An implantable diaphragm pacemaker and control method thereof

Abstract

The present invention discloses an implantable diaphragm pacemaker and a control method thereof, comprising: a controller, a body surface electrode and a photoelectrode; the controller comprises a single chip microcomputer, a human-computer interaction module, a photoelectrode driving module, a signal processing module and a constant current stimulation module; wherein the single chip microcomputer is electrically connected to the human-computer interaction module, the signal processing module and the constant current stimulation module respectively; the signal processing module is electrically connected to the body surface electrode; the photoelectrode driving module is electrically connected to the constant current stimulation module and the photoelectrode respectively. The present invention can monitor, process and analyze the patient's surface diaphragm electrical signal in real time, realize online adjustment of the stimulation signal parameters, so as to achieve the best respiratory state, without the need for manual adjustment by medical staff, thereby reducing the workload of medical staff.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and more particularly to an implantable diaphragm pacemaker and a control method thereof. Background Art

[0002] In China, every year, there are tens of thousands of patients suffering from central alveolar hypoventilation, respiratory muscle paralysis caused by central lesions such as brainstem and spinal cord, chronic obstructive pulmonary disease and post-traumatic respiratory insufficiency. The treatment of these patients mainly relies on mechanical ventilation by ventilator. However, long-term mechanical ventilation not only brings heavy economic burden to patients, but also causes the loss of speech and coughing function, and is prone to sequelae such as bedsores and respiratory infections, which seriously damages the physical and mental health of patients.

[0003] Implantable diaphragm pacing technology, also known as phrenic nerve stimulation technology, is a technology that uses an external controller to generate pulse stimulation signals to the phrenic nerve, triggering diaphragm contraction, thereby replacing the physiological respiratory movement of the human body. This technology can effectively restore the patient's autonomous breathing function, language function, social activities, and effectively reduce the economic burden, etc., and can completely replace the function of the ventilator. Implantable diaphragm pacing technology has been widely used in clinical partial or complete ventilation treatment of respiratory dysfunction in diseases such as high spinal cord injury and chronic obstructive pulmonary disease.

[0004] At present, the most widely used diaphragm pacemakers in the world are mainly produced by Avery in the United States, Atrotech in Australia and Medimplant in Finland. These three types of pacemakers have basically the same working principles except for the difference in the number of electrodes and stimulation methods. However, these diaphragm pacemakers are open-loop systems without feedback regulation function. They can only activate the diaphragm to contract the diaphragm to produce inhalation, but cannot adaptively adjust the stimulation parameters according to changes in respiratory demand, changes in electrode quality over time, or diaphragm fatigue, resulting in long-term use of diaphragm pacemakers. Will produce pacing effects that cannot meet the physiological needs of the human body. At the same time, if the pacing effect is lower than the minimum demand of the human body and there is no caregiver, it is very easy to threaten the patient's life safety. In addition, the existing implantable diaphragm pacing system uses traditional electrical stimulation methods, and the current flows in all directions of biological tissues, with low spatial resolution, and cannot achieve precise regulation of nerves.

[0005] Therefore, how to provide a diaphragm pacemaker and a control method thereof that can adaptively adjust stimulation parameters according to the physiological needs of the human body is an issue that needs to be urgently addressed by those skilled in the art. Summary of the invention

[0006] In view of this, the present invention provides an implantable diaphragm pacemaker and a control method thereof, which can monitor, process and analyze the surface diaphragm electrical signals of diaphragm pacing patients in real time, and realize online adjustment of stimulation signal parameters to optimize the respiratory state without the need for manual adjustment by medical staff, thereby reducing the workload of medical staff.

[0007] In order to achieve the above object, the present invention adopts the following technical solution:

[0008] An implantable diaphragm pacemaker, comprising: a controller, a body surface electrode and a photoelectrode; the controller comprises a single chip microcomputer, a human-computer interaction module, a photoelectrode driving module, a signal processing module and a constant current stimulation module; wherein the single chip microcomputer is electrically connected to the human-computer interaction module, the signal processing module and the constant current stimulation module respectively; the signal processing module is electrically connected to the body surface electrode; the photoelectrode driving module is electrically connected to the constant current stimulation module and the photoelectrode respectively;

[0009] The human-computer interaction module is used to set or adjust the initial stimulation parameters of the single-chip microcomputer;

[0010] The body surface electrodes are used to collect electrical signals of the diaphragm in real time;

[0011] The signal processing module predicts the actual respiratory airflow based on the electrical signal of the diaphragm;

[0012] The single chip microcomputer is used to compare the actual respiratory airflow with the ideal respiratory airflow, and adaptively adjust the initial stimulation parameters according to the comparison result to generate new stimulation parameters;

[0013] The constant current stimulation module is used to generate a constant stimulation current according to the new stimulation parameters;

[0014] The photoelectrode driving module is used to control the photoelectrode to generate a corresponding photoelectric stimulation signal according to the stimulation current.

[0015] Preferably, the photoelectrode is composed of a hydrogel substrate, a plurality of light-conducting electrode sheets and a plurality of conductive electrode sheets;

[0016] Among them, the hydrogel base includes a mounting surface and mounting ears; the mounting surface is a curved surface structure; the light-guiding electrode sheet and the conductive electrode sheet are arranged in a staggered array and embedded in the inner curved surface of the mounting surface; the mounting ears are radially installed on the outer curved surface of the mounting surface and are symmetrically arranged.

[0017] Preferably, the cross-section of the mounting surface is a 2 / 3 arc shape.

[0018] Preferably, the body surface electrode is a medical surface electrode, and its surface is coated with silver.

[0019] Preferably, the model of the single chip microcomputer is STM32F091RxT; the model of the photoelectrode driving module is TLC5940 LED.

[0020] It can be seen from the above technical solution that compared with the prior art, the present invention discloses an implantable diaphragm pacemaker. Before implantation, the doctor sets the initial stimulation parameters through the human-computer interaction module according to the patient's specific symptoms; after implantation, the body surface electrodes collect the changes in the electrical signals of the patient's diaphragm in real time, and the signal processing module converts and processes the electrical signals of the diaphragm, and converts the analog signals into digital signals; the single-chip microcomputer calculates the processed diaphragm electrical signals to determine whether the current stimulation level meets the patient's physiological needs, and when the current stimulation parameters do not match the patient's physiological needs, the stimulation parameters are adaptively adjusted to generate new stimulation parameters; under the new stimulation parameters, the constant current stimulation module generates a constant stimulation current, and the photoelectric drive module drives the photoelectrode to generate a corresponding degree of photoelectric stimulation signal according to the stimulation current, and acts on the phrenic nerve. Under the stimulation of the photoelectric signal, the phrenic nerve controls the diaphragm to pace to a corresponding degree, thereby achieving the purpose of adjusting the respiratory airflow. The controller of the present invention takes a single-chip microcomputer as its core, supplemented by a human-computer interaction module, a photoelectrode driving module, a signal processing module and a constant current stimulation module, to form a closed-loop system with feedback regulation function. It does not require real-time care from medical staff and can perform adaptive adjustments according to the patient's physiological needs, greatly improving safety and stability and ensuring the patient's life safety.

[0021] In addition, the present invention can reduce the stimulation threshold by adopting a photoelectric combined stimulation method, achieve precise regulation of the phrenic nerve, and improve the safety and efficiency of diaphragm pacing.

[0022] The present invention also provides a control method for an implantable diaphragm pacemaker, comprising the following steps:

[0023] Acquiring initial stimulation parameters of the diaphragm pacemaker and real-time electrical signals of the diaphragm;

[0024] Predict the current actual respiratory airflow based on the real-time electrical signal of the diaphragm;

[0025] Calculating an ideal respiratory airflow based on an ideal respiratory airflow model, and comparing the current actual respiratory airflow with the ideal respiratory airflow, and adaptively adjusting the initial stimulation parameters according to the comparison result to generate new stimulation parameters;

[0026] generating a constant stimulation current according to the new stimulation parameters;

[0027] The photoelectrode is controlled according to the stimulation current to generate a corresponding photoelectric stimulation signal, and acts on the contact site.

[0028] Preferably, predicting the current actual respiratory airflow according to the real-time electrical signal of the diaphragm comprises:

[0029] Performing digital bandpass filtering on the diaphragm electrical signal collected in real time by the body surface electrode to obtain a processed diaphragm electrical signal;

[0030] Calculate the sample entropy value of the processed diaphragm electrical signal;

[0031] The current actual respiratory airflow is predicted based on the sample entropy value.

[0032] Preferably, calculating the sample entropy value of the processed diaphragm electrical signal includes:

[0033] Generate a data sequence {x(i)} based on the processed diaphragm electrical signal, where i=1, 2, ..., N, and N is the total length of the data;

[0034] Based on the data sequence {x(i)}, construct m-dimensional vector matrices X(i) and X(j) respectively;

[0035] X(i)=[x(i),x(i+1),…,x(i+m-1)]; X(j)=[x(j),x(j+1),…,x(j+m-1)];

[0036] Wherein, m represents the m consecutive values ​​in the myoelectric signal data sequence; 1≤i≤N-m+1; 1≤j≤Nm; i≠j;

[0037] Determine the maximum difference d between two vectors in X(i) ij ;

[0038]

[0039] Given a similarity tolerance r, count the d in X(i) ij ≤r, and for all Nm conditions d ij The sum of the numbers ≤ r is averaged;

[0040]

[0041] In the above formula, r takes the value of 0.1-0.25SD(X), and SD represents the standard deviation of the signal; represents d in X(i) ij ≤r and the number of d ij The ratio of the number of elements in the array, B m (r) represents d under all Nm conditions ij The average value of the vector sum of numbers ≤ r;

[0042] The average value of the sum of all vectors of an m+1 dimensional vector matrix is ​​calculated using the following formula:

[0043]

[0044] The sample entropy value of the diaphragm electrical signal with a data length of N is calculated using the following formula:

[0045]

[0046] Preferably, the calculating of the ideal respiratory airflow based on the ideal respiratory airflow model, comparing the current actual respiratory airflow with the ideal respiratory airflow, and adaptively adjusting the initial stimulation parameters according to the comparison result to generate new stimulation parameters include:

[0047] Constructing an ideal respiratory airflow model and a photoelectric stimulation waveform model, and generating an ideal respiratory airflow based on the ideal respiratory airflow model;

[0048] Comparing the current actual respiratory airflow with the ideal respiratory airflow to generate a respiratory airflow difference and a difference change rate;

[0049] Fuzzifying the respiratory airflow difference and the difference change rate, adaptively adjusting the initial stimulation parameters using fuzzy rules, and determining the adaptive adjustment rules of the stimulation parameters;

[0050] Establishing a linear relationship between the adaptive adjustment rule of the stimulation parameters and the photoelectric stimulation waveform model;

[0051] Based on the linear relationship, the original stimulation parameters of the photoelectric stimulation waveform model are adjusted, and new stimulation parameters are generated.

[0052] Preferably, the calculation formula of the adaptive adjustment rule of the stimulation parameters is as follows:

[0053]

[0054] △fl(t)=fl1(t)-fl2(t);

[0055] u(t) is the system output control quantity at time t; K p is the proportionality coefficient; k i is the integral coefficient; k d is the differential coefficient; fl1(t) is the ideal respiratory airflow, and fl2(t) is the actual respiratory airflow.

[0056] It can be seen from the above technical scheme that compared with the prior art, the present invention provides a control method for an implantable diaphragm pacemaker, in which the doctor sets the initial stimulation parameters through the human-computer interaction module according to the specific symptoms of the patient; the surface electrodes collect the changes in the electrical signals of the patient's diaphragm in real time, the signal processing module converts and processes the electrical signals of the diaphragm, and predicts the current actual respiratory airflow based on the electrical signals of the diaphragm, and transmits the actual respiratory airflow to the single-chip microcomputer; the single-chip microcomputer compares the actual respiratory airflow with the ideal respiratory airflow to determine whether the current stimulation level meets the patient's physiological needs, and when the actual respiratory airflow does not match the ideal respiratory airflow, the stimulation parameters are adaptively adjusted to generate new stimulation parameters; under the new stimulation parameters, the constant current stimulation module generates a constant stimulation current, the photoelectric drive module drives the photoelectrode to generate a corresponding degree of photoelectric stimulation signal according to the stimulation current, and acts on the phrenic nerve, and the phrenic nerve controls the diaphragm to pace to a corresponding degree under the stimulation of the photoelectric signal, thereby achieving the purpose of adaptively adjusting the respiratory airflow. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0058] Figure 1 The accompanying drawing is a structural block diagram of the diaphragm pacemaker provided by the present invention;

[0059] Figure 2 The accompanying drawing is a schematic diagram of the application of the diaphragm pacemaker provided by the present invention;

[0060] Figure 3 The accompanying drawing is a schematic diagram of the structure of the photoelectrode provided by the present invention;

[0061] Figure 4 The accompanying drawing is a flow chart of a control method of a diaphragm pacemaker provided by the present invention;

[0062] Figure 5 The accompanying drawing is a flow chart of S2 provided by the present invention;

[0063] Figure 6 The accompanying drawing is a flow chart of S3 provided by the present invention. DETAILED DESCRIPTION

[0064] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0065] like Figure 1-2 As shown, an embodiment of the present invention discloses an implantable diaphragm pacemaker, comprising: a controller 1, a body surface electrode 2 and a photoelectrode 3; the controller 1 comprises a single chip computer 11, a human-computer interaction module 12, a photoelectrode driving module 13, a signal processing module 14 and a constant current stimulation module 15; wherein the single chip computer 11 is electrically connected to the human-computer interaction module 12, the signal processing module 14 and the constant current stimulation module 15 respectively; the signal processing module 14 is electrically connected to the body surface electrode 2; the photoelectrode driving module 13 is electrically connected to the constant current stimulation module 15 and the photoelectrode 3 respectively;

[0066] The human-computer interaction module 12 is used to set or adjust the initial stimulation parameters of the single-chip computer 11;

[0067] The body surface electrode 2 is used to collect the electrical signal of the diaphragm in real time;

[0068] The signal processing module 14 predicts the actual respiratory airflow based on the electrical signal of the diaphragm;

[0069] The single chip computer 11 is used to compare the actual respiratory airflow with the ideal respiratory airflow, and adaptively adjust the initial stimulation parameters according to the comparison result to generate new stimulation parameters;

[0070] The constant current stimulation module 15 is used to generate a constant stimulation current according to new stimulation parameters;

[0071] The photoelectrode driving module 13 is used to control the photoelectrode 3 to generate a corresponding photoelectric stimulation signal according to the stimulation current.

[0072] In the embodiment of the present invention, the single chip microcomputer 11 is selected from the STM32F091RxT model, which integrates high performance -M0 32-bit RISC core running at up to 48MHz, high-speed embedded memory (up to 256kbytes of flash and 32kbytes of SRAM), and high compatibility.

[0073] The photoelectrode driving module 13 uses the Texas Instruments TLC5940 LED driver, which has 16 constant current output channels and can output a maximum current of 120mA. It is connected to the micro light-emitting diode of the light-guiding and conductive photoelectrode. The microcontroller controls the output current frequency, amplitude and duty cycle, and can realize flexible adjustment of light stimulation parameters (frequency, light intensity and duty cycle).

[0074] The single-chip microcomputer 11 generates positive and negative pulses with stimulation amplitude, stimulation frequency, stimulation pulse width, and inhalation time through two DACs. The two DACs realize voltage following through two operational amplifiers, and then realize the synthesis of stimulation waveforms through one operational amplifier. In order to avoid the influence of external interference or human body impedance difference, the synthesized stimulation waveform is input to the constant current stimulation module to ensure a constant stimulation current of the system.

[0075] The signal processing module 14 uses the AD620 operational amplifier of ADI Company to filter out the noise of system components; uses the active double-T notch filter to filter out the power frequency interference, and the signal with filtered interference and noise is read and analyzed by the single-chip microcomputer ADC.

[0076] like Figure 3 As shown, the photoelectrode 3 is composed of a hydrogel substrate 31, a plurality of light-conducting electrode sheets 32 and a plurality of conductive electrode sheets 33;

[0077] Among them, the hydrogel base 31 includes a mounting surface 311 and a mounting ear 312; the mounting surface 311 is a curved surface structure; the light-guiding electrode sheet 32 ​​and the conductive electrode sheet 33 are arranged in a staggered array and embedded in the inner curved surface of the mounting surface 311; the mounting ear 312 is radially installed on the outer curved surface of the mounting surface 311 and is symmetrically arranged; a mounting hole 3121 is opened on the mounting ear 312.

[0078] In this embodiment, the light-guiding electrode sheet is a micro-light-emitting diode with a size of 200μm×260μm; the conductive electrode sheet is made of platinum material with a size of 200μm×260μm. The light-guiding and conductive electrode sheets are embedded in a staggered array into a biocompatible hydrogel substrate to achieve the functions of light guidance and conduction.

[0079] The mounting plate of the light-conducting and conductive photoelectrode is designed to be 2 / 3 arc-shaped, with two mounting ears and mounting holes on both sides, which is convenient for doctors to insert the surgical thread into the through hole to fix the electrode to the epidermis during surgery. The outer diameter of the hydrogel base is 4mm, the inner diameter is 3mm, and the height is 10mm. The doctor inserts the photoelectrode into the phrenic nerve during surgery, and the photoelectrode contacts the nerve to achieve photoelectric combined stimulation of the phrenic nerve.

[0080] In one embodiment, the body surface electrode 2 is provided in a group, each group containing 3 body surface electrodes 2. The body surface electrode 2 is attached to the human body surface skin, the position is the intersection of the horizontal right (left) line of the human chest nipple and the right (left) arm of the human body hanging naturally as the starting point, the second and fourth ribs are the first and second position points of the electrode attachment, and the third electrode is the reference electrode, which is attached to the abdomen. The body surface electrode adopts a medical surface electrode, the surface is silver-plated, and it is ready to use after disassembly, which is convenient to use.

[0081] like Figure 4As shown, the embodiment of the present invention also discloses a control method of an implantable diaphragm pacemaker, comprising the following steps:

[0082] S1, obtaining the initial stimulation parameters of the diaphragm pacemaker and the real-time electrical signal of the diaphragm;

[0083] S2, predicting the current actual respiratory airflow based on the real-time electrical signal of the diaphragm;

[0084] S3, calculating the ideal respiratory airflow based on the ideal respiratory airflow model, and comparing the current actual respiratory airflow with the ideal respiratory airflow, adaptively adjusting the initial stimulation parameters according to the comparison results, and generating new stimulation parameters;

[0085] S4, generating a constant stimulation current according to the new stimulation parameters;

[0086] S5. Control the photoelectrode to generate corresponding photoelectric stimulation signal according to the stimulation current, and act on the contact site.

[0087] The following are detailed descriptions of the above steps:

[0088] S2 specifically includes:

[0089] S21, performing digital bandpass filtering on the diaphragm electrical signal collected in real time by the body surface electrode to obtain a processed diaphragm electrical signal.

[0090] S22. Calculate the sample entropy value of the processed diaphragm electrical signal.

[0091] The fixed sample entropy processing of the surface diaphragm electrical signal adopts the moving window calculation method, that is, for a surface diaphragm electrical signal of length N, by adding a length of N w The overlapping amount of the moving window is the moving window length N w 90% of the sample entropy, and calculate the fixed sample entropy value in each moving window to obtain the sample entropy curve.

[0092] The formula for calculating sample entropy is:

[0093] S221, generating a data sequence based on the processed diaphragm electrical signal, assuming that the data sequence of each frame of the diaphragm electrical signal is {x(i)}, where i=1, 2, ..., N, and N is the total length of the data;

[0094] S222, based on the data sequence {x(i)}, construct m-dimensional vector matrices X(i) and X(j) respectively; the vector dimension m=2;

[0095] X(i)=[x(i),x(i+1),…,x(i+m-1)];X(j)=[x(j),x(j+1),…,x(j+m-1)];wherein, m represents the m consecutive values ​​in the myoelectric signal data sequence; 1≤i≤N-m+1; 1≤j≤Nm; i≠j;

[0096] S223. Define the distance d[X(i),X(j)] between X(i) and X(j) as the maximum difference d between the corresponding elements of the two. ij ;

[0097]

[0098] S224. Given a similarity tolerance r, count the number of d in X(i) ij ≤r, and for all Nm conditions d ij The sum of the numbers ≤ r is averaged;

[0099]

[0100] In the above formula, r is 0.1-0.25SD(X), SD represents the standard deviation of the signal; B i m (r) represents the d in X(i) ij ≤r and the number of d ij The ratio of the number of elements in the array, B m (r) represents d under all Nm conditions ij The average value of the sum of vectors of numbers ≤ r;

[0101] S225. Calculate the average value of the sum of all vectors of the m+1-dimensional vector matrix using the following formula:

[0102]

[0103] S226. Calculate the sample entropy value of the diaphragm electrical signal with a data length of N using the following formula:

[0104]

[0105] S23. Predict the current actual respiratory airflow based on the sample entropy value.

[0106] The diaphragm electromyographic signal X(i)_1 and the respiratory airflow signal fl(t)_1 are simultaneously collected and recorded at a sampling frequency of 2000 Hz.

[0107] (1) Processing of electromyographic signals: When collecting surface diaphragm electromyographic signals, a zero-phase fourth-order Butterworth filter with a cutoff frequency of 5-400 Hz is used for digital bandpass filtering, and fixed sample entropy calculation is performed within the moving window to obtain the processed electromyographic signal X(i);

[0108] (2) Respiratory airflow signal processing: The respiratory airflow signal is smoothed by the moving average method to remove high-frequency noise and obtain the processed respiratory airflow signal fl(t);

[0109] (3) The fixed sample entropy value of the surface diaphragm EMG signal X(i) is used to predict the respiratory airflow signal fl(t): the linear least squares (polynomial fitting) method is used to fit the given EMG signal X(i) and airflow signal fl(t). The polynomial coefficient a = [a m ,…,a1,a0], so the relationship between the respiratory airflow signal and the diaphragm electromyographic signal can be established as:

[0110] fl(t)=a*X(i);

[0111] S3 includes the following steps:

[0112] S31, constructing an ideal respiratory airflow model and a photoelectric stimulation waveform model, and generating an ideal respiratory airflow based on the ideal respiratory airflow model;

[0113] S32, comparing the current actual respiratory airflow with the ideal respiratory airflow to generate a respiratory airflow difference and a difference change rate;

[0114] S33, fuzzifying the respiratory airflow difference and the difference change rate, adaptively adjusting the initial stimulation parameters using fuzzy rules, and determining the adaptive adjustment rules of the stimulation parameters;

[0115] S34, establishing a linear relationship between the adaptive adjustment rule of stimulation parameters and the photoelectric stimulation waveform model;

[0116] S35. Based on the linear relationship, the original stimulation parameters of the photoelectric stimulation waveform model are adjusted, and new stimulation parameters are generated.

[0117] Among them, the principle of adaptive closed-loop control is as follows:

[0118] (1) Predict the airflow signal based on the collected surface diaphragm electromyographic signal, and calculate the difference △fl(t) between the ideal airflow fl1(t) and the actual respiratory airflow fl2(t) predicted based on the real-time collected surface diaphragm electromyographic signal

[0119] △fl(t)=fl1(t)-fl2(t).

[0120] (2) Calculate the error change rate △flc(t):

[0121] △flc(t)=△fl(t)-△fl(t-1).

[0122] (3) According to the ideal PID control law of the continuous control system, it is discretized to obtain:

[0123]

[0124] u(t) is the system output control quantity at time t; K p is the proportionality coefficient; k i is the integral coefficient; k d is the differential coefficient.

[0125] (4) Fuzzy controller design

[0126] The difference between the ideal airflow and the actual predicted airflow △fl(t) and its difference change rate △flc(t) are fuzzified by the membership function, and then the incremental coefficient is inferred according to the fuzzy rule to adjust the control parameter K p , k i and k d The linear relationship between the output control quantity u(t) and the stimulation parameter stim(a_1,a_2,f_1,f_2,d_1,d_2) model is established, and finally the stimulation parameters are adjusted.

[0127] The present invention predicts the actual respiratory airflow based on the surface diaphragm electrical signal, uses the predicted physical quantity of respiratory airflow as a feedback signal, and adds an adaptive fuzzy controller to form a closed-loop implantable diaphragm pacing system to change the problem of poor stimulation effect caused by long-term use of the existing open-loop implantable diaphragm pacing system. In addition, through the photoelectric combined stimulation method, the stimulation threshold is reduced, and the stability and safety of diaphragm pacing are effectively enhanced. The present invention monitors, processes and analyzes the surface diaphragm electromyographic signals of diaphragm pacing patients in real time, and realizes online adjustment of the stimulation signal parameters to optimize the respiratory state without manual adjustment by medical staff, which reduces the workload of medical staff.

[0128] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0129] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An implantable diaphragm pacemaker, characterized in that: include: Controller, body surface electrodes and photoelectrodes; the controller includes a single chip microcomputer, a human-computer interaction module, a photoelectrode driving module, a signal processing module and a constant current stimulation module; wherein the single chip microcomputer is electrically connected to the human-computer interaction module, the signal processing module and the constant current stimulation module respectively; the signal processing module is electrically connected to the body surface electrodes; the photoelectrode driving module is electrically connected to the constant current stimulation module and the photoelectrode respectively; The model of the single-chip microcomputer is STM32F091RxT. The single-chip microcomputer controls the output current frequency, amplitude and duty cycle for flexible adjustment of light stimulation parameters; the single-chip microcomputer is provided with two DACs, which respectively generate positive and negative pulses with stimulation amplitude, stimulation frequency, stimulation pulse width and inhalation time; the two DACs realize voltage following through two operational amplifiers, and then realize the synthesis of stimulation waveforms through one operational amplifier, and input the synthesized stimulation waveforms into the constant current stimulation module; The human-computer interaction module is used to set or adjust the initial stimulation parameters of the single-chip microcomputer; The body surface electrodes are used to collect electrical signals of the diaphragm in real time; The signal processing module predicts the actual respiratory airflow based on the electrical signal of the diaphragm; The signal processing module uses an AD620 operational amplifier to filter out the noise of system components; an active double-T trap filter is used to filter out power frequency interference; the signal with filtered interference and noise is read and analyzed by the single-chip microcomputer DAC; The single chip microcomputer is used to compare the actual respiratory airflow with the ideal respiratory airflow, and adaptively adjust the initial stimulation parameters according to the comparison result to generate new stimulation parameters; the calculation formula of the adaptive adjustment rule of the stimulation parameters is as follows: △fl(t)=fl1(t)-fl2(t); u(t) is the system output control quantity at time t; K p is the proportionality coefficient; k i is the integral coefficient; k d is the differential coefficient; fl1(t) is the ideal respiratory airflow; fl2(t) is the actual respiratory airflow; The constant current stimulation module is used to generate a constant stimulation current according to the new stimulation parameters; The photoelectrode driving module is used to control the photoelectrode to generate a corresponding photoelectric stimulation signal according to the stimulation current; The model of the photoelectrode driving module is TLC5940LED driver, which has 16 constant current output channels and can output a maximum current of 120mA, and is connected to the micro light emitting diode of the photoelectrode that guides light and conducts electricity; The photoelectrode is composed of a hydrogel substrate, a plurality of light-conducting electrode sheets and a plurality of conductive electrode sheets; The hydrogel substrate includes a mounting surface and mounting ears; the mounting surface is a curved surface structure; the light-guiding electrode sheets and the conductive electrode sheets are arranged in a staggered array and embedded in the inner curved surface of the mounting surface; the mounting ears are radially mounted on the outer curved surface of the mounting surface and are symmetrically arranged; the mounting ears are provided with mounting holes for doctors to insert surgical wires into the through holes to fix the electrodes to the epidermis during surgery; The light-guiding electrode sheet is made of a micro-light-emitting diode with a size of 200μm×260μm; the conductive electrode sheet is made of platinum material with a size of 200μm×260μm; the light-guiding and conductive electrode sheets are staggered and embedded in a biocompatible hydrogel substrate; The hydrogel substrate has an outer diameter of 4 mm, an inner diameter of 3 mm, and a height of 10 mm.

2. An implantable diaphragm pacemaker according to claim 1, characterized in that: The cross section of the mounting surface is a 2 / 3 arc shape.

3. An implantable diaphragm pacemaker according to claim 1, characterized in that: The body surface electrode adopts a medical surface electrode, and the surface of the electrode is coated with silver.

4. An implantable diaphragm pacemaker according to claim 1, characterized in that: The signal processing module predicts the current actual respiratory airflow according to the real-time electrical signal of the diaphragm, including: Performing digital bandpass filtering on the diaphragm electrical signal collected in real time by the body surface electrode to obtain a processed diaphragm electrical signal; Calculate the sample entropy value of the processed diaphragm electrical signal; The current actual respiratory airflow is predicted based on the sample entropy value.

5. An implantable diaphragm pacemaker according to claim 4, characterized in that: Calculate the sample entropy value of the processed diaphragm electrical signal, including: Generate a data sequence {x(i)} based on the processed diaphragm electrical signal, where i=1, 2, ..., N, and N is the total length of the data; Based on the data sequence {x(i)}, construct m-dimensional vector matrices X(i) and X(j) respectively; X(i)=[x(i),x(i+1),…,x(i+m-1)]; X(j)=[x(j),x(j+1),…,x(j+m-1)]; Wherein, m represents the m consecutive values ​​in the diaphragm electrical signal data sequence; 1≤i≤N-m+1; 1≤j≤Nm; i≠j; Determine the maximum difference d between two vectors in X(i) ij ; Given a similarity tolerance r, count the d in X(i) ij ≤r, and for all Nm conditions d ij The vector sum of the number of ≤r is averaged; In the above formula, r is 0.1-0.25SD(X), SD represents the standard deviation of the signal; B i m (r) represents the d in X(i) ij ≤r and the number of d ij The ratio of the number of elements in the array, B m (r) represents d under all Nm conditions ij The average value of the sum of vectors of numbers ≤ r; The average value of the sum of all vectors of an m+1 dimensional vector matrix is ​​calculated using the following formula: The sample entropy value of the diaphragm electrical signal with a data length of N is calculated using the following formula:

6. An implantable diaphragm pacemaker according to claim 4, characterized in that: The single chip microcomputer generates new stimulation parameters according to the following steps: Constructing an ideal respiratory airflow model and a photoelectric stimulation waveform model, and generating an ideal respiratory airflow based on the ideal respiratory airflow model; Comparing the current actual respiratory airflow with the ideal respiratory airflow to generate a respiratory airflow difference and a difference change rate; Fuzzifying the respiratory airflow difference and the difference change rate, adaptively adjusting the initial stimulation parameters using fuzzy rules, and determining the adaptive adjustment rules of the stimulation parameters; Establishing a linear relationship between the adaptive adjustment rule of the stimulation parameters and the photoelectric stimulation waveform model; Based on the linear relationship, the original stimulation parameters of the photoelectric stimulation waveform model are adjusted, and new stimulation parameters are generated.

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