This is a randomized clinical study on hemoglobin dose and patient matching. The aim of the study is to evaluate whether the targeted hemoglobin increment (2 grams per decilitre) in the patient can be predicted from the hemoglobin dose/weight of the blood bag transfused. In the test group, the hemoglobin dose needed will be calculated, whereas in the control group, the prescribed number of red cell units will be transfused.
The aim of this study is to evaluate whether the targeted hemoglobin increment (2 grams per decilitre) in the patient can be predicted from the hemoglobin dose/weight of the blood bag transfused. In the test group, the hemoglobin dose needed will be calculated, whereas in the control group, the prescribed number of red cell units will be transfused.~Hypothesis: By matching the hemoglobin dose to the individual needs of the patient the investigators will reduce the total usage of red cell concentrates.