Simulated blood composition

Abstract

A simulated blood composition comprises a gelatinizable component and a gelatinizing component, said gelatinizable component comprising an alginic acid salt and a red colouring agent, and said gelatinizing component comprising a calcium salt. The gelatinizable component and the gelatinizing component are arranged for being brought into contact with each other at the time of use, so as to simulate the formation of a blood clot. The simulated blood composition can be made in the form of a kit, comprising the gelatinizable component and the gelatinizing component in solid or liquid form. The simulated blood composition can be used in combination with an anatomical simulator for veterinary medicine or human medicine, for example for simulating a venipuncture or a bleeding from a wound.

Description

Simulated blood composition

[0001] The invention relates to a simulated blood composition that is usable for teaching purposes, in particular in the field of veterinary medicine or human medicine.

[0002] Simulated blood, or fake blood, is an important resource that is usable in human medical-surgical and veterinary simulations. This substance, which is a realistic simulacrum of human and animal blood, plays a crucial role in training health workers and surgeons. In fact, fake blood enables medical-surgical procedures and emergency situations, such as traumatic incidents, to be reproduced securely and ethically. In particular, the use of fake blood forteaching purposes enables nurses, physicians and veterinarians to acquire practical skills, improve coordination and learn to decide, even under pressure, rapidly and effectively, without however jeopardizing the life of actual (human or animal) patients.

[0003] Fake blood of known type usually consists of a mixture of compounds, in particular thickeners and dyes, that give the aforesaid mixture a consistency and an appearance that are similar to those of actual blood. A significant drawback of these mixtures consists of the fact that, although reproducing chromatic and physical properties of the real blood, unlike the latter, they are not able to simulate a clotting process.

[0004] In order to try to overcome the aforesaid drawback, fake blood compositions have been developed that are able to simulate the clotting process. Nevertheless, also these known compositions are not devoid of drawbacks because they are either expensive or use components, like for example polyvinyl alcohol, that polymerize in contact with air, thus providing a non-optimal simulation of clotting.

[0005] A further, not negligible drawback of known fake blood compositions consists of the fact that, in the composition thereof, substances - such as for example the dyes - are included that are harmful if swallowed and / or irritating for the skin and mucosae. It is nevertheless clear that during simulation of medical manoeuvres, such as for example the venipuncture or the managing of a bleeding from a wound, for a healthcare worker who is in training and is therefore not sufficiently skilful, there is a potential risk of coming accidentally into contact with the fake blood at the level of the skin / mucosae or even of swallowing the fake blood.

[0006] Therefore, the need for a fake blood enabling the drawbacks that have been described above to be overcome is strongly felt by those skilled in the art, in particular by healthcare workers in veterinary medicine or human medicine, as well as by the personnel assigned to educating and training the aforesaid operators.

[0007] Objects of the invention

[0008] One object of the invention is to improve the fake blood of known type that is used for education and training purposes.

[0009] Another object is to provide a fake blood that enables a blood-clotting process to be suitably simulated, avoiding phenomena of polymerization in contact with the air.

[0010] A further object is to provide a fake blood that avoids the risk of users coming into contact accidentally with harmful or irritating substances.

[0011] Still another object is to provide a fake blood that is substantially less costly to produce and thus marketable at lower prices than the fake blood of known type.

[0012] Short description of the invention

[0013] According to the invention, a simulated blood composition is provided, as defined in claim 1.

[0014] Owing to the invention, a simulated blood composition is made available that enables the drawbacks of the fake blood of known type to be overcome.

[0015] The composition according to the invention comprises two components, which can be brought into contact with one another at the moment of use by a user, for example a healthcare worker in training, so as to produce a simulated blood clot. More exactly, the composition comprises a gelatinizable component, which simulates an animal or human blood in terms of colour or consistency, and a gelatinizing component, which is able to react chemically with and gelatinize the gelatinizable component, so as to simulate a clotting process. However, this occurs only when the two components are brought into contact with one another, which avoids undesired polymerization phenomena caused by exposure to air, such as for example in the case of the fake blood of known type using polyvinyl alcohol.

[0016] Both the gelatinizable component and the gelatinizing component contain atoxic substances, in particular food grade substances. This avoids undesired risks for the user, if the latter accidentally comes into contact with the composition according to the invention at the level of the skin / mucosae, or even accidentally swallows the aforesaid composition. Moreover, the composition according to the invention can be prepared through a substantially simple procedure and by using inexpensive substances, which makes the aforesaid composition cheaper to produce, and thus marketable at lower prices than known products.

[0017] Short description of the drawings

[0018] The invention can be better understood and implemented with reference to the attached drawings that illustrate an embodiment thereof by way of non-limiting example, in which:

[0019] Figure 1 illustrates schematically the chemical reaction that occurs between the components of the composition according to the invention and enables blood clotting to be simulated.

[0020] Detailed description of the invention

[0021] In the description and in the attached claims:- the terms “gelatinize / gelatinizing / gelatinization” and “gel / gelling / gelification” are considered to be synonyms and can thus be used interchangeably;- the terms “simulated blood composition” and “fake blood composition” are considered to be synonyms and can thus be used interchangeably;- the indicated percentages (%) are percentages by weight;- the water contained in the aqueous solutions is preferably double-distilled water.

[0022] The composition according to the invention comprises a gelatinizable (or gelable) component and a gelatinizing (or gelling) component.

[0023] In one embodiment, the composition consists of the gelatinizable component and of the gelatinizing component, i.e. it comprises only the gelatinizable component and the gelatinizing component.

[0024] The gelatinizable component is in liquid form and comprises an aqueous solution containing a salt of alginic acid salt and a red colouring agent.

[0025] In one embodiment, the gelatinizable component consists of the aqueous solution of the salt of alginic acid and of the red colouring agent, i.e. it comprises only the aqueous solution of the salt of alginic acid and of the red colouring agent.

[0026] The red colouring agent enables the gelatinizing component to simulate an animal or human liquid blood visually, whilst the salt of alginic acid that is dissolved in water represents the component part that reacts with the gelatinizing component, as it will be disclosed in detail below.

[0027] In one embodiment, the gelatinizable component has the qualitative / quantitative formulation reported in the following Table 1 :

[0028] Table 10029] In one embodiment, the salt of alginic acid is sodium alginate.

[0030] In another embodiment, the salt of alginic acid is potassium alginate.

[0031] In another embodiment, the colouring agent consists of group B vitamins.

[0032] In a further embodiment, the salt of alginic acid is sodium alginate and the colouring agent is vitamin B12. In this further embodiment, which is recommended for syringes with a needle of calibre equal to or less than 23 G, butterfly (connected to any type of device suitable for collecting blood samples) of calibre less than or equal to 23G, catheters of calibre less than or equal to 24G, the gelatinizable component has the qualitative / quantitative formulation reported in the following Table 2:

[0033] Table 20034] In a further embodiment, the salt of alginic acid is sodium alginate and the colouring agent is vitamin B12. In this further embodiment, which is recommended for syringes with needle of calibre 21G and 22G, butterfly (connected to any type of device suitable for collecting blood samples) with 21G needle, blood gas syringe, catheters with calibre comprised between 22G and 18G, the gelatinizable component has the qualitative / quantitative formulation shown in the following Table 3:

[0035] Table 30036] In a further embodiment, the salt of alginic acid is sodium alginate and the colouring agent is vitamin B12. In this further embodiment, which is recommended for butterfly (connected to any type of device suitable for collecting blood samples) with needle of 19G calibre, the gelatinizable component has the qualitative / quantitative formulation reported in the following Table 4:

[0037] Table 40038] In a further embodiment, the salt of alginic acid is sodium alginate and the colouring agent is vitamin B12. In this further embodiment, which is recommended for syringes with needle of calibre equal to or greater than 20G, the gelatinizable component has the qualitative / quantitative formulation reported in the following Table 5:

[0039] Table 50040] In a further embodiment, the salt of alginic acid is sodium alginate and the colouring agent is vitamin B12. In this further embodiment, which is recommended for catheters of calibre greater than or equal to 16G, the gelatinizable component has the qualitative / quantitative formulation reported in the following Table 6:

[0041] Table 60042] In a further embodiment, the salt of alginic acid is sodium alginate and the colouring agent is vitamin B 12. In this further embodiment, which is recommended for the simulation of external haemorrhages (wounds), the gelatinizable component has the qualitative / quantitative formulation reported in the following Table 7:

[0043] Table ?

[0044] In the embodiments in which the salt of alginic acid is potassium alginate, also for the latter the % by weight of Tables 2 - 7 apply.

[0045] The gelatinizing component comprises a calcium salt.

[0046] In one embodiment, the gelatinizing component consists of the calcium salt, i.e. it comprises only the calcium salt.

[0047] In one embodiment, the gelatinizing component is used in the form of a aqueous solution having the qualitative / quantitative solution reported in the following Table 8:

[0048] Table 80049] In one embodiment, the calcium salt is calcium lactate (calcium salt of lactic acid).

[0050] In another embodiment, the calcium salt is calcium gluconate (calcium salt of gluconic acid).

[0051] In a further embodiment, the calcium salt is a mixture of calcium lactate and calcium gluconate.

[0052] The concentration of the calcium salt has a low clotting yield at 0.2% (concentration that is usable to simulate clotting pathologies). The recommended concentration is 4% (in the case of a simulation of venipuncture) up to 100% (concentration that is usable for simulating haemostasis actuated through the use of haemostatic powders). Therefore, in one embodiment, the calcium salt is used as such, namely in anhydrous form.

[0053] In one embodiment, both the gelatinizable component and the gelatinizing component are in solid form and are to be reconstituted in water before use. In this embodiment, therefore, the salt of alginic acid, the red colouring agent and the calcium salt are in solid form.

[0054] Figure 1 illustrates schematically the chemical reaction that enables the gelatinizable component to be gelatinized and thus the simulated blood clot to be formed. In an aqueous solution, the sodium alginate (comprised in the gelatinizable component) disassociates into sodium cations (Na+) and alginate anions, whilst the calcium lactate (comprised in the gelatinizing component) disassociates into calcium cations (Ca2+) and lactate anions. As a bivalent cation, each cation Ca2+can bind two distinct alginate anions, thus producing a gelatinous polymer mesh, which is able to simulate a blood clot effectively. As a skilled in the art person will be able to easily understand, a reaction that is similar tothe one that has been described above occurs by using the embodiment of the composition according to the invention in which the gelatinizing component is calcium gluconate.

[0055] In one embodiment, the composition according to the invention is made available in the form of a kit, comprising the gelatinizable component and the gelatinizing component, which are both in solid form and suitably packaged.

[0056] More exactly, a kit according to the invention comprises set quantities (for example, grams) of powder and / or granules of the salt of alginic acid (for example, sodium alginate), or the red colouring agent (for example, vitamin B12) and of the calcium salt (for example, calcium lactate or calcium gluconate). Such set quantities can be selected suitably by a skilled in the art person, taking account of the percentages by weight reported in Tables 1 - 3 and of the final volume of gelatinizable component and gelatinizing component solution that it is desired to obtain.

[0057] The user of the kit will be able to reconstitute the gelatinizable component and the gelatinizing component before use, by dissolving the solid components contained in the kit into set volumes of water, preferably double-distilled water.

[0058] By using the gelatinizing component and the gelatinizable component already in aqueous solution, or after reconstituting with water the gelatinizing component and the gelatinizable component comprised in the aforementioned kit, the user of the composition according to the invention can induce the formation of the simulated blood clot by placing the gelatinizing component in contact with the gelatinizable component. This can be obtained by pouring or sprinkling the calcium salt in solution directly onto the gelatinizable component, or by impregnating a fabric substrate of known type, for example a gauze, with the calcium salt in solution and then putting the substrate of impregnated fabric in contact with the gelatinizable component.

[0059] In one embodiment of the kit, the gelatinizable component and the gelatinizing component are both in liquid form, namely in aqueous solution form.

[0060] In another embodiment of the kit, the gelatinizable component and the gelatinizing component are both in solid form (to be reconstituted in water).

[0061] In a further embodiment of the kit, the gelatinizable component is in solid form (to be reconstituted in water) and the gelatinizing component is in liquid form, namely in the form of an aqueous solution.

[0062] In a yet further embodiment of the kit, the gelatinizable component is in liquid form, namely in aqueous solution form, and the gelatinizing component is in solid form (to be reconstituted in water).

[0063] In the embodiment in which the composition according to the invention is made available in the form of kit, the kit can comprise a fabric substrate of known type, for example a gauze for medical use, to be impregnated with the gelatinizing component after the latter has been reconstituted with water. In another embodiment of the kit, the latter can comprise a gauze, or another similar fabric substrate that can be impregnated with a solution, already impregnated with gelatinizing component.

[0064] Unlike other known types of fake blood, the reaction between the two components of the composition according to the invention is not promoted by exposure to air but develops only through reciprocal contact between the gelatinizable component and the gelatinizing component.

[0065] It should also be noted that all the compounds disclosed above and used in the composition according to the invention are atoxic and food grade. In fact, vitamin B12 can be taken orally, calcium lactate and sodium alginate are two food additives that are widely used in the so-called molecular gastronomy or cuisine, calcium gluconate is a food additive used as an acidity regulator and as a sequestering agent in the food industry. This avoids undesired consequences if, during use, the composition according to the invention accidentally comes into contact with the skin and / or mucosae of the user or is swallowed accidentally by the user.

[0066] The composition according to the invention can be advantageously used in the training of medical and veterinary personnel because, in combination with teaching simulators of known type (dummies or anatomical models), it enables bleeding from a wound or venipuncture procedures, like those that are necessary for taking a venous sample or for inserting an intravenous catheter, to be simulated in a significantly realistic manner.

[0067] In particular, when simulating the insertion of an intravenous catheter, the use of the composition according to the invention enables the effect of filling the cone of the catheter (with blood) to be reproduced realistically, which effect is used in actual medical and veterinary practice by the operators as confirmation of entry into the vessel.

[0068] In use, the teaching simulator (or anatomic simulator) can be loaded with the gelatinizable component, namely the latter is delivered into the simulated blood vessels that are comprised inside the teaching simulator, and the gelatinizing component can bedispensed from the outside of the simulator, for example sprinkled or poured, at the zone of the simulator, for example a simulated point of insertion of an intravenous catheter, in which it is wanted to simulate the formation of the blood clot by putting the gelatinizable component and the gelatinizing component in mutual contact.

[0069] Alternatively, a medical gauze of known type can be impregnated with the gelatinizing component and the gauze can then be applied to the zone of the simulator, such as for example a fake wound, in which it is wanted to simulate the formation of the blood clot by putting the gelatinizable component and the gelatinizing component in mutual contact.

[0070] The gelatinous polymer matrix produced by the chemical reaction between gelatinizable component and gelatinizing component, in addition to simulating realistically the formation of the blood clot and sealing the blood vessel of the simulator after making a simulated venipuncture, maintains the vessel lubricated, and thus substantially movable, inside the simulator. This permits a high degree of realism to be obtained during simulation because the veins tend to move naturally in vivo. When, on the other hand, a simulator is used to manage bleeding from a wound, the glutinous consistency of the simulated blood clot introduces an additional difficulty, which is not dissimilar from the actual practice, in suitably managing the grasping of medical-surgical instruments and devices.

[0071] By way of non-limiting example, two uses of the composition according to the invention are disclosed below: venipuncture simulation (Example 1); simulation of managing of a bleeding from a wound (Example 2).

[0072] Example 1 - Venipuncture simulation

[0073] The gelatinizable component is inserted into the lumen of the fake vessel. The venipuncture procedure is run, whether for the purposes of a (venous or arterial) sampling, an administration or in relation to the positioning of a catheter (e.g. peripheral venous catheter). At the end of the procedure, through a wad, swab or gauze soaked in aqueous solution containing the gelatinizing component, a slight compression is made in order to obtain clotting (the sequence simulates the use of a wad, swab or gauze impregnated with disinfectant). The sampling procedure can be conducted through a syringe and needle, syringe and butterfly, systems exploiting vacuum collection tubes (for example Vacuette) or other devices that are suitable for collecting blood samples.

[0074] Example 2 - Simulation of bleeding from a wound

[0075] The simulation of outside haemorrhage can relate to both venous bleedings (continuous and at low pressure flow) and arterial bleeding (high-pressure jet flow). Haemostasis can be achieved both instrumentally (e.g. through haemostatic clamp) or through compression (e.g. through gauze compresses). In all the aforesaid scenarios, clotting occurs by the contact of the gelatinizable solution and a gauze soaked with an aqueous solution of gelatinizing component, (this simulating the use of antiseptic liquid applied to the wound) or loaded with salts of calcium. A further case may provide for the use of salts of calcium applied directly to the wound to simulate the use of haemostatic powder to be followed up with compressive haemostasis (for example with bandages or gauzes).

[0076] From what has been disclosed and exemplified previously, it can be stated that the simulated blood composition according to the invention enables the drawbacks, which can be found in fake blood of known type and which have been previously disclosed, to be overcome effectively.

[0077] Variations on and / or additions to what has been disclosed above are possible. For example, although the previously disclosed compositions have been prepared on a laboratory scale, the skilled in the art person is able to select and apply preparation procedures that are suitable for a production on an industrial scale.

Claims

CLAIMS1. Simulated blood composition comprising a gelatinizable component and a gelatinizing component, said gelatinizable component comprising a salt of alginic acid and a red colouring agent, and said gelatinizing component comprising a calcium salt, wherein said gelatinizable component and said gelatinizing component are arranged for being brought into contact with each other at the time of use, so as to simulate the formation of a blood clot.

2. Composition according to claim 1, consisting of said gelatinizable component and said gelatinizing component, wherein said gelatinizable component consists of said salt of alginic acid and said red colouring agent, and said gelatinizing component consists of said calcium salt.

3. Composition according to claim 1, or 2, wherein said salt of alginic acid and said red colouring agent are dissolved in solution, and said calcium salt is in a solid form or it is dissolved in solution.

4. Composition according to claim 3, wherein said solutions are aqueous solutions.

5. Composition according to any one of claims 1 to 4, wherein the concentration of said salt of alginic acid is in the range between 0.4% by weight and 1.2% by weight on the total of said gelatinizable component.

6. Composition according to any one of claims 1 to 5, wherein the concentration of said red colouring agent is in the range between 0.03% by weight and 1% by weight on the total of said gelatinizable component.

7. Composition according to any one of claims 1 to 6, wherein said salt of alginic acid is sodium alginate or potassium alginate.

8. Composition according to any one of claims 1 to 7, wherein said red colouring agent is a group B vitamin.

9. Composition according to claim 8, wherein said group B vitamin is vitamin B12.

10. Composition according to any one of claims 3 to 9, wherein the concentration of said calcium salt in said solution is in the range between 0.2% by weight and 7% by weight on the total of said gelatinizing component.

11. Composition according to any one of claims 1 to 10, wherein said calcium salt is calcium lactate or calcium gluconate.

12. Kit containing the simulated blood composition according to any one of claims 1 to 11.

13. Kit according to claim 12, wherein said gelatinizable component and said gelatinizingcomponent are in a liquid form or in a solid form.

14. Kit according to claim 12, or 13, further comprising a fabric substrate, said fabric substrate being impregnable or being impregnated with said calcium salt.

15. Use of a composition according to any one of claims 1 to 11, or of a kit according to any one of claims 12 to 14, for simulating a venipuncture or a bleeding from a wound.

16. Use according to claim 15 in combination with an anatomical simulator for veterinary medicine or human medicine.

17. Use according to claim 15, or 16, wherein said gelatinizable component is contained inside said simulator and said gelatinizing component is added from the outside of said simulator.

Images