Field of technology

The invention concerns a gastrointestinal veterinary cannula designed for repeated manipulation with the digestive tract content (chyme), or for supplying or application of substances to the digestive tract, especially during experiments that are part of basic or applied research concerning the veterinary or human effects. The invention also describes a new method of production of veterinary cannula, which is produced into the final form according to particular needs. The invention falls within the field of veterinary tools.

Prior state of the art

The metabolism oriented human and veterinary research from the fields of biochemistry, digestivity of food, toxicology or pharmacology or many other fields necessarily requires experimental work which uses test animals, and which requires repeated manipulation with the digestive tract content, either for the purposes of sampling, or application of substances which are being tested. Modern research requires manipulation with ileal chyme, that is, it requires repeated collection of ileal chyme for the purposes of assessment of the digestivity of amino acids, or for the purposes of direct application of additives of different provenance. Three methods of manipulation with chyme are known in the prior state of the art. These are the methods of slaughter, ileorectal anastomosis or ileal cannula introduction. In the past there has been one Reentrant-type cannula on the American market; the cannula has been based on the principle that the flow of chyme temporarily leaves the abdominal space of the animal. Such type of cannula did not prove useful even after several uses, because this cannula caused bowel obstruction. Patent US 4,306,545 describes a solution of cannula with rotary multiway valve. Its disadvantages lie in the difficulty of application for different anatomical conditions; the cannula is not flexible and it causes obstruction of the chyme.

Gastrointestinal veterinary cannulas known from the prior state of art has been produced from the materials such as metal, silone or hard plastics, which caused secondary internal injuries, and which have often been broken or completely disabled by the mechanical action of the animal. Softened plastics such as polyvinyl chloride l with a plasticizer, a polydimethylsiloxane, or an ethylene-vinyl acetate copolymer proved more useful, but they have either contained harmful substances, or their physical featuress did not correspond to the requirements; they often broke when bent, or they changed their characteristics under the influence of the chemical composition of chyme. Solutions according to CN2875326Y, US6257238B1 , US2013158471A1 , CN203458675U, US2009082736A1 , US20100081881 A1 , US2010249525A1 , US2010312062A1 do not offer enough flexibility of application, they require difficult application and during their application the flows in the digestion get obstructed.

According to available data there is no flexible gastrointestinal veterinary cannula known in the prior state of the art and therefore it has been necessary to direct the activities towards its development and production. This endeavor results in following gastrointestinal veterinary cannula according to this invention.

Subject matter of the invention

Abovementioned deficiencies are significantly remedied by a gastrointestinal veterinary cannula according to this invention. The essence of this invention lies in the fact that the gastrointestinal veterinary cannula is produced by bonding from the silicone parts in small sets according to actual requirements, which allows to modify the parameters of the each set in the construction - such as inner diameter, shape of the longitudal axis, width of the wall, shape, and size of the basal part - according to location, age and weight of an animal. Gastrointestinal veterinary cannula consists of the tubular body which is connected to the basal part which is introduced into the bowel and it guarantees by its shape and size that cannula remains in the abdominal cavity of the animal, whereby it also secures the approach to chyme without obstructing its flow. It is crucial that the basal part is designed in the optimal size, because small surface of the basal part would cause the cannula to fall out, whereby large surface would deform the cross-section of the bowel and slow down or even obstruct the chyme's flow. In order to achieve this, cylindrical and conical shape of the basal part is designed, as opposed to original flat shape. Furthermore, on the tubular body (stem) there is slidingly positioned fixation cuff which falls beyond the fixation edge of the cuff created on the tubular body. The fixation cuff prevents the cannula from deflecting to the abdominal cavity and the fixation of cannula simultaneously solves the problem concerning the attachment of the collection bag. The fixation edge of the cuff is located closer to the basal part. On the remote end of the tubular body there is created a fixation edge of the cap, whereby the ring of the cap is removably locked into the fixation edge. The fixation edge of the cuff and the fixation edge of the cap are so constructionally designed that they overhang towards basal part. This makes the removal of the cannula easier; towards the direction of mounting the edge allows easy mounting of the fixation cuff, or cap, respectively, whereby in the opposite direction the edge applies greater force. Isolation is inserted between the fixation cuff and the basal part there; the advantage of the isolation is that it is produced from polyurethane foam. In a preferable arrangement, the isolation will be produced from a flexible, soft and partially absorbent material. The isolation can be also used as a carrier of the pharmacological substances for the purposes of healing of a wound and in order to prevent dermatitis of the skin around the outflow. In case the isolation with higher absorptive power is used, it can be equipped by fat, for example vaselinum album (white petrolatum) or wool wax (adeps lanae) or ceresinum album, and so on.

Flat part of the fixation cuff in the shape of annulus is attached to cylindrical part of the fixation cuff. This cylindrical part represents the sleeve which in mounted position encircles the tubular body of the cannula, whereby the sleeve can move within preset space, it can move on the tubular body and the edge of the sleeve is designed for clicking into the fixation edge. The tubular body can have multiple fixation edges for setting the fixation cuff in different positions.

The fixation edge of the cap can be designed for attachment of other objects, for example pipe coupling or the holder of the laboratory device, the bag, and so on.

The basal part is a surface of truncated cone or part of cylinder. Tubular body of the cannula follows on the basal part in "T" shape or Ύ" shape.

Solution according to this invention is also characterized by the fact that during application there can be basal parts of different shapes and sizes attached. Basal part suitable for particular application can be chosen in various ways, for example in such a way that the basal part of choice is attached to tubular body before application, or in such a way that the personnel will be provided with tubular bodies alongside with different basal parts, whereby the personnel chooses a basal part with suitable shape and size for usage in particular arrangement. Aside from the new solution of shape, which uses direct tubular body with simple stops for cuff and edge, the invention is characterized by high level of shape and size flexibility. According to this approach, separate basal parts with different profiles, shapes and sizes can be available in advance and subsequently attached to the body of the cannula. The attachment can be realized by bonding, welding, molding, or by shape lock which will be mounted on the end of the tubular body and the respective connecting zone of the basal part. Basically, any attachment will be suitable within this approach, which allows the connection of the basal part of choice with the tubular body of the cannula according to particular requirements.

Second approach to choosing suitable basal part is based on the possibility of adjusting the size of the basal part according to a particular requirement. In such case the basal parts of different shapes are in advance connected with the tubular body, and the tubular body with already attached basal part is chosen according to particular requirements, whereby the basal part is subsequently cut or truncated to required size. In such case it is preferable that the basal part, or at least its edges, is adjusted to subsequent truncation. This is achieved in such a way that the material or the width of the basal part is such that the basal part can be cut by common surgical scissors. In such case, the basal part can be produced or molded with the tubular body already.

Another crucial feature of the invention is adjustability of the position of the fixation cuff opposite to basal part. This is possible because the tubular sleeve of the fixation cuff can have different lengths. If the position of the fixation edge is fixed, the distance between the cuff and the basal part can be set by changing the length of the tubular sleeve. The sleeve can be adjusted in such a way that it can be shortened according to particular requirements. Shortening of the sleeve increases the distance between the cuff and the basal part, so the cannula can grow with an animal. It is preferable if common surgical tools, for example scissors, can be used for the shortening of the sleeve of the fixation cuff.

The tubular body and/or fixation cuff and/or the basal part are in preferable arrangement produced from plastic which is flexible, resistant to breaking and to the environment in the body of an animal as well as to chemical substances that are applied or used during the cleaning of the cannula, and it is as well sufficiently solid so the walls of the cannula are not deformed, as such deformation could lead to obstruction. It is also preferable if the material from which the cannula is produced is not only resistant to the effects of disinfectants (disinfection of cannula, disinfection of operation field), but it is also resistant to temperature changes which can result from usage of sprays, especially disinfection sprays. Compressed propellant gas expands during the application of the spray and it draws the heat from the environment, which can result in embrittlement and breaking of the cannula in particular point. The advantage of the invention at hand is the possibility to produce the basal part, cuff with sleeve as well as tubular body of the cannula from a homogenous, uniform, flexible plastic, for example silicone, which is resistant to temperature changes. The cannulas known hitherto usually had multiple, materially heterogeneous components which were inflexible.

The method of production of gastrointestinal veterinary cannula according to this invention is also new, wherein the cannula is produced into the final form from the components, semifinished products, which are chosen into the final arrangement or assembly from the sets of these elements of multiple shapes and sizes, or it is produced in such a way that the semifinished products are customized by available surgical tools and subsequently the components or parts are composed into the final arrangement or assembly. Such approach is characterized by high flexibility; such produced cannula corresponds exactly to particular requirements. In new approach the sets can be produced in advance, whereby the sets have tubular bodies with pre- produced fixation edges. The required length of the tubular body is produced by cutting to required dimensions. Subsequently, a basal part is mounted on the end. In different approach the set can contain various tubular bodies with the basal parts already attached and these can be simply cut to the required size. After choosing and adjusting, respectively, the suitable basal part, the fixation cuff with isolation is mounted onto the tubular body. The sleeve of the fixation cuff is cut according the required space between the isolation and the basal part. The cap is attached on the neck of the body.

The described method can use different level of customization of different components and it can include choice of suitable component from the set. The customization can include cutting, truncating, but also bonding, welding, molding, connecting the semifinished products.

The advantages of the gastrointestinal veterinary cannula according to this invention lie in the fact that its T arrangement allows repeated manipulation with the digestive tract content (chyme) or application of the substances into the digestive tract. T cannula according to this invention allows modifications according to the nature of the location, the age and weight of the animal, and it does so by its inner diameter, shape of its longitudal axis, width of the wall, shape and size of the basal part. The environment where the gastrointestinal veterinary T cannula is to be used is constantly wet and greasy and the fixation method used hitherto, that is, the method with medical adhesive tapes and bandages proved dysfunctional after short time. Formation of two edges from the silicone material for the fixation of the cuff and the cap of the cannula solves this problem. This technical solution preserves the possibility of regulation of the cuff from the beginning of the operation to the end of the experiment in dependence on the width of the abdominal wall, and is therefore also a solution of the problem concerning the attachment of the collection bags. During the production of the T cannula the silicone is used; silicone is harmless for animals and there are no changes in the physical properties of the material. The construction of the basal part of the T cannula allows for simple approach to chyme, without obstructing its flow.

Brief description of drawings

Invention of construction of gastrointestinal veterinary T cannula is further disclosed on the drawings, whereby on the fig. 1 there is an axonometric view of the arrangement of the composed silicone T cannula with conical and cylindrical basal part. On the fig. 2 there are individual parts of T cannulas from the fig. 1 in the disassembled state. On the fig. 3 there are T cannulas depicted in profile view. On the fig. 4a and 4b there is a cross-section view of the bonded parts of T cannulas. The bonded joints are depicted by hatching. On the fig. 4a both fixation edges are produced by bonding the ring onto the tubular body of the cannula. On the fig. 4b the fixation edge of the cuff is produced by bonding and the fixation edge of the cap is shaped directly from the material of the tubular body.

Figures 5 and 6 depict the tubular body of the cannula, whereby both fixation edges are produced by shaping of the material of the tubular body. On the fig. 5 a long sleeve of the fixation cuff is used, and it is subsequently truncated on the fig. 6, which creates a space between the cuff and the basal part. The cannula is on the fig. 6 depicted without the cap for the illustration purposes.

It is obvious that individual realizations of the invention are presented for the illustration purposes only, and cannot be interpreted as limiting the scope of technical solutions. A person skilled in art can find many equivalents to the specific realizations hereby described by routine experimentation only. Such equivalents fall within the scope of protection of subsequent patent claims. The dimensioning of the veterinary tool, as well as the choice of suitable materials and construction arrangements, present no challenges to a person skilled in art, and therefore they are not analyzed in detail.

The scales of individual parts as well as the widths and positions of the fixation edges are meant to be for the illustration purposes only and they canno be interpreted as limiting the scope of protection.

Examples of realization

Example 1

This example presents the construction of gastrointestinal veterinary T cannula according to this invention, which is depicted on fig. 1 and 3. This type of cannula was successfully used in various experiments focused on the collection of chyme from the digestive tract and on the application of different substances which required an application other than per oral. First case included experiments concerning the collection of samples from various phases of digestion. The second case included experiments concerning the application of substances with the need to eliminate the mechanical effects of the processing of the substances in the oral cavity, as well as the chemical effects (of saliva, hydrochloric acid in the stomach, and so on) in some parts of the digestive tract. This material and technical solution contributed significantly to the number of successful repeats of experiments, whereby before - without this solution - there was often obstruction, falling out, breaking or other damaging of the cannula, or there was release of the collection bag and subsequent contamination of the chyme. Gastrointestinal veterinary cannula according to this invention consists of tubular body 1 of the cannula, which is followed in one case by the "T" shape and in second case by the Ύ" shape basal part 2. Its shape in this example is cylindrical, as depicted on the figures on the right. On the tubular body is slidingly positioned fixation cuff 3 falling beyond the fixation edge 4 of the cuff created on the tubular body 1_. The fixation edge 4 of the cuff is located closer to the basal part 2. On the remote end of the tubular body 1 a fixation edge 5 of the cap is created, whereby the cap 6 is removably locked into it. The fixation edge 4 of the cuff and the fixation edge 5 of the cap are construed in such a way that they overhang towards the basal part 2. Isolation 7 is inserted between the fixation cuff 3 and the basal part 2, whereby the isolation 7 is preferably produced from polyurethane foam. Gastrointestinal veterinary cannula is produced by bonding from the silicone components, which are in the disassembled form depicted on the fig. 2, whereby on the fig. 4 one can see bonded surfaces and joints, which are depicted by hatching.

Example 2

In this example a construction of the gastrointestinal veterinary cannula according to this invention similar the one in the previous example is described. The only difference is that the basal part 2 has conical shape, as is depicted on the figures 1 , 2 and 3 on the left and on the fig. 4a.

Example 3

In this example according to figures 5 and 6 the cannula has a tubular body 1 on which two fixation edges 4, 5 are shaped. The tubular body 1 has basically uniform cross-section without transitions and strictures. Basal part 2 is welded to the body 1 which in this example has a shape of cylindrical surface. The edges of the basal part 2 are becoming thinner and they are adjusted for cutting by scissors of the suitable size. A worker takes the tubular body with the suitable shape of the basal part 2, or alternatively he or she shapes it, and then he or she cuts it by scissors into the desired size.

The worker picks suitable fixation cuff 3 from the set and he or she leaves its sleeve as it is or he or she truncates it according to the width of the abdominal wall. The fixation cuff 3 is then mounted on the tubular body 1; first it runs through the fixation edge 5 of the cap 6 and then it clicks beyond the fixation edge 4.

In another case the fixation edge 5 of the cap 6 can be substituted for a thread which corresponds to the thread of the cap 6, whereby the thread should not have a diameter bigger than the diameter of the fixation edge 4 of the cuff 3. This allows the transition of the sleeve of the fixation cuff 3 through the neck, whereby the neck does not have a stricture of its inner cross-section, so the flow is not obstructed.

Industrial applicability

Gastrointestinal veterinary cannula according to this invention can be used in humane or veterinary institutions focused mainly on the research of the metabolism in biochemistry, digestivity of the food, toxicology, pharmacology, and so on. It also can be used wherever the experiments which use test animals take place, whereby these experiments require repeated manipulation with the digestive tract's content, either for the purposes of sample collection or application of substances.

List of related symbols

1 - body of the cannula

2 - basal part

3 - fixation cuff

4 - fixation edge of the cuff

5 - fixation edge of the cap

6 - cap

7 - isolation