A method for monitoring bleeding volume

Abstract

The present invention provides a method for monitoring blood loss, which is used for a maternity pad capable of monitoring blood loss. In the present invention, the printed electrodes on the first flexible electrode layer are arranged in rows and the printed electrodes on the second flexible electrode layer are arranged in columns to form an array, and the measurement points of the maternity pad at the i-th row and the j-th column are determined; by using the design of the measurement points, after the power is turned on, the relevant voltage information V ij , liquid infiltration percentage M ij are obtained. Then, through data fitting, the area A of the group where the measurement point is located is obtained. Finally, the volume V is output via the liquid diffusion model, so as to obtain the blood loss information on the maternity pad, which is convenient for medical staff to take the next treatment measures. The detection method of the present invention can accurately detect the blood loss of the parturient during the operation and does not cause a stinging sensation, and has the value of popularization.

Description

Technical Field

[0001] The invention relates to the technical field of medical care equipment, and in particular to a bleeding volume monitoring method of a maternity pad capable of monitoring bleeding volume. Background Art

[0002] With the continuous development of science and technology and the continuous improvement of people's living standards, people are increasingly inclined to intelligent development, especially in the field of medicine and health. After giving birth, medical staff need to accurately grasp the amount of postpartum bleeding. There are many ways to evaluate the amount of bleeding. The simplest and easiest is visual estimation, but the visual estimation method needs to rely on the experience of medical staff, because everyone's experience is very different, and visual estimation of bleeding often has large errors. Researchers are more in the direction of blood volume monitoring. Patent document No. CN113049638A discloses a liquid content measurement device, system and nursing products. By arranging multiple impedance measurement units on nursing products such as diapers or maternity pads, when the humidity of the nursing products changes, the resistance value of the impedance measurement unit decreases, and then the liquid content in the current nursing products can be calculated. This method requires multiple sensors to be arranged on the nursing products, but this method uses a separate lead wire for the sensor, resulting in too many signal lines, too high cost, and is not practical.

[0003] Moreover, when conducting tests, most products require power to the impedance test unit. When nursing products such as maternity pads are soaked with blood, they will form a conductive loop with the test circuit, causing a tingling sensation in the human body, making it difficult to ensure product safety.

[0004] In view of this, we designed a monitoring system with a maximum power supply of 2.5V and a maximum current of 25uA, which can accurately detect the amount of bleeding during surgery without causing any stinging. Summary of the invention

[0005] In view of the deficiencies in the prior art, the object of the present invention is to provide a method for monitoring bleeding volume, which is accurate and efficient.

[0006] The technical solution adopted by the present invention to solve the technical problem is:

[0007] The present invention discloses a method for monitoring bleeding volume, which is used for a puerperium pad capable of monitoring bleeding volume, and comprises the following steps:

[0008] Step 1: The maternity pad is provided with a measuring point, the power of the maternity pad is turned on, and liquid is dripped into the pad to simulate liquid infiltration;

[0009] The maternity pad comprises a water-absorbing layer, and a first flexible electrode layer and a second flexible electrode layer are respectively arranged on both sides of the water-absorbing layer; the first flexible electrode layer and the second flexible electrode layer both comprise printed electrodes arranged in parallel; the printed electrodes on the first flexible electrode layer and the printed electrodes on the second flexible electrode layer are arranged in a vertical and horizontal cross pattern; the first flexible electrode layer and the second flexible electrode layer are connected with wires, and the wires are electrically connected to a power supply; the printed electrodes on the first flexible electrode layer are arranged in an array as rows and the printed electrodes on the second flexible electrode layer are arranged in columns, and the measurement points of the maternity pad in the i-th row and the j-th column are recorded;

[0010] Step 2: Scan the maternity pad and collect the voltage V at the measuring point. ij , and convert the voltage information into liquid penetration percentage M ij , the liquid penetration percentage M ij Satisfies the following formula:

[0011]

[0012] M ij =100% means 100% penetration of liquid, M ij =0% means no liquid penetration;

[0013] Step 3: According to the liquid penetration percentage M ij , and the infiltration area is determined by grouping the liquid penetration measurement points into a certain number of groups, and the start time T of the group is recorded start , infiltration time t;

[0014] The infiltration time t=clock-T start , clock is a single-chip computer clock electrically connected to the maternity pad;

[0015] Step 4: Perform equivalent fitting on each group of data of the liquid penetration area to estimate the weighted area A of the group k :

[0016] Let, the spacing between the printed electrodes of the same flexible electrode layer is (Δx, Δy), then each measurement point represents an area ΔA = ΔxΔy, then the area A of the group is calculated k for:

[0017] A k =∑ ij M ij ΔxΔyδ ij

[0018] k∈[1,2,3,...]i∈[1,2,…,m]j∈[1,2,…,n]

[0019]

[0020] Step 5: Substitute the infiltration time t of step 3 and the weighted area A of the group of step 4 k , substitute into the liquid diffusion model and output volume V;

[0021] Repeat steps 2-5.

[0022] Wherein, the liquid diffusion model described in step 5 is:

[0023]

[0024] V=Σ k V k

[0025] Among them, A k is the weighted area of ​​the group;

[0026] V is the total liquid volume, V k is the volume of the kth group of liquid;

[0027] a and b are mathematical fitting results and have no specific physical meaning;

[0028] t k is the infiltration time of a group;

[0029] t d is the diffusion time constant, t e is the evaporation time constant.

[0030] On the basis of the above scheme and as a preferred scheme of the above scheme, the water absorbing layer is made of a water absorbing resin.

[0031] On the basis of the above scheme and as a preferred scheme of the above scheme, the printed electrode is screen-printed conductive ink, and the conductive ink is one of copper foil, silver paste, and carbon paste materials.

[0032] On the basis of the above solution and as a preferred solution of the above solution, the distance between adjacent printed electrodes of the same flexible electrode layer is 45-65 mm.

[0033] On the basis of the above solution and as a preferred solution of the above solution, the voltage V at the measuring point is ij The range is 0-2.5V.

[0034] The beneficial effects of the present invention are:

[0035] Compared with the prior art, the present invention utilizes the design of the measuring point, obtains the voltage information related to the measuring point and the liquid penetration percentage after the power is turned on, and then obtains the area of ​​the group where the measuring point is located through data fitting, and finally outputs the volume through the liquid diffusion model, thereby obtaining the bleeding amount information on the maternity pad, which is convenient for medical staff to take the next step of treatment measures. The detection method of the present invention can accurately detect the bleeding amount of the parturient during the operation without causing tingling, and has promotion value. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a flow chart of the steps of the present invention;

[0037] Figure 2 This is a schematic diagram of the structure of the maternity pad of the present invention;

[0038] Figure 3 is a schematic diagram of the connection structure of the first flexible electrode layer and the second flexible electrode layer;

[0039] Figure 4 This is the fitting diagram of the liquid diffusion model;

[0040] Figure 5 Comparison chart of the measured volume of the liquid diffusion model and the actual test volume.

[0041] In the figure, 12 is the first flexible electrode layer; 13 is the water absorption layer; 14 is the second flexible electrode layer; 2 is the printed electrode; 3 is the wire. DETAILED DESCRIPTION

[0042] The present invention is further explained below in conjunction with specific embodiments, and the technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] Embodiment 1

[0044] like Figure 1-3 As shown, a method for monitoring bleeding volume comprises the following steps:

[0045] Step 1: The maternity pad is provided with a measuring point, the power of the maternity pad is turned on, and liquid is dripped into the pad;

[0046] The maternity pad comprises a water-absorbing layer 13, and a first flexible electrode layer 12 and a second flexible electrode layer 14 are respectively arranged on both sides of the water-absorbing layer 13; the first flexible electrode layer 12 and the second flexible electrode layer 14 both comprise printed electrodes 2 arranged in parallel; the printed electrodes 2 on the first flexible electrode layer 12 and the printed electrodes 2 of the second flexible electrode layer 14 are arranged in a vertical and horizontal cross pattern; the first flexible electrode layer 12 and the second flexible electrode layer 14 are connected with wires 3, and the wires 3 are electrically connected to a power supply; the printed electrodes 2 on the first flexible electrode layer 12 are arranged in rows and the printed electrodes 2 on the second flexible electrode layer 14 are arranged in columns to record the maternity pad measurement points of the i-th row and the j-th column;

[0047] Step 2: Scan the maternity pad and collect the voltage V at the measuring point. ij , and convert the voltage information into liquid penetration percentage M ij , the liquid penetration percentage M ij Satisfies the following formula:

[0048]

[0049] M ij =100% means 100% penetration of liquid, M ij =0% means no liquid penetration;

[0050] Step 3: According to the liquid penetration percentage M ij , and group the adjacent liquid penetration measurement points into a certain number of groups, determine the infiltration area, and record the start time T of the group start , calculate the infiltration time t;

[0051] The infiltration time t=clock-T start , clock is the current time recorded by the clock of the single-chip computer electrically connected to the maternity pad;

[0052] Step 4: Perform equivalent fitting on each group of data of the liquid penetration area to estimate the weighted area A of the group k :

[0053] Let, the spacing between the printed electrodes 2 of the same flexible electrode layer is (Δx, Δy), then the surface area represented by each measurement point is ΔA = ΔxΔy, then the weighted area A of the group is calculated k for:

[0054] A k =∑ ij M ij ΔxΔyδ ij

[0055] k∈[1,2,3,…]i∈[1,2,…,m]j∈[1,2,…,n]

[0056]

[0057] M ij It is M mxn The maternity pad measurement point at the i-th row and j-th column in , m and n represent the number of electrodes on the first flexible electrode layer 12 and the second flexible electrode layer 14 respectively. In this embodiment, m=8 and n=8.

[0058] Step 5: Substitute the infiltration time t of step 3 and the weighted area A of the group of step 4 k , substitute into the liquid diffusion model and output volume V;

[0059] Repeat steps 2-5.

[0060] Wherein, the liquid diffusion model described in step 5 is:

[0061]

[0062] V=Σ k V k

[0063] Among them, A k is the weighted area of ​​the group;

[0064] V is the total liquid volume, V k is the volume of the kth group of liquid;

[0065] a and b are mathematical fitting results and have no specific physical meaning;

[0066] t k is the infiltration time of a group;

[0067] t d is the fitted diffusion time constant, t e is the fitted evaporation time constant.

[0068] Specifically, V in this embodiment max is 2.5V, when V ij =2.5V, no liquid penetrates into the measuring point; when V ij = 0 V, the measuring point is completely penetrated by liquid.

[0069] Furthermore, in step 3, the infiltration time t=clock-T start , clock is the microcontroller clock electrically connected to the maternity pad, T start Start time: When there is no liquid on the maternity pad, the timer does not record time, that is, T start =clock, so the soaking time t=0. In this embodiment, in order to remove the influence of noise, ij =10%, the timer starts timing, that is, Tstart ≠clock. Further, according to the liquid penetration percentage M ij The liquid penetration measurement points are grouped into a certain number of groups and the infiltration areas are determined. The specific grouping rules are as follows:

[0070] 1. If there is liquid (M ij >0.1), but not grouped, check whether there is liquid around the measuring point (i, j): if not, create a group and record the infiltration time t of the group; if yes, classify the measuring point into the group of surrounding measuring points; if there are multiple groups around, merge all the groups, and the infiltration time t is the longest infiltration time.

[0071] 2. When there is liquid and group at the measuring point (i, j), update M ij ;

[0072] 3. No liquid (M ij ≤0.1), and continue to the next point.

[0073] Since the thickness of the maternity pad is much smaller than its length and width, the maternity pad can be regarded as a two-dimensional plane. After a small amount of liquid (1-2 ml) is dripped in, it can penetrate the water-absorbing layer 13 very quickly, resulting in supersaturation of the dripping point area (M ij >100%), and laterally penetrates to the surrounding area under supersaturated pressure to form a wet area, that is, a group. In this process, the thickness direction is completely penetrated under wet conditions. In this embodiment, the thickness of the maternity pad is 0.85-1 mm, and it is also 0.85-1 mm after infiltration.

[0074] Furthermore, the weight of the water-absorbing layer 13 in this embodiment is 176 g / m 2 , and the liquid diffusion model described in step 5 is:

[0075]

[0076] V=Σ k V k

[0077] Among them, A k is the weighted area of ​​the group;

[0078] V is the total liquid volume, V k is the volume of the kth group of liquid;

[0079] a and b are mathematical fitting results and have no specific physical meaning;

[0080] t k is the infiltration time of a group;

[0081] td is the fitted diffusion time constant, t e is the fitted evaporation time constant.

[0082] In the above formula, a is affected by the thickness of the water-absorbing layer 13. The thicker the water-absorbing layer 13 is, the greater the gram weight per unit area is, and the greater a in the formula is; aV b It refers to the maximum liquid content after the water-absorbing layer is full. In actual application, the water-absorbing layer 13 will become slightly thicker during the water-absorbing process, but the water-absorbing material per unit area is not increased, so aV in the formula is not correct. b The coefficient a will not change under the same type of maternity pad conditions.

[0083] In general practical applications, liquid diffusion has three processes, namely: rapid diffusion (0-30s), slow diffusion (1-30min), and evaporation (≥30-40min), which can be expressed by A(t) = aV b α(t)β(t) reflects liquid diffusion:

[0084] α(t) is the wetting excitation function, which is a function that increases with time from 0 to 1. The increasing speed is the liquid diffusion speed. In this case, α(t) is Used to reflect the liquid diffusion rate;

[0085] β(t) is the evaporation excitation function, which is a function that decreases with time from 1 to 0. The decreasing speed is the evaporation speed of the liquid. In this case, β(t) is It is used to reflect the evaporation rate of liquid.

[0086] aV b The maximum wetted area when the volume of liquid is V.

[0087] The liquid diffusion model of the present invention can more completely reflect the liquid diffusion process, and then use the infiltration time t of step 3 and the area A of the group in step 4 k , substituting it into the liquid diffusion model, the blood penetration volume V can be output.

[0088] Furthermore, the water-absorbing layer 13 is made of water-absorbing resin, which is a new functional polymer material with good water absorption function, and can accelerate the penetration of blood, etc. Furthermore, the printed electrode 2 is screen-printed conductive ink, and the conductive ink is one of copper foil, silver paste, and carbon paste materials to ensure good conductivity.

[0089] Furthermore, the distance between adjacent printed electrodes 2 of the same flexible electrode layer is 45 mm, which can provide relatively accurate feedback of the volume V.

[0090] like Figure 4As shown, with reference to the standard GB / T 8939-2018, a standard synthetic liquid was used as a blood equivalent liquid for simulation testing, and the liquid was dripped at a rate of 3 mL per minute and a measurement interval of 1 minute to determine the liquid diffusion model. Figure 4 This is the fitting diagram of the liquid diffusion model, and the liquid diffusion model satisfies the following formula:

[0091]

[0092] After the power is turned on, the maternity pad is scanned and tested. The infiltration time t, the area A of the group k , substitute into the liquid diffusion model, output volume V, and compare the liquid diffusion model measured volume with the actual test volume to obtain Figure 5 The comparison results. Figure 5 This is a comparison chart between the measured volume of the liquid diffusion model and the actual test volume. From the comparison information, it can be seen that the liquid measurement error is 40mL.

[0093] Embodiment 2

[0094] The difference from the above-mentioned first embodiment is that the distance between adjacent printed electrodes 2 of the same flexible electrode layer is 55 mm, and the rest is the same as the first embodiment.

[0095] Embodiment 3

[0096] The difference from the above-mentioned embodiment 1 is that the distance between adjacent printed electrodes 2 of the same flexible electrode layer is 65 mm, and the rest is the same as the embodiment 1.

[0097] Embodiment 4

[0098] Different from the above-mentioned embodiment 1, the distance between adjacent printed electrodes 2 of one flexible electrode layer is 65 mm, and the distance between adjacent printed electrodes 2 of another flexible electrode layer is 45 mm, thereby forming a rectangular unit area. The rest is the same as the embodiment 3.

[0099] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A method for monitoring bleeding volume, used for a maternity pad capable of monitoring bleeding volume, characterized in that: The following steps are involved: Step 1: The maternity pad is provided with a measuring point, the power of the maternity pad is turned on, and liquid is dripped into the pad; The maternity pad comprises a water-absorbing layer (13), and a first flexible electrode layer (12) and a second flexible electrode layer (14) are respectively arranged on both sides of the water-absorbing layer (13); the first flexible electrode layer (12) and the second flexible electrode layer (14) both comprise printed electrodes (2) arranged in parallel; the printed electrodes (2) on the first flexible electrode layer (12) and the printed electrodes (2) on the second flexible electrode layer (14) are arranged in a vertical and horizontal manner; the first flexible electrode layer (12) and the second flexible electrode layer (14) are connected with wires (3), and the wires (3) are electrically connected to a power source; the printed electrodes (2) on the first flexible electrode layer (12) are arranged in an array with the printed electrodes (2) on the first flexible electrode layer (12) as rows and the printed electrodes (2) on the second flexible electrode layer (14) as columns, and the maternity pad measurement points of the i-th row and the j-th column are recorded; Step 2: Scan the maternity pad and collect the voltage V at the measuring point. ij , and convert the voltage information into liquid penetration percentage M ij , the liquid penetration percentage M ij Satisfies the following formula: M ij =100% means 100% penetration of liquid, M ij =0% means no liquid penetration; Step 3: According to the liquid penetration percentage M ij , and group the adjacent liquid penetration measurement points into a certain number of groups, determine the infiltration area, and record the start time T of the group start , calculate the infiltration time t; The infiltration time t=clock-T start , clock is the current time recorded by the clock of the single-chip computer electrically connected to the maternity pad; Step 4: Perform equivalent fitting on each group of data of the liquid penetration area to estimate the weighted area A of the group k : Let, the spacing between the printed electrodes (2) of the same flexible electrode layer is (Δx, Δy), then the representative area of ​​each measurement point is ΔA = ΔxΔy, then the weighted area A of the group is calculated k for: Step 5: Substitute the infiltration time t of step 3 and the weighted area A of the group of step 4 k , substitute into the liquid diffusion model and output volume V; Repeat steps 2-5; Wherein, the liquid diffusion model described in step 5 is: V=∑ k V k Among them, A k is the weighted area of ​​the group; V is the total liquid volume, V k is the volume of the kth group of liquid; a and b are mathematical fitting results and have no specific physical meaning; t k is the infiltration time of a group; t d is the fitted diffusion time constant, t e is the fitted evaporation time constant.

2. A method for monitoring bleeding volume according to claim 1, characterized in that: The water absorbing layer (13) is made of water absorbing resin.

3. A method for monitoring bleeding volume according to claim 1, characterized in that: The printed electrode (2) is screen-printed conductive ink, and the conductive ink is one of copper foil, silver paste and carbon paste materials.

4. A method for monitoring bleeding volume according to claim 3, characterized in that: The distance between adjacent printed electrodes (2) on the same flexible electrode layer is 45-65 mm.

5. A method for monitoring bleeding volume according to claim 1, characterized in that: The voltage V at the measuring point ij The range is 0-2.5V.

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