A method and device for detecting infusion drip rate

Abstract

The present invention relates to a method and device for detecting the dripping rate of an infusion, and belongs to the field of medical technology, in particular to the field of medical intravenous infusion technology; it comprises ten capacitive sensing electrodes arranged on a capacitive sensing sheet from bottom to top, each of which can independently sense capacitance changes, thereby sensing liquid levels; a limiting filtering method is used to perform denoising on the collected data, thereby improving the accuracy of dripping rate calculation, and eliminating the interference of small-amplitude self-oscillation after the drop falls on the dripping rate calculation. The beneficial effect of the present invention is that the device only needs one side of the capacitive sensing electrode to be close to the Murphys dropper, and three sides can be exposed, with the smallest obstruction surface and the largest observable field of view. It can work well both under strong light and in an infrared interference environment. When the infusion is stable, the infusion droplet speed can be well detected.

Description

Technical Field

[0001] The invention relates to a method and a device for detecting an infusion dripping rate, belonging to the field of medical technology, in particular to the field of medical intravenous infusion technology. Background Art

[0002] At present, intravenous infusion is the most commonly used and most important auxiliary treatment method for diseases in clinical medical work. In the field of medical monitoring, many infusion monitoring devices and instruments have emerged for intravenous infusion. These devices have similar functions and are used to monitor the drip rate and other functions of intravenous infusion. In the scheme of detecting the drip rate of infusion, the existing infusion monitoring devices and instruments basically adopt the infrared tube scheme, that is, on the opposite sides of the Murphys tube, one side uses an infrared light emitting diode to send infrared light, and the other side uses an infrared photodiode to receive infrared light to detect the dripping of droplets, so as to calculate the infusion droplet speed. This infrared droplet detection method must have two parts, infrared emission and infrared reception. In use, it must be installed on the opposite sides of the infusion tube droplet. When patients or nurses need to directly observe the droplets in the infusion droplet, this detection method will block more observation fields. This large area of ​​the droplet blocking the infusion affects the function of the infusion tube itself to observe the infusion in a comprehensive manner, causing anxiety to patients and not conducive to patients' peace of mind infusion. In addition, the detection of droplets by infrared method is easily interfered by strong light and infrared light, resulting in the phenomenon of no detection or inaccurate detection in strong light and infrared light environment. Summary of the invention

[0003] The purpose of the present invention is to reduce the obstruction of the Murphys dropper as much as possible, detect the infusion droplets, and not be disturbed by strong light and infrared light, thereby disclosing an infusion drop rate detection method and device based on capacitive sensing.

[0004] The present invention is implemented through the following technical scheme, including ten capacitive sensing electrodes arranged from bottom to top on a capacitive sensing sheet, each of which can independently sense capacitance changes, thereby sensing liquid level; using a limiting filter method to denoise the collected data, thereby improving the accuracy of drip speed calculation and eliminating the interference of small-amplitude self-oscillation after the drop falls on the drip speed calculation.

[0005] The limiting filter method refers to setting the maximum deviation value allowed for two samples. When the deviation between the value of this sampling and the value of the last sampling is greater than the set maximum deviation value, the current sampling value is taken, otherwise it is discarded as invalid interference data. In actual tests, it is found that under different infusion heights, the influence of the small oscillation after the drop falls is different. The higher the height, the greater the oscillation period and oscillation amplitude after falling. Therefore, during the sampling process, the maximum deviation value of the limiting filter is set according to multiple liquid level heights. In addition, in the early stage of dripping, the dripping speed changes greatly. During the sampling process, the sampling time is dynamically adjusted according to the speed change, and the current collected speed value is compared with the last speed value. If the difference changes greatly, the sampling time is shortened, and if the difference changes less, the sampling time is enlarged.

[0006] The main steps of the algorithm include:

[0007] Step 1: First record the low liquid level steady state time , when the drop falls, record the transient time of the high liquid level , As the falling time of the first drop, the velocity of the first drop is calculated;

[0008] Step 2: After the first drop of liquid falls, the low liquid level steady-state time is detected and counted After the second drop of liquid falls, the high liquid level transient time is detected , as the sampling time interval for the second drop;

[0009] Step 3: Collect the droplet velocity data based on the transient time interval between the high liquid level of each two drops, calculate the difference between the velocity collected this time and the velocity collected last time, and set the sampling time interval.

[0010] Step 4: Repeat step 3 to collect multiple sets of data; usually five sets of data;

[0011] Step 5: First, perform limit filtering on the data one by one, and the amplitude value changes according to the previous sampling value, and then calculate the arithmetic mean to obtain the current dripping speed;

[0012] Step 6: Repeat the above steps 4 and 5 for the next calculation of the droplet velocity.

[0013] The present invention is also used to detect whether the liquid level in the drip bucket is too high or too low: when the capacitive sensing electrode at the highest point senses the liquid level, it indicates that the liquid level in the drip bucket is too high;

[0014] When the lower capacitive sensing electrodes cannot sense the liquid level, it indicates that the liquid level in the drip bucket is too low.

[0015] The present invention comprises a capacitive sensing sheet adhered to the wall of the drip bucket, an MCU processing unit, and ten capacitive sensing electrodes arranged from bottom to top on the capacitive sensing sheet; the processing unit of the MCU is based on the detection and processing of the DA14580 Bluetooth control chip.

[0016] The ten capacitive sensing electrodes on the capacitive sensing sheet are connected to the ten IO pins of the MCU processing unit; the MCU processing unit calculates the charge and discharge time for each IO pin, and individually detects the orderly change of the capacitance of each IO pin caused by the falling of the droplet.

[0017] The advantages and beneficial effects of the present invention are that a new droplet detection method and device are proposed, which has a small size and minimizes the obstruction of the Murphys dropper, and does not affect the normal observation function of the Murphys dropper. It can effectively detect droplets, thereby detecting the droplet rate. It solves the problem of large-area surrounding and obstruction of the Murphys dropper existing in traditional infusion detectors, and solves the problem of sensitivity to strong light and infrared interference existing in traditional infrared infusion detectors, and improves the flexibility and reliability of the infusion detector. Nurses and patients can directly observe the infusion of the dropper, and can also read the drip rate and liquid level on the infusion detector, which does not affect the original infusion function of the infusion tube, improves work efficiency, and improves the accuracy of drip rate calculation. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the MCU and the capacitive sensing sheet.

[0019] Figure 2 Schematic diagram of the capacitor sensing sheet.

[0020] Figure 3 Schematic diagram of low liquid level steady state.

[0021] Figure 4 Schematic diagram of the transient state of the high liquid level after the droplet falls. DETAILED DESCRIPTION

[0022] The following is combined with Figures 1 to 4 The preferred embodiment of the present invention is further described. The present invention includes ten capacitive sensing electrodes arranged on the capacitive sensing sheet 1 from bottom to top, marked as 11 to 110 from bottom to top, each capacitive sensing electrode can independently sense the capacitance change, thereby sensing the liquid level; the collected data is denoised by using the limiting filtering method to improve the accuracy of the dripping speed calculation and eliminate the interference of the small-amplitude self-oscillation after the drop falls on the dripping speed calculation.

[0023] The limiting filter method refers to setting the maximum deviation value allowed for two samples. When the deviation between the value of this sampling and the value of the last sampling is greater than the set maximum deviation value, the current sampling value is taken, otherwise it is discarded as invalid interference data. In actual tests, it is found that under different infusion heights, the influence of the small oscillation after the drop falls is different. The higher the height, the greater the oscillation period and oscillation amplitude after falling. Therefore, during the sampling process, the maximum deviation value of the limiting filter is set according to multiple liquid level heights. In addition, in the early stage of dripping, the dripping speed changes greatly. During the sampling process, the sampling time is dynamically adjusted according to the speed change, and the current collected speed value is compared with the last speed value. If the difference changes greatly, the sampling time is shortened, and if the difference changes less, the sampling time is enlarged.

[0024] The main steps of the algorithm are Figure 3 , Figure 4 For example, including:

[0025] Step 1: First record the low liquid level 51 steady-state time , when the first drop 41 falls, record the transient time of the high liquid level 52 , As the falling time of the first drop, the velocity of the first drop is calculated;

[0026] Step 2: After the first drop of liquid 41 falls, the low liquid level 51 is detected and the steady-state time is counted. After the second drop 42 falls, the high liquid level 52 is detected and the transient time is counted. , as the sampling time interval for the second drop;

[0027] Step 3: Collect the droplet velocity data according to the transient time interval between the high liquid level of each two droplets, calculate the difference between the velocity collected this time and the velocity collected last time, and set the sampling time interval.

[0028] Step 4: Repeat step 3 to collect multiple sets of data; usually five sets of data;

[0029] Step 5: First, perform limit filtering on the data one by one, and the amplitude value changes according to the previous sampling value, and then calculate the arithmetic mean to obtain the current dripping speed;

[0030] Step 6: Repeat the above steps 4 and 5 for the next calculation of the droplet velocity.

[0031] The present invention is also used to detect whether the liquid level in the drip bucket 3 is too high or too low: when the highest capacitive sensing electrode, that is, the capacitive sensing electrode labeled 110 senses the liquid level, it indicates that the liquid level in the drip bucket 3 is too high;

[0032] When the lower capacitive sensing electrode, i.e., the capacitive sensing electrode numbered 11, cannot sense the liquid level, it indicates that the liquid level in the drip bucket is too low. After the infusion starts, if no droplets are detected for a long time, and the liquid level is gradually reduced until the capacitive sensing electrode numbered 11 cannot sense the liquid level, it indicates that the infusion is complete. This device and method can be used to prompt patients and nurses to end the infusion or change the dressing in time, and assist nurses in working more efficiently.

[0033] The present invention includes a capacitive sensing sheet 1 attached to the outer wall of the drip bucket 3, ten capacitive sensing electrodes arranged on the capacitive sensing sheet from bottom to top, the capacitive sensing electrodes are marked as 11 to 110 from bottom to top, and an MCU processing unit 2; the MCU processing unit 2 is based on the DA14580 Bluetooth control chip detection and processing.

[0034] The ten capacitive sensing electrodes on the capacitive sensing sheet 1 are connected to the ten IO pins of the MCU processing unit 2; the MCU processing unit 2 calculates the charge and discharge time for each IO pin, and individually detects the orderly change of the capacitance of each IO pin caused by the droplet falling.

[0035] When in use, the capacitive sensing sheet 1 is attached to the outer wall of the drip bucket 3. Figure 2 As shown in FIG. 1 , each drop of liquid in the drip bucket 3 will cause the liquid level of the drip bucket wall to change before and after the drop falls, causing the capacitive sensing sheet 1 to sense different liquid levels before and after the drop falls. After stable infusion, each drop of liquid causes the same fluctuation of the liquid level. Before the first drop of liquid 41 falls, Figure 3 As shown in the figure, the steady-state sensing is a relatively low liquid level 51, the capacitive sensing electrodes 13 and 14 and the capacitive sensing electrodes below them sense a liquid state, and the capacitive sensing electrode 15 and the capacitive sensing electrode above it sense a liquid-free state; Figure 4 It is the high liquid level 52 at the moment when the first drop of liquid 41 falls. Correspondingly, the capacitive sensing plate 1 senses a relatively high liquid level 52. The capacitive sensing electrode piece numbered 16 and the capacitive sensing electrode piece below it sense a liquid state, and the capacitive sensing electrode piece numbered 17 and the capacitive sensing electrode piece above it sense a liquid-free state. The principle is that every time the liquid level in the drip bucket 3 changes significantly, the capacitive sensing electrode piece of the corresponding liquid level of the capacitive sensing plate 1 will output a larger change value, thereby detecting the generation of a drop of liquid. Minimally obstructing the Murphys dropper does not affect the normal observation function of the Murphys dropper. It can effectively detect droplets, thereby detecting the droplet speed. It solves the problem of large-area surrounding and blocking of the Murphys dropper in traditional infusion detectors, and solves the problem of sensitivity to strong light and infrared interference in traditional infrared infusion detectors, and improves the flexibility and reliability of the infusion detector operation. Nurses and patients can directly observe the infusion in the drip bucket and read the drip rate and liquid level on the infusion detector without affecting the original infusion function of the infusion tube, thereby improving work efficiency and the accuracy of drip rate calculation.

Claims

1. A method for detecting an infusion drip rate, characterized in that: Ten capacitive sensing electrodes are arranged on the capacitive sensing sheet from bottom to top, and each capacitive sensing electrode can independently sense the capacitance change, thereby sensing the liquid level; The collected data is denoised using the limiting filter method to improve the accuracy of the droplet velocity calculation and eliminate the interference of the small amplitude self-oscillation after the droplet falls on the droplet velocity calculation; The limiting filter method refers to setting the maximum deviation value allowed for two samples. When the deviation between the current sampled value and the previous sampled value is greater than the set maximum deviation value, the current sampled value is taken, otherwise it is discarded as invalid interference data. The main steps of the algorithm include: Step 1: First record the low liquid level steady state time , when the drop falls, record the transient time of the high liquid level , As the falling time of the first drop, the velocity of the first drop is calculated; Step 2: After the first drop of liquid falls, the low liquid level steady-state time is detected and counted After the second drop of liquid falls, the high liquid level transient time is detected , as the sampling time interval for the second drop; Step 3: Collect the droplet velocity data based on the transient time interval between the high liquid level of each two drops, calculate the difference between the velocity collected this time and the velocity collected last time, and set the sampling time interval. Step 4: Repeat step 3 to collect multiple sets of data; There are usually five sets of data; Step 5: First, perform limit filtering on the data one by one, and the amplitude value changes according to the previous sampling value, and then calculate the arithmetic mean to obtain the current dripping speed; Step 6: Repeat the above steps 4 and 5 for the next calculation of the droplet velocity.

2. A method for detecting an infusion dripping rate according to claim 1, characterized in that: It is also used to detect whether the liquid level in the drip bucket is too high or too low: when the highest capacitive sensing electrode senses the liquid level, it indicates that the liquid level in the drip bucket is too high; When the lower capacitive sensing electrodes cannot sense the liquid level, it indicates that the liquid level in the drip bucket is too low.

3. A device for detecting an infusion dripping rate, based on the method for detecting an infusion dripping rate according to claim 1, using a limiting filter method to perform denoising on the collected data, characterized in that: It includes a capacitive sensing sheet attached to the wall of the drip bucket, ten capacitive sensing electrodes arranged on the capacitive sensing sheet from bottom to top, and an MCU processing unit; The ten capacitance sensing electrodes on the capacitance sensing sheet are connected to the ten IO pins of the MCU processing unit; the MCU processing unit calculates the charge and discharge time for each IO pin, and individually detects the orderly change of the capacitance of each IO pin caused by the droplet falling; The collected data is denoised using the limiting filter method to improve the accuracy of the droplet velocity calculation and eliminate the interference of the small amplitude self-oscillation after the droplet falls on the droplet velocity calculation; The limiting filter method refers to setting the maximum deviation value allowed for two samples. When the deviation between the current sampled value and the previous sampled value is greater than the set maximum deviation value, the current sampled value is taken, otherwise it is discarded as invalid interference data. The main steps of the algorithm include: Step 1: First record the low liquid level steady state time , when the drop falls, record the transient time of the high liquid level , As the falling time of the first drop, the velocity of the first drop is calculated; Step 2: After the first drop of liquid falls, the low liquid level steady-state time is detected and counted After the second drop of liquid falls, the high liquid level transient time is detected , as the sampling time interval for the second drop; Step 3: Collect the droplet velocity data based on the transient time interval between the high liquid level of each two drops, calculate the difference between the velocity collected this time and the velocity collected last time, and set the sampling time interval. Step 4: Repeat step 3 to collect multiple sets of data; usually five sets of data; Step 5: First, perform limit filtering on the data one by one, and the amplitude value changes according to the previous sampling value, and then calculate the arithmetic mean to obtain the current dripping speed; Step 6: Repeat the above steps 4 and 5 for the next calculation of the droplet velocity.

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