Classifications

• • G—PHYSICS
  • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
  • G09B—EDUCATIONAL OR DEMONSTRATION APPLIANCES; APPLIANCES FOR TEACHING, OR COMMUNICATING WITH, THE BLIND, DEAF OR MUTE; MODELS; PLANETARIA; GLOBES; MAPS; DIAGRAMS
  • G09B23/00—Models for scientific, medical, or mathematical purposes, e.g. full-sized devices for demonstration purposes
  • G09B23/28—Models for scientific, medical, or mathematical purposes, e.g. full-sized devices for demonstration purposes for medicine
  • G09B23/285—Models for scientific, medical, or mathematical purposes, e.g. full-sized devices for demonstration purposes for medicine for injections, endoscopy, bronchoscopy, sigmoidscopy, insertion of contraceptive devices or enemas
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
  • A61M25/00—Catheters; Hollow probes
  • A61M25/01—Introducing, guiding, advancing, emplacing or holding catheters
• • G—PHYSICS
  • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
  • G09B—EDUCATIONAL OR DEMONSTRATION APPLIANCES; APPLIANCES FOR TEACHING, OR COMMUNICATING WITH, THE BLIND, DEAF OR MUTE; MODELS; PLANETARIA; GLOBES; MAPS; DIAGRAMS
  • G09B19/00—Teaching not covered by other main groups of this subclass
• • G—PHYSICS
  • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
  • G09B—EDUCATIONAL OR DEMONSTRATION APPLIANCES; APPLIANCES FOR TEACHING, OR COMMUNICATING WITH, THE BLIND, DEAF OR MUTE; MODELS; PLANETARIA; GLOBES; MAPS; DIAGRAMS
  • G09B23/00—Models for scientific, medical, or mathematical purposes, e.g. full-sized devices for demonstration purposes
  • G09B23/28—Models for scientific, medical, or mathematical purposes, e.g. full-sized devices for demonstration purposes for medicine
• • G—PHYSICS
  • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
  • G09B—EDUCATIONAL OR DEMONSTRATION APPLIANCES; APPLIANCES FOR TEACHING, OR COMMUNICATING WITH, THE BLIND, DEAF OR MUTE; MODELS; PLANETARIA; GLOBES; MAPS; DIAGRAMS
  • G09B23/00—Models for scientific, medical, or mathematical purposes, e.g. full-sized devices for demonstration purposes
  • G09B23/28—Models for scientific, medical, or mathematical purposes, e.g. full-sized devices for demonstration purposes for medicine
  • G09B23/30—Anatomical models
  • G09B23/303—Anatomical models specially adapted to simulate circulation of bodily fluids

Definitions

• the present inventor has developed and marketed a catheter simulator that imitates a human body (see Patent Document 1).
• a partition member is built into a mannequin body made of a transparent material, a blood vessel model as a three-dimensional model is supported on one side of the partition member, and an auxiliary device for operating the blood vessel model is disposed.
• the blood vessel model is made of silicone rubber
• the auxiliary device includes a tank, a pump, and a connecting tube.
• the tank contains a circulating fluid, and the circulating fluid is circulated through the blood vessel model via the connecting tube by the pump.
• Patent Document 2 as a document disclosing a technique related to the present invention.
• silicone oil as the circulating fluid was effective in preventing adhesions, but the physical properties of so-called oil-based silicone oils (including those dispersed in water using emulsifiers, etc.) and water-soluble silicone oils such as polyether-modified silicone are so different from those of blood that they do not provide a realistic feel when handling the catheter when it is inserted.
• the inventors have conducted extensive research to achieve lubrication properties that can withstand the same pressing force as when a catheter is inserted into an actual human blood vessel, even when a so-called aqueous circulating fluid is applied to the blood vessel model.
• a specific water-soluble polymer significantly increases the adhesion resistance of the catheter to the blood vessel model, making it closer to the characteristics of the blood vessel in an actual human body during surgery. This allows the catheter to pass through with a similar feel to an actual surgery, without adhesion between the inner surface of the blood vessel model and the catheter, even in areas where a large pressing force is likely to occur during surgery, such as the common iliac artery, aorta, and common carotid artery.
• the hydrophobic group (lipophilic group) of the water-soluble polymer is linked to the inner circumferential surface of the blood vessel model, and the hydrophilic group is exposed.
• the hydrophilic group of the water-soluble polymer is linked to the hydrophilic group, and the hydrophobic group is exposed.
• the hydrophobic group of the water-soluble polymer is linked to the hydrophobic group, and the hydrophilic group is exposed, and so on. In this way, layers of water-soluble polymers are formed on the inner circumferential surface of the blood vessel model in multiple layers.
• the catheter was able to pass easily and with a tactile feel (friction) similar to that during actual surgery, both in areas where a small compressive force is normally applied, such as the cerebral artery area, and in areas where a large compressive force is applied, such as the aorta.
• the inner surface of the blood vessel model By subjecting the inner surface of the blood vessel model to hydrophilic treatment in advance using various methods, it was possible to reproduce lubrication properties similar to those of human blood vessels; however, the properties of the hydrophilic layer formed in this way were prone to change due to deterioration over time, adhesion of foreign matter to the surface, and wear during use.
• the water-soluble polymer attached to the inner surface of the blood vessel model is lost due to wear, etc.
• the water-soluble polymer dissolved in the circulating fluid is re-attached to the inner surface of the blood vessel model to replenish it, so a certain level of properties can be continuously maintained.
• the water-soluble polymer is discharged and removed together with the circulating fluid, and is replenished with new circulating fluid at the next use, so new water-soluble polymer is always supplied and there is no fluctuation in properties.
• the sensation of inserting a catheter into the blood vessel model is close to the sensation of inserting a catheter into a blood vessel in the human body, and the multiple overlapping layers of water-soluble polymer ensure that the catheter maintains its adhesion resistance even when a large pressure is applied to it.
• water-soluble polymers having both hydrophilic and hydrophobic groups include PVA (polyvinyl alcohol) and methyl cellulose.
• Other examples include natural polymers such as proteins and starches, as well as synthetic polymers such as polyacrylic acid, polyacrylamide, polyethylene oxide, poly(vinylpyrrolidone), polyvinylamide, and polyamines.
• the molecular weight (degree of polymerization) and blending amount of these water-soluble polymers can be selected as desired depending on the diameter and area of the inner circumferential surface of the blood vessel model used in the catheter simulator, the type of catheter, etc.
• the blending amount of the water-soluble polymer is preferably about 0.5 to 8.0% by mass relative to water.
• the blending ratio of the water-soluble polymer having hydrophilic groups to the water-soluble polymer having hydrophobic groups is preferably 1:1, i.e., the total amount of hydrophilic groups to the total amount of hydrophobic groups, but is not particularly limited thereto.
• the main chain constituting the polymer needs to have a certain length.
• a lubricity regulator introduced in Patent Document 2 to the circulating fluid, the contents of which are cited herein for reference.
• the water-soluble polymer having both a hydrophilic group and a hydrophobic group, and the mixture of a water-soluble polymer having a hydrophilic group and a polymer having a hydrophobic group are also lubricity adjusters.
• a lubricity regulator it can be blended into the circulating fluid of the catheter simulator alone, together with a surfactant, or together with a surfactant and a water-soluble ionic compound.
• the role of the water-soluble ionic compound in addition to reducing the dynamic friction coefficient, is to prevent adhesion between the silicone rubber and the parts that come into contact with it (i.e., to reduce the static friction coefficient), and to further promote bonding (multilayering) of the water-soluble polymer through interactions (ionic bonds, hydrophobic bonds, hydrogen bonds, covalent bonds, etc.) between the water-soluble ionic compound, surfactant, and water-soluble polymer, while also increasing the toughness of the lubricating layer that is formed.
• the layer consisting of this surfactant and water-soluble ionic compound does not contain a water-soluble polymer, it will easily collapse when the pressure of the catheter increases, causing direct contact between the catheter and the surface of the blood vessel model, resulting in adhesion.
• Water-soluble polymers (same molecule) having hydrophilic and hydrophobic groups, like surfactants, have the effect of forming a lubricating layer between objects (such as between a silicone rubber surface and a catheter surface) to reduce the coefficient of kinetic friction.
• the lubricating layer formed on the inner surface of the blood vessel model was remarkably strong against the catheter's pressing force, especially when a surfactant, a water-soluble ionic compound, and a water-soluble polymer (same molecule) having both hydrophilic and hydrophobic groups were present, and was able to withstand the same catheter pressing force as a human blood vessel.
• aneurysm embolization coils and the like must be stably maintained in place after surgery, and are therefore designed not to slide (move) within biological blood vessels (aneurysms).
• the lubricity of the catheter and guidewire improves (the coefficient of friction drops significantly) as the amount added increases, but no change was observed in the lubricity of the aneurysm embolization coil (the coefficient of friction changes very little).
• the surfactant may be one or more selected from the group consisting of cationic surfactants, anionic surfactants, nonionic surfactants and zwitterionic surfactants, depending on the material of the catheter sheath, etc.
• deionized water it is preferable to use deionized water as the water, but tap water may also be used.
• type of surfactant according to the material of the catheter.
• Teflon registered trademark
• polyethylene which tend to become negatively charged when rubbed
• the sheath is made of a material that tends to become positively charged, such as polyamide, it is preferable to use a zwitterionic surfactant.
• the concentration of the water-soluble metal salt in the circulating fluid is preferably 1 mmol/L or more and 100 mmol/L or less, and more preferably 2 mmol/L or more and 50 mmol/L or less.
• the function of the action of these water-soluble ionic compounds is unclear, but in the absence of water-soluble ionic compounds, when a large pushing force of 5 N (approximately 0.5 kg) or more is applied to the catheter, the degree to which the catheter bites into (adheres) the inner surface of the blood vessel model increases.
• the plastic substrate 21 is fixed to the work mounting surface of a general-purpose machine tool. By operating the machine tool, the substrate 21 moves together with the work mounting surface. As a result, the entire measuring device 20 except the catheter 1 moves in any direction at any speed according to the operation set by the machine tool.
• the left end of the catheter 1 inserted into the blood vessel model 5 is connected to a force sensor, and the force sensor is fixed to the machine tool body or the installation stand of the machine tool body so as to move relative to the mounting surface.
• This reciprocating motion trajectory A was set to reproduce the "movement of vibrating the catheter in small increments at approximately the same position/dithering," which is an operation that is likely to cause adhesions (lubricating layer loss) during actual surgery.
• the small amplitude section provided in the middle of the reciprocating trajectory A is the section that is particularly intended for this operation.
• the horizontal axis of Figure 2 indicates time, and it can be seen from the change in frequency of the graph that the speed of the reciprocating motion of the arm starts slowly and then gradually becomes faster, and then slows down again.
• the circulating fluid containing a surfactant, a water-soluble ionic compound, and a water-soluble polymer was added, and the lubricating layer was maintained throughout the entire measurement period, and the catheter was reciprocated throughout the entire measurement period while maintaining its lubricity, similar to that of human blood vessels.
• Figure 5 shows the results of measurements taken with the rectangular wave-shaped reciprocating motion trajectory B shown in Figure 4 in order to measure the reaction force (insertion force) generated in the catheter during reciprocating motion in a manner that can be compared with the reciprocating motion speed, and explains the method of organizing the measurement data in Figure 6 and subsequent figures.
• the measurement results shown in Figure 6 show that, as an overall trend, in areas with slower movement speeds, the reaction force (catheter insertion force) is greater than in areas with faster movement speeds. It can be confirmed that this trend is suppressed by adding ionic compounds. It can also be confirmed that ionic compounds alone do not exhibit lubricity. It can also be confirmed that the lubricity obtained by surfactants and water-soluble polymers is enhanced by the addition of ionic compounds.
• the water-soluble polymer blended in No. 10 was PEG (molecular weight 200), and the amount added was 4.0 wt %.
• the water-soluble polymer blended in No. 11 was PEG (molecular weight 200), and the amount added was 8.0 wt %.
• the water-soluble polymer blended in No. 12 was PEG (molecular weight 200), and the amount added was 16.0 wt %.
• the water-soluble polymer blended in No. 13 was PEG (molecular weight 1000), and the amount added was 0.8 wt %.
• the water-soluble polymer blended in No. 14 was PEG (molecular weight 2000), and the amount added was 0.8 wt %.
• a pH buffer can be added to the circulating fluid as an auxiliary.
• an acidic circulating fluid with a pH below 5.0 is used, the hydrophilic coating that covers the surface of the catheter is inactivated in a short period of time, causing adverse effects such as a significant decrease in the lubricity of the catheter side.
• a lubricant that provides lubricity between a first member including a crosslinked polymeric material and a second member including a crosslinked polymeric material comprising: A lubricant comprising one or more selected from the group consisting of water, a surfactant, a water-soluble ionic compound, a first water-soluble polymer having a hydrophilic group and a hydrophobic group, a mixture of a second water-soluble polymer having a hydrophilic group and a third polymer having a hydrophobic group, and a mixture of the first water-soluble polymer and the third polymer.

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• 2024
  • 2024-10-09 JP JP2025525192A patent/JP7829978B2/ja active Active
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