitting diode, and the like. Furthermore, by determining the occurrence of upstream blockage, the determination unit 13
sends a signal to the motor controller 15. In response, the motor controller 15 stops driving the motor 16. The motor 16 rotates the pump head section 4, and when the motor 16 stops, the rotation of the pump head section 4 is stopped and the infusion is interrupted. The doctor, nurse, etc. immediately releases the upstream blockage and takes appropriate measures to promptly restore normal transfusion.

FIG. 6 is a flowchart showing the details of the determination processing by the determination section 13.

In this flowchart, the above-mentioned criterion (a) is used as the criterion for determining upstream blockage. In addition, the memory 10 is provided with three memories x ₁ , x ₂ , x ₃ , the latest sample data is stored in the memory x ₁ , the previous sample data is stored in the memory x ₂ , and the sample from the time before the previous one is stored in the memory x ₃ . I am trying to store data.

After turning on the power (step _S0 ), it is determined whether the door of the pump head section 4 is closed (step _S1 ), and if the door is open, the pump is stopped (step _S2 ).

On the other hand, when the door is closed, the process proceeds from step _S1 to step _S3 , where the sample timing is initialized.

Thereafter, the pump is kept in a stopped state until pump start is detected in step _S4 . (S ₅ steps) Then, it is determined whether it is sample timing or not (S ₆ steps), and if it is not sample timing, the above
The process returns to step _S1 , and on the other hand, when it is sample timing, the pressure value detected by the sensor 7 is sampled (step _S7 ).

Then, after completing the process of step _S7 ,
The sample data is shifted in the memory 10. That is, the storage contents of the memory x ₂ are transferred to the memory
At the same time, the contents of _{the memory x 1 are} transferred to the memory x ₂ (step S ₈ ).

Subsequently, the pressure value sampled in step _S7 is stored in the memory _x1 (step _S9 ).

Thereafter, in step _S10 , the difference between the sample data stored in the memory _x2 and the sample data stored in the memory _x1 is determined, and it is determined whether the determined difference is greater than or equal to a constant M.

If x ₂ -x ₁ ≧M, it is determined that an upstream blockage has occurred, and the process proceeds to step _S11 , where the alarm 14 issues an alarm and the pump is stopped.

If it is determined in step _S10 that x ₂ −x ₁ <M, the process proceeds to step _S12 , where the sample data stored in the memory _x3 and the memory
The difference between the sample data stored in _x1 is determined, and it is determined whether the determined difference is greater than or equal to a constant M.

If x ₃ -x ₁ ≧M, it is determined that an upstream blockage has occurred, and the process proceeds to step _S11 .

On the other hand, if it is determined in step _S12 that _x3 - _x1 <M, the process returns to step _S1 and the same process is performed.

In the above flowchart, the newest sample value is x _o , and if the sample value x _o is lower than the past sample value x _ol (l = 1, 2, 3...) by a constant value M or more, upstream blockage occurs. Although it has been determined that this has occurred, when using other criteria, it is necessary to provide a corresponding circuit configuration.

That is, the x _o is the x _ol (l=1, 2, 3...)
When determining that an upstream blockage has occurred when the e% value (100> _e ) of
In addition to providing an arithmetic circuit for determining the e% value of each value of 2, 3, . . . ), it is also necessary to provide a comparison circuit for comparing the e% values of x _o and x _ol .

Also, the difference in sample values, that is, D _o =x _o −x _o-3 ,
When using D _o+1 = x _o+1 −x _o-2 and determining that an upstream blockage has occurred when D _o+1 ≧ D _o , an arithmetic circuit for calculating the difference is provided, and D A comparison circuit is required to compare the magnitudes of _o and D _o+1 .

In short, by making a relative comparison between the sampled data, it is determined that a blockage condition has occurred in the tube.

As described above, the tube occlusion monitoring device for an infusion pump according to an embodiment of the present invention has the following configuration.

(A) A sensor 7 capable of detecting the degree of swelling of the tube 2 is provided between the pump head portion 4 of the infusion pump and the drug solution bag 1 containing the drug solution.

(B) Sample changes in the value detected by the sensor 7 at certain standard time intervals over time.

(C) Among the sample values sampled in (B) above, it has a function of storing the newest sample value x _o and past sample values x _o-1 , x _o-2 . . .

(D) Sample values x _o and x _ol (l
= 1, 2, 3...), and when it is determined by a certain criterion that the swelling of the tube 2 is clearly disappearing between x _o and x _ol , It is determined that an upstream blockage has occurred in the tube 2 between the pump head section 4 and the chemical solution storage section 1, and measures against the human body such as issuing a visual or audible alarm or stopping rotation of the pump are taken. Must have a function to avoid danger.

(E) As an example of the criteria for relative judgment in (D) above, (a) x _o is lower than x _ol (l = 1, 2, 3...) by a certain constant value or more.

(b) x _o is less than the e% value (100>e) of x _ol (l = 1, 2, 3...).

(C) If D _o =x _o −x _o-3 and D _o+1 =x _o+1 −x _o-2 , then D _o+1 ≧D _o .

<Effects> As described above, according to the present invention, in an infusion pump having a liquid medicine storage part and a head part that exerts an infusion action on a tube connected to the liquid medicine storage part by rotation of a rotating part, a detection means for detecting the bulge of the tube between the chemical solution storage part and the head part; a sample means for sampling the value detected by the detection means; a first storage means for storing sampling timing intervals in advance; a sample timing generator for generating a signal based on data stored in the first storage means; a second storage means for sequentially storing data sampled by the sampling means; and storage in the second storage means. and a determining means for determining that the tube is obstructed based on a relative determination criterion of sample data, and the tube is monitored for the obstructed condition. This prevents a situation in which the infusion is not performed and improves the reliability of the infusion pump.

[Brief explanation of drawings]

Fig. 1 is a structural diagram of a tube occlusion monitoring device for an infusion pump according to an embodiment of the present invention, Fig. 2 is an explanatory diagram of the creeping phenomenon, Fig. 3 is a graph showing changes in tube pressure, and Fig. 4 5 is a block circuit diagram of the apparatus, and FIG. 6 is a flowchart showing the contents of the tube blockage determination process. DESCRIPTION OF SYMBOLS 1...Medical solution bag (medicinal solution storage part), 2...Tube, 3...Pump system, 4...Pump head section, 5...Human body (patient), 7...Sensor, 9...
...Sample means, 10...Memory, 11...Sample timing generator, 13...Judgment means, 14
... Alarm, 15 ... Motor controller, 16
……motor.

Claims (1)

[Scope of Claims] 1. In an infusion pump having a drug solution storage section and a head section that exerts an infusion action on a tube connected to the drug solution storage section by rotation of a rotating section, the drug solution storage section and the head section a detection means for detecting a bulge of the tube between the parts; a sampling means for sampling a value detected by the detection means; a first storage means for storing sampling timing intervals in advance; and the first storage means. a sample timing generator that generates a signal based on data stored in the sample timing generator; a second storage unit that sequentially stores data sampled by the sampling unit; and a sample timing generator that generates a signal based on data stored in the sampling unit; A tube occlusion monitoring device for an infusion pump, characterized in that the tube occlusion monitoring device for an infusion pump is characterized in that the tube occlusion monitoring device is characterized in that the occlusion state of the tube is monitored, and the occlusion state of the tube is monitored. . 2. The tube occlusion monitoring device for an infusion pump according to claim 1, wherein the criterion is that the latest sample data is lower than the past sample data by a constant value or more. 3. The tube occlusion monitoring device for an infusion pump according to claim 1, wherein the criterion is that the newest sample data is less than or equal to a predetermined percentage of past sample data. 4 The above standard is based on the above sample data as X _o+1 , X _o , X _o-1 , X _o-2 , X _{o-3 ... in} order of newest, _and The tube occlusion monitoring device for an infusion pump according to claim 1, wherein when _o = X _o -X _o-3 , D _o+1 ≧D _o . 5. A tube occlusion monitoring device for an infusion pump according to claim 1, further comprising an alarm that generates an alarm when the determination means determines that the tube is obstructed. . 6. The tube occlusion monitoring device for an infusion pump according to claim 5, wherein the alarm comprises a device that outputs a visual alarm. 7. The tube occlusion monitoring device for an infusion pump according to claim 5, wherein the alarm comprises a device that outputs an audible alarm. 8. The infusion pump according to claim 1, further comprising a stop means for stopping the driving section of the head section when the judgment means judges that the tube is blocked. tube occlusion monitoring device.