Blood Transfusion in Medicine V Acute Gastrointestinal Bleeding

Gastrointestinal bleeding as a clinical entity accounts for a significant proportion of all red blood cell transfusions and such patients require a prompt response in component availability from the Blood bank. Although acute spontaneous gastrointestinal bleeding has some similarities to transfusion problems seen in patients with massive trauma (Chapter 14), patients with trauma undergoing massive transfusion are usually hemostatically normal prior to the onset of the trauma, and hence, management with crystalloids and red cells may suffice until a large loss of intravascular volume has occurred. In contrast, patients with acute gastrointestinal bleeding often have an associated underlying coagulopathy at the time of presentation, and this may require early treatment with plasma or platelets in addition to any red cells transfused. Furthermore, some of these patients may have been previously transfused, and alloantibodies to red cells may be present. This may cause an unacceptable delay in making phenotypically matched red cells available resulting in the bypassing of normal procedures with associated increased risk.

Important considerations regarding the blood transfusion support of patients with acute gastrointestinal bleeding are shown in Table 19.1. First, the requirements for a large volume transfusion, arbitrarily in excess of 10 units per 24 hours, identify a high risk population with a high mortality rate. Surgery for these patients should be anticipated, making further demands for red blood cells and other components.

Many patients presenting with acute gastrointestinal bleeding have an underlying coagulopathy. Although the underlying coagulopathy may not in itself have precipitated the bleeding, as a definable anatomical abnormality may be present, the coagulopathy may exacerbate the bleeding. In addition, moderate red cell transfusion (4-6 units) may exacerbate the coagulopathy by dilution of clotting factors. Examples are patients with liver disease who develop upper gastrointestinal bleeding from esophageal varices; patients anticoagulated with warfarin who present with lower gastrointestinal bleeding; patients taking aspirin presenting with upper gastrointestinal bleeding; or patients with hypersplenism and associated thrombocytopenia. It is important to assess the presence and severity of a coagulopathy in these patients by measurement of the prothrombin time (PT) and the platelet count. The PT may be only minimally prolonged at the time of presentation. However, as these patients are transfused with relatively small volumes of red cells, (e.g., 4-6 units), a significant dilution of clotting factors will occur, unlike hemostatically competent persons. In these patients, early resuscitation with fresh

Table Ï9.Ï. Blood transfusion considerations regarding acute gastrointestinal bleeding

I. Large volume use (10 units/24 hours) may indicate the urgent need for surgery.

II. Complicating underlying coagulopathies:

a) Clotting factor deficiencies due to liver disease or use of warfarin.

b) Platelet disorders such as thrombocytopenia from liver disease or hypersplenism or platelet dysfunction from aspirin.

c) Early development of dilutional coagulopathy with modest (4-6 units) red cell transfusion.

frozen plasma at a dose of 10-15 ml/Kg is recommended. Platelet transfusion (1 unit/10 Kg) presents a more complicated decision, but would be good practice if significant thrombocytopenia (< 50 x 109/L) is present. The role of platelet transfusion in acute gastrointestinal bleeding in patients taking aspirin is less clear. For these patients, a lower dose (3-4 units) could be given regardless of body weight, as there is evidence that only a small subpopulation of normal platelets will reverse the aspirin effect.

Patients with thrombocytopenia due to hypersplenism and who are actively bleeding require special consideration. Platelet transfusions in standard dose are unlikely to be beneficial for these patients. The most useful approach is surgical intervention to manage the anatomical site of bleeding or other kinds of manipulations, such as insertion of a tube. In the extreme situation, however, platelet transfusion should be given at a higher dose of (2-3 units/10 Kg) particularly if the platelet count is very low (< 40 x 109/L) and there is a likelihood of further dilutional coagulopathy from surgical bleeding.

Blood Pressure Health

Blood Pressure Health

Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...

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