2. Increasing oxygen delivery can be achieved by increasing any of the components of oxygen transport (arterial oxygen saturation, cardiac output and hemoglobin level). However, the oxygen delivering capabilities of stored red blood cells have been debated and adverse effects of red blood cell transfusion have been reported. Best evidence suggests a restrictive transfusion policy in the ICU (transfusion threshold 4.34 mmol/l) with an exception of severe ischemic cardiac disease.