Definition
Post-operative anemia is a manifestation of anemia that is noticed shortly after surgery. In general, one speaks of anemia when the hemoglobin level in men falls below 14g/dl. In women, the hemoglobin value should not fall below 12g/dl.
Another parameter for the diagnosis of anemia is the hematocrit value, which indicates the proportion of red blood cells in the total volume of blood. It should be 40-54% for men and 37-47% for women. Surgical intervention can aggravate a pre-existing, symptomless anemia, as bleeding occurs during surgery and frequent diagnostic blood samples may be necessary in preparation for surgery.
Surgery is a burden on the human body, the stress induced can lead to disturbances in blood formation and can also cause postoperative anemia in patients without pre-operative anemia. The injuries inflicted by the operation cause the release of messenger substances that mediate inflammation and thus lead to an inflammation-like reaction. The messenger substances released are also known as acute-phase proteins and include, for example, the inflammation parameter CRP (C-reactive protein), which is also well known in the general population.
These inflammatory messengers slow down the production of the precursor cells of the red blood cells (erythrocytes) by inhibiting the production of erythropoietin. Erythropoietin is a hormone that is mainly produced in the kidney and promotes blood formation. In addition, the inflammatory messengers reduce the absorption of iron via the intestines.
The production of the oxygen-transporting molecule on the red blood cells, hemoglobin, requires iron. Reduced iron absorption can therefore lead to iron deficiency and thus to anaemia, either due to empty iron stores even before the operation or due to a prolonged disturbance of absorption in the intestine. The more extensive an operation is, the more inflammatory messengers are released. As a result, a major operation usually causes more severe postoperative anemia than a minor operation.
Symptoms and complications
The symptoms of postoperative anemia are similar to the symptoms of anemia that was not diagnosed during surgery. Weakness, tiredness, shortness of breath, sleep disturbances and pain similar to a heart attack (angina pectoris) are among them. After an operation, patients with anemia find it more difficult to recover and get back on their feet in a reasonable time.
The greater the extent of the anemia, the longer it takes the body to regenerate itself. Severe postoperative anemia is associated with a higher rate of disease and death. Temporary, mild postoperative anemia that does not affect blood flow and circulation does not increase disease and death rates.
