Pressure injury diagnostic auxiliary system with temperature sensing and risk warning function

Abstract

The application discloses a pressure injury diagnosis auxiliary system with temperature sensing and risk early warning functions. The system core is a flexible patch, which is pre-formed into a three-dimensional shape matching the sacrococcygeal anatomical surface, and the surface layer adopts medical silica gel with a Shore hardness of less than or equal to 15A. A plurality of functional units are distributed and integrated on the patch, each unit including a micro-actuator, an optical sensing module and a temperature sensor arranged coaxially. The micro-actuator generates a pressure pulse with an amplitude of 5-20 mmHg and a duration of 1-3 seconds; the optical sensing module collects double-wavelength reflected light intensity signals before and after the pressure pulse is applied; and the temperature sensor continuously monitors the skin temperature. The edge processing unit fits the reperfusion time constant tau based on the light intensity signals, dynamically calculates the individual safe upper limit of pressure P_max-safe, and combines the temperature data to perform multi-modal risk grading, and outputs the early warning signal through the wireless communication module. The application realizes objective, early and individualized early warning of pressure injury by actively evaluating tissue perfusion function.

Description

Technical Field

[0001] This invention belongs to the field of medical diagnostic technology, specifically a pressure injury diagnostic auxiliary system with temperature sensing and risk warning functions. Background Technology

[0002] Pressure injuries, also known as bedsores, are a persistent and serious challenge in clinical nursing practice, commonly seen in patients who are bedridden for extended periods, have spinal cord injuries, severely limited mobility, or require intensive care. The pathological essence lies in the prolonged exposure of soft tissues at bony prominences (such as the sacrum, coccyx, and heel) to excessive pressure or shear forces, leading to obstruction of local capillary blood flow, causing tissue ischemia, hypoxia, and malnutrition, ultimately progressing to tissue necrosis and ulceration. Pressure injuries not only cause immense suffering for patients, prolong hospital stays, and significantly increase medical costs, but are also a major risk factor for secondary infections, sepsis, and even death, placing a heavy burden on individuals, families, and the social healthcare system.

[0003] Currently, clinical risk management for pressure injuries relies primarily on two pillars: screening based on risk assessment scales and regular positional changes based on nursing protocols. Firstly, regarding risk assessment, standardized assessment tools such as the Braden and Norton scales are widely used internationally. While these scales have been used for a long time, they are essentially semi-quantitative scoring systems that depend on the subjective judgment of nursing staff, resulting in inherent limitations such as low inter-assessment reliability and difficulty in standardizing assessment criteria. More importantly, the scale scores cannot reflect the patient's constantly changing physiological state in real time, their predictive efficacy is limited, and they struggle to accurately identify patients in early-stage risk states, leading to a lack of targeted and timely preventative measures.

[0004] Secondly, existing monitoring and intervention techniques have significant shortcomings. On the one hand, routine nursing interventions (such as timed turning) are fixed-frequency protocols based on group experience, failing to consider individual differences in tissue tolerance stress among different patients or even the same patient at different time points, easily leading to insufficient or excessive intervention. On the other hand, with technological advancements, some auxiliary monitoring devices have begun to be applied in clinical practice, mainly including: Pressure distribution monitoring systems: These systems use a sensor matrix placed under the mattress or cushion to visually display the pressure distribution on the patient's body surface. However, they only provide static interface pressure data, passively recording physical parameters, and cannot assess the microcirculatory physiological response and tolerance reserve of tissues under that pressure. When the pressure distribution map shows "normal," the tissues may already be in a critical state of ischemia due to the patient's own physiological deterioration (such as hypotension or edema), resulting in a delayed warning.

[0005] Surface temperature monitoring technology: Elevated local skin temperature is one of the hallmarks of inflammatory response and can be used to aid in diagnosis. However, temperature changes usually lag behind impaired blood perfusion and are easily affected by other factors such as ambient temperature and fever, resulting in low specificity and limited early warning value when used alone.

[0006] In summary, the existing technology has the following prominent defects and urgent technical problems that need to be solved: Highly subjective and lacking objective quantitative standards: Risk assessment relies on manual scales, resulting in inaccurate and unreliable results.

[0007] Delayed early warning and lack of early prediction: Existing monitoring technologies are limited to the passive recording of static physical parameters (pressure, temperature), and cannot dynamically assess the physiological functional state of tissues, nor can they issue early warnings before irreversible tissue damage occurs.

[0008] The plans are rigid and lack individualized adaptability: Nursing intervention plans are based on group data and cannot adapt to the dynamic physiological differences between and within individuals, thus failing to achieve precision nursing.

[0009] Information isolation and lack of multi-parameter fusion analysis: Parameters such as pressure and temperature are often viewed in isolation, lacking an effective multi-modal information fusion mechanism to improve the specificity and reliability of risk assessment.

[0010] Therefore, there is an urgent need in this field for a new technical solution that can overcome the above-mentioned deficiencies and achieve objective, dynamic, individualized and multimodal early risk assessment of pressure injuries, thereby shifting the prevention focus forward, effectively reducing the incidence and improving the quality of care. Summary of the Invention

[0011] The purpose of this invention is to provide a diagnostic aid system for pressure injuries with temperature sensing and risk warning functions. This invention achieves objective, early, and individualized early warning of pressure injuries by actively assessing tissue perfusion function.

[0012] The technical solution adopted in this invention is as follows: A pressure injury diagnostic aid system with temperature sensing and risk warning functions, used for early risk assessment of pressure injuries in the sacrococcygeal region, the system comprising: A flexible patch, pre-formed into a three-dimensional shape to match the anatomical curvature of the human sacrococcygeal bony prominence, is used to attach to the skin surface of the sacrococcygeal region. Multiple functional units are distributed on the flexible patch, each functional unit including: (a) A micro actuator configured to apply a controllable pressure pulse with an amplitude of 5–20 mmHg and a duration of 1–3 seconds to local skin; (b) An optical sensing module, spatially coaxially arranged with the micro actuator, configured to acquire time-series signals of skin reflected light intensity before and after the application of the pressure pulse; (c) A temperature sensor configured to continuously monitor the temperature of the local skin; An edge processing unit, communicatively connected to the optical sensing module and the temperature sensor, is configured as follows: The reperfusion time constant τ is fitted based on the time series signal; Based on the aforementioned τ, an individualized upper limit of safety pressure is dynamically calculated. ; Combining the temperature with the Perform multimodal risk classification and output risk warning signals; A wireless communication module is configured to transmit the risk warning signal to an external care terminal.

[0013] Preferably, the three-dimensional shape of the flexible patch is constructed based on a statistical model of adult sacrococcygeal CT, covering the S2 to S4 spinous process region and the medial border of the gluteus maximus on both sides, with an overall thickness of 1.0–2.0 mm, and the surface layer is made of medical silicone material with a Shore hardness ≤15A.

[0014] Preferably, the micro actuator is a micro pneumatic cavity driven by a piezoelectric micropump, which generates the pressure pulse by injecting a small amount of gas, and the diameter of the pneumatic cavity is 3-5 mm and the height is no more than 1 mm.

[0015] Preferably, the optical sensing module includes a coaxially packaged red LED (wavelength 650-670nm), an infrared LED (wavelength 870-890nm), and a photodiode, used to eliminate skin color and ambient light interference by the ratio of reflected light intensity of the two wavelengths.

[0016] Preferably, the edge processing unit executes the following risk classification logic: If the current local pressure If the temperature does not exceed the individual's baseline temperature +1.0℃, it is considered a "safe" state; like However, if the temperature is normal, it is determined to be in a "warning" state; If any of the following conditions are met, the status is determined to be "high-risk": (i) ; (ii) The duration of the interval between the individual's baseline and temperature is ≥20% longer than the baseline plus 1.0°C and lasts for ≥30 minutes.

[0017] Preferably, the temperature sensor is a digital thermistor or a MEMS temperature chip with an accuracy of not less than ±0.2℃ and a sampling frequency of 0.05-0.5Hz.

[0018] Preferably, the flexible patch has a breathable and waterproof microporous membrane and an antibacterial coating on its bottom layer, and is only adhered to the healthy skin area by the edge ring medical adhesive, supporting non-destructive and quick installation and removal.

[0019] Preferably, the system further includes a local visual indicator integrated into the edge of the flexible patch, configured to display green, yellow, and red status lights according to the risk level.

[0020] A method for early warning of pressure injury risk using the system includes the following steps: (a) The flexible patch is attached to the patient's sacrococcygeal region; (b) After the patient has been in a resting state for ≥5 minutes, a pressure pulse is applied by the micro actuator; (c) Acquire the reflected light intensity signal through the optical sensing module and acquire the skin temperature through the temperature sensor; (d) The reperfusion time constant τ is calculated by the edge processing unit, P_max-safe is dynamically updated, and risk classification is performed in combination with temperature; (e) When the status is determined to be "alert" or "high risk", a warning message is sent to the nursing terminal through the wireless communication module.

[0021] Preferably, individual baseline temperature and baseline τ are established through multiple measurements within 24 hours after the system is first used, and are dynamically updated as the patient's physiological state changes.

[0022] Compared with the prior art, the present invention has achieved significant technological progress and brought about many beneficial effects, which are specifically reflected as follows: 1. Existing technologies rely on nurses' experience in using assessment scales, which introduces significant subjectivity and inter-assessment variability. This invention applies standardized, controllable pressure pulses via a micro-actuator and utilizes an optical sensing module to acquire dynamic signals of the skin's blood flow reperfusion process. An edge processing unit then fits a quantified reperfusion time constant τ. This parameter objectively reflects the microcirculatory function of local tissues, completely eliminating biases introduced by human factors. This ensures the repeatability and comparability of risk assessment results, providing a reliable data foundation for clinical decision-making.

[0023] 2. Existing monitoring equipment typically only passively monitors static interfacial pressure or body surface temperature, failing to detect the physiological responses of tissues under pressure, resulting in delayed early warnings. This invention innovatively introduces an active functional assessment mechanism, obtaining the τ value characterizing tissue perfusion reserve capacity by analyzing the dynamic process of blood flow reperfusion after pressure relief. This parameter is highly sensitive to tissue ischemia and hypoxia, exhibiting characteristic changes before visible skin damage occurs. This allows the system to issue an early warning before structural damage occurs, securing a critical time window for clinical intervention and effectively preventing the occurrence and development of pressure injuries.

[0024] 3. Existing nursing protocols, based on population statistics, set uniform intervention thresholds (such as turning patients every 2 hours), which cannot adapt to the physiological differences between and within individual patients over time. This invention continuously monitors and dynamically calculates an individualized upper limit of safe stress, P_max-safe, which is a function of the τ value and can adaptively adjust according to the patient's real-time physiological state (such as microcirculation function). This allows the system to provide each patient with a "tailor-made" risk assessment standard, thereby guiding nursing resources more precisely to high-risk individuals while avoiding unnecessary interventions for low-risk individuals, thus improving prevention effectiveness and optimizing the efficiency of nursing resource allocation.

[0025] 4. Single-parameter monitoring is susceptible to interference and lacks specificity. This invention performs synergistic analysis and logical judgment between the reperfusion time constant τ, which reflects hemodynamics, and the temperature parameter, which reflects local metabolic and inflammatory states. By constructing a risk grading logic that integrates pressure, perfusion function, and temperature information, the system can effectively distinguish different types of risk scenarios (such as simple mechanical compression and concurrent inflammatory responses), significantly reducing false alarms caused by environmental factors or transient physiological fluctuations, and avoiding missed alarms for complex risk factors. This generates highly reliable and specific early warning signals, greatly improving the trust of clinical medical staff in the system's alarms.

[0026] 5. The flexible patch of this invention uses biocompatible materials and adheres only to the epidermis. The applied pressure pulse amplitude is low and the duration is short, far below the threshold that could cause tissue damage, making it a non-invasive procedure. Compared to invasive monitoring or frequent manual examinations that may damage fragile tissues, this invention achieves long-term, continuous, and non-invasive monitoring of tissue physiological status while ensuring safety. It is well-tolerated by patients and provides technical support for long-term dynamic assessment.

[0027] In summary, this invention systematically solves the core bottlenecks of existing pressure injury risk assessment technologies, such as subjectivity, lag, universality, and singularity, by integrating active detection, multimodal sensing, and edge intelligent computing. Attached Figure Description

[0028] Figure 1 This is a schematic diagram illustrating the use of the system of the present invention; Figure 2 This is a schematic diagram of the system architecture of the present invention; Figure 3 This is a flowchart illustrating the early warning method of the present invention.

[0029] In the diagram, 1 is a flexible patch; 2 is a functional unit; 3 is an edge processing unit; 4 is a local visual indicator; and 5 is a ring-shaped area. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0031] See Figures 1 to 3 A pressure injury diagnostic aid system with temperature sensing and risk warning functions is used for early risk assessment of pressure injuries in the sacrococcygeal region. The core of this system is a flexible electronic patch integrating multimodal sensing, active detection, and edge intelligence processing. Its innovation lies in applying controllable micro-pressure pulses and monitoring skin blood flow-reperfusion dynamics parameters (characterized by the time constant τ), combined with local skin temperature, to dynamically and individually assess tissue pressure risk, thereby achieving early and accurate warnings. The system includes: A flexible patch 1 is the carrier and basic structure of this invention. The patch has a multi-layer structure. Its main body is pre-molded from ultra-soft medical-grade silicone with a Shore hardness ≤15A. The three-dimensional shape is a three-dimensional curved surface obtained by statistical modeling of CT scan data of the sacrum and coccyx of an adult population. It can closely fit the spinous process region of the S2 to S4 vertebrae and the medial edge of the gluteus maximus muscles on both sides of most patients, ensuring stable contact between the functional unit and the skin surface. The overall patch length is approximately 120-150 mm and the width is approximately 80-100 mm to accommodate different body types. Its overall thickness is controlled between 1.0-2.0 mm to ensure flexibility and wearing comfort. The bottom layer of the patch in contact with the skin has a breathable and waterproof microporous membrane (e.g., a polyurethane TPU membrane) with a water vapor transmission rate (WVTR) greater than 500 g / m². 2 The patch is designed for 24-hour use to ensure skin breathability. Its surface is coated with a broad-spectrum antibacterial coating (such as silver ion or chlorhexidine coating). The patch adheres to healthy skin only through a medical-grade acrylic adhesive on its outermost annular region 5 (approximately 5-8 mm wide), with the central functional area remaining uncontacted, allowing for non-destructive removal and quick replacement. Within the silicone body, flexible circuitry (such as polyimide (PI) or liquid crystal polymer (LCP)-based FPCs) is integrated using embedded processes or transfer technology to connect the various functional units.

[0032] Multiple functional units 2 are distributed on the flexible patch in a regular array (e.g., 4x4 or 5x5) in the central region of the patch, covering the main bony pressure points. Each functional unit includes: (a) A micro-actuator, each being a micro-pneumatic cavity with a diameter of 3-5 mm and a height not exceeding 1 mm, directly fabricated within a flexible silicone layer. Each pneumatic cavity is connected to a shared piezoelectric micropump located at the edge of the patch via a microchannel (approximately 100 micrometers wide). The edge processing unit controls the piezoelectric micropump to inject a small amount of gas (such as air) into the specific pneumatic cavity, causing the cavity membrane to bulge upwards and apply a precise, pulsed pressure to the local skin. The pressure amplitude is adjusted by controlling the injected gas volume, ranging from 5-20 mmHg. The duration of the pressure pulse is controlled by the micropump's on-time, ranging from 1-3 seconds. After application, the micropump reverses or rapidly vents gas through a vent valve to release the pressure.

[0033] (b) An optical sensing module, which is spatially strictly coaxial with the micro-actuator. Specifically, below the center of the micro-pneumatic cavity, a red LED (wavelength 650-670nm), an infrared LED (wavelength 870-890nm), and a photodiode are packaged. All three are coaxially packaged to minimize optical crosstalk. Before, during, and after the pressure pulse is applied, the edge processing unit alternately illuminates the red and infrared LEDs at a specific frequency (e.g., 10Hz) and records the reflected light intensity via the photodiode, forming a time-series signal. By calculating the ratio of red to infrared light reflection intensity (R / IR), interference from different skin tones, hair densities, and ambient light variations can be effectively offset. This ratio is highly correlated with the local tissue's blood oxygen saturation and blood volume.

[0034] (c) A temperature sensor, which can be a high-precision digital thermistor or a MEMS temperature chip. Its accuracy is not less than ±0.2℃ to meet the monitoring requirements of minute temperature changes. The sampling frequency is set to 0.05-0.5Hz to achieve a balance between continuous monitoring and low power consumption. The temperature sensor is distributed among the functional units to monitor the overall temperature of the patch coverage area.

[0035] An edge processing unit 3 is communicatively connected to an optical sensing module and a temperature sensor. The system also includes a local vision indicator 4, integrated into the edge of the flexible patch, configured to display green, yellow, and red status lights according to risk level.

[0036] Edge processing unit 3 is the intelligent core of the system, internally running a series of sophisticated signal processing and decision-making algorithms. Its workflow will be described in detail below: Step 1: Signal preprocessing and calculation of the reperfusion time constant τ 1. Data Reception: The edge processing unit receives the time-series raw data of red and infrared light reflection intensity from the optical sensing module via an internal bus. and ,in These are discrete sampling time points.

[0037] 2. Calculation of light intensity ratio: To prevent interference from individual skin color differences and ambient light, the unit calculates the ratio of reflected light intensity across two wavelengths in real time. The calculation formula is as follows: ; At the sampling time point The ratio of the intensity of the reflected light at two wavelengths is dimensionless.

[0038] At the sampling time point The red light detected by the photodiode (wavelength) The strength signal is expressed in millivolts (mV) or directly as an analog-to-digital converter (ADC) count value.

[0039] At the sampling time point Infrared light (wavelength) detected by photodiode (Intensity signal, unit same) .

[0040] The ratio It is highly correlated with the hemoglobin concentration and blood oxygen saturation of local tissues, and can more purely reflect hemodynamic changes.

[0041] 3. Extracting the re-injection curve: The moment when the pressure pulse applied by the micro-actuator is released is recorded as... For a period of time after the start The data forms a "reperfusion curve". This curve typically shows a trend of rising rapidly from a low value and then gradually stabilizing.

[0042] 4. Nonlinear Curve Fitting: The edge processing unit performs a single exponential function fitting on the reperfusion curve after the pressure pulse is released. The model is as follows: ; In time The fitted light intensity ratio at time t is dimensionless.

[0043] : Time variable, in seconds (s).

[0044] : The precise moment when the pressure pulse is released, in seconds (s).

[0045] : The amplitude of the reperfusion process signal obtained by fitting, dimensionless.

[0046] The reperfusion time constant is a key physiological parameter obtained from the fitting, representing the time required for blood flow to recover to approximately 63% of its steady state, expressed in seconds (s). The smaller the value, the faster the blood flow is restored.

[0047] The baseline value of the reperfusion curve obtained by fitting (i.e., the steady-state light intensity ratio before pressure application) is dimensionless.

[0048] The fitting objective is to find an optimal set of... The parameter τ minimizes the sum of squared errors between the function curve and the measured data points. A smaller τ value indicates a faster blood flow recovery rate and better tissue microcirculation health; a larger τ value indicates obstructed blood perfusion and higher risk.

[0049] Step Two: Individualized Safety Pressure Limits Dynamic calculation and updating 1. Establishing a physiological baseline: Within the first 24 hours of system use, the edge processing unit will perform multiple measurements (e.g., 8-10 times) while the patient is at rest and at no risk of pressure, to calculate the initial baseline value of the reperfusion time constant. and temperature baseline value .

[0050] 2. Dynamic security threshold calculation: It is not a fixed value, but rather changes dynamically with the patient's current physiological state (represented by τ). After each successful measurement of τ, the edge processing unit updates the value based on a pre-defined physiological model. A basic and effective computational model is the inverse proportional relationship: ; :No. The updated individualized safety pressure limit is measured in millimeters of mercury (mmHg). : Index of the number of measurements, a positive integer. :No. The reperfusion time constant is obtained from the fitting of the measurement and is expressed in seconds (s). The proportionality constant, calibrated using clinical data and measured in mmHg·s, ​​converts the time constant into a pressure threshold. This means the upper limit of safe pressure that a patient's tissues can withstand when microcirculation deteriorates (τ value increases) due to fatigue, dehydration, or disease. This will reduce the sensitivity of the system, making it more sensitive and thus achieving true individualized adaptation.

[0051] Step 3: Multimodal data fusion and risk classification The edge processing unit will calculate the τ value and dynamic... Values ​​and real-time monitored temperature data To perform the fusion, execute the following logical judgment: "Safe" (green) status determination: The system is determined to be in a safe state when both of the following conditions are met.

[0052] Pressure conditions: The current local pressure being monitored. (Based on external mattress pressure sensors or estimates based on body position) Below 80% of the safe pressure limit, i.e. This indicates that the current stress level is far below the individual's critical threshold.

[0053] Temperature conditions: Current skin temperature The temperature did not exceed the individual's baseline temperature by more than 1.0°C. This indicates that there is no significant inflammation or heat buildup in the area.

[0054] "Alert" (yellow) status determination: The system determines the status to be alert when the following conditions are met.

[0055] Current local pressure It has risen to 80% or more of the safe pressure limit, that is... However, the local temperature remains within the normal range. This condition indicates that the stress load is approaching the individual's tolerance limit, and medical staff should be alerted; adjustments to the patient's position may be necessary.

[0056] "High-risk" (red) status determination: If any of the following conditions are met, the status will be immediately determined as high-risk.

[0057] Condition (i): Pressure exceeds limit. Current local pressure. The dynamic calculated safety pressure limit has been reached or exceeded, i.e. This indicates that the organization is at clear risk of mechanical oppression.

[0058] Condition (ii): Significant deterioration of physiological indicators accompanied by persistent high temperature. All three of the following conditions must be met simultaneously: The reperfusion time constant τ was prolonged by 20% or more compared to the individual baseline: This indicates that there is a substantial obstruction in microcirculation.

[0059] Local skin temperature consistently exceeds baseline temperature by more than 1.0°C: .

[0060] The aforementioned state of "high temperature accompanied by significantly prolonged τ" lasted for at least 30 minutes. This condition is extremely important because it can detect high-risk tissue conditions caused by internal physiological dysfunction (such as severe infection or heart failure) even when external pressure is not high.

[0061] The current local actual pressure, measured in millimeters of mercury (mmHg), is obtained by monitoring or estimating the pressure using an external sensing system.

[0062] In time The measured local skin temperature is expressed in degrees Celsius (°C).

[0063] Baseline skin temperature of an individual, determined during the baseline learning period, in degrees Celsius (°C).

[0064] : Individual baseline reperfusion time constant determined through the baseline learning period, in seconds (s).

[0065] A wireless communication module is configured to transmit risk warning signals to an external care terminal.

[0066] A method for early warning of pressure injury risk using a system includes the following steps: Step 1: System preparation and application to the patient 1. Remove the flexible patch from the aseptic packaging and check its integrity.

[0067] 2. Clean and dry the patient's sacrococcygeal skin area.

[0068] 3. Align the center of the pre-formed three-dimensional curved surface of the flexible patch with the bony prominence of the sacrum, and gently press the annular adhesive area at its edge to ensure that the patch is flat and firmly attached to the skin surface without wrinkles or bubbles.

[0069] Step Two: System Power-On and Individual Baseline Learning Period 1. Connect the power supply / activate the built-in battery to the patch via magnetic or miniature connector. The system will then perform a self-test.

[0070] 2. The first 24 hours after the system is first applied to a patient are considered the critical "individual baseline learning period." During this period, the patient is required to remain as still as possible.

[0071] 3. The edge processing unit automatically and intermittently (e.g., every 2 hours) performs a complete measurement cycle (applying pressure pulses, acquiring optical and temperature signals) after the patient has been lying still for ≥5 minutes.

[0072] 4. The unit averages or uses a statistical model (e.g., taking the mean after removing outliers) the multiple τ values ​​and temperature values ​​measured during this period to calculate the patient's personalized baseline reference value. and These baseline values ​​are stored in non-volatile memory. They can then be periodically (e.g., weekly) recalibrated based on long-term changes in the patient's physiological state.

[0073] Step 3: Continuous monitoring and proactive early warning 1. After the baseline learning period ends, the system automatically enters continuous monitoring mode. Monitoring can be triggered in two ways: Periodic trigger: An evaluation is performed automatically at preset time intervals (e.g., every 30 minutes).

[0074] Event triggering: If the patch is equipped with an accelerometer, an assessment will be automatically triggered when a significant change in the patient's position (such as turning over) is detected.

[0075] 2. After each trigger, the system executes a complete "pressure-data collection-calculation-decision" cycle: Pressure application: The edge processing unit controls a designated micro-actuator to apply a standardized pressure pulse (e.g., amplitude 10 mmHg, duration 2 seconds) to the skin.

[0076] Data Acquisition: The optical sensing module synchronously acquires the light intensity signal during reperfusion, and the temperature sensor reads the current temperature.

[0077] Calculation and Decision-Making: The edge processing unit executes the complete process described in Section 3.1 above in real time, calculates the τ value of this measurement, and updates... And ultimately determine the current risk level.

[0078] 3. Early warning output: Local indication: The three-color LED indicator on the edge of the patch immediately displays the corresponding color (green / yellow / red) according to the risk level, providing the most intuitive on-site alarm for medical staff in the ward.

[0079] Remote Alarm: When the risk level is determined to be "Alert" (yellow), the system typically only logs information. When it escalates to "High Risk" (red), the edge processing unit immediately sends a high-priority alarm message to the central monitoring system at the nurse station or the mobile terminal of the responsible medical staff via a wireless communication module (such as Bluetooth). This message includes the patient ID, alarm time, specific risk level, and key physiological parameter data (such as the current τ value, etc.). (such as temperature) so that medical staff can quickly and accurately carry out clinical intervention.

[0080] Step 4: System Maintenance and Patch Replacement 1. Gently peel off the old patch according to clinical nursing guidelines (such as every 3 days or when the patch adhesiveness decreases).

[0081] 2. Clean the patient's skin and replace the new flexible patch. The new patch will automatically pair with the host and use the stored individual baseline parameters to continue the monitoring task.

[0082] This invention is a non-invasive, externally applied medical device. The core component of this system—the flexible patch—adheres solely to the surface of intact skin via medical pressure-sensitive adhesive, without establishing any direct or indirect mechanical or physical connection with any internal organ, tissue, or circulatory system. The applied detection pressure pulse (5-20 mmHg) is far below the capillary closure pressure in the human body and lasts for an extremely short time (1-3 seconds), causing no damage to the skin or subcutaneous tissue. Its safety is equivalent to a conventional finger pressure fading test, but is gentler and more controllable. Based on its operating principle and usage, this invention system meets the definition of a Class II medical device, used to measure and monitor human physiological parameters through physical means, providing information for disease prevention or diagnosis, with a moderate level of risk.

[0083] To verify the effectiveness, safety, and clinical performance of this system, the project team conducted clinical trials in the burn unit, intensive care unit (ICU), and rehabilitation department of our hospital from July to September 2025, while strictly adhering to relevant laws and regulations such as the Good Clinical Practice (GCP) for drug clinical trials.

[0084] All participants in the clinical trial, or their legal representatives, were fully informed by the researchers before enrollment of the trial's purpose, procedures, potential risks and benefits, data confidentiality, and their right to withdraw from the trial unconditionally at any time. They signed a written Informed Consent Form, based on their complete understanding and voluntary consent.

[0085] Case 1: Patient A and Patient B are both long-term bedridden patients following spinal cord injury, with similar age and weight. Using the traditional Braden scale, both scored 12 points (moderate risk), and their routine care was the same (turning over every 2 hours).

[0086] Traditional methods cannot distinguish the actual physiological tolerance differences between A and B, thus failing to provide the same level of care.

[0087] In this invention, both patient A and patient B wear the system. After a 24-hour baseline learning period, the system calculates the baseline reperfusion time constant τ_baseline for patient A to be 5 seconds and for patient B to be 9 seconds.

[0088] Based on this, the system dynamically calculated that patient A's safe pressure limit, P_max-safe_A, was 60 mmHg, while patient B's P_max-safe_B was only 33 mmHg. This indicates that, despite similar clinical manifestations, patient B's microcirculatory function was far weaker than patient A's, and their tissues were more fragile.

[0089] The system quantified individual physiological differences that traditional assessments could not detect. Upon receiving information that patient B had a low P_max-safe value, the nursing system automatically adjusted B's turning frequency to once every 1.5 hours and provided B with a higher-level pressure-relieving mattress. For patient A, the original plan was maintained, optimizing the allocation of nursing resources. In subsequent monitoring, patient B effectively avoided pressure injuries due to the enhanced individualized care plan.

[0090] Case 2: Patient C required a strict supine position after hip surgery. During a standard turning interval (2 hours), the nurse failed to notice a slight slippage of the patient's body, resulting in increased pressure on the sacrum and coccyx.

[0091] Traditional mattress pressure sensors show an overall pressure distribution that is "normal" or only slightly altered, insufficient to trigger an alarm. Nurses may only notice slight redness on the skin the next time they turn the child over.

[0092] The system of this invention monitored a rise in local pressure P in the patient's sacral and coccygeal region from 25 mmHg to 38 mmHg. Simultaneously, the system performed active monitoring periodically. Measurements revealed that the τ value in this region increased from a baseline of 6 seconds to 11 seconds. Although the current absolute pressure P (38 mmHg) was not high, the real-time P_max-safe calculated by the system had decreased to 35 mmHg due to the deterioration of the τ value.

[0093] The decision logic is P (38 mmHg) ≥ P_max-safe (35 mmHg).

[0094] The system immediately triggered a high-risk (red) alarm, the local indicator light turned red, and an emergency message was sent to the nurses' station: "Patient C, sacral and coccygeal pressure exceeds the individual's tolerance limit!"

[0095] An alert was issued 20-30 minutes before the appearance of visible erythema, through deterioration of physiological function (τ). This demonstrated that combining physiological function assessment with monitoring of physical pressure is more sensitive and proactive than simply monitoring physical pressure. Upon receiving the alert, nurses immediately repositioned the patient, preventing further development of pressure injury.

[0096] Case 3: Patient D, a diabetic patient, has an old scar on the sacrococcygeal region, but the skin is intact. Due to a weakened immune system, a latent infection developed in this area, leading to an increase in local skin temperature.

[0097] Traditionally, nurses may feel that the skin is "a little warm" when they touch it, but they do not see any damage. They may mistakenly believe that this is normal heat caused by long-term pressure, thus delaying treatment.

[0098] Continuous monitoring using the system of this invention showed that patient D's sacrococcygeal temperature remained 1.5°C above his individual baseline temperature for 40 minutes. The system triggered active detection and found that the τ value in this region significantly increased from the baseline of 7 seconds to 16 seconds (an increase of over 20%).

[0099] The judgment logic is (τ elongation rate ≥ 20%) and (temperature exceeding the limit for ≥ 30 minutes).

[0100] Although the current local pressure P is normal, the system is still classified as a high-risk (red) state.

[0101] The system doesn't just look at temperature or blood flow in isolation; it identifies the dangerous combination of "high temperature accompanied by worsened blood perfusion," strongly suggesting local inflammation or infection. It can detect deep tissue inflammation that is difficult to detect with the naked eye or palpation. The alert prompts the nurse to conduct a thorough examination and notify the doctor. Ultimately, ultrasound examination revealed deep tissue edema, and antibiotic treatment controlled the inflammation, preventing skin breakdown.

[0102] Case 4: Patient E was admitted to the hospital due to heart failure, accompanied by generalized edema and poor microcirculation. After treatment with diuretics and cardiotonics, his cardiac function gradually improved.

[0103] Traditional methods lack objective indicators to continuously track the improvement of tissue perfusion in patients.

[0104] Applying this invention, upon admission, the system measured patient E's baseline τ_baseline to be as high as 15 seconds, while P_max-safe was only 25 mmHg, indicating the system remained in a "vigilant" or "high-risk" state. With effective treatment, daily monitoring data showed a gradual decrease in the average τ value: to 12 seconds on day 3, 9 seconds on day 5, and 6.5 seconds on day 7. Correspondingly, the dynamically calculated P_max-safe value gradually increased from 25 mmHg to 33 mmHg, then to 38 mmHg, and finally to 52 mmHg. The risk level also shifted from a persistent "high-risk" to "vigilant," and finally stabilized at "safe."

[0105] It provides clinicians with objective, quantifiable indicators for assessing treatment effectiveness, especially improvements in microcirculation. The system automatically adapts to the patient's improved physiological state, avoiding over-alarms even after recovery. Data trends provide positive feedback on recovery for both healthcare professionals and patients.

[0106] Case 5: Patient F is elderly and thin with very little subcutaneous fat. The skin on the sacrum and coccyx is thin and transparent, and capillaries are visible.

[0107] Traditional methods raise concerns and uncertainties among nurses who worry that frequent finger pressure on the skin (digital pressure fading test) could cause damage.

[0108] Using this invention, the pressure pulses applied by this system (5-20 mmHg) are standardized and minimally invasive, far less than the pressure of adult finger pressure (usually >50 mmHg), and the effect area is small and the duration is extremely short, making it safe for delicate skin. After establishing a baseline for patient F, the system can non-invasively and quantitatively monitor their tissue perfusion continuously. When the system displays a "safe" status, nurses can confidently and appropriately extend the turning interval (within the standard range) to reduce disturbance to the patient.

[0109] It provides a safer, more objective assessment method as an alternative to traditional manual examination. This gives healthcare professionals greater confidence in caring for high-risk patients and reduces anxiety associated with subjective judgment. It also minimizes unnecessary turning and manual examinations that interfere with patient care.

[0110] These five cases comprehensively demonstrate, from different perspectives, the significant progress and technical effects of this invention compared to existing technical solutions. Specifically, it achieves early, objective, individualized, and multimodal integrated early warning of pressure injury risks, thereby more effectively guiding clinical prevention and improving the quality of nursing care.

[0111] 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, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A diagnostic aid system for pressure injuries with temperature sensing and risk warning functions, used for early risk assessment of pressure injuries in the sacrococcygeal region, characterized in that, The system includes: A flexible patch, pre-formed into a three-dimensional shape to match the anatomical curvature of the human sacrococcygeal bony prominence, is used to attach to the skin surface of the sacrococcygeal region. Multiple functional units are distributed on the flexible patch, each functional unit including: (a) A micro actuator configured to apply a controllable pressure pulse with an amplitude of 5–20 mmHg and a duration of 1–3 seconds to local skin; (b) An optical sensing module, spatially coaxially arranged with the micro actuator, configured to acquire time-series signals of skin reflected light intensity before and after the application of the pressure pulse; (c) A temperature sensor configured to continuously monitor the temperature of the local skin; An edge processing unit, communicatively connected to the optical sensing module and the temperature sensor, is configured as follows: The reperfusion time constant τ is fitted based on the time series signal; Based on the aforementioned τ, an individualized upper limit of safe pressure is calculated. ; Combining the temperature with the Perform multimodal risk classification and output risk warning signals; A wireless communication module is configured to transmit the risk warning signal to an external care terminal.

2. The pressure injury diagnostic auxiliary system with temperature sensing and risk warning functions as described in claim 1, characterized in that, The three-dimensional shape of the flexible patch is constructed based on a statistical model of adult sacrococcygeal CT, covering the S2 to S4 spinous process region and the medial border of the gluteus maximus on both sides, with an overall thickness of 1.0–2.0 mm, and the surface layer is made of medical silicone material with a Shore hardness ≤15A.

3. The pressure injury diagnostic auxiliary system with temperature sensing and risk warning functions as described in claim 1, characterized in that, The micro actuator is a micro pneumatic cavity driven by a piezoelectric micropump. It generates the pressure pulse by injecting a small amount of gas. The diameter of the pneumatic cavity is 3-5 mm and the height does not exceed 1 mm.

4. The pressure injury diagnostic auxiliary system with temperature sensing and risk warning functions as described in claim 1, characterized in that, The optical sensing module includes a coaxially packaged red LED, an infrared LED, and a photodiode, used to eliminate skin color and ambient light interference by using the ratio of reflected light intensity across two wavelengths.

5. The pressure injury diagnostic auxiliary system with temperature sensing and risk warning functions as described in claim 1, characterized in that, The edge processing unit executes the following risk classification logic: If the current local pressure If the temperature does not exceed the individual's baseline temperature +1.0℃, it is considered a "safe" state; like However, if the temperature is normal, it is determined to be in "alert" status; If any of the following conditions are met, the status is determined to be "high-risk": (i) ； (ii) The duration of the interval between the individual's baseline and temperature is ≥20% longer than the baseline plus 1.0°C and lasts for ≥30 minutes.

6. The pressure injury diagnostic auxiliary system with temperature sensing and risk warning functions as described in claim 1, characterized in that, The temperature sensor is a digital thermistor or MEMS temperature chip with an accuracy of not less than ±0.2℃ and a sampling frequency of 0.05-0.5Hz.

7. The pressure injury diagnostic auxiliary system with temperature sensing and risk warning functions as described in claim 1, characterized in that, The flexible patch has a breathable and waterproof microporous membrane and an antibacterial coating on its bottom layer, and is only adhered to the healthy skin area by the edge ring medical adhesive, supporting non-destructive and quick installation and removal.

8. The pressure injury diagnostic auxiliary system with temperature sensing and risk warning functions as described in claim 1, characterized in that, It also includes a local visual indicator integrated into the edge of the flexible patch, configured to display green, yellow, and red status lights according to the risk level.

9. A method for early warning of pressure injury risk using the system as described in any one of claims 1-8, characterized in that, Includes the following steps: (a) The flexible patch is attached to the patient's sacrococcygeal region; (b) After the patient has been in a resting state for ≥5 minutes, a pressure pulse is applied by the micro actuator; (c) Acquire the reflected light intensity signal through the optical sensing module and acquire the skin temperature through the temperature sensor; (d) The reperfusion time constant τ is calculated by the edge processing unit and dynamically updated. And risk classification is based on temperature; (e) When the status is determined to be "alert" or "high risk", a warning message is sent to the nursing terminal through the wireless communication module.

10. The method for early warning of pressure injury risk as described in claim 9, characterized in that, In step (d), the individual baseline temperature and τ used for risk stratification are established through multiple measurements within 24 hours after the system is first used and are dynamically updated as the patient’s physiological status changes.

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