NMS. Casos Clínicos

280

Part II ♦ Specific Disorders

Q: What evaluation is appropriate at this point? A: Determination of the site of bleeding is essential. With rebleeding, the options for diagnosing the cause of the GI bleed include technetium-labeled RBC scan or mesenteric angiography, either with CT angiogram (Fig. 8-39) or mesen- teric angiogram. A CT angiogram can only be used for localization, whereas a therapeutic angiogram can be used for diagnosis and therapeutic interventions. The choice between these two procedures depends on the current rate of bleeding, the instability of the patient, and the surgeon’s preference: ◆ ◆ Angiography is probably better for less stable patients because of better monitoring and resuscitation capability in the angiography suite as well as for those who are bleeding at a more rapid rate . It can isolate a lesion bleeding at a rate of 0.5–1.0 mL/min or more. ◆ ◆ Technetium-labeled RBC scanning is better for more stable patients who are bleeding more slowly . It can detect bleeding at a rate of 0.1 mL/min or more. One limitation of RBC scanning is that it cannot precisely localize the site of the bleeding, making the results dif- ficult to interpret. (Fig. 8-40). An angiogram demonstrates an active bleed in the lower sigmoid area and no evidence of vascular ectasia elsewhere in the colon.

Figure 8-39: Blood in the lumen of the transverse colon in an acute diverticular bleed demonstrated on computed tomographic mesenteric angiogram (arrows demonstrated contrast extravasation from diverticular bleeding). (From Corman M, Nicholls RJ, Fazio VW, Bergamaschi R. Corman’s Colon and Rectal Surgery , 6th ed. Wolters Kluwer Health; 2012, Fig. 27-39.) Q: What is the management plan? A: The patient has clear evidence of continued bleeding , has proven cardiovascular insta- bility , and has now received 4 units of packed RBCs . At no single specific point is surgery indicated, but each of these conditions is a relative indication for surgery, and the combina- tion is certainly an indication. Many surgeons would explore most patients with lower GI bleeds once they had required 6 units of blood ; experience dictates that patients who have bled that much are likely to continue to bleed. A large amount of transfusion carries its own set of risks, such as transfusion reaction, coagulopathy, and infection. SAMPLE