Thermal devices used in the treatment of GI bleeding include contact and noncontact modalities (Table 11.2). Contact thermal devices include heater probes, which generate heat directly at the tip of the probe, and bipolar electrocoagulation probes, which generate heat indirectly by passage of an electrical current between closely spaced electrodes at the tip of the probe. Noncontact thermal devices include argon plasma coagulation and laser therapy, although the latter is rarely used nowadays.

Heat generated from these thermal devices leads to edema, coagulation of tissue proteins, contraction of vessels, and indirect activation of the coagulation cascade, resulting in a hemostatic bond [18, 20]. Heater and bipolar probes also benefit from local tamponade (mechanical pressure of the probe tip directly onto the bleeding site) combined with heat or electrical current to coagulate blood vessels, a process known as “coaptive coagulation .” This process minimizes the heat sink effect, whereby energy is lost due to blood flow through a non-compressed vessel.

The heater probe consists of a Teflon-coated hollow aluminum cylinder with an inner heating coil. A thermo-coupling device at the tip of the probe maintains a constant temperature. A foot pedal controls heat activation as well as water-jet irrigation through the probe. Heater probe activation delivers energy to the diode in the probe tip. Once the pulse has been initiated, the duration of activation is predetermined and cannot be stopped until the entire amount of preselected energy is delivered [21]. A setting of 30 J is suggested for peptic ulcer bleeding (Video 11.1) and gastric Dieulafoy lesions. A setting of 15 J is recommended for other lesions, such as a bleeding Mallory-Weiss tear and vascular ectasias.

The bipolar probe delivers thermal energy by completion of an electrical circuit between positive and negative electrodes on the tip of the probe as current flows through non-desiccated tissue. In contrast to monopolar devices, the electrical circuit is confined to the tip of the probe, and so no grounding pad is required. As the targeted tissue desiccates, there is decrease in electrical conductivity, thereby limiting the maximum temperature, depth, and area of tissue injury. A foot pedal controls the delivery of the energy in watts [20]. The usual setting for peptic ulcer bleeding and gastric Dieulafoy lesions is 20 W delivered in 7–10 s application (referred to as tamponade stations) prior to removal of the probe. Several applications, with moderate to firm probe-tissue contact pressure, may be required until active bleeding is controlled and/or white coagulum formation with shallow cavitation of the treated site is observed. A lesser amount of energy (12–15 W) and shorter application duration (3–5 s) are recommended for other lesions, such as a bleeding Mallory-Weiss tear and vascular ectasias. Similar to the heater probe, built-in water-jet irrigation in the bipolar probe facilitates identification and precise targeting of the actively bleeding point prior to coagulation and aids in sliding the probe off the coagulated, sticky tissue.

Argon plasma coagulation (APC) , a noncontact device, uses high-frequency monopolar alternating current conducted to the target tissue through a stream of ionized argon gas to achieve coagulation of superficial tissue [22]. As the coagulated tissue surface loses its electrical conductivity, the plasma stream shifts to adjacent non-desiccated (conductive) tissue, which again limits the depth of tissue injury [18]. If the APC catheter is too far from the target tissue, there is no ignition of the gas, and depression of the foot pedal results only in flow of inert argon gas. Coagulation depth is dependent on the generator power setting, duration of application, and distance from the probe tip to the target tissue [22, 23]. The optimal distance between the probe and target tissue ranges from 2 to 8 mm [24]. Commercially available APC systems (ERBE USA, Marietta, GA; ConMed Electrosurgery, Centennial, CO; Canady Technology, Pittsburgh, PA; Genii, St. Paul, MN) include a specialized electrosurgical generator capable of high-frequency monopolar current, an activation foot pedal, an argon gas cylinder, disposable grounding pads, and flexible single-use APC probes. An adjustable gas flowmeter allows argon gas flow rates of 0.5–7 l/min. APC probes are composed of Teflon with a ceramic tip encasing the tungsten electrode and are available as end-firing, side-firing, and circumferential-firing probes. APC is primarily used for the treatment of superficial mucosal vascular lesions, such as vascular ectasias and GAVE (Video 11.2). Suggested settings are a power of 30–45 W (depending on the APC generator utilized) and an argon flow rate of 1 l/min.

Endoscopic mechanical therapies include clips (Table 11.3) and band ligation devices. Through-the-scope (TTS) endoscopic clips are deployed directly onto the bleeding site (e.g., active bleeding, non-bleeding visible vessel) and typically fall off within days to weeks after placement [1, 25]. All endoscopic clipping devices have three primary components: a metallic double- or triple-pronged preloaded clip, a delivery catheter, and a handle to operate and deploy the clip. Clips are available in a variety of jaw lengths and opening widths. The delivery catheter consists of a metal cable with or without a protective sheath. The tip of the metal cable has a hook onto which the clip is attached. The handle consists of two sliding components: the first allows advancement of the metal cable holding the clip out of the protective sheath, if present, and the second is the plunger that controls the opening, closing, and deployment of the clip. After insertion of the clip through the working channel of the endoscope, the clip is extended out of the sheath, if one is present. The clip is then positioned over the target area and opened with the plunger handle. A rotation mechanism on the handle is available on some commercially available clips, and this allows the endoscopist to change the orientation of the clip at the site of bleeding. The jaws of the clip are applied with pressure and closed onto the target tissue by using the device handle [25, 26]. Some clips have reopening capabilities and can be repositioned, whereas others are permanently deployed and released upon clip closure. Similarly, some clips are automatically released on deployment, while others require repositioning of the plunger handle to release the deployed clip from the catheter. Hemostasis is achieved by mechanical compression of the bleeding site (Video 11.3). Both the operator and assistant should be well acquainted with the various clip deployment mechanisms so as to facilitate easy and efficient utilization. Clip selection is mostly dependent on device availability, operator preference, and familiarity with a particular clip.

Emerging data suggest that the over-the-scope clip (OTSC; Ovesco, Tübingen, Germany), developed for closure of small mural defects, may also be effective for the management of focal non-variceal GI bleeding lesions (e.g., peptic ulcer, Dieulafoy lesion, post-polypectomy bleeding site) (Figs. 11.1 and 11.2) [27–29]. The OTSC may prove superior to standard TTS clips because of its ability to grasp more surrounding tissue and apply a greater compressive force (Video 11.4). However, no comparative data are available at this time. The OTSC device includes an applicator cap carrying the clip, a memory-shaped nitinol clip in the form of a bear claw when released, and a rotating hand wheel for clip deployment. The applicator cap with the mounted nitinol clip is affixed to the tip of the endoscope in a manner similar to that of a variceal band ligation device. Caps are available in three sizes to accommodate various endoscope diameters: 11 mm (designed for endoscope diameters 9.5–11 mm), 12 mm (for endoscope diameters 10.5–12 mm), and 14 mm (for endoscope diameters 11.5–14 mm). Caps are also available in two depths (3 and 6 mm) to allow variation in the amount of tissue desired during suction. Clips come in three different sizes to match the cap sizes and also in three different shapes of teeth: type A (rounded teeth), type T (pointed teeth), and type GC (longer pointed teeth). Clips with rounded teeth are used when the goal is tissue compression for hemostasis, particularly in the thinner-walled esophagus and colon. The applicator cap incorporates a clip release thread, which is pulled retrograde through the working channel of the endoscope and fixed onto a hand wheel mounted on the working channel access port of the endoscope. The clip is released by turning the hand wheel, in a manner similar to deploying a variceal ligation band [27].

Endoscopic band ligation (EBL) devices , commonly used in esophageal variceal bleeding, can also be effective at treating select NVUGIB lesions. EBL involves placement of elastic bands under the suctioned target tissue to produce mechanical compression and tamponade (e.g., Dieulafoy lesion) (Fig. 11.3 and Video 11.5) [30].

In addition to fluid resuscitation and correction of coagulopathy, as previously mentioned, an assessment should be made for preemptive endotracheal intubation for airway protection, particularly in the setting of active hematemesis, encephalopathy, and/or difficult airway (e.g., short, thick neck). The procedure should also be aborted temporarily if a large amount of retained blood and clots is found in the stomach at the time of endoscopy to enable airway protection for prevention of aspiration.

A dual channel or therapeutic channel (3.7 mm) upper endoscope is recommended for the assessment of acute upper GI bleeding. The larger working channel enables better suction capability and the passage of large (10 Fr) rather than small (7 Fr) diameter thermal probes for hemostasis. A pedal-activated water-jet irrigation device coupled to the entrance port of the working channel or built in the endoscope facilitates washing the mucosa of adherent bloody material and aids in precisely identifying the actively bleeding point for targeted hemostasis.