Acute gastrointestinal hemorrhage is a common rea-son for admission to the ICU. Older age (>60 years), comorbid illnesses, hypotension, marked blood loss (>5 units), and recurrent hemorrhage (rebleeding) after 72 h are associated with increased mortality. Management consists of stabilizing the patient with rapid identification of the site of bleeding. Although volume resuscitation is similar, the clinician must attempt to differentiate between upper and lower gastrointestinal bleeding. A history of hemateme-sis indicates bleeding proximal to the ligament of Treitz. Melena often indicates bleeding proximal to the cecum. Hematochezia (bright red blood from the rectum) indicates either very brisk upper gastrointestinal bleeding (likely to be associated with hypotension) or more commonly lower gastro-intestinal bleeding. The presence of maroon stools usually localizes the bleeding to the area between the distal small bowel and the right colon.
Two large-bore intravenous cannulas should be placed, and blood should be sent for laboratory analysis (including hemoglobin, platelet count, pro-thrombin time, and activated partial thromboplastin time). The patient should also be cross-matched for at least 4 units of red cells. Serial hemoglobin or hematocrit measurements are useful but may not accurately reflect true blood loss. Intraarterial blood pressure monitoring can be helpful. Central venous cannulation is useful for both venous access and pres-sure measurements. Placement of a nasogastric tube may help identify an upper gastrointestinal source if bright red blood or “coffee grounds”–appearing material can be aspirated; inability to aspirate blood, however, does not rule out an upper gastrointestinal source.
Lavage through a nasogastric tube can help assess the rate of bleeding and facilitate esophagogastro-duodenoscopy (EGD). EGD should be performed whenever possible to diagnose the cause of bleed-ing. Arteriography should be performed if the site of bleeding cannot be visualized with endoscopy. Both EGD and arteriography can also be used therapeu-tically to stop the bleeding. In unselected patients the more common causes of upper gastrointesti-nal bleeding, in decreasing order of likelihood, are duodenal ulcer, gastric ulcer, erosive gastritis, and esophageal varices. Erosive gastritis may be due to stress, alcohol, aspirin, nonsteroidal antiinflam-matory drugs, and corticosteroids. Less common causes of upper gastrointestinal bleeding include angiodysplasia, erosive esophagitis, Mallory–Weiss tear, gastric tumor, and aortoenteric fistula.
Bleeding from peptic ulcers (gastric or duo-denal) can be coagulated via EGD. Surgery is gen-erally indicated for severe hemorrhage (>5 units) and recurrent bleeding. H 2-receptor blockers and proton pump inhibitors are ineffective in stop-ping hemorrhage but may reduce the likelihood of rebleeding. Selective arteriography of the bleeding vessel allows localized infusion of vasopressin (0.15–0.20 units/min) or embolization.
Erosive gastritis is better prevented than treated. Proton pump inhibitors, H2-receptor blockers, ant-acids, and sucralfate are all effective for prevention. In the past some have advocated that all patients with critical illness receive a proton pump inhibi-tor. However, overuse of proton pump inhibitors is associated with an increased incidence of hospital-acquired pneumonia. Data show that patients who require mechanical ventilation for more than 48 h or who are coagulopathic derive the greatest benefit from prophylaxis. Other groups of patients showing relative benefit from prophylaxis include those with AKI, sepsis, liver failure, hypotension, traumatic brain injury, a history of prior gastrointestinal hem-orrhage, recent major surgery, or those receiving large-dose corticosteroid therapy. Once bleeding has begun, there is generally no specific therapy other than embolization or coagulation.
Endoscopic therapy, either with bipolar electro-coagulation or heater probes, is the most effective nonsurgical treatment that reduces blood transfu-sions, rebleeding, hospital stay, and the need for urgent surgery. Sedation or anesthesia to facilitate these procedures is associated with an increased risk of aspiration. Intravenous vasopressin infu-sions (0.3–0.8 units/min) are not as effective; con-comitant infusion of nitroglycerin with vasopressin can help reduce portal pressure and may reduce the incidence of cardiac complications. Intravenous propranolol can also lower portal venous pressure and may reduce variceal bleeding. Balloon tampon-ade (Sengstaken–Blakemore, Minnesota, or Linton tubes) may be used as adjunctive therapy but usually requires concurrent tracheal intubation to protect the airway against aspiration.
Common causes of lower gastrointestinal bleeding include diverticulosis, angiodysplasia, neoplasms, inflammatory bowel disease, ischemic colitis, infec-tious colitis, and anorectal disease (hemorrhoids, fis-sure, or fistula). Rectal examination, anoscopy, and sigmoidoscopy can usually diagnose the more distal lesions. As with EGD, colonoscopy usually allows definitive diagnosis and is often useful therapeutically.
Radionuclide techniques can be used to identify the source of bleeding when colonoscopy cannot be car-ried out because of inadequate preparation.
Cauterization of the site of bleeding is often possible via colonoscopy. When colonoscopy is unavailable or not possible because of brisk bleed-ing, selective arteriography can be used to identify the source, which is either embolized or infused with vasopressin. Surgical treatment is reserved for severe or recurrent hemorrhage.
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