VIEWS: 16 PAGES: 26 POSTED ON: 5/24/2011
Learning objectives Discuss the general principles and the role of the GI nurse in thermal coagulation procedures and methods, including monopolar and bipolar electrosurgery, heater probes and laser photocoagulation. Discuss therapeutic treatments and endoscopic procedures used in the treatment of GI tumors. Basic Principles ◦ First confirm the location of the hemorrhage ◦ Most common causes of bleeding in the GI tract are esophagitis, gastric, duodenal, and colonic ulcers; erosive esophagitis, gastritis and duodenitis; Mallory-Weiss tears:varices; tumors, arterio-venous malformation(AVMs) and colitis. ◦ At the time of diagnostic endoscopy, the Dr. and nurse should be prepared to teat the bleeding site with injection therapy, photocoagulation, electrosurgery with monopolar or bipolar accessories, and/or endoscopic clipping Several factors affect the timing of the endoscopic examination ◦ Likelihood of finding the source of the bleeding is higher when the procedure is done within 24 hrs of the bleed ◦ Ongoing upper gi bleed requires urgent endoscopy when the pt is stable. ◦ Active lower GI bleed, colonoscopy should not be performed until the colon has been cleaned out. Causes of lower GI bleeding ◦ Rectal hemorrhoids ◦ Diverticulitis ◦ Polyps ◦ Cancer ◦ Arterio-venous malformations (AVMs) ◦ Colitis ◦ Colonic ischemia ◦ Post polypectomy bleeding Causes of upper GI Bleeding bleeding cancers AVMs Polyps Electrosurgery The terms electrocautery and electrosurgery are sometimes used interchangeably. Electrocautery refers to a direct a direct current where electrons flow in one direction and the current does not enter the pt’s body. In electrosurgery, an alternating current is used where the current enter the patient’s body and the patient is part jof the circuit. The basic circuit used in gastroenterology is electricity that flows from the wall to the ESU through the active cord, via an accessory(snare), into the tissue, through the patient and back to ESU via a grounding pad. Electricity will always seek the path of least resistance. Joint prosthesis, pacmakers/defibrillators, and gastric stimulators, jewelry, and gurnery, can alter the pathway or change the flow of current. The grounding pads that are being use today are single-patient use. The grounding pads should be placed smoothly on the skin surface and avoid tenting, gaps, or folds. Electrosurgery is contraindicated in patients with excessive bleeding,esoghageal varieces, or coagulopathy. Potential complications of electrosurgery include thermal injury, hemorrhage, perforation, transmural burns and explosion. Monopolar electrocoagulation ◦ An electrocoagulation method in which the electrical current flows between a small, active electrode that is in contact with the target tissue and a larger grounding pad that is attached to the patient’s skin. ◦ Current leakage can be a problem Current may pass through the accessory, leak through the endoscope, and pass back to the endoscopist, causing burnt to the operator. Current may pass through the accessory, leak through the scope, and pass to the patient at an internal point in which the pt is in contact with the scope, and then continue to the grounding pad. Presenting the potential for a burn at a scope-patient contact point. Bipolar electrocoagulation ◦ An electrocoagulation method in which the electrical current flows between two small electrodes on the tip of the probe, both of which are in contact with the target tissue. Heater Probes is very similar in application to the bipolar probe. It consists of a hollow aluminum cylinder with an inner heat coil and an outer coating of Teflon. The heater probe is applied directly to a vessel with firm pressure. Laser Therapy ◦ Is a acronym for light amplification by stimulated emission of radiation. ◦ Only argon and neodymium:yttrium-aluminum- garnet (Nd:YAC) lasers have been widely used in endoscopy. ◦ Endoscopic laser therapy is contraindicated in uncooperative patients oro n patients with coagulopathy, extremely large vessels in the field, or inaccessible lesions. Photocoagulation may cause a white, blanched appearance with edema. The coagulative effect of lasers allows them to be used to achieve hemostasis for acute GI bleeding and to treat GI lesions that are not actively bleeding. Photovaporization may cause a divot, charring of tissue, and smoke. The photovaporization effect of lasers allows them to destroy neoplastic tissue and to cut through normal tissue to achieve therapeutic goals. Argon Plasma Coagulation (APC) was adapted from the surgical arena for use in GI in 1991. Electrical energy is delivered to the tissue by ionizing argon gas and creating a plasma. Plasma is a gas that has been partially or completely ionized, and is a collection of charged particles containing about equal numbers of positive ions and electrons. The advantages of argon plasma coagulation compared to monopolar or bipolar electrosurgery are the ability to control the depth of burn, and that contact with the tissue is not essential. The advantages of argon plasma over the alser are the cost and portability. Photodynamic Therapy ◦ Has been used effectively to treat superficial esophageal cancers, high-grade dysplasia, Barrett’s esophagus and superficial adenocarcinomas of the colon ◦ PDT drugs called photosensitizers are injected into the patient’s body, where they collect naturally in hyperprolific cells. ◦ Brachytherapy Also known as sealed source radiotherpy or endocurietherapy, is a form of radiotherapy where a radioactive source id placed inside or next to the area requiring treatment. ◦ Endoscopic Mucosal resection Is a technique that has been developed to remove small nodules or flat lesions within the GI tract down to the submucosalayer. ◦ Endoscopic Endoluminal Radiofrequency Ablation ◦ Is a procedure that involves using different straining techniques (methylene blue or lugol’s solution) and examining the esophagus for dysplasia Infection Therapy therapy method involves the injection of a chemical agent through a needle injector into a around a bleeding site to stop bleeding through variceal thrombosis or local edema Variceal Sclerotherapy Involves the injection of a sclerosing agent in a blood vessel Transient side effects of injection sclerotherapy include mild to severe chest pain, dysphagia and fever. Complication of injection sclerotherapy include hemorrhage, aspiration, necrosis, mediastinitis, esophageal perforation, pleural effusion, sepsis orportal vein thrombosis. Endoscopic variceal ligation(EVL) ◦ Dr Gregory V.Stiegmann-developed this method ◦ A technique that has also been used successfully for the eradication of rectal hemorrhoids. ◦ Disadvantages of this technique are poor visibility with profuse bleeding, reloading bands and overtube trauma. Esophageal-Gastric Tamponade ◦ Tamponade involves the insertion of specialized tubes to provide pressure on bleeding areas of the esophagus or esophagogastric junction. ◦ Contraindicated for the patients with cardiopulmonary failure, recent surgical trauma to the esphagogastaic junction, or when variceal bleeding has stopped. ◦ Sengstaken-Blakemore tube A three-lumen tube used for esophageal-gastric tamponade: it has both gastric and esophageal balloons and a port for gastric aspiration. Linton Tube is a three-lumen tube that uses a gastric balloon, but no esophageal balloon, and provides ports for both esophageal and gastric aspiration. Minnesota Tube ◦ Is a rubber, radiopaque, 18 Fr, four lumen, double- balloon tube. ◦ The four lumens are used for gastric lavage and aspiration, esophageal aspiration, esophageal tamponade, and gastric tamponade. Confocal Endoscopy ◦ Involves a combining a standard upper endoscope or colonscope with a confocal scanner. ◦ The scanner has the ability to deliver a laser light to the tissue and the confocal imaging is returned to a processor. ◦ Still new procedure, but will expand and enhance the practice in GI.
"Hemostasis and Tumor Ablation"