Ebook Practical pediatric gastrointestinal endoscopy (2/E): Part 2
➤ Gửi thông báo lỗi ⚠️ Báo cáo tài liệu vi phạmNội dung chi tiết: Ebook Practical pediatric gastrointestinal endoscopy (2/E): Part 2
Ebook Practical pediatric gastrointestinal endoscopy (2/E): Part 2
://khothuvien.comPolypectomyGeorge GershmanKEY POINTS•Knowledge of the principles of electro-surgery Is an essential component of safe polypectomy tec Ebook Practical pediatric gastrointestinal endoscopy (2/E): Part 2chnique.•Knowledge of snare designs and choosing the appropriate snare are essential parts of a successful polypectomy.Navigation of the scope to an optimal position and a clean environment create an optimal condition for a safe polypectomy.•The size and the shape of the polyp dictates the choice of Ebook Practical pediatric gastrointestinal endoscopy (2/E): Part 2 the proper technique.•Short distances (less than 2cm) between the tip of the snare and a polyp, minimal opening of the metal loop and simultaneous adEbook Practical pediatric gastrointestinal endoscopy (2/E): Part 2
vancement of the snare toward the polyp, along with tightening of the loop are the key elements of the technique.Polypectomy of a large polyp requires://khothuvien.comPolypectomyGeorge GershmanKEY POINTS•Knowledge of the principles of electro-surgery Is an essential component of safe polypectomy tec Ebook Practical pediatric gastrointestinal endoscopy (2/E): Part 2e is the heating of the restricted area by radio-frequency alternating current (RF) without stimulation of nerves and muscles. When current alternates up to a million times per second it does not stimulate muscle and nene membranes long enough to induce depolarization before the next alternation occ Ebook Practical pediatric gastrointestinal endoscopy (2/E): Part 2urs. Cutting is produced by rapid and strong heating, which creates evaporation of intra-and extracellular fluids.Coagulation is initiated when the spEbook Practical pediatric gastrointestinal endoscopy (2/E): Part 2
eed and degree of tissue heating is slower and less intense, leading to cellular desiccation. Specific effects of different types of RF currents and h://khothuvien.comPolypectomyGeorge GershmanKEY POINTS•Knowledge of the principles of electro-surgery Is an essential component of safe polypectomy tec Ebook Practical pediatric gastrointestinal endoscopy (2/E): Part 2required to push current through the tissue. The higher the voltage, the deeper the thermal tissue destruction.•Tissue resistance (R) or impedance (for alternating current) is the force generated by tissue to resist electrical flow. It is directly proportional to the amount of tissue electrolytes.Re Ebook Practical pediatric gastrointestinal endoscopy (2/E): Part 2sistance increases dramatically during tissue heating and desiccation. Normal tissue resistance is not uniform; it is lowest along blood vessels and hEbook Practical pediatric gastrointestinal endoscopy (2/E): Part 2
ighest at the level of the skirl.•Time (T) is an essential factor of energy (E) regulation, which can be expressed as:E (in joules) = p (power in wans://khothuvien.comPolypectomyGeorge GershmanKEY POINTS•Knowledge of the principles of electro-surgery Is an essential component of safe polypectomy tec Ebook Practical pediatric gastrointestinal endoscopy (2/E): Part 2Gershman. Mike Thomson. Marvin Ament. €> 2012 Blackwell Publishing Ltd. Published 2012 by Blackwell Publishing Ltd.* Low-voltage current penetrates less through desiccation tissue and has limited ability to induce deep tissue heating.** Spikes of high-voltage coagulating current allow a deeper sprea Ebook Practical pediatric gastrointestinal endoscopy (2/E): Part 2d through desiccated tissue and induce more tissue destruction.Figure 8.1 Different types of alternating RF currents and specific tissue response.AlteEbook Practical pediatric gastrointestinal endoscopy (2/E): Part 2
rnative RF currentTissue resistanceHeatAbove 41.5°cAbove 60°Clotrc FastAbove 200”CAbove 500°C• devitalization -irreversible death of the tissueCoagula://khothuvien.comPolypectomyGeorge GershmanKEY POINTS•Knowledge of the principles of electro-surgery Is an essential component of safe polypectomy tec Ebook Practical pediatric gastrointestinal endoscopy (2/E): Part 2is of bigger vessels secondary to glue effect of desiccated glucose •tissue sticking to the active electrodeCabonization • tissue may become an electric insulator•tissue vaporization cutting •smoke productionFigure 8.2 Temperature-related tissue destruction always induced by RF current.•Heating prod Ebook Practical pediatric gastrointestinal endoscopy (2/E): Part 2uces water loss and increases resistance.•Increasing resistance shifts the distribution of current from the lowest resistance pathway.•Fluctuation ofEbook Practical pediatric gastrointestinal endoscopy (2/E): Part 2
the resistance affects the power output produced by the generator.• Some of the released heat is removed from high-temperature areas by blood flow.The://khothuvien.comPolypectomyGeorge GershmanKEY POINTS•Knowledge of the principles of electro-surgery Is an essential component of safe polypectomy tec Ebook Practical pediatric gastrointestinal endoscopy (2/E): Part 2scopy Techniques• Current density is a measure of RF current (I) which flows through a specific cross-section area (a):I I://khothuvien.comPolypectomyGeorge GershmanKEY POINTS•Knowledge of the principles of electro-surgery Is an essential component of safe polypectomy tecGọi ngay
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