Which symptom may indicate a complication after a blood transfusion?

An elevated heart rate may indicate a complication after a blood transfusion because it can be a sign of an adverse reaction, such as hemolytic transfusion reactions, febrile reactions, or circulatory overload. When a patient experiences a transfusion reaction, the body may respond by increasing the heart rate in an effort to compensate for reduced oxygenation or to manage stress related to the reaction.

Increased appetite, improved fluid status, and clear lung sounds do not typically indicate complications of a blood transfusion. Increased appetite is generally not a direct effect of transfusion and might relate to other non-specific health changes. Improved fluid status may indicate successful management of a patient's fluid balance post-transfusion, rather than a complication. Clear lung sounds are a positive sign in the context of lung function and fluid overload, suggesting that the lungs are functioning well and there is no pulmonary edema or transfusion-related lung injury. Therefore, these symptoms do not reflect the potential complications associated with blood transfusions.