EHF devices - electrosurgical high-frequency devices used for dissection of tissues and quick stop bleeding. Devices are widely used in medicine - surgery, gynecology, laparoscopy, thoracoscopy, neurosurgery and other fields.
Monopolar Coagulation
There are two main methods for conducting medical manipulation using a coagulator: monopolar and bipolar.
The monopolar method is most common in open operations. It allows operations to be carried out at a greater depth than a bipolar device. This method is simple, safe, effective for both incision and coagulation.
Monopolar electrosurgical coagulators have one electrode that produces local dissection and coagulation of tissues at the site of contact.
The current flows in a closed circle from the working tool to the second neutral electrode - the plate, which provides wide contact through the entire body of the patient. The electrode of the instrument is called the active electrode, and the plate - passive.
The coagulation effect appears on the part of the circuit with the highest concentration of current. This should be the place between the instrument of the surgical coagulator and the patient’s body, however, conditions for the passage of current can be violated, which will lead to undesirable effects in other parts of the chain, which will manifest itself after the surgery.
Therefore, when carrying out the procedure with a unipolar surgical electrocoagulator, it is necessary to take into account all the risks and comply with electrical safety rules.
Complications and side effects of monopolar electrocoagulation
A loose fit of the surgical coagulator plate leads to a decrease in the area of its contact with the patient’s body, as a result of this passive electrode becomes active. This will lead to thermal damage to the skin and underlying tissues up to the development of burns of III-IV degree.
To improve contact, sometimes a napkin moistened with saline is placed under the plate. However, when the napkin begins to dry, the concentration of current increases in its remaining moist areas, which again is fraught with burns.
Current moves through the patient’s body along the path of least resistance. If metallic objects meet on his way, the current is concentrated in them. Seam staples may be such metal objects, current builds up in them, causing coagulation of the tissue around the staple, which leads to failure of the seam. Therefore, coagulation cannot be carried out near the staple seam.
Do not coagulate near implanted metal joints. Current builds up in them, warming the prosthesis. Under the action of the heated metal of the prosthesis, the proteins of the bone on which this prosthesis is fixed are denatured. As a result, the joint loosens.
In case of carrying out the procedure by a low-quality electrosurgical coagulator or an unqualified specialist, capacitive breakdown is possible. Under certain conditions, patient tissue may no longer conduct current. For example, when the tissue dries during prolonged coagulation of one area. In this case, a dielectric appears between the two electrodes and the entire system becomes an electric capacitor. The charge accumulates on the electrodes as on the plates of a capacitor. There is no coagulation effect, which may prompt the surgeon to increase the power of the device, the charge on the plates will increase until there is a breakdown through the patient’s tissue. The current strength at this moment is huge and causes a severe burn on the entire path of the electric discharge.
Types of monopolar coagulators
Monopolar coagulators are of two types:
- contact (incision coagulators);
- non-contact (spray coagulators).
The active electrode of the contact device is in the form of a needle, loop or lancet. As a result of his work, a clean wound suitable for biopsy, or a wound with a thin layer of coagulation, is formed.
When the incision-coagulator is operated, the result of the contact of the electrode and tissue is the formation of a scab that adheres to the electrode and comes off when it is removed.
The non-contact method is used when it is necessary to affect large areas of the body. During the operation of the spray coagulator, an electric arc is created, which causes “evaporation” of the plasma of the cells locally at the point of contact. Such a point effect avoids local heating and damage to adjacent tissue sites.
The non-contact method is less traumatic, but not always safe. To obtain a spark, it is necessary to increase the power of the device, as a result, leakage currents increase and breakdown risks appear. To prevent possible complications, a special prefix supplying argon is used.
Argon plasma coagulator
An argon plasma or argon coagulator includes a generator, a tank with argon and an applicator that combines gas and charge. Under the influence of electricity, argon produces plasma, which becomes a conductive medium. The current acts through the plasma, the electrode is 1.5-2 cm distant from the patient’s tissue, therefore, sticking to the tissue of the tip of the device does not occur. In addition, argon does not interact with the patient’s tissues at elevated temperatures, which excludes carbonization and provides smokeless and wound poisoning with combustion products.
Argon-enhanced coagulation is very superficial. Coagulation necrosis penetrates the tissue only by tenths of a millimeter. Therefore, argon devices are used to treat large surfaces with diffuse bleeding, for example, parenchymal organs. But to stop bleeding from a large vessel with this device will not succeed.
The device is very expensive. If the price of a bipolar coagulator is about 500 euros, then argon - about 6500 euros.
Bipolar coagulation
The bipolar electrosurgical coagulator has two active branches. Current flows only through the area of tissue between them and does not go through the patient’s body. Therefore, all the risks that are possible when using monopolar surgical electrocoagulators are excluded.
The bipolar method of coagulation is more progressive. This type of exposure is safer because only local action is produced and only in coagulation mode. Therefore, burns and capacitive breakdowns are excluded. However, the device works due to complex electrodes, so its price is higher.
In addition, bipolar coagulators are not capable of cutting tissue, with the exception of the Trimax instrument, which cuts tissue with a conventional scalpel after coagulation. In addition, to obtain the coagulation effect, it is necessary to capture tissue with branches, which is not always possible.
However, a bipolar electrosurgical coagulator is indispensable when long-term local coagulation is necessary. Bipolar devices are usually used in operations on the respiratory tract, in urology and arthroscopy, as well as in pediatric surgery. It is convenient, for example, to coagulate the cervix or the wide ligament of the uterus, capturing the entire anatomical structure with the jaws of the instrument and coagulating it to the entire depth, without touching the surrounding tissue.
Popular coagulator models
The cost of the device depends on the rated output power for each individual instrument, the number of modes, the availability of additional features.
EHVCH device "FOTEK"
The electrosurgical apparatus "FOTEK" is produced in Russia. The device has several modifications, which have their own differences and their price.
Now on the market are models "FOTEK 80-03, 350-01, 350-02, 350-03". These devices, depending on the modification, can function in different modes:
- cutting without coagulation (biopsy);
- monopolar cutting with coagulation;
- cutting with coagulation - used in a humid environment, used in gynecology, urology;
- micro cutting (microoperation);
- smooth coagulation;
- accelerated coagulation (removal of pathologies of the upper layers of tissues);
- monopolar non-contact (spray) coagulation (extensive capillary bleeding);
- monopolar vaporization;
- bipolar coagulation;
- bipolar cutting with coagulation.
The price of the device, depending on the modification, is from 125 to 190 thousand rubles.
EHF device "MEDSI"
The devices "MEDSI" have several modifications used for different purposes:
- "MEDSI 20" is an inexpensive device (about 20 thousand rubles), which is used in beauty salons for electrolysis and removal of non-malignant formations.
- "MEDSI 20 Ophthalmology". It operates in mono-and bipolar modes. Used for microoperations on the conjunctiva, eyelids, vessels. Price - 35-40 thousand rubles.
- "MEDSI 50 epilator, coagulator." Used to remove neoplasms on the female genital organs, skin. Price - 35 thousand rubles.
- "MEDSI 50 coagulator-fulgulator." It works in several modes: cutting, coagulation, spray. It is purchased in beauty salons, veterinary clinics. Price - 40 thousand rubles.
- "MEDSI 50 spray coagulator." Used for non-contact removal of defects in the upper layers of the skin or mucous membrane.
- "MEDSI 50 dental." Used for the treatment of pathologies of the teeth and oral cavity.
- "MEDSI 50 block RC". Oncodermatologists apply for biopsies. The device operates in 5 modes.
- "MEDSI 75". It works in mono-and bipolar modes. Used in neuro-, microsurgery, veterinary medicine. Price - 65 thousand rubles.
- "MEDSI 100". Its main difference from previous modifications is the high power of each tool, which allows you to affect large volumes of pathology. Used in gynecology, otorhinolaryngology, veterinary medicine. Price - 90-115 thousand rubles.
- "MEDSI 150". They work in the modes of mono-, bipolar coagulation, cutting. If desired, the kit can be supplemented with a spray coagulation tool. Used in inpatient facilities for the treatment of ENT diseases, gastrointestinal tract, pathologies of the female genital organs. Price - from 115 thousand rubles.
Coagulation in Gynecology
Currently, the method of coagulation of the cervix with electrocoagulators is considered obsolete. With this method of removing pathologies, rough scars remain that can interfere with the normal course of labor. Therefore, cryodestruction or radio-wave coagulation is now used.
Coagulation in Ophthalmology
In ophthalmology, coagulation is prescribed for neoplasms on the mucous membrane of the eyeball, eyelid skin, purulent corneal ulcer, retinal detachment, improperly growing eyelashes and other pathologies. Currently, retinal coagulation and other procedures are performed with a laser. Electrocoagulation is not applicable. The purpose of the retinal coagulation surgery is to burn off exfoliated cornea.
Coagulation in Dermatology
Electrocoagulation is used to remove warts, papillomas, moles and other defects. Depending on the shape and location of the defect, mono- or bipolar modes of operation are used.
Maintenance
To ensure long-term operation of the device, it is necessary to follow the rules of maintenance of medical equipment. A regular check of the technical condition of the device is necessary:
- verification of operational and technical characteristics - once a year;
- completeness check - 1 time per month;
- checking the output power, overall performance - before the procedure.
To protect against dust, the inoperative device and LEDs must be covered with a dustproof cloth.
From time to time, it is necessary to disinfect the outer surfaces of the device case with a 3% hydrogen peroxide solution, adding 0.5% detergent. Do not use detergents containing organic solvents.
Maintenance of medical equipment and repairs are entitled to be carried out by specialists of repair organizations authorized by the manufacturer.
Most often, when operating coagulators, connectors for connecting accessories and tools fail. If the coagulator fails to turn on before or during the procedure, you must first check the fuse box, which is usually located in the network cable connector. If the fuses are intact, check the main power supply. To do this, the device is disassembled, the lines are checked by the tester.