CN215309187U - Passive dripping speed sensor - Google Patents
Passive dripping speed sensor Download PDFInfo
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- CN215309187U CN215309187U CN202121117114.6U CN202121117114U CN215309187U CN 215309187 U CN215309187 U CN 215309187U CN 202121117114 U CN202121117114 U CN 202121117114U CN 215309187 U CN215309187 U CN 215309187U
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- 239000007788 liquid Substances 0.000 claims description 14
- 230000008447 perception Effects 0.000 claims description 8
- 238000001802 infusion Methods 0.000 abstract description 38
- 238000012544 monitoring process Methods 0.000 description 16
- 238000000034 method Methods 0.000 description 12
- 238000010586 diagram Methods 0.000 description 9
- 230000007613 environmental effect Effects 0.000 description 9
- 230000002159 abnormal effect Effects 0.000 description 6
- 238000007493 shaping process Methods 0.000 description 6
- 238000004364 calculation method Methods 0.000 description 5
- 238000005070 sampling Methods 0.000 description 5
- 230000009977 dual effect Effects 0.000 description 4
- 238000012423 maintenance Methods 0.000 description 3
- 238000013459 approach Methods 0.000 description 2
- 238000004891 communication Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 210000002216 heart Anatomy 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 230000007704 transition Effects 0.000 description 2
- 206010020772 Hypertension Diseases 0.000 description 1
- 206010037423 Pulmonary oedema Diseases 0.000 description 1
- 238000012952 Resampling Methods 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 239000008280 blood Substances 0.000 description 1
- 210000004369 blood Anatomy 0.000 description 1
- 238000012937 correction Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 238000001990 intravenous administration Methods 0.000 description 1
- 210000003734 kidney Anatomy 0.000 description 1
- 210000004185 liver Anatomy 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 230000035772 mutation Effects 0.000 description 1
- 230000010355 oscillation Effects 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 230000001766 physiological effect Effects 0.000 description 1
- 238000007781 pre-processing Methods 0.000 description 1
- 208000005333 pulmonary edema Diseases 0.000 description 1
- 238000010992 reflux Methods 0.000 description 1
- 210000003462 vein Anatomy 0.000 description 1
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Abstract
The utility model discloses a passive dripping speed sensor, which is arranged in contact with the side wall of a dropper of an infusion apparatus and comprises: the label fixing bracket comprises a back plate and two parallel clamping plates which are arranged in an aligned mode, the back plate is embedded in the two clamping plates, and an accommodating space for embedding a dropper is formed between the two clamping plates; two clamping grooves for containing RFID labels are formed in the back plate, a groove is formed in the position, matched with the clamping plate, of the back plate, the RFID labels in the clamping grooves corresponding to the grooves are enabled to leak out of the back plate through the groove, and the leaking parts of the RFID labels are tightly attached to the surface of the dropper; and the RFID label sends a wireless radio frequency signal to an external dripping speed sensing all-in-one machine. By introducing the double-label structure, the utility model can accurately monitor the dropping speed of the infusion bottle/infusion bag under the condition of complex multipath interference in the environment.
Description
Technical Field
The utility model belongs to the technical field of RFID passive sensing and intelligent medical treatment, and particularly relates to a passive dripping speed sensor.
Background
In the current medical system, intravenous infusion is one of the most common means for clinical treatment, and it is very important that the liquid medicine flows into the vein at a specific dropping speed during the infusion process. On the one hand, if the drop rate is too high, adverse physiological effects will be exerted on the patient, such as increased blood pressure and decreased heart rate. For patients with heart, kidney or liver problems, too rapid a drip rate can lead to pulmonary edema and other hazards. On the other hand, if the drop rate is too low, e.g., the infusion drop rate goes to zero, the infusion process should be immediately ended or blood reflux may be induced. The transfusion condition of a patient is only based on the regular patrol of medical care personnel, and the accident condition is difficult to find and handle in time, so a passive dropping speed sensor is needed, and the medical care personnel can be warned in time when the abnormal dropping speed of the transfusion occurs.
The current major infusion drop rate solutions include the following:
1) the manual counting mode of nurses: the nurse estimates the drip rate of the infusion by counting the drops falling from the dropper while observing the time the clock has run. This approach is labor intensive, costly, and may be inaccurate due to human error.
2) Monitoring based on infrared sensors and the like: by arranging a pair of photoelectric emitters and receivers around the infusion dropper, the dropping speed is estimated by counting the number of times of sudden changes of light intensity caused by light beams shielded by dropping of the drops in unit time. This approach requires complex deployment around the burette and sensor operation requires power and routine maintenance.
3) Monitoring based on wireless signals: by deploying a tag on the dropper, the drop rate is estimated by counting the number of tag signal transitions caused by drop drops falling over a period of time. Since wireless signals are susceptible to environmental interference, it is difficult to stably work in a ward or an infusion hall where people are in heavy traffic.
Therefore, based on the above considerations, it is necessary to provide a passive drip speed sensor, which not only can accurately monitor the drip speed of the infusion in real time, but also needs to have strong anti-interference capability and be capable of working robustly in a real environment.
Disclosure of Invention
In view of the above-mentioned deficiencies of the prior art, the present invention provides a passive drop velocity sensor, so as to solve the problems of the prior art that the passive drop velocity sensor has a complex structure and is susceptible to environmental interference, resulting in inaccurate monitoring.
In order to achieve the purpose, the technical scheme adopted by the utility model is as follows:
the utility model discloses a passive dripping speed sensor, which is contacted with the side wall of a dropper of an infusion apparatus, and comprises: the label fixing bracket comprises a back plate and two parallel clamping plates which are arranged in an aligned mode, the back plate is embedded in the two clamping plates, and an accommodating space for embedding a dropper is formed between the two clamping plates; two clamping grooves for containing RFID labels are formed in the back plate, a groove is formed in the position, matched with the clamping plate, of the back plate, the RFID labels in the clamping grooves corresponding to the grooves are enabled to leak out of the back plate through the groove, and the leaking parts of the RFID labels are tightly attached to the surface of the dropper;
and the RFID label sends a wireless radio frequency signal to an external dripping speed sensing all-in-one machine.
Further, the back plate is embedded in one third of the two clamping plates.
Further, the distance between the inner edges of the two RFID tags is set between 1cm and 4cm, and is 2cm by default.
Further, when the label fixing support is sleeved, the lower edge of the RFID label in the label fixing support is ensured to be positioned above the liquid level in the dropper.
Further, the two RFID tags are divided into: a perception tag and a reference tag; wherein, the RFID label tightly attached to the surface of the dropper is a perception label.
Further, the signal characteristic data of the RFID tag includes EPC, signal strength, phase information and time stamp.
The utility model relates to a passive dripping speed sensor, which is applied to a transfusion dripping speed monitoring system, and the system comprises: the system comprises a passive dripping speed sensor, a dripping speed sensing integrated machine, a server platform and a dripping speed sensing client;
after being activated by a wireless radio frequency signal sent by the dripping speed sensing all-in-one machine, an RFID label in the passive dripping speed sensor continuously sends a feedback signal, and senses the dripping of liquid drops in the dropper according to the phase jump of the feedback signal;
the dripping speed sensing integrated machine is used for acquiring wireless radio frequency signals sent by the passive dripping speed sensor in real time, acquiring phase signal characteristic data of the two RFID labels, processing the acquired data to eliminate environmental interference so as to obtain the transfusion dripping speed, and sending result data to the server platform;
the server platform is used for acquiring infusion dripping speed result data sent by the dripping speed sensing all-in-one machine in real time and storing the infusion dripping speed result data in a database;
and the dripping speed sensing client acquires the infusion dripping speed calculation result from the database of the server platform in real time, judges whether the infusion dripping speed is abnormal or not, and sends out early warning when the infusion dripping speed is abnormal.
The utility model has the beneficial effects that:
1. by adopting a double-label structure, the dropping speed of the infusion bottle/infusion bag can be accurately monitored under the condition of complex multipath interference in the environment; compared with the existing single-label technology, the double-label structure has better robustness and can stably work in a more complex environment (a plurality of people move around the infusion support).
2. High-precision real-time dropping speed monitoring: the dropping speed of the infusion bottle/infusion bag is monitored with high precision, and the monitoring precision reaches the level of liquid drops (milliliters).
3. And the maintenance overhead is reduced: can use repeatedly, need not to change maintenance measures such as battery to equipment, reduce the expense, green.
4. The transfusion has no pollution: adopts non-contact sensing, does not contact with liquid, and does not pollute the transfusion process.
5. The environmental requirement is low: the requirement on the environment including the scene of light people number is low, and the device can work normally in a complex environment.
Drawings
FIG. 1 is a diagram of an infusion drop speed monitoring system;
FIG. 2 is a schematic diagram of an application of a passive drop velocity sensor;
FIG. 3 is a diagram of a passive drip rate sensor;
FIG. 4 is a flow chart of a drip rate monitoring algorithm;
FIG. 5a is a schematic diagram of drop rate monitoring;
FIG. 5b is a graph of phase data including a drop velocity peak;
FIG. 6 is a schematic diagram of dual tag interference cancellation;
FIG. 7a is a diagram of a differential signal before phase shaping;
fig. 7b is a diagram of the phase-shaped differential signal.
Detailed Description
In order to facilitate understanding of those skilled in the art, the present invention will be further described with reference to the following examples and drawings, which are not intended to limit the present invention.
Referring to fig. 2-3, a passive drop velocity sensor of the present invention comprises: the RFID tag comprises two RFID tags 1 and a tag fixing bracket 2, wherein the tag fixing bracket 2 consists of a back plate 24 and two clamping plates 21 which are arranged in parallel and aligned, the back plate 24 is embedded in one third of the two clamping plates 21, and an accommodating space 23 for embedding a dropper 3 is formed between the two clamping plates 21; two clamping grooves for containing RFID labels are arranged in the back plate 24, a groove 22 is arranged on the back plate 24 and at a position matched with the clamping plate 21, the RFID labels in the corresponding clamping grooves are leaked out of the back plate 24 through the groove, and the leaked RFID labels are tightly attached to the surface of the dropper 3;
and the RFID label sends a wireless radio frequency signal to an external dripping speed sensing all-in-one machine.
Wherein, the distance between the inner edges of the two RFID labels is set between 1cm and 4cm, and the default is 2 cm. If the spacing is too small, the tag signals in the card slot may become mutually coupled, resulting in signal unavailability. If the spacing is too large, the dual-tag scheme cannot effectively eliminate the effect of environmental interference.
It should be noted that, when the label fixing bracket is sleeved, the lower edge of the RFID label in the label fixing bracket should be ensured to be located above the liquid level in the dropper.
The two RFID tags are divided into: a perception tag and a reference tag; wherein, the RFID label tightly attached to the surface of the dropper 3 is a perception label.
The signal characteristic data of the RFID tag includes the EPC, signal strength, phase information, and time stamp.
In an example, referring to fig. 1, a passive drop rate sensor of the present invention is applied to an infusion drop rate monitoring system, and the system includes: the system comprises a passive dripping speed sensor, a dripping speed sensing integrated machine, a server platform and a dripping speed sensing client;
after being activated by a wireless radio frequency signal sent by the dripping speed sensing all-in-one machine, an RFID label in the passive dripping speed sensor continuously sends a feedback signal, and senses the dripping of liquid drops in the dropper according to the phase jump of the feedback signal;
the dripping speed sensing integrated machine is used for acquiring wireless radio frequency signals sent by the passive dripping speed sensor in real time, acquiring phase signal characteristic data of the two RFID labels, processing the acquired data to eliminate environmental interference so as to obtain the transfusion dripping speed, and sending result data to the server platform;
the server platform is used for acquiring infusion dripping speed result data sent by the dripping speed sensing all-in-one machine in real time and storing the infusion dripping speed result data in a database;
and the dripping speed sensing client acquires the infusion dripping speed calculation result from the database of the server platform in real time, judges whether the infusion dripping speed is abnormal or not, and sends out early warning when the infusion dripping speed is abnormal.
The dripping speed perception all-in-one machine comprises: the RFID system comprises an RFID reader, a processor and a communication module; the RFID reader collects wireless radio frequency signals sent by peripheral passive dripping speed sensors in real time and obtains signal characteristic data of two RFID tags in the passive dripping speed sensors; the processor processes the acquired data, eliminates the influence of environmental interference and calculates to obtain the result data of the infusion dripping speed; and the communication module sends the result data to the server platform. The RFID reader and the RFID label are in ultrahigh frequency specification, the frequency is 860-960MHz, and the RFID reader reads and writes the RFID label through EPC Global C1G 2 protocol.
Referring to fig. 4, the method for calculating the infusion drop speed result data by the drop speed sensing all-in-one machine includes:
(1) obtaining phase signal data of two RFID labels within a time window of T seconds, and recording the sensing label data as (T)1，W1) The reference tag data is denoted as (T)2，W2) T is a time stamp, and W is phase data;
(2) shaping the reference label signal, and recording the phase data of the shaped reference label as
Calculating the difference between two RFID tag signals
And carrying out high-pass filtering on the differential signal to obtain denoised phase data W4；
(3) De-noising the phase data W4Normalized to the interval [ -1, 1 [ ]]Then calculating the autocorrelation to obtain an autocorrelation sequence Rcor；
(4) With an autocorrelation sequence R cor2/3 of the medium maximum value is an initial threshold value, the initial threshold value is adjusted by a step size to be 1/25 of the maximum value, and all peaks larger than the initial threshold value are identified until the number of the peaks is not lower than K; noting the identified peak as (p)1，p2，p3，...，pK) The value of K can be from 3 to 7;
(5) calculating the interval of sampling points of adjacent wave crests to obtain (d)1，d2，d3，...，dK-1)；
(6) Clustering the sampling point intervals of adjacent wave crests, calculating the mean value of the maximum cluster of the clustering result to obtain p, recording the phase sampling rate as r, and calculating to obtain the current dropping speed s, wherein the formula is as follows:
s＝(60×r/p)。
wherein, the step (1) further comprises: preprocessing the obtained phase signal data;
(11) correcting two RFID tagsSign raw phase data W1And W2Eliminating discontinuity thereof to make phase data W1＝W1*2，W2＝W 22, let the transition of pi to 2 pi;
(12) when W is1And W2When the absolute jump between the continuous elements is larger than or equal to the jump tolerance of pi radian, compensating multiples of +/-2 pi on the elements to correct the radian phase;
(13) restoring the phase data after the jump correction to W1＝W1÷2，W2＝W2÷2；
(14) And resampling the data of the two RFID labels after the phase discontinuity is removed, wherein the sampling method is cubic spline interpolation, and the default value of the sampling interval is 10 ms.
The shaping operation in the step (2) is as follows: according to a time length deltatFor signal W1And W2Is divided into blocks W1＝{W1[0～Δt]，W1[Δt～2Δt]，...，W1[t-Δt～t]}，W2Blocking method and W1Are the same as (a); to W2Performs a transform per block in (1)
The parameters c and d satisfy
The value of (d) is minimal; time length of blocking ΔtSample times of 5 to 20 sample data are taken.
FIGS. 5a and 5b are schematic diagrams of drop velocity monitoring; the RFID signal is reflected by the liquid, and the signal received by the tag as shown in FIG. 5a comes mainly from three propagation paths, including the line-of-sight propagation path SA→TSurface of liquid reflects propagation path SA→B→TAnd an ambient reflection path SA→C→TThe resulting mixed signal propagates back to the antenna as a backscatter signal. Since the phase signal depends mainly on the distance over which the signal travels, the phase signal changes when the path of travel suddenly changes due to liquid level oscillations caused by drop dropsThe peaks resulting from the mutation are shown in FIG. 5 b. Therefore, we can estimate the drop velocity over a period of time by calculating the spacing of peaks in the phase signal over that period of time.
FIG. 6 is a schematic diagram of dual tag interference cancellation; a sensing label and a reference label are arranged around the infusion dropper, the sensing label is very sensitive to liquid level vibration and can sense the dropping speed, and the reference label is arranged on one side of the dropper and is insensitive to the liquid level vibration and used for sensing multipath interference in the environment. The distance between two RFID tags is only (1-4cm) closer, while the distance from the reader antenna to the tag pair (1-5m) is relatively much further, at which distance the environmental interference received by the two RFID tags in the tag pair can be considered to be approximately the same. Only the phase signals of the perception tags in the two RFID tags contain dripping speed information, and multipath interference in most of surrounding environments can be counteracted by calculating the difference of the phase signals of the two tags in the tag pair.
Fig. 7a and 7b are graphs comparing signals before and after phase shaping. When calculating the differential signal of the dual tag, due to the difference of the physical characteristics of the RFID tags and the like, the signals of the two RFID tags have slight difference, and it is necessary to shape the signal of the reference tag to make the signals of the two tags as similar as possible. It can be seen from fig. 7a that the calculation of the differential signal of the dual tag before the phase shaping introduces much noise, and the calculation of the differential signal after the phase shaping can extract the signal containing the drop velocity peak.
At present, most of existing methods for monitoring infusion by using an RFID technology use the reading rate or signal strength (RSSI) of a radio frequency signal to monitor whether infusion is finished, so that accurate and effective measurement and calculation of a dropping speed cannot be performed, and abnormal situations occurring in an infusion process cannot be monitored. The existing method for monitoring the dropping speed by using the phase signal of a single RFID label cannot effectively eliminate the influence of environmental interference, so that the method is difficult to stably work in an actual environment. The method of the utility model has high precision, real-time and robust drop velocity monitoring: the high-precision monitoring of the dropping speed of the infusion bottle/infusion bag is carried out, the monitoring precision reaches the level of liquid drops (milliliters), and meanwhile, the device can stably work in a complex environment.
While the utility model has been described in terms of its preferred embodiments, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the utility model.
Claims (6)
1. The utility model provides a passive dropping speed perceptron, its and the burette lateral wall contact setting of transfusion system which characterized in that contains: the label fixing bracket comprises a back plate and two parallel clamping plates which are arranged in an aligned mode, the back plate is embedded in the two clamping plates, and an accommodating space for embedding a dropper is formed between the two clamping plates; two clamping grooves for containing RFID labels are formed in the back plate, a groove is formed in the position, matched with the clamping plate, of the back plate, the RFID labels in the clamping grooves corresponding to the grooves are enabled to leak out of the back plate through the groove, and the leaking parts of the RFID labels are tightly attached to the surface of the dropper.
2. The passive drop rate sensor of claim 1, wherein the back plate is embedded in one third of the two clamping plates.
3. The passive drop velocity sensor of claim 1, wherein the spacing between the inner edges of the two RFID tags is set between 1cm and 4 cm.
4. The passive drop rate sensor of claim 1, wherein the two RFID tags are divided into: a perception tag and a reference tag; wherein, the RFID label tightly attached to the surface of the dropper is a perception label.
5. The passive drop rate sensor of claim 1, wherein the signal characteristic data of the RFID tag comprises: EPC, signal strength, phase information, and timestamp.
6. The passive drip rate sensor according to claim 1, wherein the label holder is configured to secure a lower edge of the RFID label in the label holder above a liquid level in the drip tube.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202121117114.6U CN215309187U (en) | 2021-05-24 | 2021-05-24 | Passive dripping speed sensor |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121117114.6U CN215309187U (en) | 2021-05-24 | 2021-05-24 | Passive dripping speed sensor |
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| CN215309187U true CN215309187U (en) | 2021-12-28 |
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| CN202121117114.6U Active CN215309187U (en) | 2021-05-24 | 2021-05-24 | Passive dripping speed sensor |
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- 2021-05-24 CN CN202121117114.6U patent/CN215309187U/en active Active
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