Medical anti-extubation alarm method based on human body contact induction

Abstract

The invention discloses a medical anti-extubation alarm method based on human body contact induction, and the method comprises the following steps: building a reference capacitor: pasting a medical pasting type electrode plate on the skin of a human body, and enabling the medical pasting type electrode plate and the human body to form the reference capacitor together; continuously detecting capacitance change: continuously detecting capacitance value change of the reference capacitor in real time through a core sensing module, and transmitting a detected signal to a main control unit in real time; state judgment preorder: when the medical adhesive electrode plate is attached to the skin of the human body, the reference capacitor is kept stable, and the main control unit is kept in a silent monitoring state; when the reference capacitance changes, a tube drawing event judgment link is entered, human body capacitance induction serves as a core, the physical connection state of the medical adhesive electrode slice and the skin is directly detected instead of depending on indirect pressure or tension signals, and false alarms caused by daily actions such as turning over, cough and limb movement of a patient are avoided in principle.

Description

Technical Field

[0001] This invention belongs to the field of medical safety monitoring technology, and in particular relates to a medical anti-extubation alarm method based on human body contact sensing. Background Technology

[0002] Current medical catheter anti-extraction technologies primarily monitor catheter status through physical sensing methods. Common solutions include pressure sensor-based, tension sensor-based, and infrared sensor-based methods. Pressure sensor-based methods typically embed a thin-film pressure sensor into the catheter fixing patch, triggering an alarm by detecting pressure changes when the catheter is pulled. This is widely used in monitoring nasogastric tubes and urinary catheters in general wards. Tension sensor-based methods connect the catheter to the patient's clothing with an elastic cord; an alarm is activated when the tension exceeds a threshold. This is often used for endotracheal intubation monitoring in ICUs. Infrared sensor-based methods utilize an infrared transmitter and receiver to form a light path; an alarm is triggered when the catheter displacement blocks the light path, making them suitable for high-precision scenarios such as central venous catheters. These technologies, through mechanical or optical sensing principles, achieve a certain level of monitoring for abnormal catheter movement, providing auxiliary support for clinical nursing.

[0003] However, existing technologies have several limitations in clinical applications, which contrast sharply with the beneficial effects of this method: First, the reliability of detection is insufficient. Pressure and tension sensors rely on indirect mechanical signals, and actions such as patient turning over or coughing can easily trigger false alarms. Infrared sensing is easily affected by ambient light, leading to missed alarms. Second, adaptability is limited. It cannot be easily adjusted to suit different skin conditions such as excessive sweating or dryness, and different types of catheters require different dedicated sensors, resulting in poor versatility. Third, the operation and economy are poor. The sensors are expensive, and the replacement process is complex, increasing the clinical burden. Fourth, the patient experience is poor. Rigid sensors cause a strong foreign body sensation when in contact with the skin, and prolonged wear can easily lead to discomfort. These problems make it difficult for existing technologies to meet the needs of efficient and safe monitoring in diverse clinical scenarios. Summary of the Invention

[0004] In order to overcome the above-mentioned defects of the prior art, the present invention provides a medical anti-extubation alarm method based on human body contact sensing, which solves the problems of poor reliability, low adaptability, poor economy and poor patient experience of the existing medical anti-extubation technology.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A medical anti-extubation alarm method based on human body contact sensing includes the following steps:

[0007] (1) Establishing a reference capacitance: The medical adhesive electrode pad is attached to the human skin so that the medical adhesive electrode pad and the human body together form a reference capacitance;

[0008] (2) Continuous detection of capacitance change: The core sensing module continuously detects the capacitance change of the reference capacitor in real time and transmits the detected signal to the main control unit in real time;

[0009] (3) Status judgment pre-process: When the medical adhesive electrode pad is in contact with the human skin, the reference capacitance remains stable and the main control unit maintains a silent monitoring state; when the reference capacitance changes, the extubation event judgment stage is entered.

[0010] (4) Determine the extubation event: The main control unit receives the signal output by the core sensing module. When it detects that the capacitance value of the reference capacitor decreases sharply due to the detachment of the medical adhesive electrode, it determines that the extubation event has occurred.

[0011] (5) Trigger alarm: The main control unit controls the alarm module to issue an audible and visual alarm.

[0012] Preferably, in step (1), the medical adhesive electrode is a disposable medical electrode sheet, specifically a disposable electrocardiogram monitor electrode sheet; the medical adhesive electrode sheet is connected to the core sensing module through a lead wire with a buckle, one end of the lead wire with a buckle is connected to the lead wire interface of the core sensing module, and the other end is detachably connected to the medical adhesive electrode sheet through a buckle.

[0013] Preferably, in step (2), the core sensing module is a dedicated capacitive touch sensing chip with human body capacitance detection function; when the core sensing module detects a change in the capacitance value of the reference capacitor, it converts the change in capacitance value into an electrical signal and transmits it to the main control unit.

[0014] Preferably, in step (5), the sound and light alarm is implemented through the sound alarm unit and the light alarm unit of the alarm module; the sound alarm unit emits a sound alarm through a 5V active buzzer with a driving circuit, and the light alarm unit emits a light alarm through a high-brightness red LED equipped with a current-limiting resistor.

[0015] Preferably, in step (4), the main control unit is an ultra-low power microcontroller, which is selected from STC8G1K08, ESP8266 or HeZu Air001; after receiving the signal, the main control unit analyzes the signal through a preset program to determine whether it is a tube removal event.

[0016] Preferably, the system also includes a wireless transmission step: when the alarm module triggers an audible and visual alarm, the main control unit controls the wireless transmission module to send the alarm signal to a remote terminal used by medical staff, such as a nurse station host, a nurse smart bracelet, or a PDA; the wireless transmission module is a Bluetooth BLE module or a Wi-Fi module, the Bluetooth BLE module model is HC-08, and the Wi-Fi module is an ESP8266 built-in Wi-Fi module.

[0017] Preferably, in step (4), the judgment logic of the main control unit is equipped with a delay triggering mechanism: the main control unit only determines the extubation event and controls the alarm module to work when the signal change state output by the core sensing module continues to exceed a preset time threshold and the preset time threshold is 500ms to 1000ms. This delay triggering mechanism works in conjunction with the continuous detection of capacitance change in step (2) to avoid false alarms caused by the temporary loosening of the electrode pads due to the patient turning over or moving, and improves the accuracy of the extubation judgment.

[0018] Preferably, a self-test step is also included: when the device is powered on or when the self-test function is manually triggered, the self-test circuit simulates the state of the medical adhesive electrode pad falling off to verify whether the core sensing module, main control unit and alarm module are functioning normally; if the function is abnormal, the alarm module issues a fault prompt; this self-test step is performed before the reference capacitance is established in step (1), which can eliminate equipment faults in advance and avoid the subsequent detection of capacitance changes and judgment of tube removal events being missed due to equipment problems, thus ensuring the overall reliability of the method.

[0019] Preferably, in step (2), the detection sensitivity of the core sensing module can be adjusted by the sensitivity adjustment mechanism on the outer shell of the device. The adjustment mechanism is a sensitivity adjustment potentiometer. By rotating the potentiometer, the detection threshold of the core sensing module for changes in the reference capacitance can be changed to adapt to different human skin conditions and different types of medical catheters. When adapting to different types of medical catheters, for monitoring nasogastric tubes and urinary catheters, the medical adhesive electrode is attached to the skin near the catheter fixation point, i.e., beside the nose and lower abdomen. For monitoring central venous catheters, the medical adhesive electrode is attached to the skin within 5 cm around the catheter puncture point.

[0020] Preferably, the power supply of the method is realized through a power module, which includes a rechargeable lithium battery, a charging module and a low-voltage LDO; the charging module charges the rechargeable lithium battery and provides over-discharge protection, and the low-voltage LDO regulates the output voltage of the rechargeable lithium battery to the working voltage adapted to the core sensing module and the main control unit, and then supplies power to the core sensing module and the main control unit.

[0021] The technical effects and advantages of the medical anti-extraction alarm method based on human body contact sensing of the present invention are as follows:

[0022] 1. This invention uses human body capacitance sensing as its core to directly detect the physical connection between the medical adhesive electrode pad and the skin, rather than relying on indirect pressure or tension signals. In principle, this avoids false alarms caused by patients turning over, coughing, limb movements, and other daily actions. At the same time, the electrode pad is only physically attached to the human body without any direct electrical connection, which fully complies with medical electrical safety standards and can effectively avoid the risk of infection that may be caused by direct contact between the sensor and the catheter, thus ensuring patient safety.

[0023] 2. This invention uses a delayed triggering mechanism to determine a tube removal event only when the capacitance change signal continuously exceeds a preset threshold, further filtering out invalid signals caused by temporary loosening of the electrode and improving the accuracy of tube removal judgment; the self-test step can simulate the electrode detachment state when the equipment is powered on or manually triggered, verifying the functions of the core sensing module, main control unit and alarm module in advance, eliminating equipment faults in time, avoiding missed alarms due to hardware failure, and ensuring the stability and reliability of the monitoring process.

[0024] 3. This invention utilizes sensitivity adjustment to adapt to different human skin conditions such as excessive sweating and dryness by adjusting the detection threshold, eliminating the need to change the entire monitoring scheme due to skin conditions. At the same time, by optimizing the electrode pad placement and sensitivity matching, it can adapt to the monitoring needs of various medical catheters such as nasogastric tubes, urinary catheters, central venous catheters, and peritoneal dialysis catheters, eliminating the need to design separate dedicated equipment for different catheters, and greatly improving the flexibility and universality of clinical applications.

[0025] 4. The wireless transmission step of this invention can push alarm signals to remote terminals such as nurse station host, smart bracelet or PDA in real time, reducing the workload of nurses' high-frequency on-site inspections, while avoiding the problem of not noticing the sound and light alarm due to ward noise, significantly improving the response speed of medical staff to extubation events, especially suitable for centralized monitoring scenarios such as ICU and pediatrics; in addition, the electrode replacement process is simple, and the sensitivity adjustment, self-test and other operations do not require professional technical training, reducing the operation threshold for medical staff.

[0026] 5. The core sensing module used in this invention is a low-cost dedicated capacitive touch sensing chip, which is paired with conventional disposable medical electrode pads. The overall consumable and hardware costs are far lower than existing anti-extraction solutions that rely on expensive thin-film pressure sensors, which can significantly reduce the burden of clinical consumable expenditures. At the same time, through the selection of a low-power main control unit and the design of a voltage-stabilized power supply, the power consumption of the device is effectively reduced, the continuous monitoring time after a single charge is extended, the monitoring needs of patients with long-term tube insertion are met, and the situation of monitoring interruption due to frequent charging is reduced.

[0027] 6. The medical adhesive electrode pads used in this invention are thin and soft, fitting the skin without any protruding foreign body sensation, which can effectively reduce the patient's discomfort. The electrode pads are placed in areas that avoid catheter operation and key areas of patient activity, so as not to affect the patient's basic daily needs such as eating, turning over, and washing. Moreover, there is no risk of skin irritation when changing them, which improves the patient's acceptance of long-term monitoring. Attached Figure Description

[0028] Figure 1 This is a flowchart of a medical anti-extraction alarm method based on human body contact sensing proposed in this invention. Detailed Implementation

[0029] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0030] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include," "contain," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "includes..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0031] Example 1

[0032] refer to Figure 1 This embodiment provides a medical anti-extubation alarm method based on human body contact sensing, used in basic anti-extubation alarm methods, and the specific implementation includes:

[0033] Purpose of implementation:

[0034] To address the basic need for preventing the removal of nasogastric tubes and urinary catheters in general wards (such as internal medicine and gastroenterology departments), this method provides a simple and rapid real-time monitoring approach to solve the problems of time-consuming and high false negative rates associated with traditional manual rounds.

[0035] Implementation steps:

[0036] Establish reference capacitance: Select disposable ECG monitor electrode pads (30mm in diameter, containing medical conductive gel) and flatly attach them to the skin near the patient's catheter fixation site—2cm from the nasal ala for nasogastric tube patients, and within 3cm of the catheter fixation patch for urinary catheter patients on the lower abdomen; connect the electrode pads to the core sensing module via a lead wire with a buckle. Insert one end of the lead wire into the 2.54mm terminal interface of the core sensing module, and fasten the other end to the electrode pad with a plastic clip (2mm fastening depth to ensure stable contact).

[0037] Continuous detection of capacitance changes: The core sensing module uses a dedicated capacitive touch sensing chip with human body capacitance detection function. It monitors the reference capacitance formed between the electrode plate and the human body in real time through an internal oscillation circuit (the capacitance value is about 10nF in a stable state). Every 10ms, the capacitance value is converted into an electrical signal (high level is output when the capacitance is stable, and low level is output when it changes), and transmitted to the main control unit (using an ultra-low power microcontroller STC8G1K08) through a wire.

[0038] Status judgment pre-process: The main control unit receives signals through the P1.0 pin. When the electrode pad is in good contact with the skin, the reference capacitance remains stable, and the main control unit controls the P1.1 and P1.2 pins to output a low level (the buzzer does not work and the LED does not light up), entering the silent monitoring state; when the patient's movement causes the electrode pad to loosen slightly (the capacitance value drops below 8nF), the signal fluctuates, and the main control unit automatically switches to the extubation event judgment stage.

[0039] Determining a tube removal event: The main control unit analyzes the received signal through a preset program. When it detects that the capacitance value has decreased sharply to below 10pF due to the complete detachment of the electrode plate (corresponding to a low level output by the chip), it immediately determines that a tube removal event has occurred.

[0040] Triggering the alarm: The main control unit controls the P1.1 pin to output a high level, driving the 5V active buzzer with a drive circuit to emit a continuous sound alarm (sound pressure level 85dB); at the same time, it controls the P1.2 pin to output a 1Hz square wave, driving a high-brightness red LED (luminous intensity 5000mcd) with a 1kΩ current-limiting resistor to flash, forming a synchronized sound and light alarm.

[0041] Implementation results:

[0042] The device was continuously used in 30 patients with nasogastric tubes (hospitalization period of 5-7 days), simulating 50 tube removal events (manual removal of electrode pads). The alarm response time was ≤100ms and the accuracy was 100%. The device did not trigger false alarms during the patients' daily activities such as turning over, eating, and coughing. The device's daily standby power consumption was ≤5mA, and it could be used continuously for 72 hours on a single charge, meeting the basic monitoring needs of ordinary wards.

[0043] Example 2

[0044] This embodiment provides a medical anti-extubation alarm method based on human body contact sensing, which is used for anti-extubation alarm methods with wireless transmission. The specific implementation includes:

[0045] Purpose of implementation:

[0046] For scenarios requiring centralized monitoring, such as ICUs and pediatric wards, this solution addresses the issues of nurses facing significant pressure during real-time rounds and the potential for audible and visual alarms to be overlooked due to ward noise, enabling remote push of alarm signals to medical staff.

[0047] Implementation steps:

[0048] Basic steps are implemented as follows: Same as steps 1-5 of Example 1, namely, establishing a reference capacitor, continuously detecting capacitor changes, determining the state sequence, determining the tube removal event, and triggering an audible and visual alarm.

[0049] Wireless transmission configuration: The main control unit is replaced with an ESP8266 with integrated Wi-Fi function. When the device is used for the first time, it is connected to the hospital LAN (SSID: Hospital-ICU, password: XXXX) through the nurse station computer and paired with the nurse smart bracelet (supports BLE4.0 protocol) (pairing password: 1234, communication distance ≤10m).

[0050] Wireless transmission execution: When the audible and visual alarm is triggered in step 5, the ESP8266 controls the Bluetooth BLE module (model HC-08) through the UART interface to send alarm data to the paired nurse smart bracelet in the preset format ("Patient ID-Catheter Type-Alarm Time"); after receiving the data, the bracelet immediately starts vibrating (amplitude 0.5mm) and displays the alarm information on the screen until the nurse presses the "Confirm" button on the bracelet.

[0051] Implementation results:

[0052] In a test conducted on 10 ICU beds (patients with endotracheal intubation and central venous catheters), alarm signals from 50 simulated extubation events were received in real time by the nurses' wristbands, with a transmission delay of ≤300ms and no packet loss. In noisy environments at night, the response time of medical staff to alarms was reduced from an average of 45 seconds to 15 seconds, and the patrol efficiency was improved by 67%. No adverse events were caused by failure to respond in a timely manner.

[0053] Example 3

[0054] This embodiment provides a medical anti-extubation alarm method based on human body contact sensing, which is used for an anti-extubation alarm method with time delay triggering and self-testing. The specific implementation content includes:

[0055] Purpose of implementation:

[0056] For patients in the postoperative anesthesia recovery period and those with agitation such as Alzheimer's disease, the system aims to reduce false alarms caused by temporary loosening of electrode pads due to patient turning over or limb movement; at the same time, it ensures that the equipment is functioning properly through self-testing, avoiding missed alarms due to equipment malfunction.

[0057] Implementation steps:

[0058] Basic steps: Same as steps 1-2 of Example 1 (establishing a reference capacitance and continuously detecting capacitance changes).

[0059] Delay trigger setting (optimized judgment steps): The time threshold of 800ms is preset in the program of the main control unit (STC8G1K08). When a sharp decrease in capacitance value is detected (corresponding to a low-level signal), the internal timer is started. If the low-level signal lasts for ≥800ms (confirming that the electrode is completely detached), the main control unit determines it as a tube removal event and executes an alarm. If the signal returns to a high level within 800ms (the electrode is briefly loosened and then reset), the timer is cleared and no alarm is triggered.

[0060] Self-test procedure: During daily patient handover, the nurse presses the self-test button on the side of the device. The self-test circuit sends a low-level signal simulating "electrode detachment" to the main control unit. The main control unit triggers an audible and visual alarm (LED flashing rapidly + buzzer sounding intermittently) according to the judgment steps, and the alarm automatically stops after 3 seconds. If the device is malfunctioning (such as the buzzer not sounding or the LED not lighting up), the LED will flash at a frequency of 3 times / second, indicating that the device needs to be replaced.

[0061] Subsequent steps: Same as step 5 (triggering an alarm) in Example 1.

[0062] Implementation results:

[0063] In a study of 20 agitated patients (average ≥5 limb movements per hour), the false alarm rate decreased from 12 times / day without a delay mechanism to 0.5 times / day. In 100 self-test operations, the accuracy rate of equipment fault identification was 100%, and there were no missed alarms due to equipment faults, which significantly improved the reliability of monitoring.

[0064] Example 4

[0065] This embodiment provides a medical catheter-prevention alarm method based on human body contact sensing, which is used for catheter-prevention alarm methods with sensitivity adjustment and multi-catheter adaptation. The specific implementation includes:

[0066] Purpose of implementation:

[0067] To address the issue of poor adaptability to monitoring different skin conditions (such as excessive sweating and dryness) and different types of catheters (such as central venous catheters and peritoneal dialysis catheters), and to ensure the accuracy of testing in special patients and complex scenarios.

[0068] Implementation steps:

[0069] Basic steps: Same as steps 1-2 of Example 1 (establishing a reference capacitance and continuously detecting capacitance changes).

[0070] Sensitivity adjustment operation: A 10kΩ sensitivity adjustment potentiometer is located on the side of the device casing. The detection threshold of the core sensing module can be changed by rotating the potentiometer.

[0071] For patients with excessive sweating (skin moisture ≥60%, impedance ≤1kΩ): Rotate the potentiometer clockwise to the "low sensitivity" setting and adjust the detection threshold to 15nF to avoid false alarms caused by capacitance fluctuations due to sweat;

[0072] For patients with dry skin (skin moisture ≤30%, impedance ≥10kΩ): Rotate the potentiometer counterclockwise to the "high sensitivity" setting, adjust the detection threshold to 5nF, and ensure that even slight detachment can trigger the detection.

[0073] Multi-catheter adapter operation: Adjust the electrode pad placement according to the catheter type and simultaneously match the sensitivity.

[0074] Nasogastric tube / urinary catheter: The electrode pads are attached within 3cm of the catheter fixation point (beside the nasal ala / lower abdomen), and the threshold is maintained at 5-10nF;

[0075] Central venous catheter: The electrode pads are attached within 5cm of the puncture site (avoiding the edge of the dressing), and the threshold is adjusted to 5-8nF (higher sensitivity, suitable for the low skin mobility near the puncture site).

[0076] Subsequent steps: Same as steps 3-5 of Example 1 (state judgment pre-sequence, judgment of tube removal event, triggering alarm).

[0077] Implementation results:

[0078] In 15 patients with hyperhidrosis, the false alarm rate decreased from 8% to 0% of the fixed threshold; in 10 patients with dry skin, the alarm response time remained ≤150ms; and in 20 simulated extubation tests for special catheters such as central venous catheters and peritoneal dialysis catheters, the detection accuracy was 100%, and the results were not affected by differences in skin condition or catheter type.

[0079] Example 5

[0080] This embodiment provides a medical anti-extraction alarm method based on human body contact sensing, which is an optimized power supply anti-extraction alarm method. Specific implementation details include:

[0081] Purpose of implementation:

[0082] For patients with long-term catheters (such as patients with chronic kidney disease and hemodialysis catheters, with a catheterization period of ≥30 days), this device addresses the issues of short battery life and frequent charging affecting monitoring continuity, extending the usage time per charge.

[0083] Implementation steps:

[0084] Basic steps: Same as steps 1-5 of Example 1 (establishing a reference capacitor to trigger an alarm).

[0085] Power supply configuration: It uses a 3.7V rechargeable lithium battery (capacity 1000mAh) as the power source, paired with a TP4056 charging module (Micro-USB interface); when charging, connect one end of the data cable to the charging module and the other end to a 5V power source (such as the USB interface of the nurse station). The charging current is 500mA. The module will automatically power off when fully charged (it takes about 2 hours to fully charge).

[0086] Regulated power supply: The lithium battery output voltage is regulated to 3.3V through a low-voltage LDO (AMS1117-3.3) to power the core sensing module and main control unit; when the lithium battery voltage is ≤3.0V, the main control unit controls the LED to flash slowly at a frequency of 0.5Hz to remind the nurse to charge in time.

[0087] Implementation results:

[0088] The device has a continuous standby power consumption of ≤5mA and an alarm state power consumption of ≤25mA. It can be used continuously for ≥168 hours (7 days) on a single charge. In 50 patients with long-term tubes, the device downtime rate due to insufficient power was 0. The satisfaction rate of patients and nurses with the "low power reminder" function reached 98%, which meets the battery life requirements for long-term monitoring.

[0089] Comparative Example 1

[0090] This comparative example provides existing pressure sensor-based anti-tear tube methods, including:

[0091] Method Overview:

[0092] In the prior art, the anti-pulling method based on pressure sensors is achieved through the following steps: embedding a thin-film pressure sensor into the catheter fixing patch so that the sensor is in direct contact with the catheter; when the catheter is pulled, the sensor detects the pressure signal converted from the tension (preset threshold 5N); when the pressure signal exceeds the threshold, it is transmitted to the host through a wire to trigger an alarm.

[0093] Comparison of effects with the present invention:

[0094] False alarm rate: Compared with the indirect pressure signal of the catheter being pulled, the patient's turning over, coughing and other actions can easily cause the pressure to exceed the threshold, resulting in a false alarm rate of 15%; the present invention directly detects the capacitive connection status between the electrode and the human body, and only alarms when the electrode falls off, with a false alarm rate of 0.

[0095] Patient comfort: The pressure sensor of the comparative model is ≥2mm thick and easily rubs against the skin after being embedded in the fixation patch, resulting in a patient discomfort score (1-10 points) of 7; the electrode sheet used in this invention is ≤0.5mm thick, thin and soft, and fits the skin, resulting in a discomfort score of only 2 points.

[0096] Applicable skin conditions: The pressure sensor of the standard model relies on pressure transmission. When sweating is excessive, the sensor does not make good contact with the skin, and the failure probability reaches 12%. The present invention can be adapted to different skin conditions such as excessive sweating and dryness by adjusting the sensitivity, and the failure probability is 0.

[0097] Cost per use: The unit price of the comparative thin-film pressure sensor is ≥35 yuan, and the total cost per use is 40 yuan; the unit price of the disposable electrode sheet of this invention is 1.5 yuan, the core chip cost is 2 yuan, and the total cost per use is only 8 yuan, which reduces the cost by 80%.

[0098] Compared with Examples 1-5 and Comparative Example 1, Examples 1-5 of the present invention (a medical anti-extubation alarm method based on human body contact sensing) and Comparative Example 1 (an existing pressure sensor-based anti-extubation method) differ significantly in terms of applicable scenarios, core performance, patient experience, usage cost, and battery life reliability. The former, through "capacitive sensing + dynamic step design," comprehensively solves the pain points of the latter in clinical applications. The specific comparison is as follows:

[0099] In terms of applicable scenarios, Comparative Example 1 can only be adapted to basic scenarios with simple catheter fixation environments and low patient activity. Due to its reliance on pressure signal detection, it is completely ineffective when facing complex needs such as remote monitoring in the ICU, agitated patients, multiple types of catheters (such as central venous catheters), and long-term catheterization. In contrast, Examples 1-5 provide full scenario coverage. Example 1 meets the basic monitoring needs of nasogastric tubes and urinary catheters in general wards. Example 2 is adapted to centralized monitoring in the ICU through wireless transmission. Example 3 is adapted to agitated patients after surgery by using delayed triggering and self-testing. Example 4 is adapted to hyperhidrotic / dry skin and multiple catheter types by relying on sensitivity adjustment. Example 5 optimizes battery life to adapt to patients with long-term catheterization. Its adaptability is far superior to Comparative Example 1.

[0100] In terms of core performance, Comparative Example 1, due to the detection of indirect pressure signals, is prone to false alarms when the patient turns over or coughs, with a false alarm rate of up to 15%. It also lacks a self-test function, and equipment failure can easily lead to missed alarms. Examples 1-4, on the other hand, directly detect the capacitor connection status, and the false alarm rate is controlled within 0.5 times / day (Examples 1, 2, and 4 even have zero false alarms). The alarm response time is ≤150ms. Example 3 also adds a self-test step, with a fault identification accuracy of 100% and no risk of missed alarms, resulting in significantly better reliability.

[0101] In terms of patient experience, the thin-film pressure sensor in Comparative Example 1 was ≥2mm thick and easily rubbed against the skin after being embedded in the fixation patch, resulting in a patient discomfort score of 7. Examples 1-5 all used medical adhesive electrode pads with a thickness of ≤0.5mm, which were thin, soft, and fit the skin well, resulting in a discomfort score of only 2. Moreover, the electrode pads were easy to replace, leading to higher patient acceptance.

[0102] In terms of usage cost, the unit price of the thin-film pressure sensor in Comparative Example 1 is ≥35 yuan, and the total cost per use is 40 yuan; the unit price of the disposable electrode pads in Examples 1-5 is 1.5 yuan, the core chip cost is only 2 yuan, and the total cost per use is 8 yuan, which is 80% lower than that in Comparative Example 1, greatly reducing the burden of clinical consumables.

[0103] In terms of battery life reliability, Comparative Example 1 has an unoptimized power supply design, resulting in high standby power consumption and less than 48 hours of battery life on a single charge. Example 1 has a battery life of 72 hours on a single charge, and Example 5 extends the battery life to 168 hours (7 days) through a 1000mAh lithium battery and voltage regulation design. It also adds a low battery warning and eliminates the risk of shutdown in long-term pipeline scenarios, with continuity far exceeding that of Comparative Example 1.

[0104] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of protection of the claims.

[0105] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A medical anti-extraction alarm method based on human body contact sensing, characterized in that, Includes the following steps: (1) Establishing a reference capacitance: The medical adhesive electrode pad is attached to the human skin so that the medical adhesive electrode pad and the human body together form a reference capacitance; (2) Continuous detection of capacitance change: The core sensing module continuously detects the capacitance change of the reference capacitor in real time and transmits the detected signal to the main control unit in real time; (3) Status judgment pre-process: When the medical adhesive electrode pad is in contact with the human skin, the reference capacitance remains stable and the main control unit maintains a silent monitoring state; when the reference capacitance changes, the extubation event judgment stage is entered. (4) Determine the extubation event: The main control unit receives the signal output by the core sensing module. When it detects that the capacitance value of the reference capacitor decreases sharply due to the detachment of the medical adhesive electrode, it determines that the extubation event has occurred. (5) Trigger alarm: The main control unit controls the alarm module to issue an audible and visual alarm.

2. The medical anti-extraction alarm method based on human body contact sensing as described in claim 1, characterized in that, In step (1), the medical adhesive electrode is a disposable medical electrode sheet, specifically a disposable electrocardiogram monitor electrode sheet; the medical adhesive electrode sheet is connected to the core sensing module through a lead wire with a buckle, one end of the lead wire with a buckle is connected to the lead wire interface of the core sensing module, and the other end is detachably connected to the medical adhesive electrode sheet through a buckle.

3. The medical anti-extraction alarm method based on human body contact sensing as described in claim 1, characterized in that, In step (2), the core sensing module is a dedicated capacitive touch sensing chip with human body capacitance detection function; when the core sensing module detects the change in the capacitance value of the reference capacitor, it converts the change in capacitance value into an electrical signal and transmits it to the main control unit.

4. A medical anti-extraction alarm method based on human body contact sensing as described in claim 1, characterized in that, In step (5), the sound and light alarm is implemented through the sound alarm unit and the light alarm unit of the alarm module; the sound alarm unit emits a sound alarm through a 5V active buzzer with a driving circuit, and the light alarm unit emits a light alarm through a high-brightness red LED equipped with a current-limiting resistor.

5. A medical anti-extraction alarm method based on human body contact sensing as described in claim 1, characterized in that, In step (4), the main control unit is an ultra-low power microcontroller, which is selected from STC8G1K08, ESP8266 or HeZu Air001; after receiving the signal, the main control unit analyzes the signal through a preset program to determine whether it is a tube removal event.

6. A medical anti-extraction alarm method based on human body contact sensing as described in claim 1, characterized in that, It also includes a wireless transmission step: when the alarm module triggers the audible and visual alarm, the main control unit controls the wireless transmission module to send the alarm signal to the remote terminal used by medical staff, such as the nurse station host, nurse smart bracelet or PDA; the wireless transmission module is a Bluetooth BLE module or a Wi-Fi module, the Bluetooth BLE module model is HC-08, and the Wi-Fi module is the ESP8266 built-in Wi-Fi module.

7. A medical anti-extraction alarm method based on human body contact sensing as described in claim 1, characterized in that, In step (4), the judgment logic of the main control unit is equipped with a delay triggering mechanism: the main control unit will only determine the extubation event and control the alarm module to work when the signal change state output by the core sensing module continues to exceed the preset time threshold and the preset time threshold is 500ms to 1000ms. This delay triggering mechanism works in conjunction with the continuous detection of capacitance change in step (2) to avoid false alarms caused by the temporary loosening of the electrode pads due to the patient turning over or moving, and improve the accuracy of the extubation judgment.

8. A medical anti-extraction alarm method based on human body contact sensing as described in claim 1, characterized in that, It also includes a self-test step: when the device is powered on or when the self-test function is manually triggered, the self-test circuit simulates the state of the medical adhesive electrode pad falling off to verify whether the core sensing module, main control unit and alarm module are functioning normally; if the function is abnormal, the alarm module issues a fault prompt; this self-test step is performed before the reference capacitance is established in step (1), which can eliminate equipment faults in advance and avoid the subsequent detection of capacitance changes and judgment of tube removal events being missed due to equipment problems, thus ensuring the overall reliability of the method.

9. A medical anti-extraction alarm method based on human body contact sensing as described in claim 4, characterized in that, In step (2), the detection sensitivity of the core sensing module can be adjusted by the sensitivity adjustment mechanism on the device housing, wherein the adjustment mechanism is a sensitivity adjustment potentiometer; The detection threshold of the core sensing module for changes in reference capacitance is changed by rotating the potentiometer to adapt to different human skin conditions and different types of medical catheters. When adapting to different types of medical catheters, the medical adhesive electrode is attached to the skin near the catheter fixation point, i.e., beside the nose or lower abdomen, to monitor nasogastric tubes and urinary catheters. When monitoring central venous catheters, the medical adhesive electrode is attached to the skin within 5 cm around the catheter puncture point.

10. A medical anti-extraction alarm method based on human body contact sensing as described in claim 7, characterized in that, The power supply for the method is achieved through a power module, which includes a rechargeable lithium battery, a charging module, and a low-voltage LDO. The charging module charges the rechargeable lithium battery and provides over-discharge protection. The low-voltage LDO regulates the output voltage of the rechargeable lithium battery to the working voltage adapted to the core sensing module and the main control unit, and then supplies power to the core sensing module and the main control unit.

Images