Viscoelastic composition and method for ensuring endoscope field of view

Abstract

The object of the present invention is to provide a viscoelastic composition having excellent operability and suitable for use in ensuring the field of view of an endoscope by pushing away a dark liquid that obscures the field of view of the endoscope when the dark liquid accumulates inside a tube and blocks the field of view of the endoscope, and a method for ensuring the field of view of an endoscope using the viscoelastic composition. The viscoelastic composition for ensuring the field of view of an endoscope contains a substance exhibiting viscoelastic properties and water, and preferably has a hardness of 550 N / m 2 Below, the viscosity (25°C) is 200-2000mPa·s, the loss tangent is below 0.6, and further preferably the conductivity is below 250μS / cm. The method for ensuring the field of view of the endoscope includes delivering the viscoelastic composition from the hand side of the endoscope through the channel into the front end of the endoscope.

Description

[0001] This application is a divisional application of the following application:

[0002] Invention Name: Viscoelastic composition

[0003] International filing date: September 28, 2016

[0004] International Application Number: PCT / JP2016 / 078704

[0005] National application number: 201680056961.1 Technical Field

[0006] The present invention relates to a viscoelastic composition suitable for ensuring the visual field of an endoscope and a method for ensuring the visual field of an endoscope using the viscoelastic composition. More specifically, the present invention relates to a viscoelastic composition suitable for ensuring the visual field of an endoscope by pushing away a dark liquid that obstructs the visual field of an endoscope when the dark liquid accumulates inside a canal and blocks the visual field of the endoscope, and the viscoelastic composition has excellent operability and a method for ensuring the visual field of an endoscope using the viscoelastic composition. Background Art

[0007] Endoscopes can observe the inside of thin tubes such as the digestive tract and bile duct. However, when dark liquids such as blood, intestinal fluid, bile, and other light-blocking liquids, food residues, and semi-solid substances such as excrement accumulate inside the tube, the endoscope's field of view will be blocked, and the state inside the tube cannot be fully observed. In such a case, in the past, the endoscope's field of view was ensured by sending water or air inside the tube. Sending water refers to a method of injecting water such as tap water into the tube to flush away the liquid and semi-solid substances inside the tube. This method temporarily ensures the field of view by removing the liquid and semi-solid substances inside the tube, but the removed liquid and semi-solid substances are mixed with tap water, etc., and the suspended opaque liquid will diffuse into the tube, and it is often still difficult to ensure the field of view. In addition, air supply refers to a method of sending air into the tube to remove the liquid and semi-solid substances inside the tube. This method also temporarily ensures the field of view by removing the liquid and semi-solid substances inside the tube, but it is difficult to remove blood when there is a bleeding site, and the field of view cannot be ensured. Therefore, there is a problem that the determination of the bleeding site and the operation of hemostasis treatment are accompanied by difficulties. Therefore, there is an urgent need to develop a method that has excellent operability and ensures the visual field of the endoscope.

[0008] Furthermore, Patent Document 1 discloses a method for treating urinary incontinence, anal incontinence, vesicoureteral reflux, etc. by injecting a hydrogel composed of a cross-linked polymer into the urethra or rectum.

[0009] Patent Document 2 discloses a hydrogel composition comprising polysaccharides, a synthetic polymer, and a crosslinking agent. The hydrogel composition is crosslinked and solidified using a buffer solution to form an adhesive hydrogel.

[0010] Patent Document 3 discloses a method of treating a body cavity such as the uterus by filling it with a physiological fluid such as physiological saline or lactated Ringer's solution to expand the body cavity.

[0011] Prior art literature

[0012] Patent Literature

[0013] Patent Document 1: Japanese Patent Application No. 2007-506463

[0014] Patent Document 2: Japanese Patent Application No. 2013-510175

[0015] Patent Document 3: Japanese Patent Publication No. 2000-513970 Summary of the invention

[0016] Problems to be solved by the invention

[0017] The present invention aims to provide a viscoelastic composition with excellent operability, which is suitable for use in ensuring the visual field of an endoscope by pushing away a dark liquid that obscures the visual field of an endoscope when the dark liquid accumulates inside a tube and blocks the visual field of the endoscope, and a method for ensuring the visual field of an endoscope using the viscoelastic composition. In addition, it is desirable to provide the viscoelastic composition that can assist in a simple hemostatic treatment.

[0018] Solutions for solving problems

[0019] The present inventors have conducted intensive research to solve the above problems, and as a result, have found that it is useful to use a viscoelastic composition having viscosity and elasticity, and in particular, by specifying the physical property values ​​of hardness, viscosity, and loss tangent, the operability of the endoscope is excellent and a good visual field can be ensured. Furthermore, it has been found that by adjusting the conductivity of the viscoelastic composition of the present invention, a good visual field can be ensured and a simple hemostatic treatment can be assisted.

[0020] [1] A viscoelastic composition for ensuring an endoscope field of view, comprising a thickening substance and water.

[0021] [2] The viscoelastic composition according to [1], which has a hardness of 550 N / m 2 The viscosity at 25°C is 200 to 2000 mPa·s, and the loss tangent is 0.6 or less.

[0022] [3] The viscoelastic composition according to [2], wherein the electrical conductivity is 250 μS / cm or less.

[0023] [4] A method for ensuring the field of view of an endoscope, comprising: delivering the viscoelastic composition described in any one of [1] to [3] from the hand side of the endoscope through a channel to the front end of the endoscope.

[0024] [5] The method according to [4], wherein the endoscope is a medical endoscope.

[0025] Effects of the Invention

[0026] The viscoelastic composition of the present invention has the properties of viscosity and elasticity, and can physically push away liquids such as blood, intestinal fluid, bile, food residues, and semi-solids such as excrement through its viscoelasticity. In addition, since the viscoelastic composition is difficult to mix with the previous liquid and semi-solid, it will not suspend, and since it has an appropriate consistency, it will not spread, and a good visual field can be ensured. In addition, the viscoelastic composition of the present invention reduces the conductivity by not containing or minimally containing charged substances, thereby ensuring the visual field in the presence of the viscoelastic composition and assisting hemostasis measures such as electrocuting or electrocoagulation. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a diagram showing a photograph of the hand side portion of a medical endoscope.

[0028] Figure 2A This is a conceptual diagram showing the state of the digestive tract after bleeding.

[0029] Figure 2B This is a conceptual diagram showing the state when water is introduced into the digestive tract after bleeding.

[0030] Figure 3A This is a conceptual diagram showing the state of the digestive tract after bleeding.

[0031] Figure 3B This is a conceptual diagram showing a state when the viscoelastic composition of the present invention is delivered into the digestive tract after bleeding.

[0032] Figure 4A This is a conceptual diagram showing the inside of a tube before the viscoelastic composition is injected.

[0033] Figure 4B This is a diagram for explaining an evaluation method from the viewpoint of ensuring the visual field when the viscoelastic composition is used in an endoscope. Figure 4B This is a diagram showing the viscoelastic composition of the present invention after injection.

[0034] Figure 5A This is a conceptual diagram showing the inside of a tube before the viscoelastic composition is injected.

[0035] Figure 5BThis is a diagram for explaining an evaluation method from the viewpoint of ensuring the visual field when the viscoelastic composition is used in an endoscope. Figure 5B This is a diagram showing a viscoelastic composition after injection as a comparative example.

[0036] Figure 6 This is a graph showing the relationship between the viscosity and loss tangent of a viscoelastic composition and the pass / fail status of visual field securing when used in an endoscope.

[0037] Figure 7 This is a graph showing the relationship between the viscosity and hardness of a viscoelastic composition and the suitability of operability when used in an endoscope.

[0038] Figure 8 This is a graph showing the relationship between the hardness and loss tangent of the viscoelastic composition and the acceptance / suitability of visual field and operability when used in an endoscope.

[0039] Fig. 9 This is a diagram showing an example of a camera image obtained when water is injected from the forceps port of an endoscope.

[0040] Fig.10 This is a diagram showing an example of a camera image obtained when the viscoelastic composition of the present invention is injected from the forceps port of an endoscope.

[0041] Fig.11 This is a diagram showing the results of thermal coagulation treatment using high-frequency current injected into the gas phase and performed using an endoscope.

[0042] Fig.12 This is a diagram showing the results of a thermal coagulation treatment using high-frequency current with an endoscope while injecting tap water.

[0043] Fig.13 The diagram shows the results of a thermal coagulation treatment using a high-frequency current performed by an endoscope after injecting physiological saline.

[0044] Fig.14 This is a diagram showing the results of a thermocoagulation treatment using a high-frequency current using an endoscope after injecting a viscoelastic composition having an electrical conductivity of 1.8 mS / m.

[0045] Fig.15 This is a diagram showing the results of a thermocoagulation treatment using a high-frequency current using an endoscope after injecting a viscoelastic composition having an electrical conductivity of 12.8 mS / m.

[0046] Fig.16 This is a diagram showing the results of a thermocoagulation treatment using a high-frequency current using an endoscope after injecting a viscoelastic composition having an electrical conductivity of 22.4 mS / m.

[0047] Fig.17 This is a diagram showing the results of a thermocoagulation treatment using a high-frequency current using an endoscope after injecting a viscoelastic composition having an electrical conductivity of 60.8 mS / m. DETAILED DESCRIPTION

[0048] The viscoelastic composition of the present invention contains a thickening substance and water.

[0049] The viscoelastic composition of the present invention is prepared by combining one or more thickening substances that have the effect of increasing viscosity when dispersed in water. Examples of such thickening substances include alcohols such as methanol, ethanol, 2-propanol, 1,4-butanediol, 1,3-butanediol, propylene glycol, catechin, glucose, fructose, galactose, sucrose, lactose, maltose, trehalose, xylitol, sorbitol, mannitol, glucosamine, and galactosamine;Aureobasidium culture medium, flaxseed gum, gum arabic, arabic galactan, alginic acid and its salts, propylene glycol alginate, welan gum, cassia gum, ghatti gum, curdlan, carrageenan, karaya gum, xanthan gum, guar gum, guar gum hydrolysate, psyllium seed gum, artemisia sphaerocephala seed gum, gellan gum, succinoglycan, tamarind gum, tara gum, dextran, tragacanth gum, furcellaran, funoran, pullulan, pectin, macrophage gum, neutral gum Gum), fructan, locust bean gum, acrylic starch, acetylated adipic acid cross-linked starch, acetylated oxidized starch, acetylated phosphate cross-linked starch, sodium starch octenylsuccinate, carboxymethyl cellulose and its salts, carboxymethyl ethyl cellulose, acetic starch, oxidized starch, sodium starch glycolate, hydroxypropylated phosphate cross-linked starch, hydroxypropyl cellulose, hydroxypropyl starch, hydroxypropyl methylcellulose, hydroxymethyl cellulose, hydroxyethyl methyl cellulose, hydroxyethyl cellulose, ethyl cellulose, methyl cellulose, cellulose, phosphate cross-linked starch, phosphorylated starch, phosphate monoesterified phosphate cross-linked starch, fucoidan, diutan gum, glucomannan, hyaluronic acid and its salts, keratan sulfate, heparin, chondroitin sulfate, dermatan sulfate, scleroglucan, schizophyllan, okra extract, aloe vera extract (Krantzaloe extracts), sesbania gum, agarose, agaropectin, amylose, amylopectin, pregelatinized starch, inulin, levan, graminan, agar, hydrophobic hydroxypropyl methylcellulose, sodium starch glycolate, dextran, dextrin, cross-linked sodium carboxymethyl cellulose, glucuronoxylan, arabinoxylan and other polysaccharides; gelatin, hydrolyzed gelatin, collagen and other proteins; polyamino acids such as polyglutamic acid, polylysine, polyaspartic acid;Hydrophilic polymers such as carboxyvinyl polymers, polyacrylic acid and its salts, partially neutralized polyacrylic acid, polyvinyl alcohol, polyvinyl alcohol / polyethylene glycol graft copolymers, polyethylene glycol, polypropylene glycol, polybutylene glycol, etc.; metal salts such as calcium chloride, aluminum hydroxide, magnesium chloride, copper sulfate, etc.;

[0050] The water used in the viscoelastic composition of the present invention is not particularly limited, but preferably soft water, pure water, deionized water, distilled water, or a physiological aqueous solution such as physiological saline, Ringer's solution, or Ringer's acetate solution.

[0051] The viscoelastic composition of the present invention may contain additives such as a preservative and an antiseptic agent.

[0052] The present invention aims to provide a viscoelastic composition that is excellent in operability and can ensure a good visual field, and ideally, to provide a viscoelastic composition that can assist in simple hemostasis treatment. As a result, it is believed that among these problems, the main reason why the visual field of the endoscope is blocked is that: 1) liquids such as blood, intestinal fluid, bile, food residues, semi-solids such as excrement accumulate in the lumen; 2) liquids such as blood, intestinal fluid, bile, food residues, semi-solids such as excrement mix with water and impair transparency; 3) liquids such as blood, intestinal fluid, bile, food residues, semi-solids such as excrement flow and spread due to water supply. In order to ensure a good visual field, by injecting a transparent composition having a different viscoelasticity from liquids such as blood, intestinal fluid, bile, semi-solids such as excrement into the lumen, it is possible to ensure space by physically pushing and removing these substances, and it is difficult to mix with liquids such as blood, intestinal fluid, bile, semi-solids such as excrement, so that the flow and spread of the liquid can be suppressed. The problem of excellent operability is that the viscoelastic composition can be passed through the forceps port of an endoscope without excessive resistance. The problem of being able to assist in simple hemostatic treatment is that the presence of the viscoelastic composition can confirm the bleeding site and can also assist in hemostatic treatment using high-frequency current.

[0053] The hardness of the viscoelastic composition of the present invention is 550 N / m 2 Below, preferably 400N / m 2 The viscosity (25° C.) is 200 to 2000 mPa·s, preferably 500 to 1500 mPa·s, and the loss tangent is preferably 0.6 or less.

[0054] By setting the hardness to the above range, the operability when injected through the channel of the endoscope is good. In addition, by setting the viscosity and the loss tangent to the above range, it is improved from the viewpoint of ensuring the visual field. It should be noted that, from the viewpoint of ensuring the visual field, the viscoelastic composition can be transparent.

[0055] Furthermore, the electrical conductivity of the viscoelastic composition of the present invention is preferably 250 μS / cm or less, and more preferably 200 μS / cm or less.

[0056] Furthermore, by setting the electrical conductivity within the above range, it is possible to obtain a viscoelastic composition that suppresses leakage current and is particularly suitable for treatments such as electroresection and electrocoagulation.

[0057] When the viscoelastic composition of the present invention is obtained by mixing the above-mentioned thickening substance with water, specifically, it can be obtained by combining two or more of the thickening substances; or by dissolving one thickening substance in water or the like and applying elasticity by heat treatment; etc. The viscoelastic composition of the present invention is preferably one that does not substantially contain bubbles, because bubbles in the viscoelastic composition block the field of vision.

[0058] The method for ensuring the visual field of an endoscope of the present invention comprises: delivering the viscoelastic composition of the present invention from the hand side portion of the endoscope through a channel to the front end portion of the endoscope.

[0059] Figure 1 This is a diagram showing a photograph of the hand side portion of a medical endoscope as a representative example of an endoscope. The hand side portion is equipped with: a dial 11 for performing angle operation; a scope connector portion 12 for transmitting light from a light source device and image information to a processor for an electronic endoscope; and a forceps opening 15 for inserting treatment tools such as forceps and delivering them to the front end portion 1. A channel connecting the forceps opening to the front end portion, a water supply pipe for water washing of the lens at the front end portion, an optical system, etc. are provided in an endoscope flexible tube 17. Figure 1 The forceps opening 15 of the medical endoscope shown is equipped with a forceps cover 16. One end of the tube 13 is connected to the forceps cover 16, and the other end of the tube is connected to a connector 14 for attaching a syringe or the like. The forceps cover 16 has a valve body, and one end of the tube 13 opens at the wall surface of the forceps opening 15 side of the valve body in the forceps cover 16. When a treatment tool such as forceps is inserted, the valve body prevents liquid sent through the tube from flowing out (for example, refer to Japanese Patent Publication No. 2014-155677).

[0060] Example

[0061] Reference example

[0062] An endoscope can be inserted into the digestive tract, such as the rectum, and the inside of the digestive tract can be observed using the endoscope. When bleeding occurs in the digestive tract 4, blood 3 accumulates in the digestive tract, and the bleeding site 2 cannot be observed ( Figure 2A). At this time, an attempt was made to fill a syringe with tap water, and use the syringe to send water into the digestive tract from the opening of the front end 1 of the endoscope through the tube 13, the forceps mouth 15, and the channel, and to flush out the accumulated blood with the water. However, the accumulated blood and the sent water will mix and suspend together, turning into turbid water 3". When the turbid water 3" accumulates in the digestive tract, the field of view of the endoscope is blocked by the turbid water 3", and the bleeding site 2 cannot be observed, and the operation cannot be continued ( Figure 2B , Fig. 9 ).

[0063] It should be noted that, according to the viscoelastic composition of the present invention, Figure 3A , Figure 3B As shown, when a bleeding site 2 occurs in the digestive tract 4, the viscoelastic composition is introduced from the distal end of the endoscope to push away blood 3 (blood 3') accumulated in the digestive tract, thereby enabling observation of the bleeding site 2.

[0064] Examples and Comparative Examples

[0065] In the present examples and comparative examples, the relationship between the viscoelastic properties of the viscoelastic composition used in the endoscope and the securing of the visual field and the operability during the operation of the endoscope was studied.

[0066] The following describes a method for measuring the physical property values ​​of the viscoelastic composition and an evaluation method from the viewpoint of ensuring the visual field and the viewpoint of operability when the viscoelastic composition is used in an endoscope.

[0067] (1) Viscosity and loss tangent

[0068] The viscosity / viscoelasticity was measured using HAAKE RS-6000 (Thermo Fisher Scientific Co., Ltd.). The viscoelastic composition was placed on a sample stand and measured using a P35 Ti L parallel plate (measurement conditions: temperature 25°C, gap 1.000 mm, stress 1000 mPa, frequency 0.5000 Hz), and the value was measured 30 minutes after the start of the measurement.

[0069] (2) Hardness

[0070] The measurement was performed using a Creep meter Model RE2-33005C (Yamden Co., Ltd.). The viscoelastic composition was filled into a stainless steel culture dish (outer diameter 45 mm, inner diameter 41 mm, outer dimension 18 mm, inner dimension 15 mm), aligned with the height of the culture dish and the surface of the sample was leveled. The measurement was performed using a Plunger (Yamden Co., Ltd., shape: circular plate, model: P-56, abstract: φ20×t 8) (measurement conditions: storage interval 0.02 sec, measurement distortion rate 66.67%, measurement speed 10 mm / sec, return distance 5.00 mm, sample thickness 15.00 mm, contact surface diameter 20.00 mm, contact area 0.000 mm) 2 ).

[0071] (3) Conductivity

[0072] The conductivity was measured using a conductivity meter CM-41X (DKK Toa Corporation) and a CT-57101C battery for low conductivity (measurement conditions: temperature 25° C.).

[0073] (4) Evaluation method of visual field assurance

[0074] 3 mL of 1% Evans blue solution (pigment solution) was injected into the Dean-Stark tube, and a catheter equipped with a wire was inserted. In this state, the field of vision was blocked by the pigment solution, and the wire at the top of the tube could not be observed. Figure 4A , Figure 5A ). 10 mL of viscous compositions with different loss tangents, hardnesses, and viscosities were injected into the pigment solution through a catheter (inner diameter 2.5-3 mm, length 1000 mm), and the pass or fail of visual field assurance was determined by visual inspection. When a certain viscous composition A was injected, physical space was ensured and it was difficult to mix with the pigment solution. Therefore, it was determined that the viscous composition A exerted the desired viscoelastic properties and was determined to be "passed" as a viscoelastic composition ( Figure 4B On the other hand, when a viscous composition B different from the viscous composition A was injected, the physical space was not clearly ensured, and mixing with the pigment solution was observed. Therefore, it was determined that the viscous composition B did not exhibit the desired viscoelastic properties and was judged as "unqualified" as a viscoelastic composition ( Figure 5B ).

[0075] The results obtained in the evaluation of the visual field assurance correspond to, for example, Fig. 9 , Fig.10 That is, when the endoscope is inserted into the bleeding site and tap water is injected, Fig. 9As shown in FIG. 1 , due to the turbid water, the visual field obtained from the camera is poor. In addition, when the endoscope is inserted into the bleeding site and the viscoelastic composition having the desired viscoelastic properties is injected, as shown in FIG. Fig.10 As shown, the bleeding site 2 can be clearly grasped in the field of view obtained by the camera.

[0076] (5) Operational evaluation method

[0077] Since the viscoelastic composition for visual field assurance is injected into the digestive tract through the forceps port of the endoscope (inner diameter 2.8-3.8mm), it is ideal to be able to be injected smoothly without excessive resistance. A 50mL syringe (JMS Co., Ltd.) was filled with viscoelastic compositions with different loss tangents, hardnesses, and viscosities, and a catheter (inner diameter 3mm, length 1.000mm) simulating the inner diameter of the forceps port of the endoscope was assembled at the top of the syringe, and the passability of the viscoelastic composition was subjectively determined. A viscoelastic composition that can pass smoothly or has some resistance but is within the practical allowable range will be judged as "suitable". On the other hand, a viscoelastic composition that is too impractical due to excessive resistance or too large to pass will be judged as "unsuitable".

[0078] [Test Example 1] Relationship between loss tangent, hardness and viscosity of viscoelastic composition

[0079] Viscoelastic compositions with different loss tangents, hardnesses, and viscosities were prepared, and visual field assurance and operability were determined for each viscoelastic composition. The values ​​of each physical property and their correlation were evaluated. The loss tangents of the viscoelastic compositions that were determined to be "acceptable" for visual field assurance were all about 0.6 or less, and those that exceeded this value were all "unacceptable" ( Figure 6 The hardness of the viscoelastic composition whose operability was judged to be "suitable" was about 550 N / m 2 Below, the viscosity is about 2000mPa·s or less, and if it exceeds this value, it is "unsuitable" ( Figure 7 The loss tangent and hardness of the viscoelastic composition satisfying both the visual field assurance of "acceptable" and the operability of "suitable" are the same values ​​as above ( Figure 8 ). According to these experimental examples, it is preferred that the loss tangent of the viscoelastic composition for ensuring the visual field during endoscopic treatment and excellent operability is set to 0.6 or less, and the hardness is set to 550 N / m 2 Hereinafter, the viscosity is set to 200 to 2000 mPa·s.

[0080] [Test Example 2] Electrical conductivity of viscoelastic composition

[0081] There are three methods for hemostasis using an endoscope: a method based on thermal coagulation using high-frequency current, a method using a clip, and a method using a drug. In the thermal coagulation method, a high-frequency current flows through the bleeding site, and the heat generated at the bleeding site is concentrated to coagulate the tissue to stop bleeding. At this time, generally speaking, when there is a solution or substance with high conductivity around the bleeding site, the high-frequency current will leak electricity and sufficient thermal coagulation cannot be performed.

[0082] Based on this knowledge, processing and evaluation were performed in the following steps.

[0083] A small tube (about 1.5 cm in diameter) was pressed against the surface of the rat's liver, and filled with physiological saline, distilled water, or a viscoelastic composition prepared in a manner with different conductivity. The tip of the monopole (Edge coating blade electrode E1450X) was gently pressed against the liver surface, and the current was turned on for 2 seconds in the coagulation mode (SurgiStat II, Covidien Japan Co., Ltd., coagulation output set to 20). In the gas phase ( Fig.11 ) and low conductivity tap water ( Fig.12 ) was observed to be fully thermally coagulated, but in the case of high conductivity saline ( Fig.13 ) found that the thermal coagulation was poor. In addition, in the case of a viscoelastic composition ( Fig.14 , Fig.15 ) was observed to be sufficiently thermally coagulated. In addition, at a viscoelastic composition ( Fig.16 ), thermal coagulation was observed to a degree that is not a problem in practical use, but at high conductivity, for example, 60.8 mS / m (608 μS / cm) ( Fig.17 ) was found to be poor in thermal coagulation. According to these experimental examples, considering the use of high-frequency current for thermal coagulation hemostasis, the conductivity of the viscoelastic composition for ensuring the visual field during endoscopic treatment and excellent operability is preferably 25 mS / m or less, and more preferably 20 mS / m or less. The results are also shown in the following Table 1.

[0084] [Table 1]

[0085] Table 1 Electrical conductivity of viscoelastic compositions (thermal coagulation)

[0086]

[0087] *E: Excellent (sufficient thermal coagulation was observed)

[0088] G: Good (thermal coagulation observed)

[0089] NG: Not good (insufficient heat setting)

[0090] Table 2 below shows viscoelastic compositions that were evaluated as "suitable" in terms of operability during endoscopic treatment and that achieved thermal coagulation using high-frequency current, and also shows whether visual field security was acceptable or not for each viscoelastic composition.

[0091] [Table 2]

[0092]

[0093] Description of reference numerals:

[0094] 1 Endoscope front end

[0095] 2 Bleeding site

[0096] 3. 3' Blood

[0097] 3” turbid water

[0098] 11 Dial

[0099] 12 Mirror body connector

[0100] 13 Tube

[0101] 14 Connectors

[0102] 15 Pliers mouth

[0103] 16 Pliers cover

[0104] 17 Endoscope flexible tube.

Claims

1. A viscoelastic composition for ensuring the visual field of an endoscope, wherein: Contains thickening substances and water, with an electrical conductivity of less than 250μS / cm. The field of vision of the endoscope is ensured by pushing away the dark liquid or semi-solid object that obstructs the field of vision of the endoscope when the dark liquid or semi-solid object accumulates inside the tube and blocks the field of vision of the endoscope.

2. The viscoelastic composition according to claim 1, wherein The viscoelastic composition has a loss tangent of 0.6 or less, wherein the loss tangent is a value measured 30 minutes after the start of measurement under measurement conditions of a temperature of 25 degrees, a gap of 1.000 mm, a stress of 1000 mPa, and a frequency of 0.5000 Hz.

3. The viscoelastic composition according to claim 1, wherein Hardness: 550N / m 2 Below, the viscosity at 25°C is 200 to 2000 mPa·s.

4. The viscoelastic composition according to claim 1, wherein The viscosity-increasing substance is composed of polysaccharides or hydrophilic polymers.

5. The viscoelastic composition according to claim 2, wherein The viscosity-increasing substance is composed of polysaccharides or hydrophilic polymers.

6. The viscoelastic composition according to claim 3, wherein The viscosity-increasing substance is composed of polysaccharides or hydrophilic polymers.

7. A method for ensuring the field of view of an endoscope, comprising: The viscoelastic composition according to any one of claims 1 to 6 is fed from the hand side portion of the endoscope through the channel to the front end portion of the endoscope.

8. The method according to claim 7, wherein: Endoscopes are medical endoscopes.

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