<s>[INST] context: Patients who have sustained a major thermal burn of 35% or more of their body surface area are at a predictably high risk for the development of gastric erosions and hemorrhage. Endoscopy has demonstrated that gastric erosions are present in 93% of these patients, whereas the occurrence of severe acute upper gastrointestinal hemorrhage in severely burned patients ranges between 25% to 50%. At least 60% of patients at risk develop stress erosions within 1 to 2 days after the precipitating event. Painless upper gastrointestinal bleeding may be the only clinical sign. The onset of hemorrhage is often delayed, usually occurring 3 to 10 days after the onset of the primary disease. Esophagogastroduodenoscopy is the diagnostic modality of choice to confirm the diagnosis and to differentiate stress erosion from other sources of upper gastrointestinal hemorrhage. Correct identification of the bleeding source is made in greater than 90% of instances. If endoscopy is not diagnostic, visceral angiography through selective catheterization of the left gastric or splenic vessels may provide information regarding the primary vessel supplying the bleeding site. In contrast, barium examinations are usually of little value, due to the superficial nature of stress erosions, and in fact may be detrimental by interfering with the interpretation of subsequent aeriography. [/INST] question: A 35-year-old smoker is involved in a house fire and receives a 45% total surface area burn. One half of the burned surface appears to be third degree. On the third post-burn day, the patient is noted to have bloody drainage from a nasogastric tube and a decrease of 5% in his hematocrit. Appropriate management should include which of the following? | options: A: Urgent upper gastrointestinal contrast study to delineate site of bleeding B: Immediate selective aeriography the left gastric aery to diagnose and treat presumed stress ulceration C: Urgent esophagogastroduodenoscopy to diagnosis the cause of bleeding D: Urgent intravenous infusion of vasopressin at 0.2-0.4 IU/min | answer: C </s>