Method for measuring vascular lockout pressure by hemostatic instrument for orthopedic surgery, LOP application method and hemostatic instrument

Abstract

The invention belongs to the technical field of hemostasis instruments, and provides a method for measuring blood vessel locking pressure by an orthopedic surgery hemostasis instrument, which comprises the following steps of: inflating a cuff wound on a limb until a blood vessel is completely locked, and controlling the cuff to release pressure at a constant speed, the pressure sensor and the independent pulse vibration sensor synchronously and independently collect a cuff pressure value and a pulse wave signal, the pulse wave signal is processed to obtain the trend that the amplitude of the pulse wave signal changes along with the pressure, and the amplitude is converted from a stable baseline state representing vascular atresia to the corresponding cuff pressure when the amplitude continuously rises for the first time. And the critical opening pressure of the blood vessel is accurately judged and is used as an individualized blood vessel locking pressure measurement value. The invention also discloses steps for carrying out hemostasis operation by using the method and a hemostasis instrument for realizing the method. The problem that in the prior art, measurement is not accurate due to the fact that pressure or pressure pulsation signals depend on experience is solved, and accurate measurement of the vascular locking pressure is achieved.

Description

Technical Field

[0001] This invention belongs to the field of hemostatic instrument technology. Specifically, it relates to a method for measuring vascular occlusion pressure, a method for applying LOP (Lower Optical Pressure), and a hemostatic instrument for orthopedic surgery. Background Technology

[0002] Hemostats are commonly used devices in surgical procedures. They apply controlled pressure by inflating a cuff wrapped around the patient's limb to block arterial blood flow. If the cuff inflation pressure is too low and the major arteries are not completely locked, bleeding may occur at the wound site during the operation, making it difficult for the surgeon to obtain a clear field of vision. Therefore, it is necessary to block arterial blood flow before starting limb surgery in clinical practice.

[0003] In existing technologies, there are two main blocking methods: Firstly, doctors apply pressure to the cuff based on experience. However, during orthopedic limb surgery, the pressure required to stop bleeding varies greatly depending on individual differences, and the pressure required to close the arteries in the limbs can differ significantly. Applying pressure based on experience can lead to incomplete blockage of arterial blood flow if the pressure is insufficient. On the other hand, applying excessive pressure, while blocking arterial blood flow, can cause significant harm to the patient.

[0004] Secondly, the oscillometric method is used, utilizing the variation pattern of pulse wave amplitude to find characteristic values ​​to assess systolic and diastolic blood pressure. Pulse wave acquisition and processing involves directly acquiring the pulsating signal from the pressure sensor. This pulsating signal is then isolated as a DC signal and amplified to obtain the pulse wave signal. Based on this signal, the amplitude envelope is plotted, and systolic and diastolic blood pressure are assessed using empirical formulas and characteristic values. However, in applications using tourniquets and similar devices, the high pressure and thick cuff walls result in weak arterial pulsation, reducing the sensitivity of the pressure sensor. Consequently, the acquired pulse wave signal is very weak, the waveform is not sharp, and the characteristic values ​​of the pulse wave amplitude variation pattern are not obvious, leading to low accuracy in the assessment of systolic and diastolic blood pressure. Summary of the Invention

[0005] The purpose of this invention is to provide a method for measuring vascular occlusion pressure using an orthopedic surgical hemostat, in order to solve the technical problems existing in the prior art.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for measuring vascular occlusion pressure using a hemostatic device in orthopedic surgery includes the following steps: Step S1: Cuff compression stage: Step S1.1: Wrap the cuff around the patient's limb and inflate the cuff; during the inflating process, monitor the cuff pressure in real time using a pressure sensor connected to the cuff; Step S1.2: After the cuff is inflated and pressurized to completely close the blood vessels in the patient's limb, the inflating and pressurization of the cuff is stopped; Step S2: Cuff decompression phase at a constant speed: Step S2.1: The cuff begins to depressurize at a constant speed, and during this process, the cuff pressure value P2 is collected in real time by the pressure sensor, and the pulse wave signal is acquired in real time by the pulse vibration sensor connected to the cuff. Step S2.2: Process the pulse wave signal to obtain the trend of its amplitude changing with the cuff pressure P2; Step S2.3: Based on the amplitude trend of the pulse wave signal, determine the cuff pressure value P2 corresponding to the first change of the amplitude trend from a stable baseline state to a continuous rise, and identify it as the critical locking pressure of the blood vessel. Step S3: Use the critical locking pressure as the closure pressure measurement value of the blood vessel.

[0007] Preferably, in step S1.2, the cuff is inflated and pressurized to a preset pressure value P1 that can completely close the blood vessel. When the pressure sensor collects the preset pressure value P1, it is determined that the blood vessel is completely closed and inflation is stopped.

[0008] Preferably, in step S2.1, the method for controlling the uniform depressurization of the cuff is as follows: a flow proportional valve is connected to the depressurization end of the cuff, and the cuff pressure is made to decrease uniformly at a preset speed by controlling the opening of the flow proportional valve.

[0009] Preferably, during the uniform depressurization process, the rate of change of the cuff pressure is fed back in real time, and the opening of the flow proportional valve is dynamically adjusted according to the rate of change to maintain the preset speed.

[0010] Preferably, the specific method of step S2.2 is as follows: the pulse wave signal is filtered and amplitude is detected to generate an amplitude sequence, and the amplitude sequence is associated with the synchronously acquired cuff pressure value P2 sequence.

[0011] Preferably, in step S2.3, the method for determining the initial change of pulse wave amplitude from a stable baseline state to a sustained increase is as follows: Step S2.3.1. Baseline determination: The pulse wave amplitude sequence obtained in the initial stage of uniform pressure release is subjected to median filtering, and the statistical characteristic value of the filtered data is determined as the representative value of the stable baseline state, wherein the statistical characteristic value is the mean. Step S2.3.2. Inflection point identification: During the uniform pressure relief process, the filtered pulse wave amplitude sequence is analyzed in real time. When the amplitude is detected to deviate continuously from the representative value for the first time, it is determined to be the first time that it has turned into a continuous rise.

[0012] To achieve the above objectives, the present invention also provides a method for applying the LOP (Lower Optical Position) of an orthopedic surgical hemostatic device, comprising the following steps: Step A: Using the method described above, the occlusion pressure of the blood vessel is measured. Step B: Determine the recommended hemostatic pressure value based on the measured occlusion pressure value; Step C: Control the cuff to be inflated to the recommended hemostatic pressure value and maintain it for a predetermined time to perform hemostasis.

[0013] To achieve the above objectives, the present invention also provides an orthopedic surgical hemostasis device for implementing the method described above, comprising: a cuff for wrapping around a patient's limb; a pressurization module connected to the cuff for inflating the cuff; a constant-speed depressurization module connected to the cuff for depressurizing the cuff at a constant speed; a pressure detection module connected to the cuff for real-time detection of the cuff pressure; a pulse detection module connected to the cuff for detecting pulse vibration signals through the cuff; and a control module electrically connected to the pressurization module, the constant-speed depressurization module, the pressure detection module, and the pulse detection module, respectively, for executing the method described above.

[0014] Preferably, the pulse detection module includes a pulse vibration sensor connected to the cuff. The pulse vibration sensor includes an upper housing with an air tube connector, a lower housing connected to the upper housing, a sealed chamber formed between the upper housing and the lower housing, and a piezoelectric ceramic sensor piece disposed at the bottom of the sealed chamber. The air tube connector of the upper housing is connected to the cuff.

[0015] Preferably, the pressure detection module includes a pressure sensor connected to the cuff.

[0016] Compared with the prior art, the present invention has the following beneficial effects: (1) This invention uses real-time monitoring of pulse wave signals to determine the complete closure state and critical opening point of blood vessels, fundamentally avoiding individual differences caused by relying on preset experience pressure values; at the same time, combined with the uniform pressure release process, it can accurately capture the critical pressure of blood vessels from closure to opening, thereby obtaining highly accurate blood vessel closure pressure measurement values, providing a reliable data basis for subsequent hemostasis.

[0017] (2) By obtaining accurate individualized occlusion pressure values ​​and using them as recommended hemostatic pressure, this invention can achieve precise pressure hemostasis, thereby effectively avoiding the risk of tissue and nerve damage caused by excessive pressure and preventing intraoperative bleeding caused by insufficient pressure. While ensuring hemostasis, it maximizes the safety of the patient's surgical site.

[0018] (3) In this invention, a pressure sensor and a pulse vibration sensor are used to collect two signals. The pressure signal and the pulse pulsation signal are collected independently. During the uniform decrease of the cuff pressure, the pulse vibration sensor collects the pulse fluctuation signal, and the pressure sensor collects the cuff pressure signal in real time. The pulse fluctuation signal is obtained by the pulse vibration sensor, rather than the cuff pressure signal on the pressure sensor. The critical state of the blood vessel from the closed state to the open state is captured by the pulse fluctuation signal, and the cuff pressure value collected by the pressure sensor corresponding to the critical state is used as the blood vessel closure pressure, which effectively ensures the accuracy of the measurement.

[0019] (4) In this invention, the pulse vibration sensor directly senses the minute pressure changes caused by the pulse in the sealed chamber through the piezoelectric ceramic sheet. The sealed chamber is connected to the cuff air passage, which can efficiently and sensitively capture the weak pulse vibration signal transmitted by the blood vessel wall and convert it into an electrical signal. Not only is the signal stable, but it also has strong anti-interference ability, effectively overcoming the problem of measurement in the high pressure thick wall cuff environment. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the process of the present invention.

[0021] Figure 2 This is a schematic diagram of the principle of the uniform pressure relief module in this invention.

[0022] Figure 3 This is a graph showing the trend of pulse wave signal amplitude as a function of cuff pressure.

[0023] Figure 4 This is a schematic diagram of the pulse vibration sensor in this invention.

[0024] Figure 5 This is a schematic diagram of the hemostasis device in Embodiment 3 of the present invention.

[0025] The component names corresponding to the reference numerals in the attached drawings are as follows: 1-upper housing, 2-piezoelectric ceramic sensor sheet, 3-lower housing, 4-electrode lead. Detailed Implementation

[0026] To enable those skilled in the art to have a clearer understanding of the present invention, the present invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described below are merely for illustrative purposes and to facilitate understanding. The technical solutions provided by the present invention are not limited to those provided in the following embodiments, nor should they limit the scope of protection of the present invention.

[0027] Example 1 like Figures 1-4As shown in the figure, this embodiment provides a method for measuring vascular occlusion pressure using an orthopedic surgical hemostat. The design principle of this method is to use an independent, highly sensitive pulse vibration sensor, which is combined with a pressure sensor that collects cuff pressure. During the uniform decompression of the cuff, the mechanical vibration signal (pulse wave) transmitted by the arterial wall is directly collected, and the amplitude change trend of this signal is correlated with the synchronously decreasing cuff pressure, thereby accurately finding the critical pressure point at which the blood vessel begins to open from a completely closed state, i.e., the vascular occlusion pressure.

[0028] In this embodiment, the specific method for measuring vascular occlusion pressure using an orthopedic surgical hemostasis device is as follows: Step S1, Cuff Compression Stage: S1.1: The operator wraps the cuff around the appropriate position of the patient's surgical limb (such as the upper or lower limb), and after starting the device (hemostat), the pressurization module (such as an air pump) begins to inflate the cuff; during this process, the pressure detection module (including pressure sensors) continuously transmits the pressure value inside the cuff to the control module (integrated into the device's control motherboard, ARM MCU controller, example model: STM32F103ZET6) in real time. S1.2: The control module determines whether the pressure has reached the endpoint (i.e., whether the blood vessel is completely closed) according to the preset logic. It implements the following: a preset pressure value P1 is a large pressure value that can completely close the blood vessel. The device selects to inflate the cuff to the preset pressure value P1. When the pressure sensor collects the preset pressure value P1, it determines that the blood vessel is completely closed and stops inflating. This process is very short and can be understood as the pressure being reached instantaneously, that is, the blood vessel is completely closed, so it will not cause harm to the patient.

[0029] Step S2: Cuff decompression phase at a constant speed: S2.1: After pressurization stops, the control module immediately instructs the constant-speed depressurization module to operate. This module includes a high-precision flow proportional valve connected to the cuff's depressurization passage. Based on a preset depressurization rate (e.g., a decrease of 2-3 mmHg per second), the control module calculates the target control signal to control the opening of the proportional valve, thus initiating constant-speed depressurization. Constant-speed depressurization is crucial in this step because after applying pressure to completely close a blood vessel in the upper or lower limb, the arterial occlusion pressure can only be located during a slow, constant-speed depressurization process.

[0030] To maintain a highly constant pressure relief rate, the control module reads pressure sensor data at a high frequency (e.g., 10 times per second), calculates the real-time pressure change rate (i.e., the pressure relief rate), compares this measured rate with a preset rate, and dynamically adjusts the opening of the flow proportional valve using PID and other control algorithms. If the measured rate is too slow, the opening is increased; if it is too fast, the opening is decreased. This effectively counteracts speed fluctuations caused by factors such as cuff elasticity and minor differences in valve characteristics.

[0031] In this embodiment, a control example for uniform pressure relief is provided. The control structure mainly consists of the following modules: a PID control software algorithm module for pressure sensor pressure (integrated into the MCU), a hardware module for MCU output PWM control signals, a current feedback signal sampling resistor, a high-speed proportional operational amplifier module, a constant current control MOSFET module, and a flow proportional valve. Based on the above structure, the gas relief flow rate and the valve opening of the flow proportional valve are linearly proportional, and the valve opening of the flow proportional valve and the current inside the valve body coil are linearly proportional. Therefore, in practical operation, as long as the current of the flow proportional valve is controlled, the valve opening of the flow proportional valve can be controlled, thus achieving precise control of the gas relief flow rate.

[0032] Based on the above example, the control implementation process is as follows: The PID control software algorithm module collects two cuff pressure values ​​at equal intervals and calculates the pressure difference during this time interval. This difference can be converted into the cuff depressurization rate. When the depressurization rate differs from the rate value set in the PID control software algorithm module (i.e., the preset depressurization rate), the PID control software algorithm module changes the control value output by the MCU output PWM control signal hardware module according to the algorithm. This control value changes the current of the flow proportional valve through the high-speed proportional operational amplifier module, the current feedback signal sampling resistor, and the constant current control MOSFET module, thereby controlling the valve opening of the flow proportional valve and achieving precise control of the cuff gas depressurization flow. An example of the PID control software algorithm module is as follows: (1)bp_dif0=bjy_max-B_press; (2) bias = bp_dif0 - 7, where 7 mmhg / s is the target velocity; (3) BPWMVAL-=((1600*(bias-last_bias)+800*bias+20*(bias-2*last_bias+prev_bias)) / 1000); (4) bjy_max = B_press; (5) prev_bias=last_bias; (6) last_bias = bias; In the above, bjy_max is the saved pressure value from the last cuff reading, B_press is the current cuff pressure value, and the difference between the two, bp_dif0, is the current cuff decompression rate. bp_dif0 is the current cuff decompression rate, with a target rate set at approximately 7 mmHg per second. bias is the deviation of the current rate. bias is the current rate deviation, last_bias is the previous rate deviation, and prev_bias is the rate deviation from the previous time. Based on the incremental PID algorithm, empirical coefficients are inserted to calculate the reference value that BPWMVAL needs to be adjusted. This value is used to adjust the control current of the flow proportional valve, thereby controlling the valve opening: if the decompression rate is too low, the flow proportional valve opening is increased; if the decompression rate is too high, the flow proportional valve opening is decreased. In Equation 4, bjy_max is the stored value of B_press, and BPWMVAL is the current cuff pressure value. In Equation 5, prev_bias is the stored value of the cuff pressure-speed deviation of the previous last_bias. In Equation 6, last_bias is the stored value of the cuff pressure-speed deviation of the current bias.

[0033] S2.2: Process the pulse wave signal to obtain the trend of its amplitude changing with cuff pressure P2. The signal processing unit in the control module preprocesses the raw pulse wave signal: first, it performs bandpass filtering to remove high-frequency noise and low-frequency drift; then, it performs amplitude detection, such as calculating the peak-to-peak value of the waveform in each cycle, thereby generating a pulse wave amplitude sequence. Since the pressure sequence and amplitude sequence are sampled synchronously by the same clock system, the control module maps them one-to-one according to time points, thereby establishing the correlation between each pressure value P2 and the pulse wave amplitude A at that moment, that is, obtaining the trend of amplitude changing with pressure, such as... Figure 3 As shown.

[0034] S2.3: The control module performs real-time analysis of the amplitude sequence to identify critical points.

[0035] The principle behind this step is as follows: Within the vascular locking zone, since the blood vessel is completely sealed, the only signal from the vessel wall is the radial impact force of the blood flow. This vibration is transmitted through the compressed gas inside the cuff, then through the cuff's endotracheal tube, to the pulse vibration sensor. At this time, because the state of the blood vessel and blood flow does not change significantly, the amplitude of the pulse wave signal is a small and relatively constant value; that is, the pulse wave amplitude envelope is close to a flat straight line. During the uniform degassing process, the system records the cuff pressure value for each pulse beat in real time. As the cuff pressure decreases, blood flow begins to pass through the compressed blood vessel, and the blood vessel begins to experience high-pressure blood flow. At this time, the vessel wall is subjected to the combined radial and lateral impact forces of the blood flow, causing a drastic change in vibration intensity. This increased vibration intensity is transmitted through the compressed gas inside the cuff, then through the cuff's endotracheal tube, to the pulse vibration sensor. The change in vibration of the pulse vibration sensor is converted into a change in the amount of charge in the piezoelectric sensor, resulting in a significant change in the acquired amplitude.

[0036] The implementation steps are as follows: S2.3.1 Baseline determination: Take the amplitude data within the first period after the pressure relief begins (e.g., the first 5 seconds) as the sample for the complete vascular closure period. To improve robustness, this sample data can be first filtered by median (e.g., window size of 5 sampling points) to eliminate possible pulse interference. Then, calculate the arithmetic mean of this filtered data and use this mean as the quantitative representative value of the stable baseline state. S2.3.2 Inflection Point Recognition: During the subsequent depressurization process, the real-time amplitude data is also subjected to median filtering. The control module continuously compares the filtered real-time amplitude value with the baseline value, for example, by setting a judgment threshold (e.g., threshold = baseline value + 3 times the standard deviation, or an empirical small positive value). When the amplitude of N consecutive sampling points (e.g., N=3) is detected to be greater than the threshold and shows a continuous upward trend, it is determined that the blood flow in the blood vessel has begun to recover, and the pulse wave amplitude has deviated continuously for the first time. The system immediately locks the time point at which this occurs. Then, based on this time point, the corresponding cuff pressure value is found in the synchronized pressure sequence. This value is the critical locking pressure, which is the critical pressure at which the blood vessel goes from a closed state to just beginning to open (blood flow recovery).

[0037] An example of this embodiment: such as Figure 3 As shown, due to differences in physical condition, patients A and B experience different lateral impact forces from blood pulsation on the cuff when the aorta is closed. In other words, the vibration amplitude generated by the pulse vibration sensor is different when the blood vessel is closed. Therefore, it is inaccurate to use the threshold of vibration amplitude to determine the closure state of the blood vessel. Figure 3In the diagram, point A represents the near-opening position of the blood vessel, and point B represents the maximum amplitude of the collected pulse, which physiologically can be understood as the maximum value of arterial vascular vibration. Connecting A and B, and using a linear regression algorithm, point A is located in the diagram. The pressure value at point A is the reference pressure value for the arterial locking pressure. In the algorithm processing, the pulse amplitude value and the corresponding cuff pressure value at each point are simultaneously stored in a two-dimensional array. Therefore, once the location of the reference point for the arterial locking pressure is found, the reference value for the arterial locking pressure is immediately obtained. An example of the algorithm formula is shown below:

[0038] In the first formula algorithm above, bmin_val is the reference value of the vibration wave amplitude of the blood vessel in the closed state, which is found by median filtering and sorting algorithm. b5first_val is the first five amplitude parameters of the pulse vibration sensor amplitude collected, sorted, and filtered by median algorithm to remove interference values. The second formula algorithm uses bpp_val, which represents the amplitude of the pulse vibration sensor's vibration at the point near the opening of the corresponding blood vessel. This is determined by finding point B, drawing a straight line connecting A and B, and finding the intersection of this line and a parallel line; this value represents the location of point A. Based on the amplitude pattern of the pulse vibration sensor's vibration, point A in the diagram is located, and the corresponding cuff pressure value at point A can be immediately obtained in a two-dimensional array. This pressure value at point A is the reference pressure value for the arterial locking pressure. B_pmax is a two-dimensional array containing the amplitude of the real-time pulse vibration sensor's vibration and the cuff pressure value. B_pmaxcnt is the length of the collected array, i.e., the number of elements in the two-dimensional array. bmin_val represents the amplitude of the pulse vibration sensor's vibration wave when the blood vessel is fully closed, obtained through a sorting algorithm and median filtering. bpp_val represents the amplitude of the pulse vibration sensor's vibration at the point near the opening of the corresponding blood vessel, specifically the amplitude of the pulse vibration sensor's vibration wave when the adjacent blood vessel is open.

[0039] S3, Output Stage: The control module uses the measured critical locking pressure (LOP) as the final result of this measurement—the vascular occlusion pressure measurement value—to display on the device's screen and store it in memory for subsequent steps.

[0040] Using the above method, the pulse vibration signal is acquired through a pulse vibration sensor. Then, the pulse vibration signal is combined with the cuff pressure value acquired by the pressure sensor to measure the critical lock-up pressure (LOP). Compared with the traditional technical solution that uses a single pressure sensor to acquire the pulse signal, this solution avoids the problems of very weak, unstable, and poor anti-interference ability of the pulse signal on the pressure sensor, thus ensuring the measurement accuracy of the critical lock-up pressure (LOP).

[0041] Example 2 This embodiment provides a method for applying LOP (Lower Optical Particle Size). After accurately measuring the LOP, the hemostasis procedure can proceed. Step A: The vascular occlusion pressure value (LOP) is measured using the technical solution provided in Example 1.

[0042] Step B: Determine the recommended hemostatic pressure based on LOP. A simple strategy is to directly use LOP as the recommended pressure; a safer strategy is to set the recommended pressure = LOP + ΔP (where ΔP is a small safety margin, such as 10-20 mmHg), to ensure reliable blood flow occlusion during surgery.

[0043] Step C: The control module instructs the pressurization module to restart, inflating the cuff. The pressure detection module monitors the pressure in real time, stopping inflation when the recommended hemostatic pressure is reached. The cuff will maintain this pressure for a period of time (e.g., depending on the surgical needs, a single hemostatic procedure typically lasts no more than 60-120 minutes). At this point, hemostasis preparation is complete, and the surgeon can begin the operation. After the critical surgical steps are completed, the control module controls the cuff to depressurize quickly or slowly, restoring blood flow to the limb.

[0044] Example 3 like Figure 5 As shown, this embodiment provides a surgical hemostasis device for realizing LOP measurement and hemostasis operations, which includes hardware entities and software control logic.

[0045] The hardware components of a hemostat mainly include: a cuff, used to wrap around the limb, with its internal air bladder connected to the main unit of the hemostat via a trachea.

[0046] Pressurization module: including air pump, air intake solenoid valve and related drive circuit, responsible for filling the cuff with gas.

[0047] Uniform speed pressure relief module: The core is a flow proportional valve (such as an electromagnetic proportional valve) connected to the cuff exhaust passage. By receiving the PWM signal from the control module, it precisely controls the exhaust flow rate and realizes the setting and adjustment of the pressure relief speed.

[0048] Pressure detection module: includes a pressure sensor (such as a piezoresistive sensor), whose air path is connected to the inner cavity of the cuff, and whose electrical output is connected to the ADC (analog-to-digital converter) of the control module for real-time measurement of the pressure inside the cuff.

[0049] Pulse detection module: Its core is as follows Figure 4The pulse vibration sensor shown is a combination of an upper housing 1 with a tracheal connector and a lower housing 3, which are sealed together to form a sealed chamber. A piezoelectric ceramic sensor 2 is mounted at the bottom of the chamber. The electrode leads 4 of the piezoelectric ceramic sensor 2 are electrically connected to the control module, and its output is connected to the ADC (analog-to-digital converter) of the control module. The lower housing 3 is a stepped circular plastic seal used to carry the sensor and lead wires. The upper housing 1 is a circular plastic part with a pagoda-shaped tracheal connector. The tracheal connector of the upper housing 1 is connected to the cuff airbag through a tube, so that the static pressure in the chamber is balanced with the cuff pressure. When the artery under the cuff pulsates, this mechanical vibration is transmitted to the sealed chamber through the tissue, cuff fabric and gas in the airbag, causing a small pressure fluctuation in the gas inside the chamber. This fluctuation acts on the piezoelectric ceramic plate 2, causing it to generate a charge signal (voltage signal) with the same frequency as the fluctuation. This signal is amplified by a charge amplifier circuit (for example, using a classic charge amplifier composed of a low bias current and low noise operational amplifier), and then amplified twice by an isolation DC circuit (for example, a first-order high-pass filter composed of operational amplifiers). The signal is then converted into the required digital signal in the system by the ADC converter of the control module (microcontroller). This signal has the advantages of high sensitivity, sharp waveform, strong anti-interference ability, and obvious amplitude variation law.

[0050] Control Module: This is the core of the hemostatic device's control system. It typically uses a microprocessor (ARM MCU controller, example model: STM32F103ZET6) as its core. It receives signals from pressure and pulse vibration sensors, runs the control algorithm program stored in its memory (used to implement the methods in Examples 1 and 2), and issues control commands to actuators such as the air pump and flow proportional valve. It also manages the human-machine interface (buttons, display screen). Control module control examples: Pressurization control: A switch signal is output through the GPIO port to control the air pump relay. An analog voltage is generated by filtering the DAC output or PWM signal to control the opening of the air inlet valve. Depressurization control: The flow proportional valve is controlled through another DAC or PWM signal. To achieve uniform depressurization, the control program reads the pressure value every 100ms, calculates the instantaneous depressurization rate, compares it with a preset rate, and uses a PID control algorithm to adjust the DAC output voltage value in real time.

[0051] The hardware components also include a power module, a button module, and a display screen. The power module provides power to the hemostat, the button module is used for switching the hemostat on and off and adjusting it, and the display screen is used to show the operating interface and human-machine interaction.

[0052] The software part (i.e., control logic) is embedded in the control module, and its workflow is the method steps described in Examples 1 and 2. It is responsible for synchronous acquisition of signals, digital filtering (such as median filtering in step S2.3), amplitude calculation, trend analysis, inflection point identification algorithm, and execution of closed-loop control algorithm.

[0053] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for measuring vascular occlusion pressure using a hemostatic instrument in orthopedic surgery, characterized in that: Includes the following steps: Step S1: Cuff compression stage: Step S1.1: Wrap the cuff around the patient's limb and inflate the cuff with air; During the pressurization process, the cuff pressure is monitored in real time by a pressure sensor connected to the cuff; Step S1.2: After the cuff is inflated and pressurized to completely close the blood vessels in the patient's limb, the inflating and pressurization of the cuff is stopped; Step S2: Cuff decompression phase at a constant speed: Step S2.1: The cuff begins to depressurize at a constant speed, and during this process, the cuff pressure value P2 is collected in real time by the pressure sensor, and the pulse wave signal is acquired in real time by the pulse vibration sensor connected to the cuff. Step S2.2: Process the pulse wave signal to obtain the trend of its amplitude changing with the cuff pressure P2; Step S2.3: Based on the amplitude trend of the pulse wave signal, determine the cuff pressure value P2 corresponding to the first change of the amplitude trend from a stable baseline state to a continuous rise, and identify it as the critical locking pressure of the blood vessel. Step S3: Use the critical locking pressure as the closure pressure measurement value of the blood vessel.

2. The method for measuring vascular occlusion pressure using the orthopedic surgical hemostasis device according to claim 1, characterized in that: In step S1.2, the cuff is inflated and pressurized to a preset pressure value P1 that can completely close the blood vessel. When the pressure sensor collects the preset pressure value P1, it is determined that the blood vessel is completely closed and inflation is stopped.

3. The method for measuring vascular occlusion pressure using an orthopedic surgical hemostat according to claim 1 or 2, characterized in that: In step S2.1, the method for controlling the uniform depressurization of the cuff is as follows: a flow proportional valve is connected to the depressurization end of the cuff, and the cuff pressure is made to decrease uniformly at a preset speed by controlling the opening of the flow proportional valve.

4. The method for measuring vascular occlusion pressure using the orthopedic surgical hemostat according to claim 3, characterized in that: During the uniform depressurization process, the rate of change of the cuff pressure is fed back in real time, and the opening of the flow proportional valve is dynamically adjusted according to the rate of change to maintain the preset speed.

5. The method for measuring vascular occlusion pressure using the orthopedic surgical hemostat according to claim 4, characterized in that: The specific method of step S2.2 is as follows: the pulse wave signal is filtered and amplitude is detected to generate an amplitude sequence, and the amplitude sequence is associated with the synchronously acquired cuff pressure value P2 sequence.

6. The method for measuring vascular occlusion pressure using the orthopedic surgical hemostat according to claim 5, characterized in that: In step S2.3, the method for determining the first change in pulse wave amplitude from a stable baseline state to a sustained increase is as follows: Step S2.3.

1. Baseline determination: The pulse wave amplitude sequence obtained in the initial stage of uniform pressure release is subjected to median filtering, and the statistical characteristic value of the filtered data is determined as the representative value of the stable baseline state, wherein the statistical characteristic value is the mean. Step S2.3.

2. Inflection point identification: During the uniform pressure relief process, the filtered pulse wave amplitude sequence is analyzed in real time. When the amplitude is detected to deviate continuously from the representative value for the first time, it is determined to be the first time that it has turned into a continuous rise.

7. A method for applying the LOP (Lower Optical Position) of a hemostatic instrument in orthopedic surgery, characterized in that: Includes the following steps: Step A: Using the method described in any one of claims 1 to 6, measure the occlusion pressure of the blood vessel; Step B: Determine the recommended hemostatic pressure value based on the measured occlusion pressure value; Step C: Control the cuff to be inflated to the recommended hemostatic pressure value and maintain it for a predetermined time to perform hemostasis.

8. A hemostatic device for implementing the method according to any one of claims 1 to 6, characterized in that, Includes: cuffs, used to wrap around the patient's limbs; A pressurization module, connected to the cuff, is used to inflate the cuff. A constant-speed pressure relief module, connected to the cuff, is used to release pressure from the cuff at a constant speed; a pressure detection module, connected to the cuff, is used to detect the cuff pressure in real time. A pulse detection module, connected to the cuff, is used to detect pulse vibration signals through the cuff; a control module, electrically connected to the pressurization module, the constant-speed depressurization module, the pressure detection module, and the pulse detection module, is used to execute the method as described in any one of claims 1 to 6.

9. The hemostatic device according to claim 8, characterized in that, The pulse detection module includes a pulse vibration sensor connected to the cuff. The pulse vibration sensor includes an upper housing (1) with a tracheal connector and a lower housing (3) connected to the upper housing (1). A sealed chamber is formed between the upper housing (1) and the lower housing (3), and a piezoelectric ceramic sensor piece (2) is provided at the bottom of the sealed chamber. The tracheal connector of the upper housing (1) is connected to the cuff.

10. The hemostatic device according to claim 9, characterized in that, The pressure detection module includes a pressure sensor connected to the cuff.

Images