Anemia is a condition that describes a low red blood cell count and is very common in ICU patients. Red blood cells contain hemoglobin, the substance that carries oxygen to the body cells. Anemia is suspected by a patient's symptoms and is confirmed by laboratory testing. Hematocrit percentage and hemoglobin level are the usual tests used to detect anemia. Anemia may cause symptoms such as weakness, fatigue, lightheadedness, shortness of breath, and a fast heart rate.


Many ICU patients have anemia that is due to their underlying critical illness or injury or pre-existing condition. Some patients have an obvious source of blood loss such as bleeding from an ulcer or from surgical blood loss. In other patients, the bleeding source can not be found. In addition, critically ill or injured patients typically produce red blood cells slower than normal and their red blood cells have a shortened life span. ICU patients also require frequent blood sampling that may contribute to the problem of anemia. Patients with kidney failure may have or develop anemia. The anemia associated with kidney failure is usually due to the lack of erythropoietin production by the kidney. Erythropoietin is a protein made by the kidney that normally stimulates the bone marrow to produce red blood cells.


Severe anemia, especially with ongoing obvious blood loss, is most often treated with a blood transfusion and controlling the source of the patient's blood loss. Patients with mild to moderate anemia, without obvious blood loss, may be observed. Observation of patients with mild to moderate anemia is a decision that the doctor makes depending upon the patient's condition and symptoms.


Most ICU patients have or develop anemia during their hospital stay. The exact cause of anemia is often difficult to find in patients without an obvious source of blood loss. In this case, the anemia is often due to several factors. Not finding the exact cause of an ICU patient's anemia is very frustrating for the patient, family and ICU staff. Recently, an artificial erythropoietin has been developed and tested in selected ICU patients. The preliminary results from these tests show that selected ICU patients receiving erythropoietin may need fewer blood transfusions.

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National Library of Medicine
The National Library of Medicine presents information and pictures about anemia.