Final answer:
When a reaction is suspected during a blood transfusion, cross-matching is performed to determine if the patient has antibodies against the donor red blood cells. Incompatible transfusions can lead to severe reactions with potentially life-threatening symptoms. Ideally, matching blood types should be transfused, but in emergencies, type O blood from a universal donor may be used.
Step-by-step explanation:
When a reaction is suspected during a blood transfusion, several protocols should be followed. Firstly, a small aliquot of the donor red blood cells is mixed with serum from the patient awaiting transfusion in a process called cross-matching. This is done to determine if the patient has antibodies against the donor red blood cells. If hemagglutination occurs, confirming a positive reaction, further tests such as the Coombs' reagent test may be performed to visualize the antibody-red blood cell interaction.
In the case of an incompatible transfusion, where the patient receives a blood type that they have antibodies against, a severe reaction can occur. This can lead to an inflammatory response, hemolysis of the transfused red blood cells, and potentially life-threatening symptoms such as fever, chills, pruritus, urticaria, dyspnea, hemoglobinuria, and hypotension.
It is important to prevent transfusion reactions by ideally transfusing only matching blood types. In emergency situations where there is no time for cross-matching, blood from a universal donor with type O blood may be transfused. However, the presence of antibodies and Rh factor should also be considered in these situations.