Which of the following is considered a nonimmunologic adverse effect of a transfusion?

Congestive heart failure is considered a nonimmunologic adverse effect of a transfusion because it occurs due to volume overload or underlying cardiac conditions rather than an immune response. During a blood transfusion, especially in patients with compromised cardiac function or pre-existing heart conditions, the additional volume of transfused blood can lead to increased circulatory fluid causing the heart to struggle, ultimately resulting in congestive heart failure.

In contrast, hemolytic reactions, febrile nonhemolytic reactions, and urticaria are all immunologic responses. Hemolytic reactions occur when the recipient's immune system responds to incompatible blood cells, causing the destruction of those cells. Febrile nonhemolytic reactions are typically related to the recipient's immune response to white blood cell antibodies in the transfused blood, resulting in fever. Urticaria is also an allergic reaction, often linked to the recipient's immune response to certain proteins in the transfused blood. Understanding the differences between these types of reactions is crucial for effective monitoring and management during and after blood transfusions.