A portable capillary refill time detector

Abstract

The present application relates to the technical field of medical apparatus and instruments, in particular to a portable capillary refill time detector, which comprises a shell, a finger cot fixedly connected to the shell and in communication with the shell, a pressing assembly arranged in the shell, a support rod arranged on the inner bottom wall and the inner top wall of the shell, a first connecting rod hingedly connected to the support rod, a sector gear fixedly connected to the first connecting rod, the sector gears being in mesh with each other, a second connecting rod hingedly connected to one end of the first connecting rod, one of the second connecting rods penetrating through the top wall of the shell and being in sliding fit with the top wall of the shell and being provided with a manual pressing assembly, the other second connecting rod being in vertical sliding fit with the inner bottom wall of the shell, a pneumatic telescopic piece arranged between adjacent first connecting rods, a pressing piece arranged on each of the adjacent second connecting rods, a holding assembly arranged in the pneumatic telescopic piece, and a detection assembly arranged on one of the pressing pieces. The present application can reduce the detection deviation caused by unstable manual pressing pressure in capillary refill time detection.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, specifically to a portable capillary refill time detector. Background Technology

[0002] In recent years, hemodynamic monitoring of microcirculation has received increasing attention. Direct monitoring of the microcirculation status of deep organs is difficult in clinical practice, but peripheral circulation directly reflects the body's worst microcirculatory state and is an important indicator for hemodynamic monitoring in critically ill patients. Therefore, the research and development of peripheral circulation monitoring indicators has significant clinical value. Capillary refill time (CRT) is a direct indicator for peripheral circulation monitoring. When peripheral circulatory impairment exists, capillary refill time will be significantly prolonged.

[0003] In existing technologies, capillary refill time measurement instruments are typically used to detect capillary refill time. These instruments employ a MAX30100 photoelectric chip to continuously emit 900nm near-infrared light signals to the fingertips and continuously monitor the received signals. This allows for continuous monitoring of the oxyhemoglobin content in the distal capillary bed. A manual compression device applies pressure to the distal capillary bed. When the tissue is compressed to a certain extent, arterial blood flow stops, the pulsating wave signal disappears, and the non-pulsating wave signal increases due to reduced blood flow, decreased hemoglobin content, and reduced tissue thickness. When the pressure is released, the non-pulsating arterial wave signal gradually decreases, followed by the gradual recovery of the arterial pulsating wave signal. The time it takes for the light signal value to return to the baseline level before compression is the capillary refill time.

[0004] However, in actual use of this measuring instrument, it is difficult to maintain a constant pressure during manual pressing. Initially, the operator's hand pressure typically increases gradually, but once the preset pressure is reached, the hand cannot remain absolutely stable, and the pressure may fluctuate with breathing or slight hand tremors, leading to inaccuracies in judging the capillary refill time. Therefore, it is necessary to propose a portable capillary refill time measuring instrument to solve the problem of existing capillary refill time measuring instruments where manual pressing cannot maintain a constant pressure, thus causing inaccuracies in judging the capillary refill time. Summary of the Invention

[0005] To address the aforementioned issues, this invention provides a portable capillary refill time detector that can achieve constant control of the pressure applied to the capillary bed at the fingertips through an automatic pressing component and a pressure maintaining component, thereby reducing detection deviations caused by unstable manual pressing pressure.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows: A portable capillary refill time detector includes a housing and a controller; a finger sleeve is fixedly connected to the side wall of the housing, and the finger sleeve communicates with the inside of the housing; a pressing assembly is provided inside the housing for pressing a finger that extends from the finger sleeve into the housing; the pressing assembly includes support rods symmetrically arranged on the bottom wall and top wall of the housing, each support rod is hinged with a first connecting rod, and each first connecting rod is fixedly connected with a sector gear, with adjacent sector gears meshing with each other; the end of each first connecting rod away from the support rod is hinged to... There is a second link, one of which has its top end penetrating through the top wall of the housing and slidingly engaging with the top wall of the housing, and is equipped with a manual pressing component for manually pressing the finger; the other second link is vertically slidingly engaged with the bottom wall of the housing; a pneumatic telescopic component is provided between adjacent first links for driving the first links to expand and close, and each adjacent second link is equipped with a pressing component for pressing the finger; a holding component is provided inside the pneumatic telescopic component for maintaining the pressing force of the pressing component; one of the pressing components is equipped with a detection component for detecting the capillary refill time.

[0007] The technical principles of the above solution are as follows:

[0008] With the fingertip facing upwards, insert the finger into the housing through the finger sleeve. At this point, the controller sends a start command to the pneumatic telescopic component, which then begins to move. Since the pneumatic telescopic component is located between adjacent first links, when it retracts, it applies opposing pulling forces to the first links on both sides, causing them to move in opposite directions. This, in turn, causes the second link to apply a uniform and stable clamping pressure to the finger.

[0009] The two first connecting rods are respectively hinged to the support rods on the bottom and top walls of the housing, and the sector gears fixed on the first connecting rods are symmetrically meshed, ensuring that the movement of the two first connecting rods remains symmetrical and synchronous, avoiding displacement of the pressing position due to unilateral movement deviation. At this time, the pressing force of the pressing element is maintained in real time by the holding component in the pneumatic telescopic component, ensuring that the pressing force remains constant throughout the detection process. After the pressing element completes stable pressing on the fingertip, the detection component set on one of the pressing elements will be activated to start timing and collecting the filling time of the capillary refill process in the pressing area.

[0010] The above approach has the following beneficial effects:

[0011] 1. This invention solves the problem of maintaining constant pressure in manual pressing by using a pneumatically telescopic pressing component in conjunction with a holding component. The pneumatically telescopic component drives the first and second connecting rods in a coordinated manner, combined with a synchronous transmission structure of sector gears, enabling the pressing component to apply uniform pressure to the capillary bed at the fingertip. The holding component can stabilize the pressing pressure in real time, making the measurement results of capillary refill time more accurate and providing reliable data support for clinical assessment of peripheral circulation status.

[0012] 2. The pressing component of this invention has a simple structure and high portability. Compared with electromagnetic or pneumatic pressurization methods, it has higher shock resistance. Even when subjected to external interference such as vibration and bumps, it can still accurately maintain a constant pressing pressure, ensuring that the test results are not affected by environmental factors. It provides a reliable guarantee for peripheral circulation monitoring in special scenarios such as field rescue and military medical treatment.

[0013] 3. The manual pressing component of this invention, when used in field environments, can immediately switch to manual operation mode when the device encounters sudden situations such as pneumatic telescopic component failure or energy depletion, avoiding interruption of detection work due to failure of the core automatic components of the equipment. Medical personnel can directly drive the second linkage through the manual pressing component to apply pressure to their fingers, and relying on the synchronous transmission structure of the sector gear, even manual operation can ensure that the pressing components on both sides are evenly stressed, further improving the applicability and reliability of the equipment in special scenarios such as field rescue and military medical treatment.

[0014] Furthermore, the pneumatic telescopic component includes a piston cylinder, which is hinged to one of the first connecting rods, and a piston rod is hinged to the other first connecting rod. The piston rod and the inner wall of the piston cylinder are in sliding fit. An air pipe is connected to the side wall of the piston cylinder.

[0015] A negative pressure pump is fixedly connected to the bottom wall inside the housing, and the end of the air pipe away from the piston cylinder is connected to the inlet of the negative pressure pump; the controller is used to control the operation of the negative pressure pump.

[0016] Beneficial effects: The negative pressure pump generates a stable negative pressure, which drives the piston rod and piston cylinder to slide relative to each other, providing uniform power to the pressing assembly.

[0017] Furthermore, the pressing component includes an arc-shaped pressing plate that is ball-hinged to one end of the second link.

[0018] Beneficial effects: The curved design conforms to the curvature of the fingertip, ensuring full coverage of the capillary bed when pressing; the ball joint structure can adapt to the shape of the finger and rotate accordingly, always maintaining a close fit with the fingertip.

[0019] Furthermore, the retaining assembly includes a first cavity and a second cavity within the piston cylinder. The first cavity communicates with the piston cylinder, and the second cavity communicates with the first cavity. A piston is slidably fitted within the first cavity, and a rack is fixedly connected to the piston. A tension spring is fixedly connected to the end of the rack away from the piston, and the end of the tension spring away from the rack is fixedly connected to the bottom wall of the second cavity. A rotating shaft is rotatably fitted on the inner side wall of the second cavity, and a roller is fixedly connected to the rotating shaft. A helical guide block is fixedly connected to the roller, and a gear is fixedly connected to one end of the roller, meshing with the rack. A fixing rod is fixedly connected to the bottom wall of the second cavity, and a retaining pin is slidably fitted on the fixing rod. Several limiting wheels are rotatably fitted to one end of the retaining pin, and the end of the retaining pin away from the limiting wheels passes through the side wall of the second cavity and is slidably fitted to the side wall of the second cavity. The limiting wheels are all in rolling engagement with the helical guide block. Several limiting holes are opened on the inner side wall of the piston cylinder, and the end of the retaining pin away from the limiting wheels engages with the limiting holes. A vent hole is opened on the piston cylinder, and the vent hole communicates with the piston cylinder.

[0020] Beneficial effects: By triggering the piston, rack, and gears through changes in negative pressure, the retaining needle is engaged in the limiting hole to lock the piston rod, thus achieving a constant pressing force. The vent balances the negative pressure, preventing equipment damage.

[0021] Furthermore, the detection component includes a PPG sensor fixedly connected to one of the pressure plates, and a controller for receiving finger blood flow signals sent by the PPG sensor.

[0022] Beneficial effects: PPG sensors emit light signals of a specific wavelength that penetrate the skin and tissue at the fingertips of the human body, and then receive the reflected light signals after being absorbed by hemoglobin in the blood, thereby monitoring the periodic changes in blood flow volume in capillaries in real time and capturing blood flow signals in real time.

[0023] Furthermore, the manual pressing component includes a manual pressing block fixedly connected to the top of one of the second links.

[0024] Beneficial effects: In the event of automatic component failure or power outage, the second linkage can be directly driven by the pressing block, relying on the synchronous transmission of the sector gear to ensure uniform force on both pressing plates. This saves electricity and expands the applicable scenarios of the equipment, making it especially suitable for emergency testing in complex environments such as the field and military.

[0025] Furthermore, an indicator light and a digital tube are fixedly connected to the top of the housing. The controller is used to control the digital tube to display the number of seconds based on the blood flow signal and to control the indicator light to turn on and off.

[0026] Beneficial effects: Indicator lights visually indicate the testing stage through color changes such as red and green, and the digital tube accurately displays the refill time, making it easy for operators to quickly read the results.

[0027] Furthermore, a pressure sensor is fixedly connected to one of the pressing plates. The controller is used to receive the pressure signal sent by the pressure sensor from the pressing plate on the finger, and control the digital tube to display the number of seconds and control the indicator light to turn on and off based on the pressure signal.

[0028] Beneficial effects: When manually pressed, the pressure sensor can monitor the pressure of the press plate on the finger in real time and feed the signal back to the controller. When the pressure reaches the preset threshold, the timing is triggered to ensure that the pressing pressure is consistent each time.

[0029] Furthermore, a lithium battery is fixedly connected to the bottom wall inside the housing. The lithium battery is used to power the negative pressure pump, controller, PPG sensor, indicator lights and digital tube.

[0030] Beneficial effects: Provides continuous power to all components of the device, eliminating the need for an external power source and improving portability. A single charge can support multiple tests, making it suitable for outdoor scenarios without power supply; the low-power design extends battery life, meeting the needs of continuous diagnosis and treatment, and solving the problems of traditional devices relying on mains power and having poor mobility.

[0031] Furthermore, a support plate is fixedly connected to the inner wall of the housing, and a touch switch is fixedly connected to the side wall of the support plate. The controller is used to receive the touch signal of the finger sent by the touch switch and control the operation of the negative pressure pump based on the touch signal; a flexible silicone pad is fixedly connected to the inner wall of the finger sleeve, and the surface of the silicone pad is provided with anti-slip texture.

[0032] Beneficial effects: The touch switch automatically starts the negative pressure pump after sensing the insertion of a finger, realizing "insertion and detection" and simplifying the operation process; the silicone pad increases the friction between the finger and the finger sleeve, preventing the finger from slipping during detection, while improving wearing comfort and avoiding finger discomfort caused by prolonged detection.

[0033] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0034] Figure 1 This is an isometric view of the portable capillary refill time detector of the present invention.

[0035] Figure 2 This is a lateral sectional axonometric view of the portable capillary refill time detector of the present invention.

[0036] Figure 3 for Figure 2 Enlarged view of section A.

[0037] Figure 4 This is a side cross-sectional view of the pneumatic telescopic component in the portable capillary refill time detector of the present invention.

[0038] Figure 5 for Figure 4 Enlarged view of section B.

[0039] Figure 6 This is an isometric view of the holding component in the portable capillary refill time detector of the present invention.

[0040] Figure 7 This is a top cross-sectional view of the portable capillary refill time detector of the present invention.

[0041] The reference numerals in the accompanying drawings of the instruction manual include: 1. Housing; 2. Finger sleeve; 3. Support rod; 4. First connecting rod; 5. Second connecting rod; 6. Piston cylinder; 7. Piston column; 8. Negative pressure pump; 9. Press plate; 10. First cavity; 11. Second cavity; 12. Piston; 13. Rack; 14. Tension spring; 15. Rotating shaft; 16. Roller shaft; 17. Spiral guide block; 18. Gear; 19. Fixing rod; 20. Holding pin; 21. Limiting wheel; 22. Limiting hole; 23. PPG sensor; 24. Manual pressing block; 25. Indicator light; 26. Digital tube; 27. Pressure sensor; 28. Lithium battery; 29. ​​Support plate; 30. Touch switch; 31. Sector gear. Detailed Implementation

[0042] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0044] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0045] The following detailed description illustrates the specific implementation method:

[0046] Implementation, for example, attached Figure 1 As shown: A portable capillary refill time detector includes a housing 1 and a controller. A finger sleeve 2 is fixedly connected to the side wall of the housing 1 by screws, and the finger sleeve 2 communicates with the inside of the housing 1. The housing 1 is provided with a pressing component for pressing the finger that extends from the finger sleeve 2 into the housing 1.

[0047] like Figure 2 As shown, the pressing assembly includes support rods 3 symmetrically fixed to the bottom and top walls of the housing 1 by screws. Each support rod 3 is hinged with a first connecting rod 4, and each first connecting rod 4 is integrally formed with a sector gear 31, with adjacent sector gears 31 meshing with each other. Each first connecting rod 4 is hinged with a second connecting rod 5 at the end away from the support rod 3. One of the second connecting rods 5 has its top end penetrating through the top wall of the housing 1 and slidingly engaging with the top wall of the housing 1, and is provided with a manual pressing assembly for manually pressing with a finger. The other second connecting rod 5 is vertically slidingly engaged with the bottom wall of the housing 1.

[0048] A pneumatic telescopic component is provided between adjacent first links 4 for driving the first links 4 to expand and close, and a pressing component for pressing the fingers is provided on adjacent second links 5; a retaining component is provided inside the pneumatic telescopic component for maintaining the pressing force of the pressing component.

[0049] One of the pressing components is equipped with a detection component that measures the capillary refill time.

[0050] like Figure 2 As shown, specifically, the pneumatic telescopic component includes a piston cylinder 6, which is hinged to one of the first connecting rods 4, and a piston rod 7 is hinged to the other first connecting rod 4. The piston rod 7 and the inner wall of the piston cylinder 6 are in sliding fit. An air pipe (not shown in the figure) is connected to the side wall of the piston cylinder 6.

[0051] A negative pressure pump 8 is fixedly connected to the bottom wall of the housing 1 by screws. The end of the air pipe away from the piston cylinder 6 is connected to the inlet of the negative pressure pump 8. The controller is used to control the operation of the negative pressure pump 8.

[0052] like Figure 3 As shown, specifically, the pressing component includes an arc-shaped pressing plate 9 that is ball-hinged to one end of the second link 5.

[0053] Combination Figure 2 and Figure 3As shown, during use, the finger to be tested is inserted into the housing 1 through the finger sleeve 2 with the fingertip facing upwards. The controller controls the negative pressure pump 8 to generate negative pressure. At this time, the negative pressure draws the gas in the piston cylinder 6 through the air tube, and the piston column 7 will contract. Since the sector gears 31 are meshed with each other, when the piston column 7 contracts, the piston cylinder 6 and the piston column 7 drive the first connecting rod 4 to retract towards each other. Since the second connecting rod 5 is hinged to one end of the first connecting rod 4 and slides with the top and bottom walls of the housing 1 respectively, at this time... Figure 2 The upper second link 5 moves downward in a straight line, and the lower second link 5 moves upward in a straight line, thereby driving the arc-shaped pressing plate 9 to press the finger. The ball joint structure of the pressing plate 9 can always fit against the fingertip through its own rotation, ensuring that the pressure is always applied to the target area and maintaining the stability of the pressing; thus temporarily compressing and blocking the capillaries in the finger. At this time, the fingertip will appear pale due to the interruption of capillary blood supply.

[0054] like Figure 4 , Figure 5 and Figure 6 As shown, specifically, the retaining assembly includes a first cavity 10 and a second cavity 11 opened within the piston cylinder 7. The first cavity 10 is connected to the piston cylinder 6, and the second cavity 11 is connected to the first cavity 10. A piston 12 is slidably fitted inside the first cavity 10. A rack 13 is integrally formed on the piston 12. A tension spring 14 is fixedly connected to the end of the rack 13 away from the piston 12 by a screw. The end of the tension spring 14 away from the rack 13 is fixedly connected to the bottom wall of the second cavity 11 by a screw.

[0055] A rotating shaft 15 is rotatably fitted on the inner wall of the second cavity 11. A roller 16 is integrally formed on the rotating shaft 15. A spiral guide block 17 is integrally formed on the roller 16. A gear 18 is integrally formed at one end of the roller 16. The gear 18 meshes with the rack 13.

[0056] A fixing rod 19 is fixedly connected to the bottom wall of the second cavity 11 by screws. A retaining pin 20 is slidably fitted on the fixing rod 19. A number of limiting wheels 21 are rotatably fitted at one end of the retaining pin 20. The end of the retaining pin 20 away from the limiting wheels 21 passes through the side wall of the second cavity 11 and is slidably fitted with the side wall of the second cavity 11. The limiting wheels 21 are all in rolling engagement with the spiral guide block 17.

[0057] The piston cylinder 6 has several limiting holes 22 on its inner side wall, which keep the end of the needle 20 away from the limiting wheel 21 engaged with the limiting hole 22; the piston column 7 has a vent hole (not shown in the figure), which is connected to the piston cylinder 6. In this embodiment, the diameter of the vent hole is smaller than the diameter of the air pipe.

[0058] Combining 5 and Figure 6As shown, when there is negative pressure inside the piston cylinder 6, since the first cavity 10 is connected to the piston cylinder 6, the first cavity 10 is under negative pressure. Because the negative pressure of the negative pressure pump 8 is constant, when the pressing plate 9 presses on the finger, the negative pressure pump 8 continuously generates negative pressure. At this time, the piston column 7 no longer moves, and the negative pressure inside the first cavity 10 immediately increases. When the force of the negative pressure inside the first cavity 10 is greater than the deformation force of the tension spring 14, the piston 12 will move upward under the action of negative pressure, causing the tension spring 14 to stretch and deform. When the piston 12 moves upward, it can drive the rack 13, which in turn drives the gear 18 meshing with it to rotate. When the gear 18 rotates, it can drive the rotating shaft 15, which in turn drives the roller shaft 16 to rotate. The spiral guide block 17 is rotated. Due to the rolling engagement between the limiting wheel 21 on the retaining pin 20 and the spiral guide block 17, and the sliding engagement between the retaining pin 20 and the fixing rod 19, the limiting wheel 21 can drive the retaining pin 20 to slide to the right, so that the right end of the retaining pin 20 is engaged in the limiting hole 22 on the side wall of the piston cylinder 6. At this time, the piston column 7 stops moving completely. Due to the presence of the vent hole on the piston column 7, the air outside the piston cylinder 6 can continue to be drawn into the negative pressure pump 8 through the vent hole, so that the negative pressure inside the piston cylinder 6 remains constant, avoiding damage to the negative pressure pump 8 due to the continuous increase of negative pressure. At the same time, the retaining pin 20 locking the movement of the piston column 7 can also prevent the pressing plate 9 from pressing the fingers excessively.

[0059] The force of piston 12 moving is equal to the tension of spring 14. That is, when the pressing force of pressing plate 9 is equal to the tension of spring 14, pressing plate 9 can be held, thereby locking and maintaining the pressing force of pressing plate 9.

[0060] This pressing method can also adapt to different finger sizes; specifically, regardless of finger size, when the retaining component locks the piston column 7, the pressing plate 9 can be fixed at a distance that matches the size of the finger, and the pressing plate 9 can maintain a constant pressing force on the finger, thereby further allowing the pressing component to apply uniform pressure to the capillary bed at the fingertip, and the retaining component can stabilize the pressing force in real time, making the measurement results of capillary refill time more accurate.

[0061] The piston rod 7 and piston cylinder 6 are rigidly fixed by the engagement of the retaining pin 20 and the limiting hole 22, and the two no longer slide relative to each other. This fixed relationship is directly transmitted to the first connecting rods 4 on both sides that are hinged to them. Since the first connecting rods 4 are connected to the piston cylinder 6 and piston rod 7 respectively, their closing angle is fixed and will not change significantly due to external vibration, slight shaking of the equipment or instinctive movement of the fingers, thereby improving the stability and accuracy of the invention in the field environment.

[0062] Meanwhile, compared with existing airbag-type or fixed-pressure methods, the retaining component of this invention can adapt to people with different finger sizes, achieving adaptive pressing for different finger sizes and always maintaining a constant pressing pressure without manual adjustment, greatly improving the convenience and applicability of detection.

[0063] like Figure 3 and Figure 7 As shown, specifically, the detection component includes a PPG sensor 23 fixedly bonded to one of the pressing plates 9, and a controller for receiving the finger blood flow signal sent by the PPG sensor 23. An indicator light 25 and a digital tube 26 are fixedly connected to the top of the housing 1 by screws. The controller is used to control the digital tube 26 to display the number of seconds and to control the indicator light 25 to turn on and off based on the blood flow signal.

[0064] A pressure sensor 27 is fixedly attached to one of the pressing plates 9. The controller is used to receive the pressure signal sent by the pressure sensor 27 from the pressing plate 9 on the finger, and control the digital tube 26 to display the number of seconds and control the indicator light 25 to turn on and off based on the pressure signal.

[0065] A lithium battery 28 is also fixedly connected to the bottom wall of the housing 1 by screws. The lithium battery 28 is used to power the negative pressure pump 8, the controller, the PPG sensor 23, the indicator light 25 and the digital tube 26.

[0066] A support plate 29 is fixedly connected to the inner wall of the housing 1, and a touch switch 30 is fixedly connected to the side wall of the support plate 29. The controller is used to receive the touch signal of the finger sent by the touch switch 30 and control the operation of the negative pressure pump 8 based on the touch signal. A flexible silicone pad is fixedly connected to the inner wall of the finger sleeve 2, and the surface of the silicone pad is provided with anti-slip texture.

[0067] Before detection, when a finger is inserted into the finger sleeve 2 and touches the touch switch 30, the touch switch 30 sends a touch signal to the controller. At this time, the controller controls the negative pressure pump 8 to run, and the pressing plate 9 presses the finger. When the pressing plate 9 presses the finger, the PPG sensor 23 comes into contact with the fingertip. In this embodiment, the PPG sensor 23 adopts a dual-wavelength detection mode of 660nm red light and 940nm infrared light, with a sampling rate of 100Hz and a blood flow signal resolution of 0.1μA. When it is in contact with the fingertip, the controller controls the digital tube 26 on the top of the housing 1 to start displaying the time in real time in 0.1-second increments, and the indicator light 25 lights up red to indicate that the detection has entered the timing stage.

[0068] During this process, the PPG sensor 23 continuously captures the blood flow signal of the fingertip: since the pressure plate 9 has completely blocked the capillaries, the fingertip appears pale due to the interruption of blood supply. At this time, the blood flow signal intensity detected by the PPG sensor 23 is maintained at the 0.5μA level; after 3 seconds, the controller controls the negative pressure pump 8 to stop running, and at this time the pressure plate 9 releases the pressure on the fingertip.

[0069] As the pressure is released, the capillaries gradually regain blood supply, the paleness of the fingertip gradually fades, and the blood flow signal intensity detected by the PPG sensor 23 begins to gradually increase. When the blood flow signal value rises to 8μA (in this embodiment, the blood flow signal threshold is preset to 8μA by the controller), the controller immediately stops timing, and the digital tube 26 displays the time from when the pressure stabilizes to when the blood flow recovers, which is the capillary refill time. At the same time, the controller control indicator 25 lights up green to indicate that the detection is complete.

[0070] Throughout the testing process, the lithium battery 28 inside the housing 1 continuously powers the negative pressure pump 8, controller, PPG sensor 23, indicator light 25, and digital tube 26. The controller also has a data storage function, automatically saving the recharge time for each test for easy data traceability and analysis. Furthermore, for different finger sizes (adult finger circumference 8-15mm), the retaining component precisely engages with the retaining pin 20 (diameter 1.5mm) through the limiting hole 22 (1mm spacing), stabilizing the spacing of the pressing plate 9 at the appropriate size. By selecting a tension spring 14 with a tensile deformation force of 5N, the pressing plate 9 maintains a constant pressing force of 5±0.2N on the finger, ensuring that the fit between the PPG sensor 23 and the fingertip is unaffected by finger size, thus ensuring the stability of blood flow signal acquisition and significantly improving the accuracy and reliability of the test.

[0071] like Figure 1 and Figure 2 As shown, specifically, the manual pressing assembly includes a manual pressing block 24 that is fixedly connected to the top of one of the second links 5 by screws.

[0072] In outdoor environments, when the lithium battery 28 has low power, a manual detection mode can be activated to conserve its power. Specifically, the pressure threshold of the pressure sensor 27 is set to 5N. A finger is inserted into the finger sleeve 2, and the manual pressing block 24 is pressed. The upper second link 5 slides downwards, causing the upper first link 4 to rotate clockwise, which in turn rotates the upper sector gear 31 counter-clockwise. This causes the lower sector gear 31 to rotate counter-clockwise, resulting in the lower first link 4 rotating counter-clockwise. This causes the first link 4 to retract, pressing the pressing plate 9 onto the finger. During the pressing process, the pressure sensor 27 monitors the pressing force in real time and transmits the data to the controller. When the pressing force reaches the preset threshold of 5N, the controller triggers a timing function. The digital tube 26 starts timing in 0.1-second increments, and the control indicator 25 lights up red. The pressing force on the manual pressing block 24 is maintained manually.

[0073] When the PPG sensor 23 comes into contact with the finger, it operates synchronously. After the digital display 26 shows 3 seconds, the user can slowly release the manual pressure block 24. The pressure plate 9 gradually releases pressure under the natural elasticity of the finger. As blood flow is restored, the signal strength detected by the PPG sensor 23 gradually increases. When it reaches the threshold of 8μA, the controller stops timing and displays the refill time on the digital display 26. At the same time, the indicator light 25 lights up green to indicate that the detection is complete.

[0074] The flexible silicone pad on the inside of the finger sleeve 2 increases the friction between the finger and the device, preventing finger slippage during manual pressing and ensuring testing stability. The entire manual testing process does not require the negative pressure pump 8 to operate; a single test consumes only 28mAh of lithium battery power, saving over 98% energy compared to automatic mode and effectively extending the device's usability in the field. After testing is complete, the manual pressing block 24 can be manually lifted to return it to its original position for easy manual or automatic testing next time.

[0075] This invention solves the problem of maintaining constant pressure in manual pressing in existing technologies by using a pneumatically telescopic pressing component and a holding component in conjunction. The pneumatically telescopic component drives the first link 4 and the second link 5 in a coordinated manner, combined with the synchronous transmission structure of the sector gear 31, allowing the pressing component to apply uniform pressure to the capillary bed at the fingertip. The holding component can stabilize the pressing pressure in real time, making the measurement results of capillary refill time more accurate and providing reliable data support for clinical assessment of peripheral circulation status. The pressing component has a simple structure and high portability. Compared with electromagnetic or pneumatic pressurization methods, it has higher shock resistance and can accurately maintain a constant pressing pressure even when subjected to external interference such as vibration and bumps, ensuring that the test results are not affected by environmental factors. This provides reliable protection for peripheral circulation monitoring in special scenarios such as field rescue and military medical treatment.

[0076] Meanwhile, the manual pressing component of this invention, when used in field environments, can immediately switch to manual operation mode when the device encounters sudden situations such as pneumatic telescopic component failure or energy depletion, avoiding interruption of detection work due to failure of the core automatic components of the device. Medical personnel can directly drive the second linkage 5 through the manual pressing component to apply pressure to their fingers, and relying on the synchronous transmission structure of the sector gear 31, even manual operation can ensure that the pressing components on both sides are evenly stressed, further improving the applicability and reliability of the device in special scenarios such as field rescue and military medical treatment.

[0077] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A portable capillary refill time detector, comprising a housing (1), a finger sleeve (2) fixedly connected to the side wall of the housing (1), the finger sleeve (2) communicating with the interior of the housing (1); the housing (1) is provided with a pressing component for pressing a finger that extends from the finger sleeve (2) into the housing (1), characterized in that, It also includes a controller; the pressing assembly includes support rods (3) symmetrically arranged on the bottom wall and top wall of the housing (1), each support rod (3) is hinged with a first connecting rod (4), each first connecting rod (4) is fixedly connected with a sector gear (31), and adjacent sector gears (31) mesh with each other; each first connecting rod (4) is hinged with a second connecting rod (5) at the end away from the support rod (3), one of the second connecting rods (5) has its top end penetrating through the top wall of the housing (1) and slidingly engaged with the top wall of the housing (1) and is provided with a manual pressing assembly for manually pressing the finger, and the other second connecting rod (5) is vertically engaged with the bottom wall of the housing (1); A pneumatic telescopic component is provided between adjacent first connecting rods (4) for driving the first connecting rods (4) to expand and close; the pneumatic telescopic component includes a piston cylinder (6), the piston cylinder (6) is hinged to one of the first connecting rods (4), and a piston column (7) is hinged to the other first connecting rod (4), the piston column (7) and the inner wall of the piston cylinder (6) are in sliding fit; an air pipe is connected to the side wall of the piston cylinder (6); A negative pressure pump (8) is fixedly connected to the bottom wall of the housing (1), and the end of the air pipe away from the piston cylinder (6) is connected to the inlet of the negative pressure pump (8); the controller is used to control the operation of the negative pressure pump (8); Each of the adjacent second links (5) is provided with a pressing element for pressing the finger; the pneumatic telescopic component is provided with a retaining component for maintaining the pressing force of the pressing element; The retaining assembly includes a first cavity (10) and a second cavity (11) opened in the piston column (7). The first cavity (10) is connected to the piston cylinder (6), and the second cavity (11) is connected to the first cavity (10). A piston (12) is slidably fitted in the first cavity (10). A rack (13) is fixedly connected to the piston (12). A tension spring (14) is fixedly connected to the end of the rack (13) away from the piston (12). The end of the tension spring (14) away from the rack (13) is fixedly connected to the bottom wall of the second cavity (11). The inner wall of the second cavity (11) is fitted with a rotating shaft (15), a roller shaft (16) is fixedly connected to the rotating shaft (15), a spiral guide block (17) is fixedly connected to the roller shaft (16), and a gear (18) is fixedly connected to one end of the roller shaft (16). The gear (18) meshes with the rack (13). A fixing rod (19) is fixedly connected to the bottom wall of the second cavity (11). A retaining pin (20) is slidably fitted on the fixing rod (19). A number of limiting wheels (21) are rotatably fitted at one end of the retaining pin (20). The end of the retaining pin (20) away from the limiting wheels (21) passes through the side wall of the second cavity (11) and is slidably fitted to the side wall of the second cavity (11). The limiting wheels (21) are all in rolling fit with the spiral guide block (17). The piston cylinder (6) has several limiting holes (22) on its inner side wall, which keep the end of the needle (20) away from the limiting wheel (21) engaged with the limiting hole (22); the piston column (7) has a vent hole, which is connected to the piston cylinder (6); One of the pressing components is equipped with a detection component that measures the capillary refill time.

2. The portable capillary refill time detector according to claim 1, characterized in that, The pressing component includes an arc-shaped pressing plate (9) that is ball-hinged to one end of the second link (5).

3. The portable capillary refill time detector according to claim 2, characterized in that, The detection component includes a PPG sensor (23) fixedly connected to one of the press plates (9), and a controller for receiving finger blood flow signals sent by the PPG sensor (23).

4. The portable capillary refill time detector according to claim 3, characterized in that, The manual pressing assembly includes a manual pressing block (24) fixedly connected to the top of one of the second links (5).

5. The portable capillary refill time detector according to claim 4, characterized in that, An indicator light (25) and a digital tube (26) are fixedly connected to the top of the housing (1). The controller is used to control the digital tube (26) to display the number of seconds and to control the opening and closing of the indicator light (25) based on the blood flow signal.

6. The portable capillary refill time detector according to claim 5, characterized in that, A pressure sensor (27) is fixedly connected to one of the pressing plates (9). The controller is used to receive the pressure signal sent by the pressure sensor (27) from the pressing plate (9) to the finger, and control the digital tube (26) to display the number of seconds and control the opening and closing of the indicator light (25) based on the pressure signal.

7. The portable capillary refill time detector according to claim 6, characterized in that, A lithium battery (28) is also fixedly connected to the bottom wall of the housing (1). The lithium battery (28) is used to power the negative pressure pump (8), controller, PPG sensor (23), indicator light (25) and digital tube (26).

8. The portable capillary refill time detector according to claim 7, characterized in that, A support plate (29) is fixedly connected to the inner wall of the housing (1), and a touch switch (30) is fixedly connected to the side wall of the support plate (29). The controller is used to receive the touch signal of the finger sent by the touch switch (30) and control the operation of the negative pressure pump (8) based on the touch signal. A flexible silicone pad is fixedly connected to the inner wall of the finger sleeve (2), and the surface of the silicone pad is provided with anti-slip texture.

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