Online blockage detection device based on infusion pump pipeline and detection method thereof

Abstract

The application relates to the technical field of medical infusion pump flow detection, and particularly discloses an online blockage detection device based on an infusion pump pipeline and a detection method thereof. The detection device comprises a top cover and a base fixed on and off through a connecting column and a pressure-sensitive element composed of a deformed base and a strain gauge, and can adapt to different types of infusion pumps through structural optimization design. The detection method is based on a waveform matching method, and the consistency of the blockage detection and judgment result of the infusion pump pipeline under complex working conditions is realized through difference judgment preprocessing, normalization processing and difference calculation. The infusion pump pipeline blockage detection scheme is a non-invasive detection scheme, and has the advantages of simple preparation process, small size, low cost, good reliability and the like.

Description

Technical Field

[0001] This invention relates to the field of medical infusion pump flow detection technology, specifically to an online blockage detection device and method based on infusion pump tubing. Background Technology

[0002] Blockage detection devices are crucial for the normal and stable operation of infusion pumps. With the increasingly widespread use of infusion pumps in the medical field, they have become indispensable medical equipment for postoperative analgesia, cancer pain, and childbirth analgesia, greatly alleviating the pathological, physiological, and psychological problems caused by pain in patients. Because direct contact blockage detection methods within the infusion tubing carry high risks, non-contact, indirect measurement methods are now more commonly used for blockage detection in infusion lines.

[0003] Currently, in non-contact blockage detection solutions, pressure sensing schemes that detect blockages in infusion lines based on preset pressure differences may encounter problems. These problems can arise from manufacturing errors in different batches of infusion pumps, leading to discrepancies between the actual and preset pressure differences. Other issues include differences in installation contact pre-pressure due to frequent replacement of disposable medication tubing, and reduced pump volume per cycle resulting in a lower actual pressure difference than the preset value. All of these factors negatively impact the stability of pressure detection in infusion lines, leading to inconsistent results, an inability to reliably detect abnormal blockages during infusion in the long term, a high false alarm rate, and an inability to meet normal usage requirements. Summary of the Invention

[0004] Therefore, the purpose of this invention is to address the shortcomings of existing technologies by providing an online blockage detection structure and method based on infusion pump pipelines.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: An online blockage detection device based on an infusion pump pipeline includes a top cover and a base fixed together by a connecting column. A sensitive element is provided at the end of the base near the infusion pipeline, and an arc groove matching the outer diameter of the pipeline is provided at the end of the top cover near the infusion pipeline. The sensitive element includes a deformable base and a strain gauge. The deformable base is a double-ended fixed support beam with a central protrusion structure, and the protrusion structure is oriented towards the infusion pipeline. The strain gauge is located at the bottom of the deformable base and is closely attached to the base.

[0006] As a further improvement of the present invention, the elastic modulus of the top cover material and the base material is higher than that of the infusion tubing material.

[0007] As a further improvement of the present invention, the deformable substrate material is a material with high fatigue performance and high temperature resistance.

[0008] As a further improvement of the present invention, the strain gauge is covered with an encapsulation film, and the encapsulation film material is any one of ordinary rubber, polydimethylsiloxane (PDMS), and Ecoflex series silicone rubber. The detection method based on an online blockage detection device for infusion pump tubing includes the following steps: (1) Block the infusion line and measure and record the pressure change curve and pressure sequence value detected by the sensor when the infusion pump is working. Use the pressure sequence value as the target template signal sequence under the blockage condition, denoted as y. 0。

[0009] (2) Select products from different production batches and perform (1) operation multiple times; fit the target template signal sequence using the least squares method as the blocking template signal sequence, denoted as y, and normalize the blocking template signal sequence to obtain the normalized blocking template sequence Y, i.e.: .

[0010] (3) The normalized blocking template waveform signal in (2) is used as the preset value and input into the microcontroller chip processing program in advance.

[0011] (4) Start online blockage detection, continuously collect the pressure sequence values ​​detected by the sensor, and use them as the detection signal sequence under online detection conditions, denoted as x; normalize the sequence to obtain the normalized detection signal sequence X, i.e.: .

[0012] (5) Difference Calculation: The degree of difference between the detected signal sequence and the template signal sequence is defined as D. .

[0013] (6) Set the blockage judgment threshold k. If D < k, it means that the current detection signal is similar to the target template signal under the blockage condition, that is, it is judged that the pipeline is blocked at this time; otherwise, it is normal.

[0014] As a further improvement of the present invention, a threshold judgment condition can be set before the detection signal sequence x in (4) is normalized. If max(x)-min(x)<s, it means that the circuit noise influence is the dominant factor and the detection ends; otherwise, the normal operation is performed; where s is the circuit noise threshold.

[0015] The beneficial effects of this invention are: This invention provides an online blockage detection device based on infusion pump pipelines. It employs a non-invasive detection method and optimizes the design to create a specific pressure sensor suitable for electronic infusion pumps. The device has advantages such as simple manufacturing process, small size, low cost, and long service life.

[0016] This invention, based on an online blockage detection device for infusion pump tubing, combines an optimized target template matching algorithm with preprocessing for difference judgment, normalization, and difference degree calculation. This achieves consistency in the blockage detection results for infusion pumps, effectively addressing the discrepancies between actual and preset pressure differences caused by different production batches, frequent replacement of disposable medication tubing, and variations in pump volume. It enables long-term, reliable detection of abnormal blockage events occurring during infusion pump operation, resolving the technical pain point of false alarms. Furthermore, its low chip computing power requirements significantly reduce manufacturing costs. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Appendix Figure 1 This is a flowchart of the detection method of the present invention.

[0019] Appendix Figure 2 This is a waveform diagram for the blockage detection of the present invention.

[0020] Appendix Figure 3 This is a structural diagram of the detection device of the present invention.

[0021] Appendix Figure 4 This is a partial structure of the detection device of the present invention. Figure 1 .

[0022] Appendix Figure 5 This is a partial structure of the detection device of the present invention. Figure 2 .

[0023] In the figure: top cover 1, infusion line 2, sensitive element 3, base 4, arc groove 1a, deformable base 3a, strain gauge 3b. Implementation

[0024] The technical solutions in the embodiments of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0025] like Figure 1-3 As shown, the online blockage detection structure based on the infusion pump pipeline includes a top cover 1 and a base 4 fixed vertically by connecting columns. A sensitive element 3 is mounted on the base 4 near the end of the infusion pipeline 2. The top cover 1 has an arc-shaped groove 1a matching the outer diameter of the pipeline at the end near the infusion pipeline 2. The sensitive element 3 includes a deformable base 3a and a strain gauge 3b. The deformable base 3a is a double-ended fixed support beam with a central protrusion facing the infusion pipeline 2. This design reduces the contact area between the infusion pipeline 2 and the sensitive element 3, ensuring a more concentrated pressure distribution when the sensitive element 3 is compressed by the pipeline. The strain gauge 3b is located at the bottom of the deformable base 3a and closely attached to the base 4. This invention designs a small hydraulic sensor suitable for electronic infusion pumps based on the strain gauge 3b.

[0026] Furthermore, the elastic modulus of the materials of the top cover 1 and the base 4 is higher than that of the material of the infusion tubing 2; Furthermore, the deformable substrate 3a material is made of high fatigue performance and high temperature resistance; preferably stainless steel, aluminum alloy and other metal materials or engineering plastic materials with good injection molding performance such as polyoxymethylene (POM) and polyether ether ketone (PEEK).

[0027] Furthermore, the strain gauge 3b is covered with an encapsulation film, the encapsulation film material of which is any one of ordinary rubber, polydimethylsiloxane (PDMS), or Ecoflex series silicone rubber. These materials possess high insulation, high elasticity, high elongation, and low elastic modulus, exhibiting good elastic recovery and minimal impact on sensor stability.

[0028] To improve the thermal stability of the sensor, the resistive material of the internal strain gauge 3b of the sensitive element 3 is preferably constantan or neoconstantan, which has a low temperature coefficient of resistivity, and a temperature change of one part per hundred thousand will produce a resistance change per unit degree Celsius.

[0029] The detection method based on the online blockage detection device for infusion pump pipelines includes the following steps: (1) Block the infusion line and measure and record the pressure change curve and pressure sequence value detected by the sensor when the infusion pump is working. Use the pressure sequence value as the target template signal sequence under the blockage condition, denoted as y. 0。

[0030] (2) Select products from different production batches and perform (1) operation multiple times; fit the target template signal sequence using the least squares method as the blocking template signal sequence, denoted as y, and normalize the blocking template signal sequence to obtain the normalized blocking template sequence Y, i.e.: .

[0031] (3) The normalized blocking template waveform signal in (2) is used as the preset value and input into the microcontroller chip processing program in advance.

[0032] (4) Start online blockage detection, continuously collect the pressure sequence values ​​detected by the sensor, and use them as the detection signal sequence under online detection conditions, denoted as x; normalize the sequence to obtain the normalized detection signal sequence X, i.e.: .

[0033] (5) Difference Calculation: The degree of difference between the detected signal sequence and the template signal sequence is defined as D. .

[0034] (6) Set the blockage judgment threshold k. If D < k, it means that the current detection signal is similar to the target template signal under the blockage condition, that is, it is judged that the pipeline is blocked at this time; otherwise, it is normal.

[0035] Before normalizing the detection signal sequence x in (4), a threshold judgment condition can be set. If max(x)-min(x)<s, it means that the circuit noise influence is the dominant factor and the detection ends; otherwise, the operation is normal. Where s is the circuit noise threshold.

[0036] Specifically, if the electronic infusion pump is manufactured with high precision and the dimensional differences between different batches are small, the blockage detection threshold can be appropriately lowered. Conversely, if the dimensional differences between different production batches of infusion pumps are large, i.e., the waveform differences in pressure changes during pumping are large, the blockage detection threshold can be appropriately increased. In actual use, the threshold k can be adjusted appropriately according to needs to obtain better alarm effects.

[0037] Specifically, this solution involves intermittent data acquisition by the sensor at identical time intervals, with the initial and final acquisition times being the same, and occurring within the timeframe of characteristic waveform generation during the infusion process. Normalization processing eliminates the influence of varying installation prestress, single pumping volume, and sensor temperature drift signal interference on the absolute pressure measurement of the hydraulic sensor, thereby improving the accuracy of blockage alarms.

[0038] Example 1: The target tubing is made of silicone, with an outer diameter of 4mm and an inner diameter of 2.2mm. The total infusion volume is 0.05ml, and the infusion time is 1s. The sensor is made of polyoxymethylene (POM), with the inner deformable substrate of the sensing element measuring 9mm in length, 4mm in width, and 3.3mm in height; the crossbeam is 5.5mm in length, 4mm in width, and 0.5mm in height. The strain gauges are made of constantan, 5.2mm in length and 2.2mm in width, with 5 sensing grids measuring 1.4mm in length and 1.2mm in width.

[0039] The signal acquisition time interval is 60ms, and the signal sequence length is 11. The program presets the normalized blockage template signal sequence as Y=[0,0.2,0.4,0.6,0.6,0.6,0.6,1,1,0.8,0.4], sets the blockage judgment threshold k=0.2, and the noise filtering threshold s=500. During online monitoring of pipeline blockage, a pressure sequence was detected as: x=[8035039,8035476,8036814,8037334,8037361,8037123,8037095,8037452,8038299,8037424,8036494]. At this time, max(x)-min(x)=3260>500, indicating that pressure change is the dominant factor. After normalization, X=[0,0.13,0.54,0.70,0.71,0.64,0.63,0.74,1,0.73,0.47] was obtained. The difference value D=0.13<0.2, indicating that a blockage has occurred in the pipeline.

[0040] Example 2: When there are significant manufacturing errors in the infusion pumps from different production batches, the blockage judgment threshold k can be appropriately increased to accommodate the changes in the blockage pressure waveform caused by manufacturing errors. The detection device is the same as in Example 1, with a signal acquisition time interval of 60ms and a signal sequence length of 11. The normalized blockage template signal sequence is preset in the program as Y=[0,0.2,0.4,0.6,0.6,0.6,0.6,1,1,0.8,0.4], and the noise filtering threshold s=500 is set. When performing online monitoring of pipeline blockage, if a blockage is detected, a pressure sequence is given by x=[8035447,8035759,8035764,8035809,8035769,8035908,8036020,8035838,8036024,8035903,8035798]. At this time, max(x)-min(x)=577>500, indicating that pressure change is the dominant factor. After normalization, we get X=[0,0.54,0.55,0.63,0.59,0.80,0.99,0.69,1,0.79,0.61]. The calculated difference value D=0.48>0.2, meaning that the blockage judgment threshold k needs to be increased to accommodate the pressure waveform changes caused by manufacturing errors. For example, setting k=0.5 satisfies the condition D=0.48<0.5, thus indicating that a blockage has occurred in the pipeline. It should be noted that the blockage judgment threshold k is generally adjusted during the production of the infusion pump, that is, the value of k is determined according to the manufacturing error of the current batch, and generally does not need to be manually adjusted after it is put into use.

[0041] Example 3: For different types of infusion pumps, the pressure changes in the tubing when the lower end of the tubing becomes blocked may differ. Therefore, the target template signal can be specifically adjusted. The specific dimensions of the detection device remain the same as in Example 1, the signal acquisition time interval is 60ms, and the signal sequence length is 11. The normalized blockage template signal sequence is preset in the program as Y=[0,0.3,0.6,0.85,0.85,0.85,0.85,0.9,1,0.8,0.4], the blockage judgment threshold is set to k=0.5, and the noise filtering threshold is set to s=2500. During online monitoring of pipeline blockage, a pressure sequence x=[8325918,8326955,8327497,8328171,8328745,8328687,8328767,8328126,8328561,8329172,8328927] was detected. At this time, max(x)-min(x)=3255>2500, indicating that pressure change is the dominant factor. After normalization, X=[0,0.32,0.49,0.69,0.87,0.85,0.88,0.69,0.81,1,0.92] was obtained. The difference value D=0.44<0.5, indicating that a blockage has occurred in the pipeline.

[0042] Note: Determining the value of k requires extensive testing and adjustments, as well as judgment based on the magnitude of signal changes, to ultimately determine the optimal value.

[0043] The above are the implementation methods of the embodiments of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the embodiments of this application, and these improvements and modifications are also considered to be within the protection scope of this application.

Claims

1. An online blockage detection device based on infusion pump pipeline, characterized in that, It includes a top cover and a base that are fixed together by connecting columns. A sensitive element is provided at the end of the base near the infusion tubing, and an arc groove matching the outer diameter of the tubing is provided at the end of the top cover near the infusion tubing. The sensitive element includes a deformable base and a strain gauge. The deformable base is a double-ended fixed support beam with a central protrusion structure, and the protrusion structure is oriented toward the infusion pipeline. The strain gauge is located at the bottom of the deformable base and is closely attached to the base. The detection method based on the online blockage detection device for infusion pump lines includes the following steps: (1) Block the infusion line and measure and record the pressure change curve and pressure sequence value detected by the sensor when the infusion pump is working. Use the pressure sequence value as the target template signal sequence under the blockage condition, and record it as y0; (2) Select products from different production batches and perform (1) operation multiple times; fit the target template signal sequence using the least squares method as the blocking template signal sequence, denoted as y, and normalize the blocking template signal sequence to obtain the normalized blocking template sequence Y, i.e.: ； (3) Take the normalized blocking template waveform signal in (2) as the preset value and input it into the microcontroller chip processing program in advance; (4) Start online blockage detection, continuously collect the pressure sequence values ​​detected by the sensor, and use them as the detection signal sequence under online detection conditions, denoted as x; normalize the sequence to obtain the normalized detection signal sequence X, i.e.: ； (5) Difference Calculation: The degree of difference between the detected signal sequence and the template signal sequence is defined as D. ; (6) Set the blockage judgment threshold k. If D < k, it means that the current detection signal is similar to the target template signal under the blockage condition, that is, it is judged that the pipeline is blocked at this time; otherwise, it is normal.

2. The online blockage detection device based on infusion pump pipeline according to claim 1, characterized in that, Before normalizing the detection signal sequence x in (4), a threshold judgment condition can be set. If max(x)-min(x)<s, it means that the circuit noise influence is the dominant factor and the detection ends; otherwise, the operation is normal. Where s is the circuit noise threshold.

3. The online blockage detection device based on infusion pump pipeline according to claim 1, characterized in that, The elastic modulus of the top cover material and the base material is higher than that of the infusion tubing material.

4. The online blockage detection device based on infusion pump pipeline according to claim 1, characterized in that, The deformable substrate material is made of a material with high fatigue performance and high temperature resistance.

5. The online blockage detection device based on infusion pump pipeline according to claim 1, characterized in that, The strain gauge is covered with an encapsulation film, and the encapsulation film material is any one of ordinary rubber, polydimethylsiloxane (PDMS), or Ecoflex series silicone rubber.

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