RU86475U1 - CARDIODYLATION DEVICE - Google Patents

Abstract

A pneumatic cardiodilator containing a probe in the form of a tube with one closed end and an expanding multilayer balloon connected to it, the inner and outer layers of which are made of elastic material, and the middle reinforcing layer, which provides a dumbbell-shaped balloon and inflates it only to a certain limit, is made of dense synthetic fabric, characterized in that the probe is made in the form of a tube of hard plastic, mainly PVC or PET, and the outer and inner layers of the expanding balloon are made of cre organosilicon rubbers obtained on the basis of polyorganosiloxane elastomers with a molecular weight of from 20,000 to 60,000 units. and having a shore hardness of A not higher than 40 units, mainly from polydimethylmethylvinylsiloxane.

Description

The utility model relates to medicine, namely, to devices for sensing hollow organs, and can be used for cardiodilation - expansion of the esophageal-gastric transition in the treatment of cardiospasm (cardiac achalasia).

For cardiodilation, pneumatic cardiodilators (PCD) are most often used, consisting of a radiopaque tube - a probe, on the closed end of which an elastic balloon is expanded, expanding with air pressure.

As a rule, PKD cylinders are a single-layer or multi-layer (two-, three-layer) construction with different wall thickness depending on the required strength and a given diameter.

Among the well-known PCDs, for several years preference was given to atraumatic products (USSR author's certificate SU 249570), where the probe is made of solid rubber with a multilayer dumbbell-shaped cylinder fixed at its end, the inner and outer layers of which are also made of rubber, and the middle layer is of dense synthetic fabric . Moreover, the diameter of the outer elastic layer of the cylinder is less than the diameter of the inner layers.

The non-invasiveness of such a PCD is provided, first of all, by the softness of the external rubber balloon shell, whose hardness in conditions of units (according to Shore A) is not more than 40 units and elongation at break reaches 100%.

When deflating the rubber balloon described above, its outer shell remains soft and does not prevent the PCD from entering the esophagus and withdrawing from the esophagus without injuring the latter.

However, despite a number of obvious advantages of all-rubber PKD, their release and use are currently discontinued. This circumstance is due to two significant drawbacks of these products. So, rubber products are not resistant to biological environments of the body, primarily to acidic environments. Under the influence of an acidic environment, rubber products quickly age, while losing their basic properties necessary for cardiodilation - softness and elasticity. Sterilization by ionizing radiation and some types of chemical sterilization have a similar effect on solid-rubber PCDs.

In addition, due to the flexibility of the rubber probe, it is possible to conduct the PCD through the throat and esophagus only with the help of a guide (conductor), usually metal with a spring tip. To this end, an obliquely short channel is provided at the end of the probe. As a result, passing along the guide through the esophagus using a short oblique channel, the end of the PCD, as a rule, meets resistance in the narrowing zone, as a result of which the probe bends in the enlarged part of the esophagus. All this causes pain in the patient, complicates the conduct of PKD through the narrowing zone and fixation of the dumbbell-shaped balloon at the desired location.

In recent years, for the manufacture of PCDs and other dilatation devices used in medicine, various plastics, as well as various synthetic textile (woven or woven) materials, have been used as systems that reinforce balloon shells.

Numerous US patents: No. 4540404, 4637396, 4710181, 4738666, 5033007, 5066298, 5116318, 5417707, 5425710, 5868707, describe PKD and other devices for dilating various designs, for the manufacture of which various plastic materials are used.

Among the recommended plastics are polyethylene and its copolymers with polyacrylic and polymethacrylic acid, copolymers of polymethacrylic acid, fluorinated polymers, polyurethane, polyvinyl chloride (PVC).

Currently, PCDs are widely used by the well-known medical corporation Wilson-Cook (USA), which specializes in the production of medical polymer products. So, in the application for the invention of this incorporation (US application for invention No. 384114 dated 02/06/95) and in its patents (US patents Nos. 5681344 and 6488653) there are PKD with cylinders, the outer shell of which is made of polyethylene terephthalate (PET).

The PKD described above are more resistant to aggressive environments and easier to maintain than solid rubber, as they can wind up in the esophagus due to the included PVC or PET probes, the rigidity of which is sufficient to perform this manipulation without the use of guides.

At the same time, modern PCDs need further improvement. Medical personnel who use them in practice are faced with such negative phenomena as the folding of the outer shell of dilatation cylinders, as well as the lack of a dumbbell shape in their design. The latter circumstance greatly complicates the fixation of the dumbbell balloon in the obstruction of the esophageal-gastric transition.

When plastic cylinders are blown away, as a rule, rigid assemblies are formed on the outer surface of the cylinders, regardless of their design, that traumatize the mucous membrane of the patient’s pharynx and esophagus, both during institution and when the doctor removes the PCD at the beginning and end of the procedure.

In addition, microcracks form in the places of wrinkling on the outer surface of the cylinders, which prevents the long-term use of PCDs. The service life of plastic PCDs intended for individual use only does not exceed 3-4 cycles.

Even the use of such a flexible and soft polymer as medical polyurethane, which is characterized by low hardness, from 70 units for the manufacture of a PCD balloon shell. Shore A and high elongation at break (up to 700%), does not exclude this drawback.

Thus, the task of creating a PCD that meets the requirements of modern medicine, atraumatic, easy to use and at the same time designed for long-term use, has not yet been completely resolved.

The claimed utility model allows you to find the solution you need.

The problem is solved due to the fact that the PKD contains a probe in the form of a tube with one closed end and an expanding multilayer balloon, the inner and outer layers of which are made of elastic material, and the middle reinforcing layer, providing a dumbbell-shaped balloon and inflating it only to a certain limit, made of dense synthetic fabric, while the probe is made in the form of a tube of hard plastic, and the outer and inner layers of an expanding balloon of organosilicon rubbers obtained on the basis of poly rganosiloksanovyh elastomers having a molecular weight of from 20,000 to 60,000 units. and having a shore hardness of not higher than 40 units.

As a material for the manufacture of the probe used PVC or PET.

The outer and inner layers of the expanding balloon are made of polydimethylmethylvinylsiloxane (PDMMVS).

The technical result from the use of the utility model is to increase the operational properties of the product by eliminating the formation of microcracks and wrinkles on the outer surface of the cylinders, improving the comfort of the PCD installation, as well as increasing the durability of the product and making it possible to repeatedly sterilize without compromising product quality.

The technical result is achieved due to the fact that the PCD is performed in the form of a combination of a relatively rigid plastic probe and a soft and flexible multilayer balloon, the reinforcing layer of which is formed by a semi-synthetic fabric, and the inner and outer layers are made of silicone rubber based on PMMVS with a molecular weight of from 20,000 to 60,000 units

The achievement of the technical result is due to the fact that such organosilicon rubbers have increased softness, characterized by a Shore A hardness index of 20-30 units and a relative elongation at break of at least 1000%. Silicone balloons based on them do not form folds when deflated, which avoids the trauma of patients. Cracking of the cylinders is also not observed, and the combination of a sufficiently rigid probe with a smooth and soft, easily deformable shell of the external balloon simplifies the insertion and passage of the PCD through the narrowing of the esophagus. At the same time, the placement of x-ray sensitive labels in various areas of the PCD greatly facilitates its reliable fixation at the site of the esophageal-gastric transition.

Since organosilicon rubbers, as well as plastics selected for the manufacture of probes (usually PVC or PET), are resistant to body fluids and sterilizing treatments, PCDs made using these materials are much longer (4-5 times) than whole-rubber products whose service life does not exceed six months.

It should be noted that the choice of organosilicon rubbers made from PDMMVS with a molecular weight of from 20,000 to 60,000 units. due to a number of factors. So, from organosilicon rubbers based on PDMMVS with a molecular weight of less than 20,000 units. it is not possible to form a balloon shell of the required strength. The conditional tensile strength of the PCD balloon shells must be at least 6 MPa. With a decrease in molecular weight PDMVVS below 20,000 units. this value drops sharply.

With an increase in the molecular weight of PDMMVS more than 60,000 units. the viscosity of the systems used to form the cylinders increases sharply and reaches values that exclude the formation of balloon shells of the required thickness (not more than 1.0 mm).

Obtained during the formation of viscous systems, cylinders with shells with a thickness of more than 1.0 mm are inflated only at pressures significantly exceeding the allowable limit of 300 mm Hg. Meanwhile, at pressures above the specified limit, there is a danger to patients, since balloon rupture during the treatment of cardiospasm can cause serious injury to the esophagus up to its rupture.

In addition, thick silicone balloon liners lose their softness and can form wrinkles when they are deflated.

Thus, the combination of relatively rigid tubular probes with cylinders made of soft silicone rubber based on polysiloxane elastomers like PDMMVS with a molecular weight of 20,000 to 60,000 allows you to create a PCD that fully meets the requirements of modern medicine.

The utility model is illustrated in the drawing, which shows a General view of the claimed device.

In the drawing, the positions indicated:

1 - probe;

2 - three-layer cylinder;

3 - the inner layer of the container;

4 - reinforcing layer;

5 - outer layer.

The pneumatic cardiodilator (PCD) consists of a plastic probe closed at one end in the form of a tube 1, usually made of PVC or PET, equipped with a multilayer (three-layer) expanding dumbbell-shaped balloon 2, the reinforcing (middle) layer 5 of which is made of semisynthetic fabric, and the inner 3 and the outer 4 layers are made of silicone rubber based on PDMMVS with a molecular weight of from 20,000 to 60,000 units.

To obtain organosilicon rubbers with increased softness, as well as to obtain conventional organosilicon rubbers, compositions containing rubbers, fillers, as well as vulcanizing agents and vulcanization catalysts are used.

The composition used in the proposed utility model includes two miscible components (A and B), in each of which there is a PDMMVS with an average molecular weight of from 20,000 to 60,000 units. in the amount of 100 mass parts and aerosil as a filler-20 mass parts.

In total, after the mixing of components A and B, the finished composition should contain 200 mass parts of rubber and 40 mass parts of aerosil.

In addition to these ingredients, the composition includes 2 parts by weight of component A of a polyfunctional vulcanizing agent — oligodimethylmethylhydridesiloxane with an active hydrogen content of 0.7 to 1.0 mole percent, and 2 parts by weight of component B of the vulcanization catalyst — tetraorganoammonium salt of platinum chloride in form of its solution in toluene with a concentration of 0.25 mol / liter.

The composition obtained after mixing the components A and B to dilute it and accordingly the film-forming properties is diluted three times with heptane, and then used to form balloon shells.

The formation of balloon shells is carried out by dipping special aluminum molds, the surface of which is similar to the surface of a swollen balloon, into the prepared composition, followed by drying and vulcanization of the shell formed on the surface of these molds.

The operation of forming the outer balloon shells is carried out in the following order:

The first dipping is carried out, after which the forms are fixed in an upright position and held in air for 10 minutes at room temperature.

Subsequent dipping is then performed. After each dipping, the molds are also fixed in a vertical position and at the same time are turned over when fixed. Such alternation is performed to obtain balloon shells uniform in thickness. The latter circumstance requires at least two dips when forming shells.

The balloon shell is dried after the last dipping, without removing the shell from the mold. To do this, the mold is suspended in air for 10 minutes, and then placed in a heating cabinet, where the casing is vulcanized for 20 minutes at a temperature of 185 ± 10 ° С.

On the mold cooled down after vulcanization, cuts are made along the edges on the surface of the molded balloon membrane and the membrane is removed from the mold.

Several samples are made simultaneously, including control ones.

After testing the control samples and obtaining the required characteristics, the finished balloon shells are fixed on the probe blanks.

Example No. 1. In accordance with the above-described regulations, a composition is prepared containing PDMMVS with an average molecular weight of 40,000 units. Dipping during molding of the outer balloon membrane is performed 7 times, which ensures the production of shells with a thickness; 0.7 mm

The control sample of the shell after drying and vulcanization has a conditional tensile strength of about 8.0 MPa and a Shore A hardness of 20 units.

After attaching the pneumocardiodillator to the probe, the resulting balloon membranes are easily inflated to the desired volume even at a pressure of 260-280 mm Hg.

Example No. 2. In accordance with the above-described regulations, a composition is obtained containing PDMMVS with an average molecular weight of 20,000 units. To obtain samples of the balloon shell with a conditional tensile strength of 6 MPa, dipping is performed 20 times.

The hardness of such shells in Shore is 15 units.

The resulting shells have a thickness of 0.9 mm and, after attaching to the probe of the cardiocardiator, are inflated to the desired volume at a pressure of 280-300 mm Hg.

Example No. 3. A composition is obtained containing PDMMVS with an average molecular weight of 19,000. Dipping is performed 20 times. The resulting shells have a thickness of 0.9 mm. The strength of the control samples does not exceed 5.4 MPa. An additional five-fold dipping gives a shell with a strength of 6.0 MPa and a thickness of 1.2 mm.

The shell, although it has a Shore hardness of 15 units, begins to swell only at a pressure of 340 mm Hg. Upon reaching the required volume, a break in individual samples was observed.

Example No. 4. A composition is obtained containing PDMMVS with an average molecular weight of 60,000. Dipping is performed twice. The resulting shells have a thickness of 0.80 mm, tensile strength of 8.0-8.2 MPa.

The shore hardness is 25 units. The shells are inflated at a pressure of 300 mm Hg. to the desired volume.

Example No. 5. A composition is obtained containing PDMMVS with an average molecular weight of 61,000. Dipping is performed twice.

The obtained shell samples have a thickness of 1.1 mm, tensile strength of 8.7 ÷ 9.0 MPa, Shore hardness - 25 units. and pressure when inflating to the desired volume of 430 mm Hg.

Claims (1)

A pneumatic cardiodilator containing a probe in the form of a tube with one closed end and an expanding multilayer balloon connected to it, the inner and outer layers of which are made of elastic material, and the middle reinforcing layer, which provides a dumbbell-shaped balloon and inflates it only to a certain limit, is made of dense synthetic fabric, characterized in that the probe is made in the form of a tube of hard plastic, mainly PVC or PET, and the outer and inner layers of the expanding balloon are made of cre organosilicon rubbers based on polyorganosiloxane elastomers with a molecular weight of from 20,000 to 60,000 units. and having a shore hardness of A not higher than 40 units, mainly from polydimethylmethylvinylsiloxane.