Electrical impedance analyzer, system and puncture device for evaluating hematoma of physiological tissue

Abstract

The invention discloses an electrical impedance analyzer and system for evaluating hematoma of physiological tissue and a puncture device, and relates to the technical field of biomedical engineering. The electrical impedance analyzer is connected with the electrical impedance measuring structure and can receive electrical impedance data, sent by the electrical impedance measuring structure, of the physiological tissue in real time and evaluate whether hematoma exists or not according to change information of electrical impedance. The method can sensitively, timely and accurately recognize the hematoma occurrence and development risk of the physiological tissue, so that the clinical medical safety quality is improved, and the perioperative prognosis of a patient is improved.

Description

Technical Field

[0001] The present invention relates to the field of biomedical engineering technology, and in particular to an electrical impedance analyzer, system and puncture device for evaluating physiological tissue hematoma. Background Art

[0002] In clinical surgery, anesthesia is a key means to ensure the success of the operation and relieve the pain of patients. Among them, epidural anesthesia (full name: epidural space block anesthesia) is a technique commonly used for intrathecal analgesia. It can effectively reduce the use of opioids while achieving satisfactory analgesic effects. It is more commonly used in limb surgeries below the abdomen (such as painless childbirth). The main component used in this anesthesia method is the anesthesia catheter, which needs to be placed in the narrow epidural space. Since the catheter itself is usually made of a polymer material that is relatively soft and cannot penetrate human tissue, it is necessary to use an epidural puncture needle to establish a channel to the epidural space. The operation process is summarized as follows: first use the epidural puncture needle to penetrate the epidural space, and then insert the epidural catheter (ie, anesthesia catheter) through the inner lumen of the puncture needle into the epidural space, and then pull out the puncture needle, leaving the epidural catheter in the epidural space. In order to achieve a better anesthesia effect, after the epidural catheter enters the epidural space, it needs to advance a distance along the longitudinal direction of the epidural space toward the human head in order to achieve a better anesthesia effect, see. Figure 1 shown.

[0003] Epidural anesthesia also carries potential hazards. One of the main risks is the occurrence of epidural hematoma (EH). Although this condition is relatively rare (approximately 6 / 1 million), once it occurs, it can have serious consequences: epidural hematoma can compress the spinal cord, leading to neurological dysfunction, including loss of movement and sensation, and even permanent paralysis. In addition, the formation of epidural hematoma is often accompanied by symptoms such as acute pain, lower limb weakness, and difficulty urinating, seriously affecting the patient's quality of life.

[0004] Epidural hematomas (EHs) are primarily caused by puncture trauma and abnormal coagulation function. While medical professionals adhere to strict aseptic techniques and technical specifications during epidural puncture, hematomas can still develop due to improper handling or individual vascular variations. The risk of hematomas forming around an indwelling epidural catheter is particularly high. Currently, the detection of epidural hematomas relies primarily on imaging techniques, including magnetic resonance imaging (MRI), computed tomography (CT), and ultrasound. MRI offers high resolution and can clearly demonstrate the location and extent of the hematoma, but it is expensive and time-consuming. CT is fast and accurate, but it uses radiation, making continuous or dynamic monitoring difficult. Ultrasound, while noninvasive, rapid, and bedside, is limited in its ability to detect deep hematomas. In addition, some hematoma detection methods utilize neuroelectrophysiological tests, such as electromyography (EMG) and evoked potentials (EP). These primarily assess neurological function and conduction capacity to determine the presence of a hematoma. These procedures are complex and time-consuming, making early diagnosis and timely treatment difficult. As can be seen, existing monitoring methods are not sensitive for the early detection of epidural hematomas (EHs), especially in the early stages of symptoms, when doctors may not be able to identify them promptly.

[0005] It should be noted that for epidural and subdural hematomas, the existing technology also provides some convenient operation solutions. As an example, Chinese patent application CN202210350139.3 discloses an epidural and subdural hematoma monitoring system, a computer storable medium and a device, which detects the hematoma signal of the patient's head, then pre-processes the detected signal, and converts the actual coordinate value into a reference coordinate value through a coordinate correction algorithm; reconstructs the detection signal input into the reconstruction model to obtain detection data, and finally outputs the detection result through the component; wherein, the detection component includes a plurality of detection units, and the detection unit is used to detect the thickness of the epidural and subdural hematoma at a local position point on the patient's head; the detection unit includes a signal transmitter and a signal receiver, and there are multiple signal receivers around the signal transmitter, the signal transmitter emits near-infrared light, and the signal receiver receives near-infrared light, which uses the strong penetrating ability of near-infrared light to detect the thickness of the hematoma. For another example, Chinese patent application CN202280070398.9 is a system for detecting and / or evaluating subdural hematoma, comprising: a wearable structure configured to be worn on the head of a subject; an optical subsystem mounted on the wearable structure and configured to emit light toward a predetermined position relative to the wearable structure and sense the emitted light returned from the predetermined position, wherein the optical subsystem is also configured to generate a corresponding set of signals in response to the interaction of the emitted light with a substance contained in the subject's skull; a radio transceiver subsystem configured to emit sub-optical radiation and generate signals in response to the interaction of the radiation with a substance contained in the subject's skull; and a data processor configured to: analyze the signals of the optical subsystem and the signals of the radio transceiver subsystem, and detect and / or evaluate the subject's subdural hematoma based on the analysis. The above solutions are all based on optical technology for detection, need to be worn at the detection site, and have limited penetration depth. They are mainly suitable for superficial hematomas, such as subscalp hematoma detection on the head, and are difficult to use for spinal epidural hematoma detection (located deep in the spine).

[0006] Meanwhile, with the development of bioimpedance technology, BIA (Bioelectrical Impedance Analysis) has been widely applied in basic and clinical sciences. For example, it can clearly assess the state of biological tissues, such as skin, muscle, fat, blood, bone, and cavities, by analyzing their structure, composition, and state, and their resistance to electrical current. Summary of the Invention

[0007] The purpose of the present invention is to overcome the shortcomings of the existing technology and provide an electrical impedance analyzer, system and puncture device for the assessment of physiological tissue hematomas. The present invention is based on bioelectrical impedance measurement technology and utilizes the characteristic that the electrical impedance of biological tissue changes when its state changes. It provides an electrical impedance analyzer that can be used for the assessment of physiological tissue hematomas. The electrical impedance analyzer is connected to the electrical impedance measurement structure and can receive the electrical impedance data of the physiological tissue sent by the aforementioned electrical impedance measurement structure in real time, and evaluate whether there is a hematoma based on the change information of the electrical impedance. The present invention can sensitively, timely and accurately identify the occurrence and development risks of hematomas in physiological tissues, thereby helping to improve the quality of clinical medical safety and improve the perioperative prognosis of patients.

[0008] To achieve the above objectives, the present invention provides the following technical solutions: An electrical impedance analyzer for evaluating physiological tissue hematoma is connected to an electrical impedance measurement structure. The electrical impedance analyzer is used to receive electrical impedance data of physiological tissue sent by the aforementioned electrical impedance measurement structure in real time, and evaluate whether there is hematoma based on the change information of the electrical impedance.

[0009] Furthermore, the electrical impedance analyzer is provided with a hematoma risk analysis module, which is configured to: Calculate the change in the electrical impedance value Ri within each time interval Ti according to the received data and the preset time interval T; where i represents the number of periods and is an integer greater than or equal to 1, i=1, 2, 3, ...; Ti represents the i-th time interval; and Ri represents the change in the electrical impedance value within the i-th time interval; Compare Ri with the preset change amplitude threshold Rk; when Ri is greater than or equal to Rk, it is determined that there is a risk of evolving towards hematoma, that is, there is a hematoma risk; when Ri is less than Rk, it is determined that there is no hematoma risk at present.

[0010] Furthermore, when there is a risk of hematoma, a hematoma risk warning is issued and a hematoma depth detection is prompted; When there is no risk of hematoma, continue monitoring as usual.

[0011] Furthermore, the value of Rk is set by the system by default or personalized by the user.

[0012] Furthermore, in the electrical impedance analyzer, corresponding reference resistance values Rb and amplitude threshold reference ratios λ are configured for different biological tissue types in combination with several commonly used current injection situations. Rb represents the reference resistance value of the biological tissue type under normal circumstances and when no hematoma occurs. λ is used to calculate the aforementioned Rk, which is the product of the reference resistance value Rb and the amplitude threshold reference ratio λ.

[0013] Furthermore, the electrical impedance analyzer further comprises a user interface and an initialization module; The user interface is used to collect biological tissue type and current injection type information input by the user, or to collect target biological tissue type and current injection type information selected by the user; The initialization module is used to obtain the target biological tissue type and current injection type input or selected by the user, obtain Rb and λ corresponding to the target biological tissue type and current injection type from the aforementioned configuration information, and determine the corresponding Rk value based on Rb and λ.

[0014] Furthermore, in the electrical impedance analyzer, a corresponding hematoma-electrical impedance change law model is configured for each biological tissue type; The hematoma risk analysis module in the electrical impedance analyzer is configured to: Obtaining a target biological tissue type input or selected by a user, and obtaining a hematoma-electrical impedance change law model corresponding to the target biological tissue type; The electrical impedance values obtained from the electrical impedance measurement structure and the corresponding current time information are sorted in chronological order to form a real-time change pattern of the electrical impedance values over time; The real-time change pattern is compared with the electrical impedance change pattern recorded in the aforementioned hematoma-electrical impedance change pattern model; when the matching degree between the two is greater than or equal to the preset threshold, it is determined that there is a risk of hematoma development; when the matching degree between the two is less than the preset threshold, it is determined that there is no risk of hematoma development at present.

[0015] Furthermore, when there is a risk of hematoma development, a hematoma development warning is issued and a hematoma depth detection is prompted; When there is no risk of hematoma development, continue monitoring as usual.

[0016] The present invention also provides a system for physiological tissue hematoma assessment, comprising an electrical impedance measurement structure and an electrical impedance analyzer. The electrical impedance measurement structure is arranged corresponding to the implanted segment of the physiological tissue and is used to measure the electrical impedance value around the implanted segment and transmit it to the electrical impedance analyzer; wherein the electrical impedance measurement structure uses a two-electrode method or a four-electrode method to measure the electrical impedance value around the implanted segment and transmits the electrical impedance data including the electrical impedance value and time information to the electrical impedance analyzer in real time; The electrical impedance analyzer is the aforementioned electrical impedance analyzer.

[0017] The present invention also provides an epidural puncture device, comprising an epidural puncture needle and an epidural catheter, wherein the epidural puncture needle comprises a needle body and a needle seat, and the epidural catheter is used to enter the epidural space through the epidural puncture needle, wherein the front end of the epidural catheter is an insertion section, which is inserted longitudinally along the epidural space after entering the epidural space; An electrical impedance measurement structure is provided corresponding to the implanted segment for measuring the electrical impedance value around the implanted segment and transmitting the measured value to the electrical impedance analyzer; wherein the electrical impedance measurement structure uses a two-electrode method or a four-electrode method to measure the electrical impedance value around the implanted segment and transmits the impedance data including the impedance value and time information to the electrical impedance analyzer in real time; The electrical impedance analyzer is the aforementioned electrical impedance analyzer.

[0018] Due to the adoption of the above technical solution, the present invention has the following advantages and positive effects compared with the prior art, as an example: Based on bioelectrical impedance measurement technology, the present invention utilizes the characteristic that the electrical impedance of biological tissue changes when its state changes. This provides an electrical impedance analyzer that can be used to assess physiological tissue hematomas. The analyzer is connected to an electrical impedance measurement structure and can receive real-time electrical impedance data of physiological tissue transmitted by the electrical impedance measurement structure. The analyzer then assesses the presence of a hematoma based on this information. This device can sensitively, promptly, and accurately identify the risk of hematoma development and progression in physiological tissue, thereby contributing to improved clinical medical safety and perioperative outcomes.

[0019] In another aspect, the present invention also provides a specific method for hematoma risk analysis. Furthermore, considering that hematoma formation occurs gradually, during which the electrical impedance changes of epidural tissue exhibit a certain regularity, a specific method for hematoma development risk assessment is also provided.

[0020] On the other hand, an epidural puncture device comprising the aforementioned electrical impedance analyzer is provided, which evaluates the presence and characteristics of a hematoma by detecting changes in the electrical impedance of the epidural space. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of the placement of an epidural catheter in the epidural space.

[0022] Figure 2 Schematic diagram of the spine cross section.

[0023] Figure 3 A schematic structural diagram of a puncture device with hematoma monitoring function provided in an embodiment of the present invention.

[0024] Figure 4 Schematic diagram of an epidural puncture needle provided in an embodiment of the present invention.

[0025] Figure 5 Schematic diagram of an epidural catheter with an insertion section provided in an embodiment of the present invention.

[0026] Figure 6 A schematic diagram of the state of the catheter insertion section after being placed in place provided by an embodiment of the present invention.

[0027] Figure 7 This is a schematic structural diagram of an electrode before expansion provided by an embodiment of the present invention.

[0028] Figure 8 This is a schematic diagram of the structure of the electrode after expansion provided by an embodiment of the present invention.

[0029] Figure 9 A schematic diagram of an electrode structure using an airbag expansion ring provided in an embodiment of the present invention.

[0030] Figure 10 A schematic diagram of the insertion section structure including an inner tube and an outer tube provided in an embodiment of the present invention.

[0031] Figure 11 A schematic diagram of the structure of an implantation segment with a dynamic measurement segment provided in an embodiment of the present invention.

[0032] Description of reference numerals: Puncture device 10; Epidural puncture needle 100, needle body 110, needle head 111, needle seat 120; Epidural catheter 200, catheter attachment 201, insertion section 210, inner tube 2101, outer tube 2102, tube unit 21, dynamic measurement section 22, catheter head section 211, electrode 212, conductive layer 2121, balloon cavity 2122, opening 2123, delivery tube 2124, guide wire 213; Electrical impedance analyzer 300; Anesthetic syringe 400. DETAILED DESCRIPTION

[0033] The following is a further detailed description of the electrical impedance analyzer, system and puncture device for physiological tissue hematoma assessment disclosed in the present invention in conjunction with the accompanying drawings and specific embodiments. It should be noted that the technical features or combinations of technical features described in the following embodiments should not be considered isolated, and they can be combined with each other to achieve better technical effects. In the drawings of the following embodiments, the same reference numerals appearing in each drawing represent the same features or components, which can be applied to different embodiments. Therefore, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0034] It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not intended to limit the conditions under which the invention can be implemented. Any structural modification, change in proportional relationship, or adjustment of size should fall within the scope of the technical content disclosed in the invention without affecting the efficacy and purpose of the invention. The scope of the preferred embodiments of the present invention includes alternative implementations, in which the functions can be performed in a non-described or discussed order, including performing the functions in a substantially simultaneous manner or in a reverse order according to the functions involved, which should be understood by those skilled in the art of the art to which the embodiments of the present invention belong.

[0035] Technologies, methods, and apparatus known to persons of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, such technologies, methods, and apparatus should be considered part of the specification. In all examples shown and discussed herein, any specific values should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0036] In the description of the embodiments of this application, " / " represents "or," and "and / or" is used to describe the association relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" represents the following three situations: A and B exist alone, B exists alone, and A and B exist at the same time. In the description of the embodiments of this application, "plurality" means two or more. Example

[0037] Electrical impedance is the resistance that interferes with the flow of electric current. It is determined by the vector sum of resistance and reactance. In the human body, the difference between impedance and resistance is small, and the two can be used interchangeably. As a fundamental physical parameter of biological tissue, electrical impedance has long garnered extensive attention from biophysicists and physiologists.

[0038] Bioelectrical impedance measurement is a testing technology that uses the electrical properties of biological tissues and organs and their patterns of change to extract biomedical information related to human physiological and pathological conditions. It typically uses a system of electrodes placed on the body surface to deliver a small AC current or voltage to the subject, detecting the corresponding electrical impedance and its changes. Based on the application, relevant physiological and pathological information is then obtained. Currently, two-electrode and four-electrode methods are commonly used for measuring the impedance of biological tissues. The two-electrode method introduces a current signal into the tissue being measured through a pair of electrodes, and then uses the same pair of electrodes to detect the voltage across the electrodes. The four-electrode method typically consists of four metal electrodes arranged in a row, with the outer pair of electrodes serving as the excitation electrodes and the inner pair of electrodes serving as the measurement electrodes. During measurement, the metal electrodes can be inserted into the tissue being measured or applied to its surface.

[0039] The epidural space, also known as the epidural space, is the space between the dura mater and the periosteum on the inner surface of the spinal canal. It contains the intravertebral venous plexus, loose connective tissue and fat, and spinal nerves pass through it. Since the epidural space does not communicate with the brain, this space has a slightly negative pressure. Figure 2 As shown, the epidural space is a discontinuous space, roughly divided into four compartments, anterior and posterior, and lateral, by the nerve roots on either side. The posterior epidural space is located posterior to the epidural root, between the vertebral periosteum and the ligamentum flavum. Throughout the cervical region, the posterior space is very narrow, typically approximately 1.5 mm, and may be closed in the upper cervical region. From the thoracic region downward, the posterior space widens, reaching approximately 2-4 mm in the midthoracic region and up to 6 mm at L2-3. The posterior space contains a well-developed internal vertebral venous plexus, but is less abundant near the posterior midline. This is the site for epidural catheter placement (the catheter is typically placed 2-5 cm into the epidural space, but this can be adjusted based on patient age, weight, and other factors). During epidural catheter placement, the catheter displaces and penetrates some of the connective tissue and fat in the epidural space during advancement, potentially damaging blood vessels and increasing the risk of hematoma formation around the catheter.

[0040] The present invention is based on bioelectrical impedance measurement technology, utilizing the characteristic that the electrical impedance of biological tissue changes when its state changes. By detecting the electrical impedance changes of biological tissue (such as the aforementioned epidural space), the presence and characteristics of hematoma are evaluated - because hematoma can cause changes in tissue electrical impedance.

[0041] Specifically, the present invention provides a puncture device with a hematoma monitoring function. After the epidural catheter is inserted, a weak current is applied to the epidural space tissue through the indwelling catheter and the voltage is measured. The electrical impedance is calculated based on the measured value, and the hematoma occurrence information in the epidural space is evaluated based on the change in electrical impedance.

[0042] See also Figure 3The figure illustrates a typical structure of a puncture device with hematoma monitoring function provided by the present invention. The puncture device 10 includes an epidural puncture needle 100 and an epidural catheter 200. The epidural catheter 200 is provided with an impedance measurement structure for measuring the impedance around the catheter insertion section and transmitting the impedance value to an impedance analyzer 300. The epidural catheter is also connected to an anesthetic syringe 400.

[0043] See also Figure 4 As shown, the epidural puncture needle 100 includes a needle body 110 and a needle seat 120 .

[0044] The needle body 110 may include a needle tube made of medical stainless steel. One end of the needle tube comprises a needle tip 111, and the other end is secured with a needle hub 120 that extends through the needle tube. The front end of the needle tip 111 forms a needle opening, which is elliptical and nearly circular. The needle hub 120 may be provided with an operating handle and a catheter insertion connector, the rear end of which is sealed with a flap-type sealing valve.

[0045] The rear end of the tube insertion connector of the needle hub 120 is used to detachably connect to the tube insertion attachment 201 of the epidural catheter 200. When a tube is needed, the tube insertion attachment 201 is plugged into the rear end interface of the tube insertion connector, and the epidural catheter 200 is inserted through the inner lumen of the needle hub and the inner lumen of the needle tube, so that the epidural catheter 200 enters the epidural space through the epidural puncture needle 100.

[0046] During use, the epidural puncture needle is inserted into the currently located human tissue. When the puncture needle passes through the ligamentum flavum and reaches the epidural space between the ligamentum flavum and the spinal dura mater (with a noticeable sense of empty space), it is determined that the needle tip 111 of the needle tip has reached the epidural space. Then, the epidural catheter 200 is inserted into the needle tip. After the tip of the epidural catheter 200 enters the epidural space through the lumen of the puncture needle, it bends toward the patient's head through the needle opening under the guidance of the needle tip 111 and advances longitudinally in the epidural space. After the catheter is inserted, the puncture needle is withdrawn, and the catheter is left in the epidural space. After the catheter is secured, the local anesthetic is administered through the catheter. The epidural catheter 200 is a flexible tube, and a reinforced epidural catheter (with a reinforced inner lining) can be used. The reinforced epidural catheter has a built-in spring in the catheter wall to resist bending, prevent kinking and breakage, and reduce the risk of blockage and tube breakage.

[0047] See also Figure 5 As shown, the front end of the epidural catheter 200 is the insertion section 210, which is inserted longitudinally along the epidural space after entering the epidural space and is substantially parallel to the longitudinal direction of the epidural space. Figure 6 shown.

[0048] The front end of the insertion section 210 is a catheter tip section 211, which is provided with openings for fluid passage (e.g., for administering anesthetic drugs). The openings can be provided on the tip and / or sidewall of the catheter tip section 211, and can be arranged in multiple rows, such as four rows, with each row having one or more openings.

[0049] An electrical impedance measurement structure is provided corresponding to the implantation section 210 for measuring the electrical impedance value around the implantation section and transmitting it to the electrical impedance analyzer 300. The electrical impedance analyzer 300 is configured to receive the aforementioned electrical impedance value and assess whether there is a hematoma in the epidural space based on the impedance change information.

[0050] In a specific configuration, the electrical impedance measurement structure includes at least an excitation electrode, a measurement circuit, and a processor.

[0051] The excitation electrodes are a pair and can be located at both ends of the catheter insertion section 210. Figure 5 and Figure 6 As shown, a pair of metal electrodes 212 are respectively arranged at both ends of the insertion section 210 as excitation electrodes, wherein the first electrode is located at the distal end of the insertion section 210 close to the catheter head section 211, and the second electrode is located at the proximal end of the insertion section 210 away from the catheter head section 211 (close to the dural puncture needle).

[0052] The excitation electrode is used to apply a current signal to the periphery of the implanted segment. The applied current signal can be a constant current or an alternating current with a constant amplitude.

[0053] The measurement circuit is configured to measure the voltage signal between the two excitation electrodes at both ends of the implanted segment when the excitation electrodes apply a current signal to the periphery of the implanted segment (in a two-electrode method, the excitation electrodes also serve as the measurement electrodes). In this case, the measurement circuit directly measures the voltage between the two excitation electrodes, requiring only two electrodes.

[0054] Alternatively, the measuring circuit is used to measure the voltage signal between the measuring electrodes located between the excitation electrodes at both ends when the excitation electrode applies a current signal to the periphery of the implanted segment. In this case, a segment is selected between the two excitation electrodes to measure the voltage corresponding to the segment. In this case, the implanted segment also needs to be provided with at least two measuring electrodes, and the tissue length between the two measuring electrodes is the measuring segment. Taking the setting of four electrodes as an example, four metal electrodes can be arranged in a row, with the outer pair of metal electrodes serving as excitation electrodes for injecting the measuring current, and the inner pair of metal electrodes serving as measuring electrodes for measuring the voltage drop (corresponding to the four-electrode method, separating current injection and voltage measurement), see Figure 7 shown.

[0055] The processor is configured to calculate the corresponding electrical impedance based on the aforementioned current signal and the real-time voltage signal, as the electrical impedance value around the implanted segment at the current time. Specifically, the processor is configured to perform the following calculations: obtain the measured voltage drop V and the injected current I, calculate the resistance R = V / I according to Ohm's law, and use this calculated value as the electrical impedance value around the implanted segment; and provide real-time feedback of the calculation results to the electrical impedance analyzer, with the feedback data including the electrical impedance value and current time information.

[0056] In this embodiment, the electrodes of the electrical impedance measurement structure are disposed on the insertion section 210 (located in the epidural space). The measurement circuit specifically includes an external cable and a voltage measurement assembly. The voltage measurement assembly can be disposed at the end of the epidural catheter 200. The external cable is routed through the catheter wall of the epidural catheter 200, connecting the internal electrodes and the external voltage measurement assembly. The processor is located outside the body and can be integrated with the voltage measurement assembly and disposed at the end of the epidural catheter 200. The processor is in communication with the electrical impedance analyzer 300 for information exchange.

[0057] In this embodiment, the electrical impedance analyzer 300 can receive the electrical impedance data sent by the processor in real time and continuously, and then evaluate whether there is a hematoma in the epidural space based on the change information of the electrical impedance.

[0058] Specifically, the electrical impedance analyzer 300 may be provided with a hematoma risk analysis module, which is configured to: calculate, based on the received data and according to a preset time interval period T, the change Ri of the electrical impedance value within each time interval period Ti, where i represents the number of periods and is an integer greater than or equal to 1, i=1, 2, 3, ..., Ti represents the i-th time interval period, and Ri represents the change in the electrical impedance value within the i-th time interval period, in units of Ω; and compare the change Ri with a preset change amplitude threshold Rk. When the change Ri is greater than or equal to the change amplitude threshold Rk, it is determined that there is a risk of the epidural space evolving into a hematoma, that is, there is a hematoma risk, and a hematoma risk warning may be issued and a prompt may be given to perform a hematoma depth test. When the change Ri is less than the change amplitude threshold Rk, it can be determined that there is no hematoma risk at present, and monitoring can continue in the existing manner.

[0059] The change amplitude threshold Rk is mainly related to factors such as the type of biological tissue, the magnitude of the injected current during measurement, the current alternating amplitude (if alternating current testing is used), etc. In this embodiment, it can be set by the system by default or customized by the user as needed.

[0060] Preferably, in the electrical impedance analyzer, corresponding reference resistance values Rb and amplitude threshold reference ratios λ are configured for different biological tissue types in combination with several commonly used current injection situations. The reference resistance value Rb represents the reference resistance value of the biological tissue type under normal conditions (no hematoma). The amplitude threshold reference ratio λ is used to calculate the aforementioned variable amplitude threshold Rk. As an example, for example, taking a certain biological tissue type as an example, the corresponding current injection situations are divided into two types (one is a preset constant current injection, and the other is an alternating current injection with a preset amplitude), and corresponding reference resistance values Rb and amplitude threshold reference ratios λ are configured for these two situations.

[0061] At this time, the electrical impedance analyzer may include a user interface and an initialization module.

[0062] The user interface is configured to collect biological tissue type and current injection type information input by the user in the information collection field. Alternatively, the user interface is configured to collect target biological tissue type and current injection type information selected by the user. In this case, a list of options is provided for the user to select, and the user can select a specific type from the biological tissue type and current injection type displayed in the list of options.

[0063] The initialization module is configured to: obtain the target biological tissue type and current injection type input or selected by the user, obtain the reference resistance value Rb and amplitude threshold reference ratio λ corresponding to the target biological tissue type and current injection type from the aforementioned configuration information, and determine the corresponding change amplitude threshold Rk based on the reference resistance value Rb and the amplitude threshold reference ratio λ, wherein the change amplitude threshold Rk is the product of the aforementioned reference resistance value Rb and the amplitude threshold reference ratio λ.

[0064] As an example and not a limitation, for example, if the biological tissue type selected by the user is epidural space tissue, the current injection type is injection of constant current I0, and the corresponding amplitude threshold reference ratio λ obtained is 10%, then the change amplitude threshold Rk is the aforementioned reference resistance value Rb multiplied by 10%.

[0065] Furthermore, considering that hematoma is a gradual process of formation, the electrical impedance changes of the epidural space tissue show a certain regularity during this process. Therefore, a corresponding hematoma-electrical impedance change law model is configured for each biological tissue type in the electrical impedance analyzer. The hematoma-electrical impedance change law model records the electrical impedance change law of the biological tissue when the biological tissue develops from no hematoma to a hematoma of a preset size (which can be obtained based on a bioelectrical impedance measurement experiment conducted on the biological tissue).

[0066] At this time, the hematoma risk analysis module is also configured to: obtain the target biological tissue type input or selected by the user, and obtain the hematoma-impedance change law model corresponding to the target biological tissue type; sort the impedance value obtained from the impedance measurement structure and the corresponding current time information in chronological order to form a real-time change law of the impedance value over time, and compare the real-time change law with the impedance change law recorded in the aforementioned hematoma-impedance change law model. When the matching degree between the real-time change law and the impedance change law is greater than or equal to a preset threshold value - for example, 70%, it is determined that there is a risk of hematoma development, a hematoma development warning is issued, and a hematoma depth detection is prompted; when the matching degree between the real-time change law and the impedance change law is less than the preset threshold value, it can be determined that there is no risk of hematoma development at present, and at this time, monitoring can continue in the existing manner.

[0067] Preferably, the hematoma development warning information may also include hematoma development stage information. For example, the hematoma development stage may include five stages: micro-hematoma stage, small hematoma stage, medium hematoma stage, medium-large hematoma stage, and large hematoma stage. In the hematoma-impedance change law model, the impedance reference range of each of the above hematoma development stages is configured. After determining that there is a hematoma development risk, the hematoma risk analysis module may also be configured to: obtain the current N latest impedance value data at a certain moment, determine which stage of the impedance reference range the impedance value data at the aforementioned N moments falls within, and use the corresponding stage as the current hematoma development stage. The N is an integer greater than or equal to 2.

[0068] Furthermore, when N=2, and the two electrical impedance value data are respectively located in two hematoma development stages, the more serious stage can be selected as the current hematoma development stage; when N is greater than or equal to 3, and the N electrical impedance value data are located in different hematoma development stages, the stage in which the most data falls can be selected as the current hematoma development stage.

[0069] In this way, the electrical impedance analyzer can receive the electrical impedance data sent by the aforementioned processor in real time and continuously, and then evaluate whether there is a hematoma in the epidural space and the development information of the hematoma based on the change information of the electrical impedance.

[0070] In a preferred embodiment, the electrode is an annular structure and is sleeved outside the catheter of the insertion section 210. The annular electrode can be raised relative to the outer surface of the insertion section catheter or flush with the outer surface of the insertion section catheter, see Figure 7 As shown, at this time, the outer diameter of the ring electrode is equal to the outer diameter of the catheter, the inner side of the ring electrode can be embedded in the catheter wall of the insertion section 210 but the outer surface is exposed in the epidural space so that a current signal can be applied to the cavity.

[0071] In one embodiment, an expandable structure may be provided inside the annular electrode to form an expandable ring.

[0072] The expandable structure has a non-expanded state and an expanded state. In the non-expanded state, the annular electrode is accommodated in the catheter wall and flush with the outer surface of the catheter. In the expanded state, the annular electrode can be driven to bulge outward relative to the catheter to form a protruding electrode structure. Figure 8 As shown, it is convenient to measure the electrical impedance.

[0073] Specifically, the expandable structure may include an expandable body and an expansion control circuit, and the expansion control circuit is communicatively connected with the electrical impedance analyzer to enable information exchange.

[0074] The electrical impedance analyzer is configured to send an expansion control instruction to the expansion control circuit when it is determined that the epidural space is evolving towards a hematoma.

[0075] The expansion control circuit is configured to control the expansion of the expandable body after receiving the expansion control instruction issued by the electrical impedance analyzer.

[0076] In a preferred embodiment, the expandable body is an airbag having a hollow capsule body, which is connected to an external inflatable structure so that the capsule body can be inflated. Figure 9 As shown, the balloon is provided with an opening 2123, which is connected to an external inflation structure (such as an air pump) via a delivery line 2124. A conductive layer 2121 is provided on the outside of the balloon as an electrode, which is connected to an external voltage measurement component via a wire 213 (and an external cable). The wire 213 can be led out through the delivery line 2124, which can be located on the wall of the epidural catheter 200. When the balloon is inflated, a balloon cavity 2122 is formed, which drives the annular electrode to expand and bulge outward.

[0077] Preferably, the conductive layer 2121 is a conductive material coated on the surface of the capsule, or a metal ring formed of a metal spiral, which can expand and contract with the capsule. Alternatively, the conductive layer 2121 is a conductive ring assembled from multiple arcuate metal sheets, and the arcuate metal sheets can be connected by a conductive elastic structure (such as a spring) to accommodate the expansion and contraction of the capsule.

[0078] Taking into account the need to adjust the monitoring range, the catheter structure of the insertion section is improved in this embodiment.

[0079] See also Figure 10As shown, in one embodiment, the insertion section 210 of the epidural catheter 200 may include an inner tube 2101 and an outer tube 2102 arranged in a nested manner. The inner tube 2101 serves as an anesthesia catheter and is provided with at least a first electrode. The outer tube 2102 is sleeved outside the inner tube and is movable relative to the inner tube 2101 and is provided with at least a second electrode.

[0080] A traction structure is provided corresponding to the outer tube 2102, and the traction structure is connected to an external traction controller. The traction controller drives the traction structure to adjust the relative position of the outer tube 2102 and the inner tube 2101, that is, to control the movement of the outer tube 2102 relative to the inner tube 2101, so as to adjust the distance between the electrodes 212, thereby adjusting the monitoring range.

[0081] As an example of a typical method, the traction structure can adopt a traction line, which can be one or more traction lines. One end of each traction line is fixedly connected to the outer tube, and the other end is connected to an external traction controller. The traction controller drives the traction line to wind so that the outer tube moves relative to the inner tube.

[0082] Continue to see Figure 10 As shown, taking the two-electrode method as an example, current is introduced into the biological tissue to be measured through a pair of excitation electrodes 212, and then the voltage across the pair of excitation electrodes 212 is measured. By adjusting the distance between the two excitation electrodes 212, the monitoring range around the implanted segment is adjusted.

[0083] When using the four-electrode method, a pair of measuring electrodes is also included. To adjust the distance between the measuring electrodes and thus the measurement range, a first excitation electrode and a first measuring electrode can be provided on the inner tube 2101, with the first excitation electrode positioned outside the first measuring electrode. A second excitation electrode and a second measuring electrode can be provided on the outer tube 2102, with the second excitation electrode positioned outside the second measuring electrode. By controlling the movement of the outer tube 2102 relative to the inner tube 2101, the distance between the two excitation electrodes 212 changes, and the distance between the two measuring electrodes also changes, thereby adjusting the measurement range.

[0084] See also Figure 11As shown, in another embodiment, the insertion section 210 of the epidural catheter 200 may include an inner tube 2101 and an outer tube 2102 arranged in a nested manner. The inner tube 2101 serves as an anesthesia catheter, and the outer tube 2102 is sleeved outside the inner tube and can move relative to the inner tube 2101. The outer tube 2102 includes a plurality of tube units 21, and adjacent tube units 21 are connected by a dynamic measurement section 22, and each tube unit 21 is provided with an excitation electrode 212; the dynamic measurement section 22 is connected to an external adjustment controller, and the adjustment controller is used to change the axial length of the dynamic measurement section 22 in the insertion section of the catheter to adjust the distance between the plurality of tube units, thereby adjusting the distance between the electrodes and thus adjusting the monitoring range.

[0085] In a preferred embodiment, the dynamic measurement section 22 adopts a flexible airbag tube, both ends of the airbag tube are fixedly connected to the two side tube units 22 respectively, and the airbag tube is connected to the adjustment controller through a conveying pipeline, and the adjustment controller includes a filling device and a suction device.

[0086] The adjustment controller is configured to: receive a dynamic measurement adjustment instruction, and when the dynamic measurement adjustment instruction is to increase the monitoring range, control the delivery pipeline to be connected to the filling device to inflate the airbag tube, thereby increasing the axial length of the dynamic measurement section in the insertion section catheter; when the dynamic measurement adjustment instruction is to reduce the monitoring range, control the delivery pipeline to be connected to the suction device to deflat the airbag tube, thereby reducing the axial length of the dynamic measurement section in the insertion section catheter.

[0087] It should be noted that Figure 11 The two-electrode method is used as an example to illustrate the adjustment of the distance between two electrodes. When using the four-electrode method, a pair of measuring electrodes is also included. In this case, preferably, at least four tube units 21 can be provided, and adjacent tube units 21 are connected by a dynamic measuring section 22, that is, three dynamic measuring sections 22 are provided. Each tube unit 21 is provided with an electrode. For example, the first tube unit 21 can be provided with a first excitation electrode, the second tube unit 21 can be provided with a first measuring electrode, the third tube unit 21 can be provided with a second measuring electrode, and the fourth tube unit 21 can be provided with a second excitation electrode. The first excitation electrode is located outside the first measuring electrode, and the second excitation electrode is located outside the second measuring electrode. When the dynamic measuring sections 22 between the tube units 21 are inflated or deflated, the length of the dynamic measuring sections 22 changes, and the distance between the tube units 21 also changes, causing the distance between the electrodes to change, thereby adjusting the monitoring range.

[0088] Another embodiment of the present invention also provides a hematoma monitoring and evaluation system.

[0089] The system includes a puncture device and a user terminal.

[0090] The puncture device includes an epidural puncture needle and an epidural catheter, and the epidural catheter is provided with an electrical impedance measurement structure for measuring the electrical impedance value around the catheter insertion section and transmitting it to an electrical impedance analyzer. The epidural catheter is also connected to an anesthetic syringe.

[0091] The epidural puncture needle comprises a needle body and a needle seat.

[0092] The epidural catheter is used to enter the epidural space through the epidural puncture needle; the front end of the epidural catheter is the insertion section, which is inserted longitudinally along the epidural space after entering the epidural space, and the corresponding insertion section is set to measure the electrical impedance value around the insertion section and transmit it to the electrical impedance analyzer.

[0093] The electrical impedance analyzer is used to receive the aforementioned electrical impedance value and evaluate whether there is a hematoma in the epidural space based on the change information of the electrical impedance.

[0094] The user terminal is configured to: receive analysis results from the electrical impedance analyzer and display the output; and collect user operation instructions and control the electrical impedance measurement structure and / or the electrical impedance analyzer to perform corresponding operations according to the operation instructions.

[0095] For other technical features, please refer to the description of the previous embodiment and will not be repeated here.

[0096] In the above description, the disclosure of the present invention is not intended to limit itself to these aspects. Rather, within the scope of the intended protection of the present disclosure, the components can be selectively and operationally combined in any number. In addition, terms such as "including", "encompassing" and "having" should be interpreted as inclusive or open by default, rather than exclusive or closed, unless they are explicitly defined to the contrary. All technical, scientific or other terms have the meaning understood by those skilled in the art unless they are defined to the contrary. Common terms found in dictionaries should not be interpreted too idealistically or too impractically in the context of relevant technical documents, unless the present disclosure explicitly defines them as such. Any changes and modifications made by a person of ordinary skill in the field of the present invention based on the above disclosure are within the scope of protection of the claims.

Claims

1. An electrical impedance analyzer for physiological tissue hematoma assessment, connected to an electrical impedance measurement structure, characterized in that: The electrical impedance analyzer is used to receive the electrical impedance data of the physiological tissue sent by the electrical impedance measurement structure in real time, and to evaluate whether there is a hematoma based on the change information of the electrical impedance.

2. The electrical impedance analyzer according to claim 1, wherein: The electrical impedance analyzer is provided with a hematoma risk analysis module, which is configured to: Calculate the change in the electrical impedance value Ri within each time interval Ti according to the received data and the preset time interval T; where i represents the number of periods and is an integer greater than or equal to 1, i=1, 2, 3, ...; Ti represents the i-th time interval; and Ri represents the change in the electrical impedance value within the i-th time interval; Compare Ri with the preset change amplitude threshold Rk; when Ri is greater than or equal to Rk, it is determined that there is a risk of evolving towards hematoma, that is, there is a hematoma risk; when Ri is less than Rk, it is determined that there is no hematoma risk at present.

3. The electrical impedance analyzer according to claim 2, wherein: When there is a risk of hematoma, a hematoma risk warning will be issued and a hematoma depth detection will be prompted; When there is no risk of hematoma, continue monitoring as usual.

4. The electrical impedance analyzer according to claim 2 or 3, characterized in that: The value of Rk is set by the system by default or customized by the user.

5. The electrical impedance analyzer according to claim 2 or 3, characterized in that: In the electrical impedance analyzer, corresponding reference resistance values Rb and amplitude threshold reference ratios λ are configured for different biological tissue types in combination with several commonly used current injection situations. Rb represents the reference resistance value of the biological tissue type under normal circumstances when no hematoma occurs. λ is used to calculate the aforementioned Rk, which is the product of the reference resistance value Rb and the amplitude threshold reference ratio λ.

6. The electrical impedance analyzer according to claim 5, characterized in that The electrical impedance analyzer also includes a user interface and an initialization module; The user interface is used to collect biological tissue type and current injection type information input by the user, or to collect target biological tissue type and current injection type information selected by the user; The initialization module is used to obtain the target biological tissue type and current injection type input or selected by the user, obtain Rb and λ corresponding to the target biological tissue type and current injection type from the aforementioned configuration information, and determine the corresponding Rk value based on Rb and λ.

7. The electrical impedance analyzer according to claim 1, 2, 3 or 6, characterized in that: In the electrical impedance analyzer, a corresponding hematoma-electrical impedance change law model is configured for each biological tissue type; The hematoma risk analysis module in the electrical impedance analyzer is configured to: Obtaining a target biological tissue type input or selected by a user, and obtaining a hematoma-electrical impedance change law model corresponding to the target biological tissue type; The electrical impedance values obtained from the electrical impedance measurement structure and the corresponding current time information are sorted in chronological order to form a real-time change pattern of the electrical impedance values over time; The real-time change pattern is compared with the electrical impedance change pattern recorded in the aforementioned hematoma-electrical impedance change pattern model; when the matching degree between the two is greater than or equal to the preset threshold, it is determined that there is a risk of hematoma development; when the matching degree between the two is less than the preset threshold, it is determined that there is no risk of hematoma development at present.

8. The electrical impedance analyzer according to claim 7, characterized in that When there is a risk of hematoma development, a hematoma development warning will be issued and a hematoma depth detection will be prompted; When there is no risk of hematoma development, continue monitoring as usual.

9. A system for physiological tissue hematoma assessment, characterized in that: Including electrical impedance measurement structure and electrical impedance analyzer, The electrical impedance measurement structure is arranged corresponding to the implanted segment of the physiological tissue and is used to measure the electrical impedance value around the implanted segment and transmit it to the electrical impedance analyzer; wherein the electrical impedance measurement structure uses a two-electrode method or a four-electrode method to measure the electrical impedance value around the implanted segment and transmits the electrical impedance data including the electrical impedance value and time information to the electrical impedance analyzer in real time; The electrical impedance analyzer is the electrical impedance analyzer according to any one of claims 1 to 8.

10. An epidural puncture device comprising an epidural puncture needle and an epidural catheter, wherein the epidural puncture needle comprises a needle body and a needle holder, and the epidural catheter is used to enter the epidural space through the epidural puncture needle. The front end of the epidural catheter is an insertion section, which is inserted longitudinally along the epidural space after entering the epidural space. The device is characterized by: An electrical impedance measurement structure is provided corresponding to the implanted segment for measuring the electrical impedance value around the implanted segment and transmitting the measured value to the electrical impedance analyzer; wherein the electrical impedance measurement structure uses a two-electrode method or a four-electrode method to measure the electrical impedance value around the implanted segment and transmits the impedance data including the impedance value and time information to the electrical impedance analyzer in real time; The electrical impedance analyzer is the electrical impedance analyzer according to any one of claims 1 to 8.

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