Whenever possible, the cause of anemia should be treated. Red blood cell transfusions can in the event that the hemoglobin level falls to dangerously low levels, increase the O2 transport capacity for a short time. Limits are for. B. <7 g / dl in patients without cardiopulmonary comorbidities or higher values ??in patients with such comorbidities. A red blood cell transfusion should be reserved for patients with high risk of cardiopulmonary symptoms With active, uncontrolled blood loss with any form of hypoxic or ischemic organ failure (eg. As neurological ischemic symptoms, angina pectoris, tachycardia in patients with underlying heart failure or severe COPD). The transfusion of blood and blood components is discussed elsewhere, introduction to transfusion medicine.