Closed-loop transotracheal phrenic nerve stimulation control system and method thereof

Abstract

The invention provides a closed-loop transtracheal phrenic nerve stimulation control system and a method thereof, the closed-loop transtracheal phrenic nerve stimulation control system is characterized by comprising a control unit, a stimulation generator, a tail end electrode and a detection unit, the control unit drives the stimulation generator to generate stimulation current, the stimulation current stimulates a diaphragm through the tail end electrode, and the detection unit detects the diaphragm. The detection unit detects electromyographic signals of the diaphragm through the tail end electrode, the control unit receives and processes the electromyographic signals in real time and dynamically adjusts stimulation current parameters according to a preset algorithm, and therefore closed-loop regulation and control are achieved; the control unit is in communication connection with the respirator to ensure synchronization of electrode stimulation and autonomous respiration. The invention has the advantages that: a closed-loop feedback control strategy is adopted, through the tail end electrode integrating stimulation and detection functions, accurate electrical stimulation of diaphragm and real-time monitoring of electromyographic signals (EMG) are realized, the system integration level is improved, and the implantation burden is reduced.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, specifically to a closed-loop transtracheophrenic nerve stimulation control system and method that automatically adjusts electrical stimulation parameters by real-time monitoring of diaphragmatic motion, for reducing ventilator-induced lung injury (VILI) and diaphragmatic dysfunction (VIDD). Background Technology

[0002] Mechanical ventilation uses a ventilator to replace, control, and modify spontaneous breathing to maintain airway patency, improve ventilation and oxygenation, prevent hypoxia and carbon dioxide buildup, help the body overcome respiratory failure caused by underlying diseases, create conditions for the treatment of underlying diseases, and is also an effective measure for rescuing patients with respiratory failure in various critical illnesses. However, mechanical ventilation can cause harm to patients, namely ventilator-induced lung injury (VILI). Numerous studies have confirmed that VILI not only further exacerbates respiratory function deterioration but may even increase the mortality rate of critically ill patients. There are many causes of VILI, one of which is that the diaphragm does not need to move during mechanical ventilation. Clinical studies have shown that the combination of mechanical ventilation and prolonged (more than 18 hours) immobility of the diaphragm can lead to atrophy of the diaphragm muscle fibers, also known as "ventilator-induced diaphragmatic dysfunction." This dysfunction increases the risk of lung injury, causing negative pressure pulmonary edema, air sloshing, and other problems.

[0003] While existing phrenic nerve stimulation techniques can activate the diaphragm, they lack real-time feedback on the diaphragm's contraction state and cannot dynamically adjust parameters based on the diaphragm's response, posing a risk of overstimulation or understimulation. Summary of the Invention

[0004] The purpose of this invention is to provide a closed-loop transtracheophrenic nerve stimulation control system and method that integrates stimulation and detection functions to achieve precise electrical stimulation of the diaphragm.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution: The closed-loop transtracheophrenic nerve stimulation control system includes a control unit, a stimulator, an end electrode, and a detection unit. The control unit drives the stimulator to generate a stimulating current, which stimulates the diaphragm via the end electrode. The detection unit detects the electromyographic signals of the diaphragm through the end electrode. The control unit receives and processes the electromyographic signals in real time and dynamically adjusts the stimulating current parameters according to a preset algorithm, thereby achieving closed-loop control. The control unit is connected to the ventilator to ensure that electrode stimulation is synchronized with spontaneous breathing.

[0006] Furthermore, the control unit performs time-domain and frequency-domain analysis on the received electromyographic signals, calculates key characteristic parameters such as amplitude, frequency, and slope, and then dynamically adjusts the intensity, pulse width, and frequency of subsequent stimulation currents.

[0007] Furthermore, the terminal electrode is an electrode array integrated into the endotracheal tube, which can detect diaphragmatic electromyographic signals and impedance signals in real time.

[0008] The control method of the closed-loop transtracheophrenic nerve stimulation control system includes the following steps: S1) System initialization, preset parameters, including initial stimulus value, upper limit stimulus value, control baseline, and target physiological response; S2) Start the ventilator and apply electrical stimulation at specific phases of the respiratory cycle according to preset parameters; S3) Switch to detection mode during the interval between stimulation pulses to collect spontaneous or induced electromyographic signals of the diaphragm; The S4 system filters and removes interference from the acquired electromyographic signals, and then adjusts the stimulation parameters according to the preset parameters of the control benchmark and the target physiological response. S5) Continue to apply electrical stimulation at specific phases of the respiratory cycle according to the control parameters, and repeat steps S3) to S5).

[0009] Furthermore, in step S4), if the electromyographic signal is detected to be lower than 80% of the control benchmark for three consecutive times, the system will automatically increase the stimulation current by 10%, and increase it step by step until the target physiological response is reached. If the stimulation current has been increased to the upper limit of stimulation but the electromyographic signal is still detected to be lower than 80% of the control baseline for three consecutive times, it is determined that the diaphragm is fatigued or the response is insufficient. The system will automatically stop the electrical stimulation, issue an alarm, and record the event log for clinical evaluation.

[0010] Furthermore, the initial stimulation value is 2mA, and the upper limit of stimulation value is 10mA.

[0011] Compared with the prior art, the present invention has the following advantages: The present invention relates to a closed-loop transtracheophrenic nerve stimulation control system and method, which adopts a closed-loop feedback control strategy and achieves precise electrical stimulation of the diaphragm and real-time monitoring of electromyographic (EMG) signals through an end electrode that integrates stimulation and detection functions, thereby improving system integration and reducing implantation burden. Attached Figure Description

[0012] Figure 1 This is the system architecture diagram of the present invention.

[0013] Figure 2 This is a schematic diagram of the adaptive control algorithm of the present invention.

[0014] Figure 3 This is a schematic diagram of the current stimulation circuit of the present invention.

[0015] Figure 4This is a schematic diagram of the electromyography signal detection circuit of the present invention. Detailed Implementation

[0016] The embodiments of the present invention will now be described in further detail with reference to the accompanying drawings.

[0017] like Figure 1 As shown, the closed-loop transtracheophrenic nerve stimulation control system includes a control unit, a stimulator, an end electrode, and a detection unit. The control unit drives the stimulator to generate a stimulating current, which stimulates the diaphragm via the end electrode. The detection unit detects the electromyographic (EMG) signal of the diaphragm through the end electrode. The control unit receives and processes the EMG signal in real time and dynamically adjusts the stimulating current parameters according to a preset algorithm (adaptive algorithm), thereby achieving closed-loop control. The control unit is communicatively connected to the ventilator to ensure that electrode stimulation is synchronized with spontaneous breathing.

[0018] The main control chip of the control unit can be a high-performance MCU or DSP, undertaking the following core functions: real-time acquisition and processing of EMG signals from ADS1299; time-domain and frequency-domain analysis of EMG signals to calculate key characteristic parameters such as amplitude, frequency, and slope; dynamic adjustment of the intensity, pulse width, and frequency of subsequent stimulation current based on a preset adaptive algorithm to achieve individualized, closed-loop control; and communication between the control unit and the external ventilator to synchronize the electrical stimulation timing with the patient's spontaneous breathing rhythm, ensuring that the stimulation timing accurately matches the respiratory cycle, thereby improving ventilation efficiency and patient comfort.

[0019] Specifically, the control unit drives the stimulation generator to output a constant current pulse, with a current range of 0.1mA to 10mA, to ensure the safety and physiological effectiveness of the stimulation; the stimulation current is transmitted to the phrenic nerve or diaphragm via platinum-iridium alloy electrodes, inducing controllable muscle contraction. Figure 3 The diagram shows a constant current stimulation circuit, an example of a single-channel stimulation circuit. DAC_IN is the digital-to-analog conversion signal output from the control unit, used to set the target current value. VOUT is the stimulation output terminal, connected to the implanted end electrode, and its output current is precisely adjusted through a feedback control mechanism. The end electrode is an electrode array integrated into the endotracheal tube, capable of real-time detection of diaphragmatic electromyographic and impedance signals.

[0020] Specifically, such as Figure 4As shown, the system employs a stimulus-detection multiplexed electrode design. During non-stimulation periods, the same set of electrodes is used to acquire electromyographic (EMG) signals generated by the diaphragm. The EMG signals are input to the high-precision analog front-end chip ADS1299, using an external reference electrode (REF) as a reference point, to acquire the biopotential difference between the in vivo electrode and the reference electrode, thereby extracting high-quality diaphragmatic EMG signals. Electrodes 1 to 8 of the terminal electrodes are physically connected at the catheter tip, jointly participating in signal detection and improving the stability and signal-to-noise ratio of signal acquisition.

[0021] like Figure 2 As shown, the control method of the closed-loop transtracheophrenic nerve stimulation control system includes the following steps: S1) System initialization: Execute self-test program to detect electrode impedance and signal baseline noise to ensure normal system operation; preset parameters, including initial stimulation value, upper limit stimulation value, control benchmark, and target physiological response; specifically, initialize stimulation parameter to 2mA, set upper limit stimulation value to 10mA, and set target EMG_RMS value as feedback control benchmark. S2) Start the ventilator and apply electrical stimulation at specific phases of the respiratory cycle according to preset parameters; S3) Switch to detection mode during the interval between stimulation pulses to collect spontaneous or induced electromyographic signals of the diaphragm and avoid interference from stimulation artifacts; The S4 system filters and removes interference from the acquired electromyographic signals. Specifically, it eliminates power frequency interference (such as 50 / 60Hz) and other environmental noise, extracts the real physiological signals, calculates their EMG_RMS values, and then adjusts the stimulation parameters according to the preset parameters of the control benchmark and the target physiological response. If the EMG_RMS value is detected to be below 80% of the target value for three consecutive times, the system will automatically increase the stimulation current by 10%, and increase it step by step until the target physiological response is reached. If the stimulation current has been increased to the upper limit of stimulation (10mA) but the EMG_RMS value is still detected to be lower than 80% of the control baseline for three consecutive times, it is determined that the diaphragm is fatigued or the response is insufficient. The system will automatically stop the electrical stimulation, issue an alarm, and record the event log for clinical evaluation. S5) Continue to apply electrical stimulation at specific phases of the respiratory cycle according to the control parameters, and repeat steps S3) to S5).

[0022] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and modifications without departing from the concept of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A closed-loop transtracheophrenic nerve stimulation control system, characterized in that: It includes a control unit, a stimulator, an end electrode, and a detection unit. The control unit drives the stimulator to generate a stimulating current, which stimulates the diaphragm through the end electrode. The detection unit detects the electromyographic signals of the diaphragm through the end electrode. The control unit receives and processes the electromyographic signals in real time and dynamically adjusts the stimulating current parameters according to a preset algorithm, thereby achieving closed-loop control. The control unit is connected to the ventilator to ensure that electrode stimulation is synchronized with spontaneous breathing.

2. The closed-loop transtracheophrenic nerve stimulation control system according to claim 1, characterized in that: The control unit performs time-domain and frequency-domain analysis on the received electromyographic signals, calculates key characteristic parameters such as amplitude, frequency, and slope, and then dynamically adjusts the intensity, pulse width, and frequency of subsequent stimulation currents.

3. The closed-loop transtracheophrenic nerve stimulation control system according to claim 1, characterized in that: The terminal electrode is an electrode array integrated into the endotracheal tube, which can detect diaphragmatic electromyographic signals and impedance signals in real time.

4. The control method of the closed-loop transtracheophrenic nerve stimulation control system as described in claim 1, characterized in that... Includes the following steps: S1) System initialization, preset parameters, including initial stimulus value, upper limit stimulus value, control baseline, and target physiological response; S2) Start the ventilator and apply electrical stimulation at specific phases of the respiratory cycle according to preset parameters; S3) Switch to detection mode during the interval between stimulation pulses to collect spontaneous or induced electromyographic signals of the diaphragm; The S4 system filters and removes interference from the acquired electromyographic signals, and then adjusts the stimulation parameters according to the preset parameters of the control benchmark and the target physiological response. S5) Continue to apply electrical stimulation at specific phases of the respiratory cycle according to the control parameters, and repeat steps S3) to S5).

5. The closed-loop transtracheophrenic nerve stimulation control method according to claim 4, characterized in that: In step S4), if the electromyographic signal is detected to be lower than 80% of the control baseline for three consecutive times, the system will automatically increase the stimulation current by 10%, and increase it step by step until the target physiological response is reached. If the stimulation current has been increased to the upper limit of stimulation but the electromyographic signal is still detected to be lower than 80% of the control baseline for three consecutive times, it is determined that the diaphragm is fatigued or the response is insufficient. The system will automatically stop the electrical stimulation, issue an alarm, and record the event log for clinical evaluation.

6. The closed-loop transtracheophrenic nerve stimulation control method according to claim 5, characterized in that: The initial stimulation value is 2mA, and the upper limit of stimulation value is 10mA.

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