JP2010022723A - Thermometric conductivity measuring instrument, skin tissue blood circulation evaluation device and decubitus diagnostic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermometric conductivity measuring instrument being simply usable anywhere by anyone. <P>SOLUTION: This thermometric conductivity measuring instrument 11 includes: a thermal stimulation generation section 24 applying a thermal stimulation to a living body for a predetermined time; a temperature measuring section 25 measuring a temporal change in the temperature of the living body imposed with the thermal stimulation by the thermal stimulation generation section 24; and thermometric conductivity calculation sections 331 and 332 calculating the thermometric conductivity of the living body from the measurement result of the temperature measurement section 25 based on a biological heat conduction equation. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a device for measuring the temperature conductivity of a living body, and further to a device for evaluating the blood flow rate of a living body from the temperature conductivity and a device for determining a pressure ulcer risk.

  Pressure ulcers are skin diseases in which, when a patient becomes bedridden or the like in the same position for a long period of time, the contact portion with the bed is compressed to become ischemic and the surrounding tissues are necrotized. Conventionally known methods for predicting the occurrence of pressure ulcers include a pressure ulcer diagnosis device that evaluates the pressure ulcer risk from the OH scale and the shape of pressure ulcer recurrent sites (see, for example, Patent Document 1).

The OH scale is a scale for evaluating the risk of pressure ulcer development from self-reposition, pathologic bone protrusion, edema, and joint contracture. Each item consists of 0 to 3 points, and the higher the score, the higher the risk of pressure ulcers. In addition, the conventional pressure ulcer diagnosis device measures the height of each other part with respect to the gluteal muscle part in each part such as the gluteal muscle part, the sacrum part, the lumbar part, and the back part on the surface of the human body. The diagnosis is performed.
JP 2000-51181 A

  Since the OH scale performs subjective evaluation on each of the items of self-position change, pathological bone protrusion, edema, and joint contracture, a high degree of expertise is required for predictive diagnosis. Therefore, accurate prediction diagnosis is difficult for nurses and home caregivers who have little experience.

  Further, Patent Document 1 describes that by predicting the occurrence of pressure ulcer from the shape of a pressure ulcer frequent occurrence site, a diagnosis result independent of the skill of the diagnostician can be obtained. However, this pressure ulcer diagnosis device is merely an automated measurement of the shape of the pressure ulcer occurrence site, and there is essentially no difference from the OH scale that predicts the occurrence of pressure ulcer from the appearance.

  On the other hand, a blood flow state in the skin tissue can be considered as an internal factor of pressure ulcer development. As a conventional blood flow rate measuring device, a laser Doppler type or ultrasonic Doppler type blood flow rate measuring device, a thermography for evaluating the skin tissue blood circulation state by measuring the skin surface temperature, and the like are known. However, these devices are complicated, large in size, difficult to operate, and very expensive. Therefore, they are used only in basic research and the like, and are difficult to use in clinical or general homes.

  Therefore, the present invention has been made in view of such a situation. A temperature conductivity measuring device that can be easily used by anyone anywhere, skin tissue blood that evaluates blood flow using temperature conductivity. It aims at providing a circulatory evaluation apparatus and a pressure ulcer diagnostic apparatus.

  In order to achieve the above object, a temperature conductivity measuring device according to the present invention includes a thermal stimulation generating unit that applies thermal stimulation to a living body for a predetermined time, and a living body that has been subjected to thermal stimulation by the thermal stimulation generating unit. A temperature measurement unit that measures a temporal change in temperature; and a temperature conductivity calculation unit that calculates a temperature conductivity of the living body from a measurement result of the temperature measuring unit based on a living body heat conduction equation, Measure the rate.

  The temperature conductivity measuring apparatus having the above configuration can measure the temperature conductivity only by bringing the thermal stimulus generation unit and the temperature measurement unit into contact with the measurement site, and thus does not invade the human body. In addition, since the operation is simple, a general nurse or home caregiver who does not have specialized knowledge can easily measure the temperature conductivity of the patient's skin.

  In this specification, “calculating the temperature conductivity of the living body based on the biological heat conduction equation” means substituting the measurement result of the temperature measuring unit into the biological heat conduction equation stored in the temperature conductivity measuring device. Not only calculating the temperature conductivity but also calculating the temperature conductivity based on a temperature conductivity estimation table obtained using the biological heat conduction equation as described below.

The living body temperature before applying the thermal stimulus is t ₁ , the living body temperature at the time when the predetermined time has passed is t ₂ , and t ₁ / t ₂ is a predetermined value from the time at which the predetermined time has passed. The time to reach is defined as the time constant. The temperature conductivity calculator includes a storage unit that stores a temperature conductivity estimation table that holds a relationship between a time constant and a temperature conductivity that are calculated in advance based on a biological heat conduction equation; and A time constant calculating unit that calculates a time constant based on the detection result; and a temperature conductivity estimating unit that estimates the temperature conductivity of the living body from the time constant based on the temperature conductivity estimation table. Thereby, the temperature conductivity of a living body can be obtained immediately.

  The thermal stimulus generator may be a cooling stimulus generator that applies a cooling stimulus to the living body. “Thermal stimulation” in the present specification includes both cooling stimulation and warming stimulation, but from the viewpoint of measuring temperature conductivity with high accuracy, the cooling stimulation is superior to the heating stimulation. .

  For example, the thermal stimulation generation unit may be configured by a Peltier element. Thereby, it is possible to easily switch between the cooling stimulus and the warming stimulus only by changing the direction of the current flowing in the Peltier element.

  Moreover, the temperature conductivity measuring device according to the present invention includes the sticking member that holds the thermal stimulus generation unit and the temperature measurement unit and is affixed to the surface of a living body, the thermal stimulus generation unit, and the temperature measurement unit. A measuring device including the temperature conductivity calculating unit, a measuring device control unit that controls the operation of the measuring device, and a display unit that displays the temperature conductivity of the living body calculated by the temperature conductivity calculating unit. And an operation terminal connected in a state where data can be transmitted and received.

  Further, the sticking member may be formed of a material that can be deformed along the surface of the living body, and the temperature measuring unit may be disposed so as to protrude from a surface facing the living body surface of the sticking member. . As a result, a highly accurate measurement result can be obtained regardless of the shape of the measurement site.

  Further, the measuring device and the operation terminal are preferably wirelessly connected. Thereby, temperature conductivity can be measured without worrying about the wiring.

  A skin tissue blood circulation evaluation device according to the present invention stores the temperature conductivity measurement device according to any one of the above and a blood flow rate evaluation table that holds a relationship between a previously calculated temperature conductivity and a blood flow rate. And a blood flow rate evaluation unit that evaluates the blood flow rate of the living body from the calculation result of the temperature conductivity calculation unit based on the blood flow rate evaluation table. Since the skin tissue blood circulation evaluation apparatus having the above configuration evaluates the blood flow rate based on an objective numerical value such as temperature conductivity, a highly accurate diagnosis is possible regardless of the skill of the evaluator.

  A pressure ulcer diagnostic apparatus according to the present invention includes a temperature conductivity measuring device according to any one of the above, and a storage unit that stores a pressure ulcer risk determination table that holds a relationship between a previously calculated temperature conductivity and pressure ulcer risk. And a pressure ulcer risk determination unit that determines the risk of pressure ulcers on the living body surface from the calculation result of the temperature conductivity calculation unit based on the pressure ulcer risk determination table. Since the pressure ulcer diagnosis apparatus having the above-described configuration evaluates the risk of pressure ulcer based on an objective numerical value such as temperature conductivity, highly accurate diagnosis is possible regardless of the skill of the evaluator.

  A program according to the present invention includes a thermal stimulus generation unit that applies thermal stimulation for a predetermined time, and a temperature measurement unit that measures a temporal change in the temperature of a living body to which thermal stimulation is applied by the thermal stimulus generation unit. It is executed by the conductivity measuring device, and includes a temperature conductivity calculating step for calculating the temperature conductivity of the living body from the measurement result of the temperature measuring unit based on the biological heat conduction equation.

  The present invention can be realized not only as a temperature conductivity measurement device, a skin tissue blood circulation evaluation device, and a pressure ulcer diagnosis device, but also as a program that causes a computer to execute the characteristic steps included in these devices. You can also. Such a program can be distributed via a recording medium such as a CD-ROM (Compact Disc-Read Only Memory) or a communication network such as the Internet.

  According to the present invention, it is possible to obtain a temperature conductivity measuring device that can easily measure temperature conductivity even by a general nurse or home caregiver who does not have specialized knowledge. Further, by applying this temperature conductivity measuring device, it is possible to obtain a skin tissue blood circulation evaluation device and a pressure ulcer diagnostic device that can be easily used by anyone anywhere.

  With reference to FIGS. 1-3, the temperature conductivity measuring apparatus 11 which concerns on one Embodiment of this invention is demonstrated. 1 is a schematic diagram showing the configuration of the temperature conductivity measuring device 11, FIG. 2 is a block diagram showing the configuration of the temperature conductivity measuring device 11, and FIG. 3 is a cross-sectional view showing the structure of the measuring instrument 21.

  First, as shown in FIGS. 1 and 2, the temperature conductivity measuring device 11 is a device that can easily measure the temperature conductivity of a living body, and includes a measuring device 21 attached to a patient's body and a nurse at the time of measurement. Etc., and the two are connected in a state where data can be transmitted and received.

  The measuring device 21 measures the temperature change of the living body, the communication part 22 for connecting to the operation terminal 31, the sticking member 23 stuck on the surface of the living body, the thermal stimulation generating part 24 for applying thermal stimulation to the living body. The temperature measuring unit 25 is mainly provided. The measuring device 21 applies a thermal stimulus to the living body based on an instruction from the operation terminal 31, measures a temperature change of the living body, and transmits a measurement result to the operation terminal 31.

  The communication unit 22 is a communication interface for transmitting / receiving data to / from a communication unit 32 (described later) of the operation terminal 31. The measuring instrument 21 and the operation terminal 31 in this embodiment are wirelessly connected. Although a specific connection form is not particularly limited, for example, the connection is performed by infrared rays, Bluetooth, or the like. In addition, since the communication part 32 mentioned later is also the same, description is abbreviate | omitted.

  The affixing member 23 is a flat plate-like member affixed to the measurement site, and is formed of a material that can be deformed along the surface of the living body, such as silicon. This improves the reliability of the measurement results even when affixing to a undulating skin surface. Particularly, pressure ulcer sites such as the sacral region are highly undulating, and therefore have advantageous effects when used for pressure ulcer diagnosis described later. In addition, the sticking member 23 holds a thermal stimulus generation unit 24 and a temperature measurement unit 25.

  As shown in FIG. 3, the thermal stimulus generator 24 includes a cylindrical case 241, a heat conduction probe 242 that is stacked inside the case 241, a Peltier element 243, a heat sink 244, and a heat dissipation fan 245. The temperature gradient is generated in the living body by applying thermal stimulation to the surface of the living body. In addition, the thermal stimulus generation unit in this embodiment is a cooling stimulus generation unit that applies a cooling stimulus to a living body, and applies a stimulus having a temperature (25 ° C. to 30 ° C.) that is approximately 5 ° C. lower than the skin temperature.

  The Peltier element 243 is a semiconductor element that absorbs heat on one surface and generates heat on the other surface when a direct current is passed. Since the Peltier element 243 in this embodiment is used as a cooling element, the heat conduction probe 242 is disposed on the side that absorbs heat, and the heat sink 244 and the heat dissipation fan 245 are disposed on the side that generates heat.

  The heat conduction probe 242 is made of a material having high heat conductivity, such as copper or aluminum, and has one end on the heat absorbing surface of the Peltier element 243 and the other end on the center of the sticking member 23. It penetrates. Further, a temperature control sensor 242 a is attached to the heat conduction probe 242. The heat sink 244 and the heat dissipation fan 245 are attached to the heat generating surface of the Peltier element 243, and release the heat of the heat generating surface.

  The temperature measurement unit 25 is a fine thermocouple configured by joining two kinds of metals having different thermoelectric powers, and measures a temporal change in the temperature of the living body. In this embodiment, the temperature measurement unit 25 is concentrically arranged at the tip position of the heat conduction probe 242 and at a plurality of locations 4 mm away from this position. Further, the temperature measuring unit 25 is disposed so as to protrude from the surface (the lower surface in FIG. 3) facing the living body surface of the sticking member 23. Thereby, since it closely_contact | adheres to the biological body surface, a highly accurate temperature measurement is attained.

  The operation terminal 31 includes a communication unit 32 for connection to the measuring instrument 21, a CPU 33 (Central Processing Unit) for controlling the operation terminal 31, a ROM 34 (Read Only Memory) for storing various programs, and the temperature conductivity. A RAM 35 (Random Access Memory) that stores an estimation table and a display unit 36 that displays an operation screen of the measuring instrument 21 and measurement results are mainly provided.

  The CPU 33 reads a time constant calculation program, a temperature conductivity estimation program, a measurement device control program, etc. stored in the ROM 34, and operates as a time constant calculation unit 331, a temperature conductivity estimation unit 332, a measurement device control unit 333, and the like. .

  The time constant calculation unit 331 calculates a time constant based on the detection result of the temperature measurement unit 25. The temperature conductivity estimation unit 332 estimates the temperature conductivity of the living body from the time constant based on a temperature conductivity estimation table 351 described later. The time constant calculation unit 331 and the temperature conductivity estimation unit 332 constitute a temperature conductivity calculation unit.

  The measuring instrument control unit 333 controls the operation of the measuring instrument 21. Specifically, the temperature of the thermal stimulation generator 24 is adjusted based on the cooling temperature and cooling time of the thermal stimulation generator 24, the measurement time of the temperature measurement unit 25, and the detection result of the temperature control sensor 242a. .

  The RAM 35 as a storage unit stores a temperature conductivity estimation table 351. Instead of the RAM 35, another storage device such as a hard disk drive may be employed. The temperature conductivity estimation table 351 holds the relationship between the time constant and the temperature conductivity. FIG. 5 shows a temperature conductivity estimation table 351 that is graphed.

  The display unit 36 is a liquid crystal screen that displays an operation screen of the measuring instrument 21 and a measurement result. If an organic EL display is employed instead of the liquid crystal screen, the operation terminal 31 can be further reduced in size and thickness.

Next, a method for calculating the temperature conductivity of the living body from the detection result of the temperature measurement unit 25 will be described with reference to the equations (1) to (3) and FIG. FIG. 4 is a graph plotting theoretical values and measured values of temperature response when a cooling stimulus is applied to a living body. In the formulas (1) to (3), T is skin tissue temperature (° C.), T _s is skin surface temperature (° C.), T _b is environmental temperature (° C.), and ρ _t is skin tissue density. (Kg / m ³ ), C _t is the specific heat (J / K) of the skin tissue, ΔT is the temperature difference (° C.) between the skin tissue temperature (T) and the skin tissue temperature (T ₀ ) at the start of measurement. , Λ _t is the skin tissue thermal conductivity (m ² / s), ρ _b is the blood density (kg / m ³ ), C _b is the blood specific heat (J / K), and W _b is the tissue unit. Blood flow rate per volume (ml / s), λ _e is total heat transfer rate (m ² / s), Qm is heat produced by metabolism (J), Qe is calorific value (J) per unit volume , Α _t = λ _t / ρ _t C _t indicate the temperature conductivity (m ² / s), respectively.

  First, Equation (1) is Penne's bioheat equation. The left side is the heat accumulation in the skin tissue due to changes over time, the first term on the right side is the heat flow due to heat conduction based on the temperature gradient, the second term is the heat transfer from the arterial blood to the skin tissue, the third term Represents heat production due to metabolism of skin tissue. The third term gives a boundary condition at z = 0.

Next, consider the heat conduction equation at the skin surface and skin tissue cross section. That is, if z = 0 and T = T _s in equation (1), equation (2), which is the heat conduction equation of the skin surface, and y = 0 in equation (1), heat conduction in the skin tissue cross section. Equation (3), which is an equation, can be obtained. In addition, in Formula (2) and Formula (3), it is set as the thing which does not produce heat by metabolism (the 3rd term = 0 of Formula (1)).

In the above formulas (2) and (3), if W _b = 0, an unsteady heat conduction equation is obtained. If these are numerically analyzed, the “apparent temperature conductivity (α _t )” including the influence of the blood flow rate can be calculated. In the present specification, these are referred to as “local skin tissue heat conduction model”.

  Next, an example of calculating the temperature conductivity of a living body using the above-described local skin tissue heat conduction model will be described. First, the temperature response of the skin surface due to cooling stimulation is actually measured (measured value). Specifically, a cooling stimulus is applied for 60 seconds (cooling stimulus period), and the temperature response at the stimulus center position is measured for 120 seconds after the cooling stimulus is released immediately after the start of cooling. The measurement results are indicated by “*” in FIG. On the other hand, the temperature response under the same conditions is numerically calculated by a local skin tissue heat conduction model (theoretical value). The calculation result is indicated by “◯” in FIG.

Next, the temperature conductivity can be identified by adjusting the parameters (especially α _t , λ _e ) of Equation (2) so that the integrated error between the measured value and the theoretical value converges to the minimum value. Finally, the “apparent temperature conductivity” can be calculated by multiplying this temperature conductivity by a correction coefficient. The “correction coefficient” can be obtained by performing the above measurement with a substance having a known temperature conductivity (silicon rubber or the like) and dividing the actual temperature conductivity by the temperature conductivity obtained by experiments.

  In the above description, an example is shown in which only the temperature response at the stimulation center position is measured, but the measurement is performed in the same manner at other portions (in this embodiment, a position 4 mm away from the stimulation center position). By making measurements at multiple locations, the reliability of the results is improved.

  The above method needs to repeatedly calculate equation (2), and requires enormous calculation time. Therefore, a method for simply estimating the temperature conductivity will be described with reference to FIG. FIG. 5 is a diagram showing the relationship between the apparent temperature conductivity and the corresponding time constant.

First, the “apparent temperature conductivity” and a corresponding time constant are calculated using the above-mentioned local skin tissue heat conduction model. In this embodiment, the time from when the cooling stimulus is released (60 seconds) until t ₁ / t ₂ = 0.63 is used as the time constant. The result (FIG. 5) obtained by repeating this procedure is used as the temperature conductivity estimation table 351. If this temperature conductivity estimation table 351 is used, it is possible to calculate a time constant from the measurement result as shown in FIG. 4 and to immediately estimate the temperature conductivity from the time constant.

  Next, the operation of the temperature conductivity measuring device 11 will be described with reference to FIG. FIG. 6 is a diagram showing a procedure for measuring the temperature conductivity by the temperature conductivity measuring device 11. Further, the temperature conductivity estimation table 351 in the RAM 35 holds the relationship as shown in FIG.

  First, the affixing member 23 is affixed to the temperature conductivity measurement site. The thermal stimulation generator 24 applies thermal stimulation to the living body for a predetermined time based on an instruction from the measuring instrument controller 333 (S1). Thereby, a temperature gradient is generated in the living body. In addition, although the time which gives a thermal stimulus can be set arbitrarily, in this embodiment, it demonstrates as 60 seconds. At this time, the measuring instrument controller 333 receives the detection result of the temperature control sensor 242a in real time, and controls the thermal stimulus generator 24 so as to apply a constant thermal stimulus.

  Next, the temperature measurement unit 25 starts measuring the temperature change of the living body at the same time as applying the thermal stimulus, and continues the measurement from the release of the thermal stimulus (after 60 seconds) to a predetermined time (S2). The measurement of the temperature change is preferably continued until the temperature gradient is stabilized (returns to the state before applying the thermal stimulus), and thus continues for about 120 seconds after the release of the thermal stimulus. Further, the measurement result is transmitted to the time constant calculation unit 331 in real time.

Next, the time constant calculation unit 331 calculates a time constant based on the detection result of the temperature measurement unit 25 (S3). Specifically, the time from when the thermal stimulus is released (after 60 seconds elapses) until t ₁ / t ₂ = 0.63 is calculated.

Next, the temperature conductivity estimation unit 332 estimates the temperature conductivity of the living body from the time constant calculated by the time constant calculation unit 331 based on the temperature conductivity estimation table 351 (S4). Then, the result is displayed on the display unit 36. For example, if the time constant calculated by the time constant calculation unit 331 is “16”, “temperature conductivity = 2.9 × 10 ⁻⁷ (m ² / s)” is displayed.

  Since the temperature conductivity measuring device 11 having the above-described configuration only needs to affix the affixing member 23 to the measurement site, there is no invasion of the living body. In addition, since complicated operations are not required, a general nurse or home caregiver who does not have specialized knowledge can easily measure the temperature conductivity of the patient's skin.

  In each of the above embodiments, an example has been shown in which the temperature conductivity is estimated based on the temperature conductivity estimation table 351. However, the present invention is not limited to this, and the temperature conductivity may be calculated by another method. . For example, when the temperature conductivity measuring device 11 is equipped with a very high-speed CPU 33, the temperature conductivity may be calculated using the above-mentioned “local skin tissue heat conduction model”.

  Further, in each of the above embodiments, the example in which the measuring instrument 21 and the operation terminal 31 are wirelessly connected has been described. However, the present invention is not limited to this, and any other connection form can be employed. For example, both may be connected by wire, or may be connected via a network such as a LAN (Local Area Network) or the Internet.

  Further, in each of the above-described embodiments, an example in which the measuring device 21 and the operation terminal 31 are connected on a one-to-one basis has been described. May be controlled. For example, in a hospital, if a plurality of measuring devices 21 assigned to each patient and an operation terminal 31 installed in a nurse station or the like are connected via a hospital network, the measurement results of a plurality of patients are concentrated. Can be managed.

  Further, in each of the above-described embodiments, the example in which the temperature conductivity measuring device 11 is configured by the measuring instrument 21 and the operation terminal 31 has been described. It may be a rate measuring device. Thereby, since the communication parts 22 and 32 become unnecessary, an apparatus structure is further simplified.

  Within the skin tissue, the blood flow of the skin blood vessels plays a leading role in regulating heat transfer. That is, it is considered that the blood circulation state of the skin tissue can be evaluated from the temperature conductivity estimated by the temperature conductivity measuring device 11. Furthermore, it can be applied to the diagnosis of diseases caused by poor blood circulation.

  7 to 14, the relationship between the temperature conductivity and the blood circulation state will be verified, and a skin tissue blood circulation evaluation device 11A as an application example of the temperature conductivity measurement device 11 will be described.

  First, the relationship between the temperature conductivity and the blood circulation state is verified with reference to FIGS. FIG. 7 and FIG. 10 are diagrams showing the results of numerical calculation of the time change of the temperature response of the skin tissue after the thermal stimulation is applied using Equation (2). Specifically, 20 seconds (□), 40 seconds (◇), 60 seconds (△), 80 seconds (×), 100 seconds (*), 120 seconds (◯), 140 seconds (+) after release of thermal stimulation. , 160 seconds (■), 180 seconds (♦), 200 seconds (▲), and 220 seconds (●), the temperature is calculated numerically at intervals of 0.5 mm from the skin surface to a depth of 5 mm. FIG. 7 is a diagram showing a temperature response when a cooling stimulus is applied for a predetermined time, and FIG. 10 is a diagram showing a temperature response when a heating stimulus is applied for a predetermined time.

  Referring to FIG. 7, when a cooling stimulus is applied, the temperature gradient near the skin surface (around 0 mm to 1.5 mm) is very high immediately after the stimulus is released (up to 20 seconds later). Thereafter, the temperature of the skin surface (0 mm) hardly changes between 20 seconds and 100 seconds, the temperature inside the skin (particularly 0.5 mm to 3.0 mm) decreases, and after 100, the temperature gradient is close to a straight line. It becomes. Thereafter (from 100 seconds to 220 seconds), the temperature gradient becomes closer to a straight line, and the gradient gradually decreases.

  On the other hand, with reference to FIG. 10, when a warming stimulus is applied, immediately after the stimulus is released (˜20 seconds), the temperature near the skin surface (0 mm to 2.5 mm) is a negative temperature gradient (the temperature in the deep layer becomes lower). ), The deep layer portion (2.5 mm to 5.0 mm) has a positive temperature gradient (the temperature of the deep layer portion increases). Thereafter, the temperature of the skin surface (0 mm) hardly changes between 20 seconds and 100 seconds, the temperature inside the skin (especially 0.5 mm to 2.0 mm) rises, and after 100 seconds, the temperature is almost negative over the entire area. Temperature gradient. After that, the temperature decreases in almost the entire skin tissue (0 mm to 4.5 mm), but the temperature decreasing rate becomes higher as it is closer to the skin surface. After 120 seconds, the temperature is in an equilibrium state (the temperature is almost constant in the entire skin tissue). After that, the temperature gradient is reversed (becomes a positive temperature gradient).

  As described above, there is a difference in temperature response between when the cooling stimulus is applied and when the warming stimulus is applied. This is because the outside air temperature in a normal environment is lower than the body temperature, so that there is a positive temperature gradient from the skin surface toward the deep layer. That is, heat is transferred from the deep layer of the body through the skin tissue to the outside environment. However, when a warming stimulus is applied, this flow is temporarily reversed (a negative temperature gradient is generated in the vicinity of the skin surface), and a phenomenon in which the temperature gradient is reversed in the middle is observed.

  Next, FIG. 8 and FIG. 11 are the results of numerical calculation of the temperature response of the skin surface when the blood flow rate is changed using the equation (2). Specifically, based on a blood flow rate of 1000 (ml / s), the blood flow rate is a reference value (□), twice the reference value (◇), three times the reference value (△), and four times the reference value. (×) and the temperature response when the reference value is 5 times (◯) are numerically calculated. FIG. 8 is a diagram showing a temperature response when a cooling stimulus is applied for a predetermined time, and FIG. 11 is a diagram showing a temperature response when a heating stimulus is applied for a predetermined time.

  Referring to FIG. 8, when the cooling stimulus is applied, the temperature response is improved as the blood flow rate is increased. On the other hand, referring to FIG. 11, when the warming stimulus is applied, the temperature response is improved as the blood flow rate is decreased. Further, when FIG. 8 is compared with FIG. 11, it is observed that the temperature response is improved when the cooling stimulus is applied (FIG. 8).

  Next, FIG. 9 is a diagram showing a result of deriving the relationship between the temperature conductivity and the blood flow rate from the result of FIG. 8 based on the equation (2). Similarly, FIG. 12 is a diagram showing the result of deriving the relationship between the temperature conductivity and the blood flow rate from the result of FIG. 11 based on the formula (2).

With reference to FIG. 9 and FIG. 12, it was found that there was a linear relationship between temperature conductivity and blood flow rate when either cooling stimulus or warming stimulus was applied. If the blood flow rate is x and the temperature conductivity is y, the relationship of y = 2.0 × 10 ⁻⁸ x + 2.0 × 10 ⁻⁷ in FIG. 9 and y = 1.0 × 10 in FIG. It became clear that the relationship of ⁻⁸ x + 2.0 × 10 ⁻⁷ was established.

  As described above, since it has been clarified that there is a linear relationship between the temperature conductivity and the blood flow rate, the temperature conductivity of the patient's skin can be measured using the temperature conductivity measuring device 11. For example, the blood flow rate at the measurement site can be evaluated. Moreover, as an application example of the temperature conductivity measuring device 11, a skin tissue blood circulation evaluation device 11A as shown in FIGS. 13 and 14 can be obtained. FIG. 13 is a block diagram of the skin tissue blood circulation evaluation apparatus 11A, and FIG. 14 is a diagram illustrating a blood flow evaluation procedure performed by the skin tissue blood circulation evaluation apparatus 11A. 13 includes the configuration of FIG. 2 and FIG. 14 includes the configuration of FIG. 6, common portions are denoted by the same reference numerals and description thereof is omitted.

  First, referring to FIG. 13, in addition to the configuration of the temperature conductivity measuring device 11, the skin tissue blood circulation evaluation device 11A reads the blood flow rate evaluation program stored in the ROM 34A by the CPU 33A of the operation terminal 31A. The RAM 35A functions as the evaluation unit 334, and the blood flow rate evaluation table 352 is stored.

  The blood flow rate evaluation unit 334 evaluates the blood flow rate of the living body from the calculation result of the temperature conductivity estimation unit 332 based on the blood flow rate evaluation table 352. The blood flow rate evaluation table 352 holds the relationship between the temperature conductivity calculated in advance and the blood flow rate. Specifically, the relationship shown in FIG. 9 is maintained when a cooling stimulus is applied, and the relationship shown in FIG. 12 is maintained when a heating stimulus is applied.

Next, the operation of the skin tissue blood circulation evaluation apparatus 11A will be described with reference to FIG. The skin tissue blood circulation evaluation device 11A measures the temperature conductivity of the living body in the same procedure as the temperature conductivity measurement device 11 (S1 to S4). Next, the blood flow rate evaluation unit 334 evaluates the blood flow rate of the living body from the temperature conductivity calculated by the temperature conductivity estimation unit 332 based on the blood flow rate evaluation table 352 (S5). Then, the evaluation result is displayed on the display unit 36. For example, if the calculated temperature conductivity is 2.7 × 10 ⁻⁷ (m ² / s), “blood flow rate = 2” or “blood flow rate = 2000 (ml / s)” is displayed.

  According to the skin tissue blood circulation evaluation apparatus 11A having the above-described configuration, the blood flow rate is evaluated based on an objective numerical value such as temperature conductivity. Therefore, a highly accurate diagnosis is possible regardless of the skill of the evaluator. .

  Next, pressure ulcer (bed slippage) is taken as an example of a disease caused by poor blood circulation, and the relationship between temperature conductivity and the risk of pressure ulcers is verified with reference to FIGS. A pressure ulcer diagnosis device 11B as an application example of the rate measuring device 11 will be described.

  First, with reference to FIGS. 15 to 17, the causal relationship between the temperature conductivity and the risk of pressure ulcer occurrence will be verified. 15 is a histogram showing the results of measuring the temperature conductivity of healthy elderly people, FIG. 16 is a histogram showing the results of measuring the temperature conductivity of elderly hospitalized people, and FIG. 17 is a risk assessment of pressure ulcers based on the OH scale. It is a figure which shows the relationship with the temperature conductivity of an evaluation site | part. In addition, in this specification, an elderly person 65 years or older who has the ability to perform daily life by himself is a “healthy elderly person”, spends a lot of time in a bed or wheelchair, and cannot perform daily life without assistance. Elderly people over the age of 65 are defined as “hospitalized elderly”.

Referring to FIGS. 15 and 16, the average value of the temperature conductivity of healthy elderly people is 2.443 × 10 ⁻⁷ (m ² / s), and the standard deviation is 0.557 × 10 ⁻⁷ (m ² / s). ), However, the average temperature conductivity of hospitalized elderly was 2.004 × 10 ⁻⁷ (m ² / s) and the standard deviation was 0.695 × 10 ⁻⁷ (m ² / s). there were. Moreover, it was recognized that the peak of the healthy elderly in the histogram is higher than the peak of the hospitalized elderly.

  Next, when the risk assessment of pressure ulcer based on the OH scale and the temperature conductivity of the evaluation site are measured for a plurality of elderly people in hospital, etc., a strong negative correlation is found between them as shown in FIG. It turned out to be. Accordingly, when the regression line in FIG. 17 was obtained by setting the risk level of pressure ulcer on the OH scale to x and the temperature conductivity to y, y = −0.2392x + 2.9225.

  As described above, it has been clarified that there is a strong negative correlation between the temperature conductivity and the pressure ulcer risk. Therefore, the temperature conductivity of the patient's skin is measured using the temperature conductivity measuring device 11. If measured, the risk of pressure ulcers at the measurement site can be evaluated. Further, as an application example of the temperature conductivity measuring device 11, a pressure ulcer diagnosis device 11B as shown in FIGS. 18 and 19 can be obtained. FIG. 18 is a block diagram of the pressure ulcer diagnostic device 11B, and FIG. 19 is a diagram showing the pressure ulcer risk level evaluation procedure by the pressure ulcer diagnostic device 11B. 18 includes the configuration of FIG. 2 and FIG. 19 includes the configuration of FIG. 6, common portions are denoted by the same reference numerals and description thereof is omitted.

  First, referring to FIG. 18, in addition to the configuration of the temperature conductivity measuring device 11, the pressure ulcer diagnosis device 11B reads the pressure ulcer risk determination program stored in the ROM 33B by the CPU 33B of the operation terminal 31B and determines the pressure ulcer risk level. The RAM 35B functions as the unit 335 and stores the pressure ulcer risk determination table 353.

  The pressure ulcer risk determination unit 335 determines the risk of pressure ulcers on the living body surface from the calculation result of the temperature conductivity estimation unit 332 based on the pressure ulcer risk determination table 353. The pressure ulcer risk determination table 332 holds the relationship between temperature conductivity and pressure ulcer risk. Specifically, the relationship as shown in FIG. 17 is maintained.

Next, the operation of the pressure ulcer diagnostic apparatus 11B will be described with reference to FIG. The pressure ulcer diagnosis device 11B measures the temperature conductivity of the living body in the same procedure as the temperature conductivity measurement device 11 (S1 to S4). Next, the pressure ulcer risk determination unit 335 evaluates the blood flow rate of the living body from the temperature conductivity calculated by the temperature conductivity estimation unit 332 based on the pressure ulcer risk determination table 353 (S5). Then, the evaluation result is displayed on the display unit 36. For example, if the calculated temperature conductivity is 2.0 × 10 ⁻⁷ (m ² / s), “pressure ulcer risk = 4 (OH scale)” is displayed.

Further, as a modified example, at least one threshold value for temperature conductivity may be held in the pressure ulcer risk determination table 353 instead of the relationship shown in FIG. The pressure ulcer risk may be simply evaluated from the calculated temperature conductivity and this threshold value. Specifically, the pressure threshold risk determination table 353 is set to 1.5 × 10 ⁻⁷ (m ² / s) as the first threshold and 2.0 × 10 ⁻⁷ (m ² / s) as the second threshold. Remember it. If the temperature conductivity calculated by the temperature conductivity estimation unit 332 is less than the first threshold value, “high pressure ulcer risk”, and if it is not less than the first threshold value and less than the second threshold value, “pressure ulcer risk” If it is “moderate” or more than the second threshold value, “small pressure ulcer risk” may be displayed on the display unit 36.

  According to the temperature conductivity measuring device 11B having the above-described configuration, since the risk level of pressure ulcer is evaluated based on an objective numerical value called temperature conductivity, a highly accurate diagnosis is possible regardless of the skill of the evaluator. Become.

  In the above embodiment, an example of a pressure sore has been described as a disease caused by poor blood circulation. However, the present invention is not limited to this, and can be applied to diagnosis of other diseases. For example, the present invention can be applied to diagnosis of cerebral infarction as well as peripheral circulatory disorders such as Reynold's disease and white wax disease.

  Moreover, in each said embodiment, although the example which provided the cooling stimulus as a heat stimulus was shown, it is not restricted to this, A temperature conductivity can be estimated even if a heat stimulus is provided. However, as verified using FIG. 7 and FIG. 10, when a heating stimulus is applied, the flow of heat is reversed in the middle, so it is desirable to apply a cooling stimulus from the viewpoint of measurement accuracy. .

  Furthermore, the present invention can be realized not only as the temperature conductivity measuring device 11, the skin tissue blood circulation evaluation device 11A, and the pressure ulcer diagnostic device 11B as described above, but also the characteristic components included in these devices. Steps (that is, steps described in FIGS. 6, 14, and 19) are realized as temperature conductivity measurement methods, skin tissue blood circulation evaluation methods, and pressure ulcer diagnosis methods, and characteristic steps included in these devices It can also be realized as a program for causing a computer to execute. Such a program can be distributed via a recording medium such as a CD-ROM or a communication network such as the Internet.

  As mentioned above, although embodiment of this invention was described with reference to drawings, this invention is not limited to the thing of embodiment shown in figure. Various modifications and variations can be made to the illustrated embodiment within the same range or equivalent range as the present invention.

  The present invention is advantageously used in a temperature conductivity measuring device that measures the temperature conductivity of a living body.

It is the schematic which shows the structure of the temperature conductivity measuring apparatus which concerns on one Embodiment of this invention. It is a block diagram of a temperature conductivity measuring device. It is sectional drawing of the measuring device of FIG. It is the figure which plotted the theoretical value and measured value of the temperature response when a cooling stimulus is provided to the living body. It is a figure which shows the relationship between apparent temperature conductivity and a corresponding time constant. It is a figure which shows the measurement procedure of the temperature conductivity by a temperature conductivity measuring apparatus. It is a figure which shows the time change of the temperature response of the skin tissue after giving a cooling stimulus. It is a figure which shows the temperature response of the skin surface with respect to the cooling irritation | stimulation when changing a blood flow rate. It is a figure which shows the relationship between the temperature conductivity when a cooling stimulus is provided, and the blood flow rate. It is a figure which shows the time change of the temperature response of the skin tissue after giving a heating stimulus. It is a figure which shows the temperature response of the skin surface with respect to a heating irritation | stimulation when changing a blood flow rate. It is a figure which shows the relationship between the temperature conductivity when a warming stimulus is provided, and the blood flow rate. 1 is a block diagram of a skin tissue blood circulation evaluation apparatus according to an embodiment of the present invention. It is a figure which shows the evaluation procedure of the blood flow by the skin tissue blood circulation evaluation apparatus. It is a histogram which shows the result of having measured the temperature conductivity of healthy elderly people. It is a histogram which shows the result of having measured the temperature conductivity of the hospitalized elderly person. It is a figure which shows the relationship between temperature conductivity and the risk assessment of pressure ulcer by OH scale. It is a block diagram of the pressure ulcer diagnostic apparatus which concerns on one Embodiment of this invention. It is a figure which shows the evaluation procedure of the pressure ulcer risk by a pressure ulcer diagnostic apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Temperature conductivity measuring apparatus 11A Skin tissue blood circulation evaluation apparatus 11B Pressure ulcer diagnostic apparatus 21 Measuring device 22, 32 Communication part 23 Pasting member 24 Thermal stimulus generation part 25 Temperature measuring part 33, 33A, 33B CPU
34, 34A, 34B ROM
35, 35A, 35B RAM
36 Display unit 241 Case 242 Thermal conduction probe 242a Temperature control sensor 243 Peltier element 244 Heat sink 245 Heat dissipation fan 331 Time constant calculation unit 332 Temperature conductivity estimation unit 333 Measuring instrument control unit 334 Blood flow rate evaluation unit 335 Pressure ulcer risk determination unit 351 Temperature conductivity estimation table 352 Blood flow rate evaluation table 353 Pressure ulcer risk determination table

Claims (10)

A temperature conductivity measuring device for measuring the temperature conductivity of a living body,
A thermal stimulation generator that applies thermal stimulation to the living body for a predetermined time;
A temperature measuring unit for measuring a temporal change in the temperature of a living body given thermal stimulation by the thermal stimulation generating unit;
A temperature conductivity measuring device comprising: a temperature conductivity calculating unit that calculates a temperature conductivity of a living body from a measurement result of the temperature measuring unit based on a living body heat conduction equation. The living body temperature before applying the thermal stimulus is t ₁ , the living body temperature at the time when the predetermined time has passed is t ₂ , and t ₁ / t ₂ is a predetermined value from the time at which the predetermined time has passed. If time to reach is defined as a time constant,
The temperature conductivity calculator is
A storage unit for storing a temperature conductivity estimation table that holds a relationship between a time constant and a temperature conductivity calculated in advance based on a biological heat conduction equation;
A time constant calculating unit for calculating a time constant based on the detection result of the temperature measuring unit;
The temperature conductivity measurement device according to claim 1, further comprising: a temperature conductivity estimation unit that estimates a temperature conductivity of a living body from the time constant based on the temperature conductivity estimation table. The temperature conductivity measuring device according to claim 1, wherein the thermal stimulus generator is a cooling stimulus generator that applies a cooling stimulus to the living body. The temperature conductivity measuring device according to any one of claims 1 to 3, wherein the thermal stimulation generator is configured by a Peltier element. An adhesive member that holds the thermal stimulus generation unit and the temperature measurement unit and is affixed to the surface of a living body, a measuring instrument including the thermal stimulus generation unit and the temperature measurement unit,
The temperature conductivity calculation unit, a measurement device control unit for controlling the operation of the measurement device, and a display unit for displaying the temperature conductivity of the living body calculated by the temperature conductivity calculation unit, and transmission and reception of data with the measurement device The temperature conductivity measuring device according to any one of claims 1 to 4, comprising an operation terminal connected in a possible state. The sticking member is formed of a material that can be deformed along the surface of a living body,
The temperature conductivity measuring device according to claim 5, wherein the temperature measuring unit is disposed so as to protrude from a surface of the sticking member facing the living body surface. The temperature conductivity measuring device according to claim 5 or 6, wherein the measuring device and the operation terminal are wirelessly connected. The temperature conductivity measuring device according to any one of claims 1 to 7,
A storage unit for storing a blood flow rate evaluation table that holds a relationship between the temperature conductivity calculated in advance and the blood flow rate;
A skin tissue blood circulation evaluation apparatus comprising: a blood flow rate evaluation unit that evaluates a blood flow rate of a living body from a calculation result of the temperature conductivity calculation unit based on the blood flow rate evaluation table. The temperature conductivity measuring device according to any one of claims 1 to 7,
A storage unit for storing a pressure ulcer risk determination table that holds a relationship between a pre-calculated temperature conductivity and pressure ulcer risk;
A pressure ulcer diagnosis apparatus comprising: a pressure ulcer risk determination unit that determines the risk of pressure ulcers on the surface of a living body from the calculation result of the temperature conductivity calculation unit based on the pressure ulcer risk determination table. The thermal conductivity measuring device includes a thermal stimulation generating unit that applies thermal stimulation for a predetermined time, and a temperature measuring unit that measures a temporal change in the temperature of the living body given thermal stimulation by the thermal stimulation generating unit. A program
A program including a temperature conductivity calculating step of calculating a temperature conductivity of a living body from a measurement result of the temperature measuring unit based on a living body heat conduction equation.

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