The high frequency electrosurgical unit (high frequency surgical instrument) is an electrosurgical instrument that replaces a mechanical scalpel for tissue cutting. It uses the high-frequency and high-voltage current generated by the effective electrode tip to heat the tissue when it contacts the body, thereby achieving separation and coagulation of the body tissue, thereby cutting and stopping bleeding.
First, the application brief
The high-frequency electrosurgical knife has been used in clinical practice since 1920 and has a history of more than 70 years. It has experienced a change in spark plug discharge - high power transistor - high power transistor - high power MOS tube four generations. With the popularization, application and development of computer technology, automatic adjustment of power waveform, voltage and current under various functions, detection of various safety indicators, and detection and indication of program control and faults have been implemented. Therefore, the safety and reliability of the device itself are greatly improved, and the operation process of the doctor is simplified.
At the same time, with the development of medical technology and clinical requirements, the composite electrosurgical equipment based on high-frequency surgical devices has also developed accordingly: high-frequency argon air knife, high-frequency ultrasonic surgery system, high-frequency electric cutting Speculum treatment systems, high-frequency rotary-cutting and fat-removing machines and other devices have achieved remarkable results in the clinic. The various accessories for high-frequency surgical devices (such as bipolar electric cutting, bipolar resectoscope, resectoscope vaporizing roller electrodes, etc.) derived from it have also opened up a wider range of applications for clinical surgery.
Second, classification
According to the function and use of the high frequency surgical device, it can be roughly divided into the following types:
1, multi-function high-frequency electric knife: with pure cutting, mixed cutting, unipolar coagulation, electrocautery, bipolar coagulation;
2, single-pole high-frequency electric knife: with pure cutting, mixed cutting, unipolar coagulation, electrocautery;
3, bipolar coagulator: bipolar coagulation;
4, electric burner: unipolar electrocautery;
5, endoscope special high-frequency generator: with pure cutting, mixed cutting, unipolar coagulation;
6, high-frequency argon gas knife: with argon protection cutting, argon arc jet coagulation;
7, multi-function high-frequency beauty instrument: with point condensation, point burning, ultra-high frequency electric burning.
Third, the basic composition
The high-frequency electric knife is composed of the main unit and the electric knife handle, the patient plate, the bipolar switch, and the foot switch.
Fourth, the working principle
Unipolar mode
In unipolar mode, a complete circuit is used to cut and solidify the tissue, which consists of a high frequency generator in the high frequency electrosurgical unit, patient plates, connecting wires, and electrodes. In most applications, current is passed through the patient through active leads and electrodes, and the patient plate and its leads are returned to the generator of the high frequency electrosurgical unit.
The heating effect of a high-frequency electrosurgical knife that can destroy a diseased tissue is not caused by a heated electrode or a cutter head, like an electric cautery. It concentrates the high current density of high currents and directly destroys the tissue at a point in contact with the tip of the effective electrode. Coagulation occurs when the temperature of a tissue or cell that is in contact with or adjacent to an effective electrode rises to the protein in the cell. This precise surgical effect is caused by the waveform, voltage, current, type of tissue, and electrode. The shape and size are determined.
In order to avoid burning the tissue as the current returns from the patient returning to the electrosurgical knife, the patient plate in the monopolar device must have a relatively large area in contact with the patient to provide a low impedance and low current density channel. . Some high-frequency electrosurgical knives used in doctor's clinics have lower current and lower density, and can be used without patient plates. However, most general-purpose high-frequency electrosurgical knives use a large current, thus requiring patient plates.
The ground-isolated output system eliminates the need for an auxiliary channel between the patient and the ground, thereby reducing the risk of burning of the body that may be in contact with the ground. With a ground-based system, the risk of burns is greater than that of an insulated output system.
Bipolar mode
Bipolar coagulation provides high-frequency electrical energy to the body tissue through the two tips of the bipolar forceps, so that the blood vessels between the ends of the bipolar forceps are dehydrated and solidified to achieve the purpose of stopping bleeding. Its scope of action is limited to the ends of the scorpion. The extent of damage to the body tissue and the extent of its impact are much smaller than those of the unipolar method. It is suitable for the closure of small blood vessels (diameter <4mm) and fallopian tubes. Therefore, bipolar electrocoagulation is often used in more elaborate operations such as brain surgery, microsurgery, ENT, obstetrics and gynecology, and hand surgery. The safety of bipolar coagulation is gradually being recognized, and its use range is gradually expanding.
Five, cutting principle
When the high-frequency high-voltage current generated by the high-frequency electric knife passes through the high-impedance structure, heat is generated in the tissue, causing the tissue to vaporize or solidify. Resistance during electrical electrosurgery varies from 100 ohms to 2000 ohms. As the tissue solidifies, the water in the cells will vaporize, causing the tissue to dry, causing the resistance to increase, and finally the current is completely stopped.
Six, use
And more and more used in a variety of endoscopic surgery, such as: laparoscopic, prostate cutting, gastroscope, cystoscopy, hysteroscopy and other operations.
Because the high-frequency electrosurgical knife can simultaneously cut and coagulate, it is widely used in the surgery that the mechanical scalpel is difficult to enter and implement (such as abdominal tube ligation, prostatic urethral tumor resection).
The high-frequency electrosurgical prominence of coagulation makes it widely used in diffuse oozing sites such as liver, spleen, thyroid, breast, and lung surgery.
Other functions
In addition to the basic functions of performing surgery, a comprehensive high-frequency electrosurgical knife has the following important functions:
1. Output power indication;
2. Power preset and adjustment;
3, patient plate detection alarm;
4. Working audio indication;
5, the output port prevents mis-insertion;
6, manual control, foot control function.
Seven, advantages
1. Fast cutting speed, good hemostasis effect, simple operation, safe and convenient.
2, compared with the traditional use of mechanical scalpel, the use of high-frequency electrosurgical in the clinic can greatly shorten the operation time, reduce the amount of blood loss and blood transfusion, thereby reducing complications and surgery costs.
3. Compared with other electrosurgical instruments (such as laser knives, microwave knives, ultrasonic knives, water jets, semiconductor heat condensing knives, etc.), high-frequency electrosurgical knives adapt to a wide range of operations, easy to enter the surgical site, easy to operate, reasonable performance price ratio Other advantages.
Eight, matters needing attention
1. There must be no flammable or explosive gas, liquid or other substances in the operating room. Because high-frequency electrosurgical surgery will produce sparks and arcs, flammable and explosive materials will burn or explode when exposed to sparks or arcs.
2. Patients with cardiac pacemakers generally cannot use high-frequency electrosurgical knives because high-frequency interference can interfere with cardiac pacemakers, making them work abnormally or even stop. If you must use a high-frequency electric knife, you must take necessary and effective precautions according to the instructions of the pacemaker.
3. The plates must be properly connected and placed, and the contact surface with the patient's skin should be large enough.
4. Do not blindly increase the output power of the electrosurgical unit, just to ensure the surgical effect is limited. Because any risk in high-frequency electrosurgery surgery increases with increasing power. When the power required for surgery is significantly greater than the normal value (generally, the power used in electrosurgical electrosurgery is about 20-80W, special surgery such as amputation requires more, and single pole is less than 200W). Check the placement of the plates, plates and Do not increase the output power setting value by the degree of integrity of the cutter head cable, the state of the machine, and the degree of suspension of the patient. When the normal power cannot be predicted, it should be gradually tested from small to large until it is just used. Before the end of the machine use and before starting, you should ensure that the output power setting value is at a low value, otherwise the excessive power will suddenly be added to the patient.