Inclusion Criteria:  Patient with a solid tumor and age ≥ 18 years Admission to the ICU due to postoperative care after being submitted to a major surgical procedure (defined as having a duration of three hours or more) Expected ICU stay of more than 24 hours Presenting Hb value of 9,0g/dL or less during ICU stay, within the first 7 days post-surgical procedure  Exclusion Criteria:  Hematological malignancy Chronic anemia (defined as presenting Hb ≤9,0g/dL at hospital admission and / or diagnosed hematological disease) Presence of active bleeding at the moment of inclusion in the study (defined as visible bleeding with fall of 2,0g/dL in Hb levels in the last 12 hours or need to reoperate) Transfusion of RBC during the current ICU stay before the inclusion in the study Patient refusal to receive blood transfusions Pregnancy Postoperative care of cardiac surgery or surgery for correction of hip fracture Patients with terminal oncological disease in palliative care Arterial ischemic event in the current hospital stay or in the past twelve months (includes stroke, myocardial infarction, unstable angina, mesenteric ischemia, peripheral ischemia)