RU2334494C2 - Device for limb frostbite treatment - Google Patents

Abstract

FIELD: medical equipment.

SUBSTANCE: device for limb frostbite treatment contains SHF-oven, which includes source of SHF radiation and working volume, and means for bringing SHF radiation to object of exposure. Means for bringing SHF radiation to object of exposure is made in the form of separate screened working chamber connected with working volume of SHF oven by window made in their common wall. Separate screened working chamber is supplied with hole, on whose perimeter opening of flexible hose made from metal net placed between fabric layers, is fixed. In addition, in working volume of oven there is radiation absorber made in the form of vessel with water, partially filling oven working volume.

EFFECT: efficient treatment of frostbites at low cost, simplicity of design and minimal impact of SHF radiation on patient and operating personnel.

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Description

The invention relates to medical equipment and is intended to reduce the severity of the effects of cold injuries.

Frostbite according to domestic and foreign authors account for up to 15% of all trauma cases [Kotelnikov V.P. Frostbite. - M .: Medicine, 1988. - 256 p.]. Disability with deep lesions ranges from 20-90%. The number of frostbite reaches 20% of the bed capacity. The overwhelming majority of those affected are people of the most working age - from 20 to 50 years old, of which 65% with deep frostbite. Most often in clinical practice there are frostbite of the extremities [Murazyan R.I. Frostbite of limbs. - M .: Medicine, 1984. - 112. S.], since more severe cases are usually fatal.

The current level achieved in the field of the treatment of frostbite is reflected in the publication [Proceedings of the Third Scientific and Practical Conference on the Problem of Cold Injury. - St. Petersburg, April 8, 2002 // St. Petersburg: Publishing House VMAA, 2002. - 90 p.]. The main therapeutic actions for deep frostbite are conservative. Using traditional methods, the duration of treatment in hospitals is an average of 65 days. Disability according to the determined outcome is up to 70%, mortality 6%. Thus, there is an objective need for an effective and massive remedy for the treatment of frostbite.

Despite the importance of the problem, specialized equipment for the treatment of frostbite does not exist. Meanwhile, in the first two to three days after a cold injury, it is possible to exclude its irreversible consequences. The main damaging factor is, as a rule, vasospasm, leading to the cessation of tissue nutrition. Cramping is a protective reaction of the body aimed at isolating the affected segment in the interest of preserving vital organs. The restoration of vascular microcirculation is able to restore the disturbances that occurred in the tissues, prevent the appearance of necrosis and loss of limb segments. Of particular importance is the provision of effects on spasmodic vessels located in the depth of the affected segment. Surface heating using traditional means does not solve this problem and even exacerbates the situation, since the lack of nutrition from the remaining spasmodic deep vessels leads to ischemia of heated tissues requiring oxygen and nutrition, as well as the removal of metabolic products.

Among the traditional means used specifically for the treatment of frostbite, there are no direct analogues of the invention. As a rule, such means are heating pads, water baths, etc.

The main idea implemented in the present invention is the use of microwave (microwave) heating to restore vascular microcirculation in the affected limb. In world practice, for all kinds of applications related to microwave heating, the frequency range 2400-2485 MHz (wavelength 12 cm) has been allocated. Industrial, domestic and medical installations operate in the indicated range and there is a developed technical base for the creation of new devices and methods. Microwave waves penetrate tissue and can cause deep heat. However, with all the obvious advantages of the microwave heating method and the prevalence of various technological and therapeutic installations of this kind in the world, there is no specialized equipment for the treatment of frostbite through microwave heating.

The technical data of modern devices suitable for the treatment of frostbite on the principle of microwave heating are given in the CONUS-MEDIC Information and Analytical Bulletin published on 10/31/2003 [http://medprom.ru/medprom/60408]. Common to them is the presence of a microwave source and means of bringing it to the target. In all known devices, the means for supplying microwave radiation to the object of exposure are represented by applicators of the external or intracavitary type, as indicated by the source of information [http://medprom.ru/medprom/60392].

One of the analogues, close in technical essence to the proposed invention, is the device Thermatur m250, a description of which is given in the information source [http://www.asvomed.ru/php/content.php?id=557]. The device contains a source of microwave radiation and a means of bringing it to the object of exposure. As for other known devices, these funds are represented by external applicators emitters. The cost of the device is approximately 6.9 thousand dollars. Main technical specifications:

The radiation frequency is 2450 MHz (wavelength 12.25 cm).

Output power in continuous mode 250 watts.

Power consumption 650 watts.

Power supply 230 V (± 10%), 50 Hz.

Dimensions: 380 × 380 × 850 mm.

Weight: 40 kg.

The level of radiated microwave power allows tissue warming up to the temperature of necrotization, which is used to treat cancer.

However, this device is unsuitable for the treatment of frostbite due to several factors. Due to the open configuration of the emitter, creating one-way radiation, the device does not provide uniform comprehensive impact on the affected limb. In addition, the lack of volumetric localization of exposure increases the negative effect of exposure to the patient and staff. The device does not allow mass replication, satisfying the objective need for the treatment of frostbite, as it has a high cost and complex design.

A device is known that is suitable for the treatment of frostbite of the extremities according to the principle of microwave heating ["Microwave", RU 2196620, A61N 5/02, publ. January 20, 2003], which differs from the above analogue in a greater degree of volume localization of microwave radiation. The device comprises a microwave oven, including a source of microwave radiation and a working volume, and means for supplying microwave radiation to the target. According to these characteristics, this device is selected as a prototype. The working volume of the furnace is convenient for placing structural elements that serve to bring microwave radiation to the object of influence. In the prototype, the means for supplying microwave radiation to the target is represented by a set of probes immersed at an adjustable depth in the holes made in the furnace wall, each probe is connected to a separate emitter by means of a cable and a phase shifter connected in series. The presence of several emitters can slightly increase the degree of volumetric localization of microwave radiation in the area of the target. At the same time, this device has several disadvantages. Like the above analogue (Thermatur m250), the device is not effective enough in the treatment of frostbite, because it does not provide uniform comprehensive impact on the object due to the finite number of emitters. The device is also characterized by an insufficient degree of volume localization of microwave radiation, that is, it creates additional exposure to the patient and maintenance personnel, since a significant part of the radiation power is dissipated in the surrounding space, and its part that falls on the object of influence cannot be determined. In addition, the device has a complex structure and high cost, which are caused by the need to use a whole range of technical tools such as immersion probes, their adjustment mechanisms, connecting cables and cable joints, adjustable phase shifters, radiators and devices for their fixation (tripods).

The technical result of the invention is the provision of the possibility of effective treatment of frostbite, simplifying the design and the associated cost reduction, minimizing the impact of microwave radiation on the patient and staff.

The specified technical result is achieved by the fact that in the device for treating frostbite of the extremities, comprising a microwave oven including a microwave radiation source and a working volume, and means for supplying microwave radiation to the target, the means for supplying microwave radiation to the target is made in the form of a separate shielded a working chamber associated with the working volume of a household microwave oven with a window made in their common wall, while a separate shielded working chamber is provided with an opening, the perimeter of which is fixed with askryvom flexible sleeve made of a metal mesh sandwiched between layers of fabric, and in the working volume of the furnace has a radiation absorber configured as a vessel with water partially filling the furnace working volume.

The reachability of the claimed technical result is confirmed by the following.

1. The possibility of effective treatment of frostbite is due to the implementation of a comprehensive volumetric exposure in a closed shielded chamber. Due to multiple re-reflections of waves from the screen, the walls of the working chamber play the role of many elementary emitters, creating a generally uniform radiation flux to the object. Such an effect provides uniform warming, leading to the restoration of micro- and macrocirculation in the entire volume of the affected limb, including in the depths where the main supply vessels are located. As a result, the surface layers during heating do not suffer from a deficiency of oxygen and nutrients, as well as from accumulating metabolic products.

2. Simplification of the design and the associated cost reduction due to the exclusion from the design of a large number of discrete elements present in the prototype (probes, immersion mechanisms, cables, adjustable phase shifters, radiators, tripods). Instead of them, in the inventive device there is only a shielded working chamber having a wall in common with the working volume of the microwave oven with a window made therein. The window is the simplest communication element, simplifying the design of the device as much as possible. Diversion into a separate working chamber through the communication window of the dosed portion of the microwave power excludes thermal damage to the patient by an undetected power, which is usually 600-1000 watts. Excess power is dissipated in the radiation absorber located in the working volume of the furnace. In addition, the simplification and cheapening of the design of the device is due to the use of a domestic microwave oven in it, which is the cheapest and most affordable product, including a microwave source and standard controls for the duration and average exposure power.

3. Minimizing the impact of microwave radiation on the patient and staff is due to the possibility of placing in the working chamber only that part of the body that is to be heated. Design features that determine this possibility are a hole in the wall of the working chamber and a flexible sleeve fixed with its opening along the perimeter of the specified hole. A sleeve made of a metal mesh placed between the layers of fabric prevents the emission of microwave waves into the space outside the working chamber. Reliability of isolation of the external space from the microwave field is provided by the flexibility of the sleeve, allowing dense wrapping of the limb. A harmless level of radiation outside the working chamber allows personnel to be with the patient during the procedure and control the treatment process.

4. The placement of a layer of metal mesh in a flexible sleeve between the layers of fabric provides non-traumatic contact with the patient’s skin, hygiene and the possibility of sanitization at the same time as the microwave field screening function, which also ensures high treatment efficiency.

The invention is illustrated in figures 1 and 2.

A device for treating frostbite of the extremities (Fig. 1) comprises a domestic microwave oven 1 and means for supplying microwave radiation to the object of influence, represented by a separate shielded working chamber 2. The microwave oven includes a generator unit 3 and a working volume 4. The working volume of the furnace is placed radiation absorber 5, made in the form of a vessel with water, partially filling the working volume of the furnace. The transmission of microwave radiation to the working chamber 2 is carried out by means of a communication window 6, made in its wall, common with the working volume of the furnace 4. The working chamber is equipped with an opening 7, around the perimeter of which a flexible sleeve 8 is fixed by its opening. The sleeve (Fig. 2) is made of a metal mesh 9 placed between the layers of fabric 10.

The device operates as follows. The microwave radiation entering the working volume of the furnace 4 is partially absorbed in the radiation absorber 5, and partially penetrates through the window 6 into the shielded working chamber 2. The proportion between the absorbed and penetrating parts of the power is established by choosing the area of the window. Partial filling of the working volume of the furnace with a radiation absorber contributes to the removal of heat due to ventilation provided by the design of the furnace. The use of a vessel with water as an absorber of radiation ensures maximum simplicity of the device. Impacted object 11 — a frostbitten limb is placed in the working chamber through the opening 7. The penetration of microwave radiation into the space outside the working chamber is prevented by the shielding effect of the metal mesh 9, which serves as the basis for the flexible sleeve 8. To exclude the contact of the mesh with the patient’s skin, the metal mesh placed between the layers of fabric 10. This prevents corrosion, trauma to the skin with the ends of the metal threads in case of their accidental fracture, easier care of the flexible sleeve. The limb introduced into the working chamber is tightly wrapped in a flexible sleeve, fixing, for example, with an elastic bandage. When you turn on the microwave radiation source, its power is distributed between the radiation absorber and the object of influence located in the working chamber. As a result of the distribution, the power level of the radiation penetrating the working chamber is reduced to a safe value that does not allow burns. The need for attenuation is due to the relatively high power level of the microwave source - from 600 to 1000 watts. Direct exposure to radiation at this power level can cause burns even with short exposure times. Reducing power by changing the magnetron's power supply mode is ineffective due to the fact that the limits of changes in the operating mode are small, and going beyond these limits makes the generator unstable [Sretensky V.N. Fundamentals of the use of electronic devices of superhigh frequencies. - M .: Owls. Radio, 1963. - P.97-99]. Thus, an acceptable option is the dissipation of excess power in the absorber. The localization of the microwave field in the volume of the shielded working chamber ensures uniform heating of the object of influence from all directions due to the multiple reflection of waves from the walls of the shielded working chamber. Under the influence of a microwave field, heat is generated in the object of influence, not only on the surface, but also in depth. Along with the effect of attenuation of the field with depth, the effect of refraction and focusing in fragments and inhomogeneities of the limb structure takes place, as a result of which the field distribution is uniform on average. The thermal effect, penetrating to the full depth, is optimal for the treatment of frostbite, characterized by a spasm of deep-lying vessels. As a result of heating, the intensity of biochemical reactions increases, the self-heating mechanism starts, blood flow in the vessels and capillaries is restored, tissue metabolism is provided in the entire volume of the affected limb. Temporal and power modes of thermal exposure to microwave radiation are established experimentally.

Thus, the proposed device, having constructive simplicity and low cost, provides effective treatment for frostbite with a minimum level of exposure to the patient and staff.

Conducted on experimental animals, tests of a device made in accordance with the claimed technical solution confirmed the effect of a steady increase in temperature and restoration of blood flow in the deep layers of frostbitten limbs. Objective monitoring was provided by layered thermometry and rheovasography. The level of microwave radiation outside the working chamber was controlled using a wattmeter connected to a horn antenna. It was found that the power flux density does not exceed a safe level of 10 μW / cm ² , which allows personnel to work with the device during the working day.

Additional advantages of the present invention include the possibility of expanding the scope of application for various types of vascular pathologies.

Claims (1)

A device for treating frostbite of the extremities, comprising a microwave oven including a microwave radiation source and a working volume, and means for supplying microwave radiation to the target, characterized in that therein, means for supplying microwave radiation to the target is made in the form of a separate shielded working a chamber associated with the working volume of a household microwave oven by a window made in their common wall, while a separate shielded working chamber is provided with an opening along the perimeter of which a flexible sleeve is fixed with its opening, nenny metal mesh sandwiched between layers of fabric, and in the working volume of the furnace has a radiation absorber configured as a vessel with water partially filling the furnace working volume.

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