The basic principle of high-frequency electric knife and precautions in use
2019-08-14
High-frequency surgical equipment, commonly known as high-frequency electrosurgery, is a surgical medical electrical equipment that uses high-frequency current to cut biological tissue and coagulate blood. It sends high-frequency current into the human body through electrodes, forming high-density current in the local tissue under the electrosurgery pen, thereby generating local high heat to achieve two electrosurgical effects: cutting and coagulation. The use of high-frequency electrosurgery has small incisions, fast cutting speed, good hemostasis, simple operation, safety and convenience, greatly shortening the operation time, reducing the patient's blood loss and blood transfusion, thereby reducing complications and surgical costs. Compared with other electrosurgical devices (such as laser knife, microwave knife, ultrasonic knife, water jet, semiconductor thermal coagulation knife, etc.), high-frequency electrosurgery has a wide range of operations and is easy to enter the surgical site. It has been widely used.
1.0 Basic structure
High-frequency electrosurgery generally consists of high-voltage power supply, low-voltage power supply, oscillation unit, power output, electrocution, electrocoagulation selection and other units. The electrode unit includes a power transformer, etc., with a primary input of 220V and a secondary output of high voltage and low voltage. The oscillation unit includes an oscillation coil, a capacitor, a tube or a transistor, etc., and its function is to generate high-frequency current. The power output unit includes a transistor and an output power adjustment circuit, and its function is to amplify the high-frequency current and output it to the electrosurgical components. The electrocution and electrocoagulation selection unit is mainly used to select the electrocution and electrocoagulation power required for clinical use. The clinical tasks of cutting and coagulation can be completed through a special handle.
2.0 Working principle
High-frequency electrosurgery is an electrosurgical instrument that replaces mechanical scalpels for tissue cutting. It heats the tissue through the high-frequency and high-voltage current generated by the effective electrode tip when it comes into contact with the body, thereby achieving the separation and coagulation of the body tissue, thereby achieving the purpose of cutting and stopping bleeding. According to the principles of medical physics, when high-frequency current passes through human tissue, because the electrical pulse time of each oscillation is extremely short, it is difficult for ions to cause migration. They only vibrate in the viscous body fluid and generate heat due to friction. High-frequency electrosurgery is developed by utilizing the "skin effect" principle of high-frequency current passing through the human body. When cutting with high-frequency electric knife, the high-frequency current only flows through the human skin and does not flow through the human internal organs. The high-frequency electric spark generated by the high-density current of the knife head is used to quickly melt the surface tissue and split the tissue under the electrode. It can form a non-bleeding, narrow, flat, and several millimeter deep incision, and it can also coagulate the blood in the blood vessels to a certain depth, replacing ligation and completing the hemostasis of the incision.
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