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Hemostasis and Tumor Ablation

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Hemostasis and Tumor Ablation Powered By Docstoc
					                                      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.

				
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