Detection of poor injection sites

Abstract

When an venous catheter connected to an infusion set is inserted into a venous insertion site, a first venous rhythm of the patient is detected above the venous insertion site, and simultaneously with the first venous rhythm, a second venous rhythm is detected at a location remote from the venous insertion site. Irregularities between the first venous rhythm and the second venous rhythm are identified, and a malfunction of the venous catheter is determined based on the identified irregularity satisfying an irregularity threshold. An alarm may be provided upon detection of an abnormal or malfunctioning venous catheter.

Description

[Background technology]

[0001] If a catheter is positioned incorrectly or shifts to the wrong position after intravenous placement, the injected fluid may leak into the surrounding tissue. Depending on the type of medication or fluid, such leakage can result in potentially serious and troubling problems, including harmful effects to the patient. If the fluid is non-exanthetic (e.g., does not generally irritate tissue), the leakage may be referred to as "infiltration." If the fluid is exanthetic (e.g., a type of fluid known to irritate tissue), the leakage may be referred to as "extravasation." Fluid leakage at or within an injection site may not be immediately apparent and may remain undetected for long periods of time. Summary of the Invention

[0002] According to various aspects of the present technology, a method includes detecting a first venous rhythm in a patient above a venous insertion site when a venous catheter is inserted into the patient's venous insertion site, the venous catheter being connected to an infusion set that provides fluid from a fluid source to the venous insertion site; detecting a second venous rhythm at a location remote from the venous insertion site concurrently with the first venous rhythm; identifying an irregularity between the first venous rhythm and the second venous rhythm; and detecting a malfunction of the venous catheter based on the identified irregularity satisfying an irregularity threshold. Other aspects include corresponding systems, devices, and computer program products for implementation of the corresponding methods and features thereof.

[0003] It is understood that other configurations of the present technology will become readily apparent to those skilled in the art from the following detailed description, in which various configurations of the present technology are shown and described by way of illustration. As will be understood, the present technology is capable of other different configurations, and its several details are capable of modifications in various other respects, all without departing from the scope of the present technology. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not restrictive.

[0004] For a better understanding of the various implementations described, reference should be made to the following description of implementations in conjunction with the following drawings, in which like reference numerals refer to corresponding parts throughout the figures and description. [Brief explanation of the drawings]

[0005] [Figure 1] 1 depicts an exemplary infusion device shown in use in its intended environment. [Figure 2A] 1 depicts an exemplary infusion site failure detected by the present technique. [Figure 2B] 1 depicts an exemplary infusion site failure detected by the present technique. [Figure 2C] 1 depicts an exemplary infusion site failure detected by the present technique. [Figure 2D] 1 depicts an exemplary infusion site failure detected by the present technique. [Figure 3] FIG. 1 depicts an exemplary pulse waveform for detecting infusion site failure, in accordance with various aspects of the present technique. [Figure 4] FIG. 1 depicts an exemplary process flow diagram for detecting infusion site failure, in accordance with various aspects of the present technique. [Figure 5] FIG. 1 depicts a first exemplary system for detecting infusion site failure, in accordance with various aspects of the present technology. [Figure 6] FIG. 10 depicts a second exemplary system for detecting infusion site failure, in accordance with various aspects of the present technology. [Figure 7]FIG. 10 depicts a third exemplary system for detecting infusion site failure, in accordance with various aspects of the present technology. [Figure 8] 10 depicts an exemplary process for detecting infusion site failure, in accordance with various aspects of the present technology. [Figure 9] FIG. 1 is a conceptual diagram illustrating an exemplary electronic system for detecting infusion site failure, in accordance with various aspects of the present technique. DETAILED DESCRIPTION OF THE INVENTION

[0006] Reference will now be made to implementations, examples of which are illustrated in the accompanying drawings. In the following description, numerous specific details are set forth in order to provide an understanding of the various implementations described. However, it will be apparent to those skilled in the art that the various implementations described may be practiced without these specific details. In other instances, well-known methods, procedures, components, circuits, and networks have not been described in detail so as not to unnecessarily obscure aspects of the implementations.

[0007] FIG. 1 illustrates an exemplary infusion device 10 in accordance with various aspects of the present technology in its intended environment of use. In particular, the infusion device 10 is shown attached to an IV pole 12, which holds a fluid source 14 containing intravenous (IV) fluid. The fluid source 14 is connected in fluid communication with an upstream fluid line 16. The fluid line 16 is conventional IV infusion-type tubing commonly used in hospital or medical settings and is made from any type of flexible tubing suitable for use in infusing therapeutic fluids into a patient, such as polyvinyl chloride (PVC). In some implementations, the flexible fluid line 18 is attached in operative engagement with a peristaltic pumping apparatus 19 for pumping fluid through a downstream fluid line 20, for example, into a patient's arm 22.

[0008] Those skilled in the art will appreciate that upstream fluid line 16, flexible line 18, and downstream fluid line 20 may be continuous lengths of flexible tubing, with those lengths defined by the location of peristaltic pump 19. For convenience, the continuous length of flexible tubing is designated by the numeral 21. A roller clamp 23 (e.g., configured to provide mechanical compression of the line to block flow) may be positioned on downstream fluid line 20 between pump 10 and patient's arm 22. In this context, the term "upstream" refers to the portion of flexible tubing extending between the fluid source and the peristaltic pump, and the term "downstream" refers to the portion of flexible tubing extending from the peristaltic pump to the patient.

[0009] Also shown in FIG. 1 is a secondary administration setup, generally designated 24. Secondary administration setup 24 includes a secondary fluid container 25, which can be filled with a second therapeutic fluid for infusion into patient 22. Fluid from secondary fluid container 25 flows through secondary fluid line 26 to fluid line 16 through connector 27. A manual valve 28 is located in secondary line 26 to control the flow of fluid from secondary container 25 to upstream fluid line 16. A one-way check valve 29 is disposed in upstream fluid line 16 between primary fluid container 14 and connector 27, and is configured such that when the fluid height in secondary container 25 exceeds that of the primary container, a pressure differential in line 16 closes the check valve, preventing secondary fluid from flowing into primary container 14 and also preventing fluid from flowing out of primary container 14. In this way, check valve 29 generally prevents mixing of the primary and secondary infusion fluids.

[0010] 2A-2D depict exemplary infusion site failures detected by the present technology. While the figures depict a patient's arm, it should be understood that the present technology may be used on other parts of the body. For example, the present technology may be used to monitor infusion sites on the patient's torso. In FIG. 2A, catheter 30 is inserted through the patient's epidermis 32, threaded into a vein, and then punctured into the wall of the vein (other than the entry puncture). In FIG. 2B, fluid from the vein is leaking from venous insertion site 33 of catheter 30.

[0011] Signs and symptoms may include fluid leakage, pain, redness, burning, pallor, lack of blood return, edema, decreased IV flow or flush, etc. Figure 2C shows fluid leaking from the injection site 34 and redness 36 surrounding the site. Figure 2D depicts redness and / or swelling 38 and obvious superficial tissue damage 40, including blistering, to the area surrounding the injection site.

[0012] Punctures and fluid leaks can be caused, for example, by venous fragility or medical professional error, or by increased venous permeability. In some cases, the catheter 30 may back out of the insertion site, for example, when it is inserted or due to patient movement. Damage caused by infusion site failure can extend to involve nerves, tendons, and joints and can continue for months after the initial injury. If treatment is delayed, surgical debridement, skin grafting, and even amputation can be unfortunate consequences of the injury. This technology detects signs of fluid leaks, including extravasation and infiltration, i.e., leakage of intravenously infused fluid, and minimizes the leakage of potentially damaging medication into extravascular tissue around the infusion site 22, thereby avoiding patient harm. In this regard, multiple sensors are used to monitor the infusion site, and signals are compared to determine whether an infusion site failure (e.g., a leak) has occurred or is occurring.

[0013] 3 depicts an exemplary pulse waveform for detecting infusion site failure in accordance with various aspects of the present technology. As will be further explained, the disclosed system determines catheter failure based on detecting a first venous rhythm of a patient above a catheter venous insertion site and a second venous rhythm at a location remote from the venous insertion site and identifying an irregularity between the first and second venous rhythms. The illustrated waveforms are indicative of these detected venous rhythms.

[0014] Peripheral venous waveforms can be captured by direct transduction through a peripheral catheter, noninvasive piezoelectric transduction, or collected from other waveforms such as a plethysmograph. An exemplary raw venous waveform is shown on the left side of the figure in the time domain, and on the right side in the frequency domain. The top waveform is an exemplary central venous waveform (CVP), followed by a peripheral venous waveform analysis (PIVA) based on a signal obtained from direct transduction, and the bottom waveform is a noninvasive waveform analysis (NIVA) using a piezoelectric sensor. f0 corresponds to the fundamental frequency, which may be equal to the pulse rate. The harmonic components of the pulse rate can be represented by f1 and f2, as well as a low-frequency component (frr) corresponding to the respiratory rate ra.

[0015] According to various implementations, pulse rates obtained based on different modalities (CVP, PIVA, and / or NIVA) can be compared to determine whether an infusion site problem has occurred. For example, NIVA waves can be captured by a piezoelectric sensor and compared to peripheral venous waveforms captured by direct transduction through a peripheral catheter. In the illustrated example, noninvasive waveforms are captured by a piezoelectric sensor and / or photoplethysmography (PPG), which allows for external capture and verification of peripheral venous pressure rhythms and detection of infusion abnormalities such as infiltration or extravasation. According to various implementations, the fundamental frequency (f0) can be compared. However, in some implementations, the fundamental frequency (f0) can also be compared to harmonics (f1, f2, etc.).

[0016] 4 shows an exemplary process flow diagram for detecting an infusion site failure in accordance with various aspects of the present technology. According to various implementations, a first signal 402 indicative of a first venous rhythm is received by a first sensor 404, and a second signal 406 indicative of a second venous rhythm is received by a second sensor 408. As described below, the first and second sensors 404, 408 may each be a piezoelectric sensor, a plethysmograph, or a photoplethysmograph, such as an optical heart rate monitor, an optical sensor, or an optical sensor for detecting light absorption. The first and second sensors 404, 408 simultaneously receive the first and second signals 402, 406 and pass them to a processor 410 for processing. The processor then processes the received simultaneous rhythm signals and / or waveforms to identify irregularities between the first and second venous rhythms.

[0017] The system may identify irregularities by comparing the signals 402, 406. The signals (fundamental frequency and / or harmonics) are expected to match under normal conditions. If the signals match (e.g., within an irregularity threshold), it may be determined that there is no irregularity (at least initially). If the two signals do not match (e.g., outside the irregularity threshold), an irregularity may be determined. For example, a first signal may be from a piezoelectric sensor on the catheter, and a second signal may be from an optical heart rate monitor on the patient's wrist (e.g., on a smart watch). If the signal from the catheter does not match the signal from the heart rate monitor, the system may detect an irregularity. Additionally, if one or more of the signals is unavailable, the system may determine a system failure, provide an alarm, and / or perform diagnostic processing to determine whether signal anomalies can be identified and corrected.

[0018] 5 shows a first exemplary system 500 for detecting infusion site failure in accordance with various aspects of the present technology. An infusion set 502 is connected to an venous catheter, which may be inserted into a vein in the usual manner by a clinician. The infusion set may then be connected to the downstream fluid line 20 (FIG. 1) by a luer or y-connector 503.

[0019] A pressure transducer (sensor 404, not shown) is provided in or attached to the venous catheter 504. In some implementations, the infusion set 502 is configured to position the transducer over the venous insertion site and at least a portion of the venous catheter 504 when the venous catheter 504 is inserted into the venous insertion site. For example, the infusion set 502 may be a winged infusion set or may include wings or stabilizers 506 to provide for shallow angle insertion and stabilization of the catheter. The wings or stabilizers 506 may include a non-invasive piezoelectric or optical sensor configured to monitor the pulsatile rhythm of the vein into which the catheter 504 is inserted.

[0020] In the illustrated example, the peripheral venous pressure rhythm at the infusion site is detected by a pressure transducer 404 and compared to a second venous rhythm signal obtained by a photoplethysmograph 408. According to various implementations, the comparison (and other processing described herein) may be performed by a processor of an electronic device, such as a smart watch. In some implementations, as further described, the catheter 504 may include a light-emitting diode, and the first venous rhythm may be detected using a photodetector in the wings or stabilizer 506. In the illustrated example, the second venous rhythm is obtained from an optical heart rate monitor 408 in the smart watch 508. In some implementations, the second venous rhythm may be obtained, for example, using a fingertip-mounted pulse oximeter (e.g., a sensor 408 within the pulse oximeter). A smart watch, pulse oximeter, or other secondary device responsible for detecting a second venous rhythm may be operably connected to the first sensor via wire 510, which may be separate from the infusion set 502 or incorporated within the infusion set 502.

[0021] In some implementations, the processor 410 may be implemented by a smart watch 508. In this regard, the system may include operating instructions stored on the watch 508 (e.g., in the form of an app) that receive data from the first and second sensors 404, 410 and process the data to compare waveforms. If an irregularity or malfunction of the venous catheter is detected, an alert may be provided to the user. The electronic device (e.g., a smart watch) may include an alarm device, such as an audio device (e.g., a speaker), a display device (e.g., an LCD screen), and / or a haptic device (e.g., a vibration device integrated within the electronic device). The alert may be provided via the alarm device in the form of an audio, visual, or haptic alarm (e.g., from the audio device, display device, or haptic device). The alert may additionally or alternatively be provided to a remotely connected computing device (e.g., via a wireless connection or network). For example, an alarm device may include a network or wireless communication module configured to provide an alert to a remote computing device over a wired or wireless communication channel or network.

[0022] 6 shows a second exemplary system for detecting infusion site failure in accordance with various aspects of the present technology. In some implementations, the infusion set of the disclosed infusion site failure detection system may include a housing 512 that rests on the surface of the skin 513 (or epidermis) above the infusion site. In this manner, the housing 512 may include one or more transducers for detecting venous rhythms associated with the vein 511 into which the catheter 504 is inserted. According to some implementations, the housing 512 may constitute or be part of wings or stabilizers 506.

[0023] The exemplary housing includes two optical sensors 514, 516 and a power source 518 for an external pressure sensor 520. According to various implementations herein, sensor 514 is interchangeable with sensor 404, and sensor 520 is interchangeable with sensor 408. In the illustrated example, the patient's first venous rhythm is detected above the insertion site using plethysmographic techniques. For example, housing 512 may include a photoplethysmograph to detect pulse through the skin. Referring briefly to FIG. 5, pressure sensor 520 may be positioned on a portion of the fluid line of infusion set 502.

[0024] In various implementations, the first and second venous rhythms are compared to determine whether a threshold irregularity is met. For example, the two waveforms may be compared to determine whether they match within a predetermined tolerance (e.g., 70% or greater match, within one standard deviation on either side of the mean). In some implementations, the baseline amplitude of each signal may be determined for a predetermined period of time after the catheter is installed, e.g., in response to a user input at a corresponding computing device indicating that the catheter has been inserted into the vein. A decaying pulsatile amplitude of the first venous rhythm without a change in the baseline pulsatile amplitude of the second venous rhythm may indicate a potential leak.

[0025] In some implementations, the second sensor 516 can be configured to detect a change in light absorption or color associated with an area 521 of skin adjacent to the injection site (and sensor 516). In some implementations, the second sensor 516 includes ultrasound configured to detect changes in skin topography. When an irregularity is detected based on comparing sensors 514, 520, the sensor 516 can be used to determine whether there is a change in skin topography or light absorption adjacent to the venous insertion site. If no change is detected by sensor 516, infiltration can be determined. On the other hand, if a change is detected by sensor 516, the system can determine that extravasation has occurred. In some implementations, the system determines that extravasation has occurred based on the change in topography or light absorption meeting an extravasation threshold.

[0026] 7 illustrates a third exemplary system for detecting an infusion site failure in accordance with various aspects of the present technology. In the illustrated example, the sensor 514 includes a photodetector configured to detect light emanating from below the epidermis. The emitter 522 (light source) is embedded within the catheter 504 and positioned to be properly positioned when the catheter is inserted into the vein 511. According to some implementations, the housing 512 (e.g., wings or stabilizer 506) can be connected to the catheter 504 such that the sensor 514 and the light source 522 are aligned and / or such that the light source 522 can be detected by the sensor 514 with a predetermined accuracy (see FIG. 5).

[0027] In some implementations, the housing may include a processor 410 that processes data from the first and second sensors 404, 410. If an irregularity or malfunction of the venous catheter is detected, an alert may be provided to the user. The alert may be in the form of an audio, visual, or haptic alarm (e.g., from an alarm device such as an audio device, a display device, or a haptic device). The alert may additionally or alternatively be provided to a connected computing device.

[0028] According to various implementations, the light source 522 generates a constant amount of light, from which a default or baseline light amount can be set. If the catheter 504 is moved deeper into the subcutaneous tissue, the amount of light absorbed by the sensor 514 changes (e.g., decreases). For example, pulsation amplitude is represented as the amount of light reaching the sensor 514, and the venous rhythm is detected based on detecting the time-varying amplitude of the light source 522. If the amount of pulsating light decreases relative to the baseline pulsation amplitude, it can be determined that the catheter 504 has moved (to the side or deeper in the tissue). This determination may be particularly true if the amplitude of a first venous rhythm attenuates relative to the baseline pulsation amplitude of a second venous rhythm (e.g., as measured by the sensor 520 / 408).

[0029] The system may measure a pulse sinusoid based on the fluctuations in light and normalize the intensity of the light detected at sensor 514 based on the average value of the pulsating sinusoid. If the intensity of light source 522 (measured by sensor 514) increases, the system may determine that venous catheter 504 has moved closer to the surface of the skin. If the intensity of light (measured by sensor 514) decreases, the system may determine that venous catheter 504 has moved or penetrated deeper into the tissue. The determination of whether the catheter has moved closer to or away from the surface may be made based on determining whether the increase or decrease in light meets a threshold for increase or decrease, respectively.

[0030] If the tip of the catheter 504 becomes clogged or a blood clot forms in the vein 511, the pressure amplitude or the amplitude of the light source 522 may decrease over time. In some implementations, if such attenuation is detected (e.g., if such attenuation exceeds the catheter's abnormality threshold), the amplitude of the signal may be compared to a baseline signal. For example, the system may normalize the light signal. In other words, a baseline light intensity may be determined (e.g., without considering modulation due to pulsation) or the average intensity over a period of time may be measured. If, upon checking, the baseline does not change and only the pulsatile amplitude attenuates, the system may determine that this amplitude change is due to an occlusion and not to movement of the catheter 504. On the other hand, if the baseline light intensity also changes, the system may determine that the catheter has moved. It is expected that the average value of the pulsatile sine wave will not change as long as the catheter remains in the vein, even if the amplitude is attenuated due to an occlusion.

[0031] FIG. 8 illustrates an exemplary process 550 for detecting infusion site failure in accordance with aspects of the present technology. For purposes of explanation, various blocks of the exemplary process 550 are described herein with reference to FIGS. 1-7 and the components and / or processes described herein. One or more of the blocks of the process 550 may be implemented by, for example, one or more computing devices or other electronic devices, for example, in the housing 512, or the smart watch 508, or an operably connected computing device (e.g., wirelessly connected to the sensors 404, 408). In some implementations, one or more of the blocks may be implemented based on one or more algorithms. In some implementations, one or more of the blocks may be implemented separately from other blocks and implemented by one or more different processors or devices. For further explanation, the blocks of the exemplary process 550 are described as occurring serially or linearly. However, multiple blocks of the exemplary process 550 may be performed in parallel. Additionally, the blocks of the example process 550 do not have to be performed in the order shown, and / or one or more of the blocks of the example process 550 do not have to be performed.

[0032] In the illustrated example, a first venous rhythm of the patient is detected above the patient's venous insertion site when the venous catheter is inserted into the venous insertion site (552). As previously described, the venous catheter is connected to an infusion set 502 that provides fluid from a fluid source to the venous insertion site. With reference to FIG. 1 , the infusion set 502 is configured to connect the venous catheter to an infusion line 20 that provides infusion fluid from a fluid source, such as an infusion device 10. The venous rhythm may be detected, for example, by a first sensor 404, 514 above or near the infusion site. In some implementations, the first sensor 404, 514 includes a transducer or piezoelectric circuit configured to detect time-varying pressure in fluid passing through the infusion set 502.

[0033] In some implementations (e.g., in FIG. 6 ), the infusion set 502 is configured to position the transducer over the venous insertion site and at least a portion of the venous catheter 504 when the venous catheter 504 is inserted into the venous insertion site (e.g., intravenously). In some implementations, the transducer can be positioned away from the insertion site, for example, at a location 520 attached to the infusion set 502 2 inches from the venous insertion site, as shown in FIG.

[0034] As previously described, in some implementations, the transducer 514 includes a photodetector configured to detect the light source 522 emitting light toward the surface of the skin and toward the transducer 514. In this manner, time-varying changes in the light source passing through the subcutaneous tissue between the light source and the transducer are detected. Thus, peaks in the detected sinusoid (e.g., light, pressure, or other modality) may represent a first venous rhythm.

[0035] Concurrently with the first venous rhythm, a second venous rhythm is detected 554 at a location remote from the venous insertion site. In some implementations, the second venous rhythm is detected using a second sensor 408, such as a photoplethysmograph. For example, a heart rate monitor on a smart watch may be used as the second sensor. The remoteness of the second sensor from the venous insertion site (and / or the first sensor) may include two sensors with 5.08 cm (2 inches) between the second sensor and the venous insertion site (and / or the first sensor).

[0036] An irregularity between the first venous rhythm and the second venous rhythm is identified (556), and a venous catheter malfunction is detected (558) based on the identified irregularity satisfying an irregularity threshold. The irregularity may include, for example, a difference in frequency between the first venous rhythm and the second venous rhythm. In some implementations, the irregularity may be a difference in amplitude of the first venous rhythm from a baseline amplitude of the first or second venous rhythm. For example, the pulsatile amplitude of the first venous rhythm may be identified as attenuated relative to the baseline pulsatile amplitude of the second venous rhythm. In some implementations, waveforms of each of the venous rhythms may be generated or determined, and an intelligent algorithm may compare the waveforms using pattern matching.

[0037] According to various implementations, a venous catheter malfunction may include fluid leakage from the infusion site or into tissue surrounding the infusion site. In one example, a fluid leakage may be detected when the pulsatile amplitude of a first venous rhythm exhibits a threshold attenuation (e.g., greater than 25%) compared to the baseline pulsatile amplitude of a second venous rhythm.

[0038] In some implementations, the first venous rhythm is detected based on detecting the time-varying amplitude of the light source 522. Based on the light source intensity increasing to meet a first threshold, the system may determine that the venous catheter has moved or is moving closer to the surface of the skin. Based on the light source intensity decreasing to meet a second threshold, the system may determine that the venous catheter has penetrated deeper into the tissue beneath the skin.

[0039] In some implementations, the system may make a determination as to whether the decaying pulsatile amplitude of the first venous rhythm is due to a fluid leak, such as infiltration or extravasation, or due to an obstruction in the vein 511. An obstruction may be detected based on determining that the pulsatile amplitude of the first venous rhythm is decaying while the baseline pulsatile amplitude of the first venous rhythm remains unchanged.

[0040] In some implementations, the system may make a determination as to whether the dampened pulsatile amplitude of the first venous rhythm is due to fluid infiltration or extravasation by activating a second sensor 516 to detect whether there is a change in the topography, color, or light absorption of a portion of the epidermis 521 adjacent to the venous insertion site. In this regard, the second sensor 516 may include an optical sensor configured to detect color or light absorption of the epidermis 521, or an ultrasound sensor configured to measure topography. The sensor 516 may initially be activated for a predetermined period at the start of the infusion (e.g., upon receiving user input indicating that the infusion has started or that the catheter has been inserted) to baseline the surface characteristics (light, topography, color) of the epidermis. Upon detecting an irregularity between the first sensor 404, 514 and the second sensor 408, 520 (e.g., if the two venous rhythms or waveforms do not match), the sensor 516 measurements can be read to determine whether the current characteristics match previous (stored) characteristics. In some implementations, the system (e.g., an algorithm) determines whether the current and previous characteristics match within a predetermined tolerance threshold. Thus, if the pulsatile amplitude of the first venous rhythm decays while the pulsatile amplitude of the second venous rhythm remains relatively unchanged, the system may determine that extravasation has occurred.

[0041] The example process 550 described above and many of the related features and applications may also be implemented as a software process specified as a set of instructions recorded on a computer-readable storage medium (also referred to as a computer-readable medium) and executed automatically (e.g., without user intervention). When these instructions are executed by one or more processing units (e.g., one or more processors, processor cores, or other processing units), they cause the processing units to perform the actions indicated in the instructions. Examples of computer-readable media include, but are not limited to, CD-ROMs, flash drives, RAM chips, hard drives, EPROMs, etc. Computer-readable media does not include carrier waves and electronic signals traveling wirelessly or over wired connections.

[0042] The term "software" is intended to include, where appropriate, firmware resident in read-only memory or applications stored on magnetic storage that may be loaded into memory for processing by a processor. Also, in some implementations, multiple software aspects of the present disclosure may be implemented as subparts of a larger program while remaining separate software aspects of the present disclosure. In some implementations, multiple software aspects may also be implemented as separate programs. Finally, any combination of separate programs that together implement the software aspects described herein is within the scope of the present disclosure. In some implementations, a software program, when installed to operate on one or more electronic systems, defines one or more specific machine implementations that execute and perform the operations of the software program.

[0043] A computer program (also known as a program, software, software application, script, or code) may be written in any form of programming language, including compiled or interpreted, declarative or procedural, and it may be deployed in any form, including as a standalone program or as a module, component, subroutine, object, or other unit suitable for use in a computing environment. A computer program may, but need not, correspond to a file in a file system. A program may be stored in part of a file that holds other programs or data (e.g., one or more scripts stored in a markup language document), in a single file dedicated to that program, or in multiple coordinated files (e.g., a file storing one or more modules, subprograms, or portions of code). A computer program may be deployed to be executed on one computer or on multiple computers at one site or distributed across multiple sites and interconnected by a communications network.

[0044] 9 is a conceptual diagram illustrating an exemplary electronic system 600 for detecting infusion site failure, in accordance with aspects of the present technology. The electronic system 600 may be a computing device for execution of software associated with one or more portions or steps of the method 500, or the components and methods provided by FIGS. 1-8, including, but not limited to, the infusion device 10, or the computing hardware within the smart watch 508, the housing 512, and / or any computing device or related terminal disclosed herein.

[0045] Electronic system 600 may include various types of computer-readable media and interfaces for various other types of computer-readable media. In the depicted example, electronic system 600 includes a bus 608, a processing unit 612, a system memory 604, a read-only memory (ROM) 610, a persistent storage device 602, an input device interface 614, an output device interface 606 (e.g., an alarm device, such as an audio device, a display device, or a haptic device), and one or more network interfaces 616. In some implementations, electronic system 600 may include or be integrated with other computing devices or circuits for operation of the various components and methods previously described.

[0046] Bus 608 collectively represents all system, peripheral, and chipset buses that communicatively connect the various internal devices of electronic system 600. For example, bus 408 communicatively connects processing unit 612 with ROM 610, system memory 604, and persistent storage device 602.

[0047] From these various memory units, the processing unit 612 retrieves instructions to execute and data to process in order to perform the processes of the present disclosure. The processing unit may be a single processor or a multi-core processor in different implementations.

[0048] The ROM 610 stores static data and instructions needed by the processing unit 612 and other modules of the electronic system. The persistent storage device 602, on the other hand, is a read-and-write memory device. This device is a non-volatile memory unit that stores instructions and data even when the electronic system 600 is turned off. Some implementations of the present disclosure use a mass storage device (such as a magnetic or optical disk and its corresponding disk drive) as the persistent storage device 602.

[0049] Other implementations use a removable storage device (such as a floppy disk, flash drive, and its corresponding disk drive) as the persistent storage device 602. Like the persistent storage device 602, the system memory 604 is a read-and-write memory device. However, unlike the storage device 602, the system memory 604 is a volatile read-and-write memory, such as random access memory. The system memory 604 stores some of the instructions and data needed by the processor during execution. In some implementations, the processes of the present disclosure are stored in the system memory 604, the persistent storage device 602, and / or the ROM 610. From these various memory units, the processing unit 612 retrieves instructions to execute and data to process in order to execute the processes of some implementations.

[0050] The bus 608 also connects to an input device interface 614 and an output device interface 606. The input device interface 614 allows a user to communicate information and selected commands to the electronic system. Input devices used with the input device interface 614 include, for example, an alphanumeric keyboard and a pointing device (also called a "cursor control device"). The output device interface 606 allows, for example, the display of images generated by the electronic system 600. Output devices used with the output device interface 606 include, for example, a printer and a display device such as a cathode ray tube (CRT) or a liquid crystal display (LCD). Some implementations include devices such as a touch screen that function as both an input device and an output device.

[0051] 6, bus 608 also couples electronic system 600 to a network (not shown) via network interface 616. Network interface 616 may include, for example, a wireless access point (e.g., Bluetooth® or Wi-Fi®) or radio circuitry for connecting to a wireless access point. Network interface 616 may also include hardware (e.g., Ethernet® hardware) for connecting a computer to a network of computers, such as a local area network ("LAN"), a wide area network ("WAN"), a wireless LAN, or an intranet, or to a portion of a network of networks, such as the Internet. Any or all components of electronic system 600 may be used in conjunction with the present disclosure.

[0052] The functions described above may be implemented in computer software, firmware, or hardware. The techniques may be implemented using one or more computer program products. The programmable processor and computer may be included in or packaged as a mobile device. Processes and logic flows may be implemented by one or more programmable processors and by one or more programmable logic circuits. General-purpose and special-purpose computing and storage devices may be interconnected via a communications network.

[0053] Some implementations include electronic components such as a microprocessor, storage, and memory that store computer program instructions on a machine-readable or computer-readable medium (also called a computer-readable storage medium, machine-readable medium, or machine-readable storage medium). Some examples of such computer-readable media include RAM, ROM, read-only compact discs (CD-ROMs), recordable compact discs (CD-Rs), rewritable compact discs (CD-RWs), read-only digital versatile discs (e.g., DVD-ROMs, dual-layer DVD-ROMs), various recordable / rewritable DVDs (e.g., DVD-RAMs, DVD-RWs, DVD+RWs, etc.), flash memory (e.g., SD cards, mini-SD cards, micro-SD cards, etc.), magnetic and / or solid-state hard drives, read-only and recordable Blu-Ray® discs, ultra-high density optical discs, any other optical or magnetic medium, and floppy disks. The computer-readable medium can store a computer program executable by at least one processing unit and including a set of instructions for performing various operations. Examples of computer programs or computer code include machine code, such as produced by a compiler, and files containing high-level code that are executed by a computer, electronic component, or microprocessor using an interpreter.

[0054] Although the above description primarily refers to microprocessors or multi-core processors executing software, some implementations are performed by one or more integrated circuits, such as application specific integrated circuits (ASICs) or field programmable gate arrays (FPGAs). In some implementations, such integrated circuits execute instructions stored on the circuitry itself.

[0055] The terms "computer," "server," "processor," and "memory," as used herein and in any claims of this application, all refer to electronic or other technological devices. These terms exclude a person or group of people. For purposes of this specification, the terms display or displaying mean displaying on an electronic device. The terms "computer readable medium" and "computer readable media," as used herein and in any claims of this application, are strictly limited to tangible, physical objects that store information in a form that is readable by a computer. These terms exclude wireless signals, wired download signals, and any other ephemeral signals.

[0056] To provide for user interaction, implementations of the subject matter described herein may be implemented on a computer having a display device, e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor, for displaying information to the user, and a keyboard and pointing device, e.g., a mouse or trackball, by which the user can provide input to the computer. Other types of devices may be used to provide for user interaction as well; for example, feedback provided to the user may be any form of sensory feedback, e.g., visual feedback, auditory feedback, or tactile feedback, and input from the user may be received in any form, including acoustic input, voice input, or tactile input. Additionally, the computer may interact with the user by sending and receiving documents to and from devices used by the user, e.g., by sending web pages to a web browser on the user's client device in response to a request received from the web browser.

[0057] Implementations of the subject matter described herein may be implemented in a computing system that includes back-end components, e.g., data servers, or middleware components, e.g., application servers, or front-end components, e.g., client computers having a graphical user interface or web browser through which a user can interact with implementations of the subject matter described herein, or any combination of one or more such back-end, middleware, or front-end components. The components of the system may be interconnected by any form or medium of digital data communication, e.g., a communications network. Examples of communications networks include local area networks ("LANs") and wide area networks ("WANs"), internetworks (e.g., the Internet), and peer-to-peer networks (e.g., ad hoc peer-to-peer networks).

[0058] A computing system may include clients and servers. Clients and servers are generally remote from each other and may interact through a communication network. The relationship of client and server arises by virtue of computer programs running on the respective computers and having a client-server relationship to each other. In some implementations, a server sends data (e.g., HTML pages) to client devices (e.g., to display the data to and receive user input from a user interacting with the client device). Data generated at the client device (e.g., the result of user interaction) may be received from the client device at the server.

[0059] Those skilled in the art will appreciate that the various illustrative blocks, modules, elements, components, methods, and algorithms described herein can be implemented as electronic hardware, computer software, or a combination of both. To illustrate this interchangeability between hardware and software, the various illustrative blocks, modules, elements, components, methods, and algorithms have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends on the particular application and design constraints imposed on the overall system. The described functionality can be implemented in various ways for each particular application. The various components and blocks may be arranged differently (e.g., arranged in a different order or partitioned differently), all without departing from the scope of the present technology.

[0060] It is understood that the specific order or hierarchy of steps in the processes disclosed is an illustration of sample approaches. Based on design preferences, it is understood that the specific order or hierarchy of steps in the processes may be rearranged. Some of the steps may even be performed simultaneously. The accompanying method claims present elements of the various steps in a sample order, and are not intended to be limited to the specific order or hierarchy presented.

[0061] Examples of clauses of this technology: Various examples of aspects of the present disclosure are described as numbered clauses (1, 2, 3, etc.) for convenience. These are provided as examples and are not intended to limit the present technology. Figure and reference number identification is provided below solely for illustration and illustrative purposes, and the clauses are not limited by those identifications.

[0062] Clause 1. A method for detecting an infusion site malfunction, the method comprising: detecting a first venous rhythm of a patient above a venous insertion site when a venous catheter is inserted into the patient's venous insertion site, the venous catheter being connected to an infusion set that provides fluid from a fluid source to the venous insertion site; detecting a second venous rhythm at a location remote from the venous insertion site concurrently with the first venous rhythm; identifying an irregularity between the first venous rhythm and the second venous rhythm; and detecting a venous catheter malfunction based on the identified irregularity satisfying an irregularity threshold.

[0063] Clause 2. The method of clause 1, wherein identifying the irregularity comprises detecting leakage of injected fluid into tissue near the venous insertion site based on the pulsatile amplitude of the first venous rhythm being attenuated relative to the baseline pulsatile amplitude.

[0064] Clause 3. The method of clause 2, further comprising: detecting a first venous rhythm based on detecting a time-varying amplitude of the light source; determining that the venous catheter has moved closer to the surface of the skin based on the intensity of the light source increasing to meet a first threshold; and determining that the venous catheter has been inserted deeper into the tissue based on the intensity of the light source decreasing to meet a second threshold.

[0065] Clause 4. The method of any one of clauses 1 to 3, further comprising detecting an occlusion associated with the venous insertion site based on a decay in the pulsatile amplitude of the first venous rhythm while the baseline light intensity of the first venous rhythm remains unchanged.

[0066] Clause 5. The method of any one of clauses 1 to 4, further comprising, when an irregularity is identified, detecting a change in topography or optical absorption of a portion of the epidermis adjacent to the venous insertion site, and determining that extravasation has occurred based on the change in topography or optical absorption satisfying an extravasation threshold.

[0067] Clause 6. The method of any one of clauses 1 to 5, further comprising providing an audio, visual, or haptic alarm in response to detecting a malfunction of the venous catheter.

[0068] Clause 7. The method of any one of clauses 1 to 6, further comprising providing an infusion set configured to connect the venous catheter to an infusion line that provides infusion fluid from a fluid source, the infusion set comprising a transducer configured to detect a first venous rhythm.

[0069] Clause 8. The method of clause 7, wherein the transducer comprises a piezoelectric circuit, and the method further comprises detecting the first venous rhythm by detecting time-varying pressure in the fluid passing through the infusion set using the piezoelectric circuit.

[0070] Clause 9. The method of clause 7, wherein the infusion set is configured to position a transducer over the venous insertion site and at least a portion of the venous catheter when the venous catheter is inserted into the venous insertion site, the venous catheter comprising a light source and the transducer comprising a photodetector, and the method further comprises detecting the first venous rhythm by using the photodetector to detect time-varying changes in the light source passing through the subcutaneous tissue between the light source and the transducer.

[0071] Clause 10. The method of any one of clauses 1 to 9, further comprising detecting a second venous rhythm using photoplethysmography.

[0072] Clause 11. A system for detecting injection site failure, comprising one or more processors and a memory device having stored thereon computer-readable instructions that, when executed by the one or more processors, implement the method of any one of clauses 1 to 10.

[0073] Clause 12. A system for detecting injection site failure, comprising one or more processors and a memory device having stored thereon computer-readable instructions that, when executed by the one or more processors, implement the method described in any one of clauses 1 to 7.

[0074] Clause 13. The system described in Clause 12, further comprising a pressure transducer and a photoplethysmograph, wherein one of the first venous rhythm and the second venous rhythm is detected by the pressure transducer and one of the first venous rhythm and the second venous rhythm is detected by the photoplethysmograph.

[0075] Clause 14. The system described in Clause 12, further comprising a piezoelectric transducer and a photoplethysmograph, wherein one of the first venous rhythm and the second venous rhythm is detected by the piezoelectric transducer and one of the first venous rhythm and the second venous rhythm is detected by the photoplethysmograph.

[0076] Clause 15. The system described in Clause 12, further comprising an optical sensor and a photoplethysmograph, wherein the first venous rhythm is detected by the optical sensor based on detecting the time-varying amplitude of a light source connected to or within the catheter, and the second venous rhythm is detected by the photoplethysmograph.

[0077] Clause 16. A non-transitory computer-readable medium having stored thereon instructions that, when executed by one or more processors, perform the method of any one of clauses 1 to 10.

[0078] Clause 17. A system for detecting infusion site failure, comprising: a first sensor configured to detect a first venous rhythm of the patient above a venous insertion site when a venous catheter is inserted into the patient's venous insertion site, the venous catheter being connected to an infusion set that provides fluid from a fluid source to the venous insertion site; a second sensor configured to detect a second venous rhythm at a location remote from the venous insertion site concurrently with the first venous rhythm; and an electronic device comprising an alarm device, the electronic device configured to: receive an indication of the patient's first venous rhythm above the patient's venous insertion site from the first sensor when the venous catheter is inserted into the venous insertion site; receive an indication of the second venous rhythm from the second sensor concurrently with the first venous rhythm; identify an irregularity between the first venous rhythm and the second venous rhythm based on the first and second indications; detect a venous catheter failure based on the identified irregularity satisfying an irregularity threshold; and provide an alarm via the alarm device in response to detecting a venous catheter failure.

[0079] Clause 18. The system described in Clause 17, wherein identifying the irregularity comprises detecting leakage of injected fluid into tissue near the venous insertion site based on the pulsatile amplitude of the first venous rhythm being attenuated relative to the baseline pulsatile amplitude.

[0080] Clause 19. The system described in Clause 18, wherein the first sensor comprises an optical sensor, and the first venous rhythm is detected based on detecting the time-varying amplitude of a light source, and further comprising determining that the venous catheter has moved closer to the surface of the skin based on the intensity of the light source increasing and satisfying a first threshold, and determining that the venous catheter has penetrated deeper into the tissue based on the intensity of the light source decreasing and satisfying a second threshold.

[0081] Clause 20. The system described in Clause 19, wherein the electronic device is further configured to detect an occlusion associated with the venous insertion site based on a decay in the pulsatile amplitude of the first venous rhythm while the baseline light intensity of the first venous rhythm remains unchanged.

[0082] Clause 21. The system of any one of clauses 17 to 20, further comprising an infusion set configured to connect the venous catheter to an infusion line providing infusion fluid from a fluid source, the first sensor comprising a transducer on the infusion set and configured to detect a first venous rhythm.

[0083] Clause 22. The system described in Clause 21, wherein the transducer comprises a piezoelectric circuit and the electronic device is further configured to detect the first venous rhythm by detecting time-varying pressure in the fluid passing through the infusion set using the piezoelectric circuit.

[0084] Clause 23. The system of clause 22, wherein the second sensor comprises a photoplethysmograph, and the electronic device is further configured to detect the second venous rhythm using photoplethysmography.

[0085] Clause 24. The system of clause 21, wherein the infusion set is configured to position a transducer over the venous insertion site and at least a portion of the venous catheter when the venous catheter is inserted into the venous insertion site, the venous catheter comprising a light source and the transducer comprising a photodetector, and the method further comprises detecting the first venous rhythm by using the photodetector to detect time-varying changes in the light source passing through the subcutaneous tissue between the light source and the transducer.

[0086] Clause 25. The system of clause 24, wherein the second sensor comprises a photoplethysmograph, and the electronic device is further configured to detect the second venous rhythm using photoplethysmography.

[0087] Clause 26. The system of any one of clauses 17 to 20, wherein the electronic device is further configured to detect a change in topography or optical absorption of a portion of the epidermis adjacent to the venous insertion site when an irregularity is identified, and determine that extravasation has occurred based on the change in topography or optical absorption satisfying an extravasation threshold.

[0088] Clause 27. A system according to any one of clauses 17 to 20, wherein the alarm device comprises an audio device, a display device, or a haptic device, and wherein the electronic device is further configured to, in response to detecting a malfunction of the venous catheter, provide an audio alarm via the audio device when the alarm device comprises an audio device, provide a visual alarm via the display when the alarm device comprises a display device, or provide a haptic alarm via the haptic device when the alarm device comprises a haptic device.

[0089] Clause 28. A system according to any one of clauses 17 to 27, wherein the electronic device comprises one or more processors and a memory device having stored thereon computer-readable instructions which, when executed by the one or more processors, detect a fault and provide an alarm via the alarm device.

[0090] Clause 29. A system described in any one of clauses 17 to 20, wherein the first and second sensors comprise a pressure transducer and a photoplethysmograph, and one of the first venous rhythm and the second venous rhythm is detected by the pressure transducer and one of the first venous rhythm and the second venous rhythm is detected by the photoplethysmograph.

[0091] Clause 30. A system described in any one of clauses 17 to 20, wherein the first and second sensors comprise a piezoelectric transducer and a photoplethysmograph, and one of the first venous rhythm and the second venous rhythm is detected by the piezoelectric transducer, and one of the first venous rhythm and the second venous rhythm is detected by the photoplethysmograph.

[0092] Clause 31. A system described in any one of clauses 17 to 20, wherein the first and second sensors comprise an optical sensor and a photoplethysmograph, and the first venous rhythm is detected by the optical sensor based on detecting the time-varying amplitude of a light source connected to or within the catheter, and the second venous rhythm is detected by the photoplethysmograph.

[0093] Further considerations: It is understood that the specific order or hierarchy of steps in the disclosed processes is an illustration of example approaches. Based on design preferences, it is understood that the specific order or hierarchy of steps in a process may be rearranged. Some of the steps may be performed simultaneously. The accompanying method claims present elements of the various steps in a sample order, and are not intended to be limited to the specific order or hierarchy presented. The foregoing description is provided to enable those skilled in the art to practice various aspects described herein. The foregoing description provides various examples of the technology, and the technology is not limited to these examples. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects. The claims are hereby not intended to be limited to the aspects set forth herein but are to be accorded the full scope consistent with the claims language, and references to elements in the singular are not intended to mean "one and only one" unless expressly stated as such, but rather "one or more." Unless expressly stated otherwise, the term "some" refers to one or more. Masculine pronouns (e.g., his) include feminine and neuter forms (e.g., her and its) and vice versa. Headings and subheadings, if any, are used for convenience only and do not limit the invention described herein.

[0094] The terms "configured to," "operable to," and "programmed to" do not imply any particular tangible or intangible modification of the subject matter, but rather are intended to be used interchangeably. For example, a processor configured to monitor and control operations or components may also mean that the processor is programmed to monitor and control operations, or that the processor is operable to monitor and control operations. Similarly, a processor configured to execute code may be interpreted as a processor programmed to execute code or operable to execute code.

[0095] The term automatic, as used herein, may include performance by a computer or machine without user intervention, e.g., by instructions in response to a predicated action by a computer or machine or other initiating mechanism. The word "example" is used herein to mean "serving as an example or illustration." Any aspect or design described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other aspects or designs.

[0096] The use of a phrase such as "aspect" does not imply that such aspect is essential to the technology or that such aspect applies to all configurations of the technology. Disclosure of an aspect may apply to all configurations, or to one or more configurations. An aspect may provide one or more examples. A phrase such as "aspect" may refer to one or more aspects, and vice versa. A phrase such as "implementation" does not imply that such implementation is essential to the technology or that such implementation applies to all configurations of the technology. Disclosure of an implementation may apply to all implementations, or to one or more implementations. An implementation may provide one or more examples. A phrase such as "implementation" may refer to one or more implementations, and vice versa. A phrase such as "configuration" does not imply that such configuration is essential to the technology or that such configuration applies to all configurations of the technology. Disclosure of a configuration may apply to all configurations, or to one or more configurations. A configuration may provide one or more instances. A phrase such as "configuration" may refer to one or more configurations, and vice versa.

[0097] As used herein, a "user interface" (also referred to as an interactive user interface, graphical user interface, or UI) may refer to a network-based interface that includes data fields and / or other control elements for receiving input signals or providing electronic information, and / or for providing information to a user in response to any received input signals. Control elements may include dials, buttons, icons, selectable areas, or other perceptible indicators presented via the UI that, when interacted with (e.g., clicked, touched, selected, etc.), initiate data exchange for the device presenting the UI. A UI may be implemented, in whole or in part, using technologies such as hyper-text markup language (HTML), FLASH®, JAVA®, .NET®, C, C++, web services, or rich site summaries (RSS). In some implementations, a UI may be included in a standalone client (e.g., a thick client, a fat client) configured to communicate (e.g., send or receive data) according to one or more of the described aspects. The communication may be between the medical device or a server in communication therewith.

[0098] As used herein, the terms "determine" or "determining" encompass a wide variety of actions. For example, "determining" may include calculating, computing, processing, deriving, generating, obtaining, retrieving (e.g., searching in a table, database, or another data structure), ascertaining, etc., via a hardware element without user intervention. Also, "determining" may include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory), etc., via a hardware element without user intervention. "Determining" may include resolving, selecting, choosing, establishing, etc., via a hardware element without user intervention.

[0099] As used herein, the terms "provide" or "providing" encompass a wide variety of actions. For example, "providing" may include storing a value at a location on a storage device for later retrieval, transmitting a value directly to a recipient via at least one wired or wireless communication medium, transmitting or storing a reference to a value, etc. "Providing" may also include encoding, decoding, encrypting, decrypting, verifying, checking, etc. via a hardware element.

[0100] As used herein, the term "message" encompasses a wide variety of formats for communicating (e.g., sending or receiving) information. A message may include a machine-readable collection of information, such as an XML document, a fixed-field message, a comma-separated message, JSON, a custom protocol, etc. A message, in some implementations, may include a signal utilized to transmit one or more representations of information. While stated in the singular, it will be understood that a message may be created, sent, stored, received, etc., in multiple parts.

[0101] The terms "selectively" or "selective" as used herein may encompass a wide variety of actions. For example, a "selective" process may include determining one option from multiple options. A "selective" process may include one or more of dynamically determined inputs, pre-configured inputs, or user-initiated inputs to make a decision. In some implementations, an n-input switch may be included to provide selective functionality, where n is the number of inputs used to make a selection.

[0102] As used herein, the terms "correspond" or "corresponding" encompass a structural, functional, quantitative, and / or qualitative correlation or relationship between two or more objects, data sets, information, etc., preferably where the correspondence or relationship may be used to translate one or more of the two or more objects, data sets, information, etc. so that they appear identical or equivalent. Correspondence may be evaluated using one or more of thresholds, value ranges, fuzzy logic, pattern matching, machine learning evaluation models, or combinations thereof.

[0103] In some implementations, generated or detected data may be transferred to a “remote” device or location, where “remote” means a location or device other than the location or device where the program is executed. For example, a remote location could be another location in the same city (e.g., an office, a lab, etc.), another location in a different city, another location in a different state, another location in a different country, etc. Thus, when an item is referred to as being “remote” from another item, this means that the two items may be in the same room but apart, or at least in different rooms or different buildings, and that the two items may be at least 1 mile, 10 miles, or at least 100 miles apart. “Communicating” information refers to transmitting data representing that information as electrical signals over a suitable communications channel (e.g., a private or public network). "Forwarding" an item refers to any means of moving the item from one location to another, whether by physically transporting the item or (possibly) otherwise, and includes, at least in the case of data, physically transporting the medium carrying the data or communicating that data. Examples of communication media include radio or infrared transmission channels, as well as network connections to another computer or networked device, and the Internet, or email transmissions, information stored on websites, and the like.

Claims

1. A method for detecting an injection site defect, When a venous catheter is inserted into a patient's venous insertion site, the detection of the patient's first venous rhythm above the venous insertion site, wherein the venous catheter is connected to an infusion set that provides fluid from a fluid source to the venous insertion site, and the detection of the first venous rhythm is performed. Simultaneously with the detection of the first venous rhythm, a second venous rhythm is detected at a location away from the venous insertion site. Identifying the irregularity between the first venous rhythm and the second venous rhythm, Based on the fact that the identified irregularity satisfies the irregularity threshold, a defect in the venous catheter is detected. A method that includes [a certain feature].

2. Identifying the aforementioned irregularities is, Based on the fact that the pulse amplitude of the first venous rhythm is attenuated relative to the baseline pulse amplitude, leakage of the injected fluid into the tissue near the venous insertion site is detected. The method according to claim 1, comprising:

3. The first venous rhythm is detected based on detecting the time variation amplitude of the light source. Based on the increase in the intensity of the light source and the meeting of a first threshold, it is determined that the venous catheter has moved closer to the surface of the skin, Based on the decrease in the intensity of the light source and the satisfying of a second threshold, it is determined that the venous catheter has penetrated deeper into the tissue. The method according to claim 2, further comprising:

4. To detect an occlusion related to the venous insertion site based on the fact that the pulse amplitude of the first venous rhythm is attenuated while the baseline light intensity of the first venous rhythm remains unchanged. The method according to any one of claims 1 to 3, further comprising the above.

5. When the aforementioned irregularity is identified, a change in topography or light absorption of a portion of the epidermis adjacent to the venous insertion site is detected. Determining that extravasation has occurred based on the fact that the aforementioned change in topography or light absorption satisfies the extravasation threshold. The method according to any one of claims 1 to 3, further comprising the above.

6. To provide an audio, visual, or haptic alarm in response to the detection of the aforementioned defect in the venous catheter. The method according to any one of claims 1 to 3, further comprising the above.

7. To provide an infusion set configured to connect a venous catheter to an infusion line that provides an infusion fluid from a fluid source, wherein the infusion set comprises a transducer configured to detect the first venous rhythm. The method according to any one of claims 1 to 3, further comprising the above.

8. The transducer comprises a piezoelectric circuit, and the method is The first venous rhythm is detected by detecting the time-varying pressure in the fluid passing through the injection set using the piezoelectric circuit. The method according to claim 7, further comprising:

9. The infusion set is configured to position the transducer over the venous insertion site and at least a portion of the venous catheter when the venous catheter is inserted into the venous insertion site. The venous catheter comprises a light source, the transducer comprises a photodetector, and the method The first venous rhythm is detected by using the photodetector to detect the time-varying change of the light source as it passes through the subcutaneous tissue between the light source and the transducer. Furthermore, The method according to claim 7.

10. To detect the second venous rhythm using photoplethysmography. The method according to any one of claims 1 to 3, further comprising the above.

11. A system for detecting defective injection sites, One or more processors, A memory device storing computer-readable instructions that, when executed by one or more processors, implement the method according to any one of claims 1 to 3, A system equipped with these features.

12. Pressure transducer and Photoplethysmography and Furthermore, One of the first venous rhythm and the second venous rhythm is detected by the pressure transducer, and one of the first venous rhythm and the second venous rhythm is detected by the photoplethysmograph. The system according to claim 11.

13. Piezoelectric transducer and Photoplethysmography and Furthermore, One of the first venous rhythm and the second venous rhythm is detected by the piezoelectric transducer, and one of the first venous rhythm and the second venous rhythm is detected by the photoplethysmograph. The system according to claim 11.

14. Light sensor and, Photoplethysmography and Furthermore, The first venous rhythm is detected by the optical sensor based on detecting the time-varying amplitude of a light source connected to or located within the catheter, and the second venous rhythm is detected by the photoplethysmograph. The system according to claim 11.

15. A non-temporary computer-readable medium storing instructions for performing the method according to any one of claims 1 to 3, when executed by one or more processors.

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