A blood and infusion warmer is a device that warms blood or other fluids to prevent hypothermia. The cells in the blood are preserved by keeping it cold. Keeping it at the proper temperature is critical not just to avoid hypothermia, but also to avoid hemolysis, or the breaking of blood cells. These devices are essential for patients who require transfusion of blood rapidly to maintain homeostasis within the body. Without blood warmers, the patient could have serious complications from blood loss; warmers provide a way to replace the blood quickly without damaging it.