NMS. Casos Clínicos

282 Part II ♦ Specific Disorders pathology. Then the planned colectomy takes place. Because of the cathartic effect of blood in the colon, most patients with massive lower GI bleeds have a sufficiently clean colon to allow performance of a primary anastomosis. When patients are unstable or severely malnourished, and primary anastomoses are less likely to heal, colostomy is a safer option. Q: Are there any situations in which it is necessary to proceed to the operating room sooner? A: Certain patients should be explored before they require 4–6 units of blood. ◆ ◆ Patients who become unstable with the bleeding (perhaps), especially those patients with significant coronary artery disease and angina who have instability in vital signs ◆ ◆ Patients with hard-to-determine blood types , including unusual antibodies, or patients who desire no transfusion, such as Jehovah’s Witnesses . Performing surgery at an earlier time would lessen the risk associated with hemorrhage. Q: If a patient is bleeding rapidly and subsequently hypotensive in the angiography suite, are there any ways to lessen the rate of bleeding? A: If the bleeding site is identified, it is possible to control active hemorrhage with the direct infusion of a vasoconstrictor into the bleeding vessel. This temporary maneuver may occur during preparation for surgery. The commonly used agent is vasopressin , which is not given for a prolonged period of time for two reasons: (1) its coronary vasoconstrictor effect and (2) 50% of patients having a recurrence of bleeding within 12 hours after it is discontin- ued. Another means of treatment during angiography is embolization . However, the deter- mination of which patients should have surgery versus embolization has not been clearly elucidated.

Q: Why not bypass the preoperative angiogram and determine the site of bleeding in the operating room? A: It is very difficult to attempt to determine the site of bleeding in the operating room, and the results are unreliable . Because they do not know the site of the bleeding, many surgeons would perform a total abdominal colectomy as long as the bleeding is localized to the colon. In part, this is based on the experience that rebleeding after lesser procedures (i.e., blind left or right hemicolectomy) is associated with a high rebleeding rate and high mortality. An 88-year-old who is receiving long-term care in a nursing home is brought to the emergency department with a history of constipation and a recent deterioration in mental status. The BP is 100/60 mm Hg, with a heart rate of 120 beats per minute. The patient has abdominal distention and moans when you examine the abdomen. Rectal examination reveals no stool. SAMPLE OTHER BENIGN LOWER GASTROINTESTINAL TRACT DISORDERS Case 8.35  Syndromes of Acute Colonic Dilation and Obstruction