A 78-year-old female received 4 units of Red Blood Cells in the past 6 hours. Which reaction is she most likely experiencing if she presents with coughing and difficulty breathing?

The scenario describes a 78-year-old female who has received multiple units of red blood cells in a short time frame—specifically four units within six hours. The symptoms of coughing and difficulty breathing are indicative of fluid overload, which is commonly associated with circulatory overload, also known as transfusion-associated circulatory overload (TACO).

When blood products are transfused rapidly, especially in elderly patients or those with preexisting health issues, the body's capacity to manage the increased blood volume can be overwhelmed. This can lead to pulmonary edema, resulting in symptoms such as dyspnea (difficulty breathing), cough, and sometimes hypertension due to elevated blood volume.

If this patient were experiencing a hemolytic reaction, symptoms would typically include fever, chills, lower back pain, and hemoglobinuria, among others, which are not present in this case. An allergic reaction usually manifests as hives, itching, or fever rather than respiratory distress. A febrile reaction would also be characterized by fever and chills but would not typically present the respiratory symptoms noted.

Understanding the context of the symptoms and the rapid volume of blood transfusion is key to recognizing that circulatory overload is the most likely reaction in this patient.