Less frequently, dyspnea, wheezing, and incontinence may occur, indicating a generalized spasm of smooth muscle. Rarely, anaphylaxis may occur. Medications must never be mixed with the blood. If an allergic reaction occurs, the transfusion is stopped. When cardiac reserve is deficient, eg, in heart disease with anemia, transfusions may raise the venous pressure and cause acute heart failure.
Whole blood is contraindicated.
A rise in venous pressure can be avoided by infusing RBCs at a slowed rate. The patient should be observed for signs of increased venous pressure or pulmonary congestion. Acute respiratory symptoms develop, and chest x-ray has a characteristic pattern of noncardiogenic pulmonary edema. General supportive therapy typically leads to recovery without long-lasting sequelae. Air embolism is largely a complication of pressure infusion of blood but it can also happen when an IV set is changed or a plastic blood bag is erroneously vented.