Final answer:
Patients with cold agglutinin disease undergoing cardiac surgery are at an increased risk of bleeding. Emergency transfusions require O-negative blood as the universal donor type. Blood type AB is indicated by agglutination in both anti-A and anti-B antibody wells.
Step-by-step explanation:
The condition of a patient with cold agglutinin disease undergoing a cardiac operation is one of increased risk of bleeding. This autoimmune disorder affects the red blood cells (RBCs), causing them to agglutinate, or clump together, at low temperatures. In the context of cardiac surgery, which often involves cooling of the blood, this can lead to complications including an increased risk of bleeding.
Patients needing a blood transfusion in an emergency situation where there is severe bleeding and no time to determine blood type will receive type O-negative blood, which is considered the universal donor type and minimizes the risk of transfusion reactions.
When determining a patient's blood type, a sample of their blood is mixed with anti-A and anti-B antibodies. If agglutination occurs in both wells, this indicates that the patient has blood type AB, which expresses both A and B antigens.