There are a variety of reactions that can occur with the transfusion of any blood product. Most reactions usually occur during or shortly after transfusions. Dogs that have had previous blood transfusions are at a higher risk for severe reactions to transfusion than other dogs.
Reaction to a blood transfusion may be acute or delayed. Symptoms will usually surface in the course of three to fourteen days.
Symptoms of an acute reaction may include fever, vomiting, weakness, incontinence, shock, collapse, and general loss of transfusion effectiveness while that of a delayed reaction are usually not directly apparent and result only in a loss of the transfusion’s effectiveness.
Symptoms also vary depending on the exact cause. Transfusion of contaminated blood can result in fever, shock, and septicemia. Circulatory overload resulting from rapid or excessive transfusion can result in vomiting, cough, and heart failure. Hypothermia can happen due to transfusion of cold refrigerated blood. This usually happens in smaller dogs or already hypothermic dogs and is characterized by shivering and impaired platelet function.