Page 8 - Gastrointestinal Bleeding (Xuất huyết tiêu hóa)

282 PART III Symptoms, Signs, and Biopsychosocial Issues

Severe obscure overt GI bleeding

Hematochezia Melena

Urgent colonoscopy EGD and/or
after colonic purge push enteroscopy

Source identified: No source Source identified: No source identified:
Treat identified Treat Colonoscopy with
examination of terminal
ileum

Source identified: No source identified:
Treat Capsule endoscopy
Source identified

No source identified:
Deep endoscopy*

In proximal In distal
small intestine small intestine

Fig. 20.5 Algorithm for the management
Deep Retrograde ileoscopy Source identified: No of severe obscure overt GI bleeding.
enteroscopy* (via deep Treat or laparotomy source identified: *Deep enteroscopy includes double-
enteroscopy* or and intraoperative Supportive care
colonoscopy) enteroscopy balloon enteroscopy, single-balloon
enteroscopy, and spiral enteroscopy.

Endoscopic Hemostasis perforation (and absence of thermal burn damage) than thermal
techniques. Epinephrine injection is not as effective, however,
Thermal contact probes have been the mainstay of endoscopic for definitive hemostasis as thermal coagulation, hemostatic clip
hemostasis since the 1970s. These probes come in diameters of placement (hemoclipping [see later]), or combination therapy. 35,36
7 and 10 Fr and in lengths that can fit through panendoscopes, Injection therapy can also be performed with a sclerosant, such
enteroscopes, or colonoscopes. Contact probes can physically as ethanolamine or alcohol, but these agents are associated with
tamponade a blood vessel to stop bleeding and interrupt underly- increased tissue damage and other risks.
ing blood flow; thermal energy is then applied to seal the under- Endoscopic hemoclips (or clips) have been available since
lying vessel (coaptive coagulation). The most commonly used 1974, and have become popular following technical improve-
37
probe is a multipolar electrocoagulation (MPEC) probe, also ments. Hemoclips serve to apply mechanical pressure to a
referred to as a bipolar electrocoagulation probe, with which bleeding site. The first-generation endoscopic hemoclips could
heat is created by current flowing between intertwined electrodes not stop bleeding in vessels larger than a diameter of 1 mm,
38
on the tip of the probe. In animal studies, optimal coagulation but subsequent hemoclips have been larger and stronger and have
has been shown to occur with low-power settings (12 to 16 W) had a grasp-and-release mechanism that improves endoscopic
applied for a moderate amount of time (8 to 10 seconds) with deployment and hemostasis. Hemoclips are especially useful for
32
moderate pressure on the bleeding site. Heater probes provide patients with malnutrition or coagulopathy but can also be dif-
39
a predetermined amount of joules of energy, which does not vary ficult to deploy depending on the location of the bleeding site,
with tissue resistance and can effectively coagulate arteries up the degree of fibrosis of the underlying lesion, and limitations to
to 2 mm in diameter, a diameter considerably larger than most endoscopic access. Newer, large, over-the-endoscope hemoclips
secondary or tertiary branches of arteries (usually 1 mm) found grasp more tissue, adhere to fibrotic ulcers better, and can con-
in resected bleeding human peptic ulcers. 33,34 The main risk of trol severe ulcer bleeding better than standard ulcer hemostatic
using a thermal probe is perforation with excessive application of techniques. 40
coagulation or pressure, especially in acute or nonfibrotic lesions. With band ligation, mucosal (with or without submucosal) tis-
Thermal probes can also cause a coagulation injury that can make sue is suctioned into a cap placed on the end of the endoscope,
lesions larger and deeper and may induce delayed bleeding in and a rubber band is rolled off the cap and over the lesion to com-
patients with a coagulopathy. Argon plasma coagulation is a non- press its base. This technique is widely used for the treatment of
contact thermal therapy (see later). esophageal varices (see Chapter 92) and can occasionally be used
Injection therapy is most commonly performed with a sclero- for other bleeding lesions. It is relatively easy to perform, but suf-
therapy needle and submucosal injection of epinephrine, diluted ficient mucosa must be suctioned into the cap for ligation to be
to a concentration of 1:10,000 or 1:20,000, into or around the successful. Depending on the manufacturer, some band ligation
bleeding site or stigma of hemorrhage (see later). The advan- devices can only fit on diagnostic endoscopes, and switching from
tages of this technique are its wide availability, relatively low a larger therapeutic endoscope to a smaller diagnostic endoscope
cost, and safety in patients with a coagulopathy, and lower risk of is necessary.