Automatic recanalization system for central venous catheter blockage

Abstract

The invention discloses an automatic recanalization system for blockage of a central venous catheter, which comprises a main controller, a three-way valve control module, a double-injector driving module and a pressure monitoring module, and can fully automatically execute standard recanalization operation circulation including injection attempt, negative pressure suction and liquid transfer. Operation parameters and processes are intelligently adjusted according to real-time pressure feedback; high-strength manual operation is replaced by a machine, a safe and efficient re-passing process is achieved based on closed-loop pressure control, and the problems that a traditional manual method seriously depends on physical experience of an operator, efficiency is low and safety risks exist are solved.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and in particular to an automatic recanalization system for central venous catheter occlusion. Background Technology

[0002] Central venous catheters are important infusion channels in clinical practice, but occlusion of their lumen is a common complication. When complete occlusion occurs, the standard recanalization method usually relies on healthcare professionals manually operating a three-way valve and two syringes (one usually placed vertically for injection and the other for aspiration) to form a closed loop. By repeatedly and rapidly switching the three-way valve access and alternating injection-aspiration operations, the positive and negative pressure impacts of the fluid and mechanical forces are used to dissolve or remove the blockage.

[0003] The above procedure requires the operator (usually a nurse) to continuously, rapidly, and forcefully push and pull the syringe plunger and turn the three-way valve repeatedly for several minutes or even longer. This not only puts a huge strain on hand strength and endurance, easily leading to muscle fatigue, soreness, and even occupational strain, but also causes a rapid decline in the rhythm, force, and accuracy of the operation when fatigued, directly affecting the recanalization effect and efficiency. Furthermore, the entire recanalization process lacks objective and continuous mechanical feedback monitoring; the operator relies solely on touch to judge resistance, unable to quantify the injection pressure and aspiration negative pressure. This carries the risk of catheter rupture or thrombus dislodgement due to excessive force, or insufficient force to effectively clear the blockage.

[0004] Therefore, in response to the problems mentioned above, this invention proposes an automatic recanalization system for central venous catheter occlusion. Summary of the Invention

[0005] To overcome the problems of existing manual recanalization methods, which heavily rely on operator physical strength and experience, are inefficient, and pose safety risks, this invention proposes an automatic recanalization system for central venous catheter occlusion. This system automatically executes the recanalization operation procedure through an integrated electromechanical control module and sensors, monitors the pipeline pressure in real time, and replaces manual labor to complete high-intensity and highly repetitive operations, thereby achieving safe and efficient catheter recanalization.

[0006] The technical solution of the present invention is: an automatic recanalization system for central venous catheter occlusion, comprising: The main controller is used to execute the automatic reconnection procedure and coordinate the operation of various modules in the system; A three-way valve control module electrically connects to and drives a three-way valve having three ports respectively connected to a patient's central venous catheter, a first syringe, and a second syringe. The three-way valve control module switches the flow path of the three-way valve according to instructions from the main controller, cyclically switching between at least three states: a first state connecting the central venous catheter to the first syringe; a second state connecting the central venous catheter to the second syringe; and a third state connecting the first syringe to the second syringe. The syringe driving module includes a first driving unit and a second driving unit, which independently drive the plunger movement of the first syringe and the second syringe, respectively. When the three-way valve is in a first state, the first driving unit performs a reciprocating push-pull operation on the plunger of the first syringe. When the three-way valve is in a second state, the second driving unit performs a reciprocating push-pull operation on the plunger of the second syringe. Furthermore, when the three-way valve is in a third state, the first and second driving units are coordinated and controlled to transfer liquid between the first and second syringes. The pressure monitoring module monitors the pressure in the tubing connected to the central venous catheter in real time and feeds the pressure data back to the main controller. The cycle control module, integrated into the main controller, controls the three-way valve control module and the syringe drive module based on preset program parameters and / or feedback from the pressure monitoring module. This cycle repeats the re-opening operation procedure, which includes the following steps, with each cycle optimized to within 3-5 seconds: S1: Control the three-way valve to switch to the state where the central venous catheter is connected to the first syringe, start the first drive unit, and slowly push the plunger of the first syringe with a preset initial injection force of 5-15N. At the same time, the pressure monitoring module records the pressure rise curve. If the pressure rapidly exceeds the first preset pressure threshold (e.g., 30kPa) within 1 second and the plunger displacement is less than 0.1ml, the main controller immediately determines that a hard blockage has been encountered and jumps to S2; if the pressure rises slowly and stabilizes at a level below the first preset pressure threshold, it is determined that there is a partial blockage or patency, and subsequent parameters can be adjusted.

[0007] S2, control the three-way valve to switch to the state of connecting the central venous catheter with the second syringe, start the second drive unit to generate a continuous negative pressure of not less than 60 kPa to aspirate the plunger of the second syringe. The aspiration duration is dynamically adjusted according to the pressure peak of stage S1. For every 10 kPa that the pressure peak exceeds the first preset threshold, the aspiration time is extended by 0.5 seconds, but the total duration does not exceed 5 seconds.

[0008] S3 controls the three-way valve to switch to a state that connects the first syringe and the second syringe, and coordinates the control of the first drive unit and the second drive unit to transfer all the liquid in the first syringe to the second syringe.

[0009] The cycle control module repeatedly executes S1 to S3 to form a complete re-circulation cycle, which continues. The re-circulation success criteria are: in the S1 stage of three consecutive cycles, the monitored peak injection pressure is consistently lower than 50% of the first preset pressure threshold, and the second syringe can stably aspirate the expected volume of liquid in the S2 stage. If the success criteria are not met even after reaching the preset maximum number of safe cycles (e.g., 20 times), the system will automatically stop and issue an alarm.

[0010] Preferably, the system also includes a human-machine interface for the operator to input or modify program parameters, including but not limited to a first preset threshold, a second preset threshold, a preset number of cycles, the duration of each step in a single cycle, a preset injection force of the first drive unit, and the maximum negative pressure value of the second drive unit; wherein, the human-machine interface also displays the current number of cycles, real-time pressure waveform, volume of aspirated liquid, clogging degree assessment results, and system status in real time.

[0011] Preferably, the first syringe is pre-filled with a thrombolytic solution for recanalization, and the second syringe is initially an empty syringe. Before starting the recanalization procedure, the circulation control module controls the three-way valve and the syringe drive module to perform an initialization procedure, injecting a predetermined dose of thrombolytic agent from the first syringe into the central venous catheter and allowing it to stand for a predetermined time before starting the recanalization procedure.

[0012] The beneficial effects of this invention are: 1. This invention completely replaces the traditional, physically demanding manual operation of repeatedly pushing and pulling syringes and turning three-way valves by medical staff through a fully automated electromechanical execution system. The integrated stepper or servo drive unit can always perform the "push-aspiration-transfer" cycle operation with a constant and adjustable force and speed. This not only completely liberates the operator from the heavy and repetitive labor that is prone to causing muscle strain, but more importantly, it eliminates the decrease in operating force and rhythm disorder caused by the operator's physical decline, thereby ensuring the stability and efficiency of the re-pass process.

[0013] 2. This invention introduces a closed-loop intelligent control and dynamic decision-making mechanism based on real-time pressure monitoring, which significantly improves the accuracy and success rate of recanalization. The system continuously collects pipeline pressure changes through a high-frequency pressure sensor and uses this as the core feedback signal to intelligently judge the blockage status and assess the degree of blockage. Based on this, it adjusts key parameters such as injection force, suction negative pressure, and step duration in real time. This closed-loop control simulates and surpasses the clinical judgment of experienced medical personnel. It can adaptively adopt the optimal recanalization strategy for blockages of different hardness and properties, avoiding blind force or insufficient force caused by the lack of quantitative feedback in manual operation. Attached Figure Description

[0014] Figure 1 The diagram shown is a schematic representation of the system framework of the present invention. Figure 2 The diagram shown illustrates the workflow of this invention. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0016] Please see Figure 1 This invention provides an embodiment of an automatic recanalization system for central venous catheter occlusion, comprising: In this embodiment, the three-way valve control module will be described in detail: The three-way valve control module includes a micro motor (such as a stepper motor or servo motor). The main controller precisely controls the rotation of the three-way valve to three preset stable states by sending "angle positioning commands" to this module, including: Status 1 (First Injector - Catheter Access): The first injector is connected to the patient's central venous catheter, and the second injector is closed.

[0017] Status 2 (Second syringe - catheter access): The second syringe is connected to the patient's central venous catheter, and the first syringe is closed.

[0018] State 3 (inter-syringe passage): The first syringe and the second syringe are directly connected, and both are disconnected from the catheter.

[0019] Each switch is driven by a motor, ensuring absolute reliability of the fluid circuit connection and avoiding leakage or incorrect connection caused by incomplete or excessive positioning that might occur with manual rotation. The switching speed is adjustable, typically completed within 0.5-1 second, ensuring efficiency while reducing the impact of transient fluid circuit changes on blood vessels.

[0020] In this embodiment, the syringe driving module will be described in detail: The module consists of two completely independent drive units with identical structures. Each drive unit includes a motor (a servo motor is preferred due to its excellent force control characteristics), a transmission mechanism that converts the motor's rotational motion into linear motion, a push rod for clamping and directly driving the syringe plunger tail plate, and a high-precision linear displacement sensor.

[0021] During the injection phase, the main controller can instruct the drive unit to operate in "force control mode". The system sets a target thrust value (e.g., 15N, approximately equivalent to medium to high manual force), and the motor output torque is adjusted in real time to maintain this thrust. If the plunger cannot move (completely blocked), the system will maintain this thrust for a period of time; if it can move, the system automatically switches to "position control mode" to push the plunger a predetermined small stroke (e.g., 0.1mL).

[0022] During the aspiration phase, the drive unit operates in "position control mode" but pulls back the plunger at an extremely high speed, generating negative pressure in the syringe chamber. The system can limit the maximum negative pressure value (e.g., -500 mmHg) by controlling the speed and stroke of the pullback, thus avoiding excessive negative pressure that could damage the vascular endothelium or cause catheter collapse.

[0023] When the two syringes are connected (state 3), the two drive units are coordinated and controlled. For example, the first drive unit advances slowly while the second drive unit pulls back at a matching speed, so as to achieve a smooth transfer of liquid from the first syringe to the second syringe.

[0024] In this embodiment, the pressure monitoring module will be described in detail: This module includes a high-sensitivity pressure sensor (typically a medical-grade solid-state pressure sensor), signal conditioning circuitry (amplification and filtering), and an analog-to-digital converter. The pressure sensor is installed on the manifold connected to the central venous catheter to ensure the detection of pressure changes proximal to the catheter. The module monitors the dynamic pressure within the tubing in real time, with a sampling frequency typically no lower than 100Hz to ensure the capture of rapid pressure transients. Simultaneously, the main controller performs real-time analysis of the pressure data, including calculating instantaneous pressure, average pressure, pressure rise slope (dP / dt), and identifying pressure peaks and troughs.

[0025] The system has multiple preset pressure thresholds, including a first preset threshold (e.g., 150 mmHg) to determine whether significant blockage resistance has been encountered. A second preset threshold (e.g., 300 mmHg) serves as a safety warning line, triggering protective operations.

[0026] In this embodiment, the human-computer interaction interface is described in detail: This interface is typically implemented using a color touchscreen and is divided into a parameter setting area, a process monitoring area, and a status and alarm area. In the parameter setting area, before starting the program, the operator can set the maximum number of recanalization cycles (e.g., 50 times), the first / second pressure threshold, the time for a single injection attempt, the negative pressure aspiration time, and the thrombolytic settling time. The process monitoring area displays the current number of cycles, the current step (injection / aspiration / transfer), a real-time pressure waveform, the current pressure value, and the real-time positions (converted to volume) of the first and second syringe plungers. The status and alarm area displays the system status ("Running," "Paused," "Block Cleared," "Alarm") and uses color blocks and text to indicate the current assessed level of blockage (e.g., "Mild," "Moderate," "Severe"). When a safety protection is triggered, a prominent alarm message pops up accompanied by an audible alert.

[0027] In this embodiment, the safety protection module and the congestion assessment module are described in detail: In each re-circulation cycle, during state 1, the blockage assessment module not only determines whether the pressure exceeds the threshold but also records key parameters, specifically: The time from the start of injection to the pressure reaching the first preset threshold. The shorter the time and the higher the rate, the denser the blockage. In a complete cycle, the difference between the volume attempted to be injected in state 1 (calculated by plunger displacement) and the volume actually aspirated in state 2 is consistently positive and large, indicating that the thrombolytic agent or fluid may have been forced into the area around the blockage but not effectively aspirated, suggesting a stubborn blockage.

[0028] Based on the combined analysis of these parameters, the system classifies the degree of blockage into three levels in real time: mild, moderate, and severe, and displays this information on the interface. According to the assessed level, the system automatically fine-tunes the parameters. For example, for "severe" blockage, the system will slightly increase the upper limit of the injection force in step a in subsequent cycles and extend the negative pressure aspiration time in state 2. When the system assesses "severe" blockage, and the volume of fluid aspirated in five consecutive cycles is less than 0.1 mL (minimum volume threshold), it indicates that the current recanalization strategy may be ineffective, and forcibly continuing may be risky. At this time, the main controller will immediately stop all drives, switch the three-way valve to a safe position (e.g., close all pathways), and display an alarm on the human-machine interface stating "Recanalization difficult; it is recommended to assess the catheter status or seek other solutions," to prevent ineffective operations and potential complications.

[0029] This invention provides Embodiment 1: Please see Figure 2 This embodiment describes the core process of the present invention and is applicable to the recanalization of the most common thrombotic or mixed blockages in clinical practice.

[0030] (1) The operator installs the first syringe pre-filled with 3 mL of normal saline or thrombolytic agent (such as 2 mg / 2 mL rt-PA solution) in the first drive position, installs an empty 10 mL second syringe in the second drive position, connects the disposable sterile tubing kit to the three ports of the three-way valve, and connects them to the first syringe, the second syringe and the patient's central venous catheter interface respectively. Check that each connection is secure, and select the standard recanalization mode on the interface.

[0031] (2) If the first syringe is pre-filled with thrombolytic agent, the operator can select the "Pre-injection" option. After startup, the system automatically controls the three-way valve to switch to state 1 (first syringe - catheter). The first drive unit pushes the plunger at a very slow speed (e.g., 0.5 mL / min) to inject 1.5 mL of drug solution into the catheter. The pressure is monitored during this process. If the pressure rises abnormally, the process is paused. After the injection is completed, the three-way valve switches to an isolation state (closing the catheter port). The system starts a 30-minute static countdown, and the interface displays "Thrombolytic agent is infiltrating".

[0032] (3) After the resting period (or start directly), the system enters the core loop: 1) When the three-way valve is switched to state 1, the first drive unit starts in force control mode, with the target thrust set to 12N (approximately equivalent to 1200mmHg in a specific pipeline). Simultaneously, the pressure monitoring module samples at a frequency of 100Hz. If the plunger moves smoothly and the pressure remains below the first preset threshold (150mmHg), the system determines that the flow is unobstructed, pushes a preset small volume (0.2mL), and then directly jumps to the end stage. If the plunger is blocked within 0.5 seconds, the pressure rapidly rises and exceeds 150mmHg. The system records this peak pressure (e.g., 280mmHg) and the pressure rise time (e.g., 0.3 seconds).

[0033] 2) Immediately (within 0.2 seconds), switch the three-way valve to state 2. The second drive unit pulls back the plunger at maximum speed, with a stroke corresponding to a volume of 5 mL, generating negative pressure and continuing suction for 2 seconds. The displacement sensor records the actual volume of liquid drawn back (e.g., 0.4 mL).

[0034] 3) Switch the three-way valve to state 3. The first drive unit and the second drive unit move synchronously to transfer all the remaining liquid in the first syringe (including any blockage fragments that may be pushed back) to the second syringe. This step directly empties the first syringe and prepares for the injection in the next cycle.

[0035] 4) Based on the data from this cycle, including "peak pressure 280 mmHg", "rise time 0.3 seconds", and "aspiration volume 0.4 mL", the clogging severity assessment module determines the clogging level to be "moderate". Based on this data, the system decides to slightly increase the injection force in step 1) to 13 N and extend the aspiration time in step 2) to 2.5 seconds in the next cycle, then return to step 1) to begin the next cycle.

[0036] (4) The main loop terminates when any of the following conditions are met: 1. In step 1), if the peak pressure of three consecutive injection attempts remains consistently below 100 mmHg and the plunger moves smoothly, the system determines that "the blockage has been cleared." 2. When the preset maximum number of cycles (e.g., 50 cycles) is reached, the system stops and provides a result prompt based on the data from the last few cycles (e.g., "partially reopened, recheck recommended" or "reopening unsuccessful"). 3. When the safety protection logic is triggered, after termination, the system automatically places the three-way valve in the safe position, displays the final result and summary report on the interface, and prompts the operator to perform subsequent catheter flushing and evaluation.

[0037] This invention provides Embodiment 2: This embodiment, based on embodiment 1, integrates pressure feedback more deeply to achieve a dynamic and non-fixed rhythm cycle. In this mode, the system no longer mechanically executes steps at fixed times, but drives the process with "pressure events".

[0038] Injection Phase: In state 1, the first drive unit begins injection, and the system monitors the pressure curve in real time. If the pressure rises gradually and reaches the first preset threshold (150 mmHg) within 3 seconds, then switch to suction step 2 immediately upon reaching this threshold as originally planned.

[0039] If the pressure rises sharply and exceeds the higher second preset threshold (300 mmHg) within 1 second, it indicates that an unusually strong resistance point has been encountered. The system will immediately interrupt the current injection and directly switch to state 2 without waiting for the first threshold to be reached. At the same time, this aspiration step 2) will be marked as "high-pressure protective aspiration", and the aspiration duration will be automatically extended to 4 seconds (normally 2 seconds). The system will also slightly reduce the upper limit of the injection force for the next cycle, adopting a more "gentle" but more sustained strategy.

[0040] In step 2) of this embodiment, the system not only records the aspiration volume, but also analyzes the negative pressure establishment curve. If the negative pressure quickly reaches -600 mmHg and is maintained at the start of aspiration, but the aspirated volume is very small (<0.1 mL), this suggests that the blockage may be gel-like or adsorbed on the tube wall and is not easily pulled out by the negative pressure as a whole. The blockage assessment module will adjust the strategy accordingly. In subsequent cycles, it may try a smaller amplitude pulse injection (rapid push-stop-push) in step 1).

[0041] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments that can be applied to other fields. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. An automated recanalization system for central venous catheter occlusion, characterized in that, Including: The main controller is used to execute the automatic reconnection procedure and coordinate the operation of various modules in the system; A three-way valve control module electrically connects to and drives a three-way valve having three ports respectively connected to a patient's central venous catheter, a first syringe, and a second syringe. The three-way valve control module switches the flow path of the three-way valve according to instructions from the main controller, cyclically switching between at least three states: a first state connecting the central venous catheter to the first syringe; a second state connecting the central venous catheter to the second syringe; and a third state connecting the first syringe to the second syringe. The syringe driving module includes a first driving unit and a second driving unit, which independently drive the plunger movement of the first syringe and the second syringe, respectively. When the three-way valve is in a first state, the first driving unit performs a reciprocating push-pull operation on the plunger of the first syringe. When the three-way valve is in a second state, the second driving unit performs a reciprocating push-pull operation on the plunger of the second syringe. Furthermore, when the three-way valve is in a third state, the first and second driving units are coordinated and controlled to transfer liquid between the first and second syringes. The pressure monitoring module monitors the pressure in the tubing connected to the central venous catheter in real time and feeds the pressure data back to the main controller. The cycle control module, integrated in the main controller, is used to control the three-way valve control module and the syringe drive module to repeatedly perform the re-opening operation program based on preset program parameters and / or feedback from the pressure monitoring module.

2. The automatic recanalization system for central venous catheter occlusion according to claim 1, characterized in that, The re-circulation procedure includes the following steps: S1, control the three-way valve to switch to the first state and start the first drive unit to attempt to push the plunger of the first syringe with a preset injection force, while monitoring pressure changes; S2, if the pressure exceeds the first preset threshold and the plunger displacement does not reach the expected value in step S1, it is determined that a blockage resistance is encountered. Then, the three-way valve is controlled to switch to the second state, and the second drive unit is started to draw the plunger of the second syringe with the maximum negative pressure. S3, control the three-way valve to switch to the third state, and coordinate the control of the first drive unit and the second drive unit to transfer the contents of the first syringe to the second syringe; S4. Repeat steps S1 to S3 to form a cycle until the injection pressure detected by the pressure monitoring module in step S1 is lower than the first preset threshold and continues for a predetermined time or reaches the preset number of cycles.

3. An automatic recanalization system for central venous catheter occlusion according to claim 2, characterized in that, The feedback from the pressure monitoring module is used to adjust the execution logic of the cycle control module: when the peak injection pressure monitored in step S1 exceeds a second preset threshold higher than the first preset threshold, the main controller temporarily interrupts the current cycle, controls the three-way valve to switch to the second state, and extends the negative pressure suction duration of the second drive unit.

4. An automatic recanalization system for central venous catheter occlusion according to claim 3, characterized in that: The circulation control module also includes a blockage assessment module. The blockage assessment module classifies the severity of the blockage based on at least one parameter, including the time required to reach the first preset threshold in step S1, the rate of pressure increase, and the volume of liquid pumped out by the second drive unit in a single cycle. Based on the classification results, the preset injection force in step S1, the maximum negative pressure value in step S2, and the liquid transfer speed in step S3 in subsequent cycles are adjusted.

5. An automatic recanalization system for central venous catheter occlusion according to claim 4, characterized in that, The system also includes a safety protection module, which includes: when the blockage severity determined by the blockage assessment module reaches the highest level, and the volume of liquid extracted in step S2 is lower than the minimum volume threshold in a predetermined number of consecutive cycles, the main controller stops the automatic re-opening program and issues an alarm indicating that the tubing may need to be replaced.

6. An automatic recanalization system for central venous catheter occlusion according to claim 5, characterized in that: The first and second drive units of the syringe drive module are both driven by stepper motors or servo motors and equipped with displacement sensors for precise control of the plunger's stroke and speed and real-time monitoring of the plunger's position.

7. An automatic recanalization system for central venous catheter occlusion according to claim 6, characterized in that: The system also includes a human-machine interface for operators to input or modify program parameters, including but not limited to a first preset threshold, a second preset threshold, a preset number of cycles, the duration of each step in a single cycle, the preset injection force of the first drive unit, and the maximum negative pressure value of the second drive unit. The human-machine interface also displays the current number of cycles, real-time pressure waveform, volume of aspirated liquid, clogging assessment results, and system status in real time.

8. An automatic recanalization system for central venous catheter occlusion according to claim 7, characterized in that: The first syringe is pre-filled with a thrombolytic solution for recanalization, and the second syringe is initially an empty syringe. Before starting the recanalization procedure, the circulation control module controls the three-way valve and the syringe drive module to execute an initialization procedure, injecting a predetermined dose of thrombolytic agent from the first syringe into the central venous catheter and allowing it to stand for a predetermined time before starting the recanalization procedure.

9. An automatic recanalization system for central venous catheter occlusion according to claim 8, characterized in that, The initialization procedure includes: controlling the three-way valve to connect the central venous catheter to the first syringe; the first drive unit slowly pushes the plunger at a low speed to inject the thrombolytic agent into the catheter; after the injection is completed, the three-way valve is switched to isolate the catheter and enter the resting stage; the main controller displays the resting countdown on the human-machine interface.

10. An automatic recanalization system for central venous catheter occlusion according to claim 9, characterized in that: The system is integrated into a portable device housing, wherein a three-way valve, a first syringe, and a second syringe are mounted in designated functional positions within the housing in a quick-detachable manner.

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