Fig. 2. Plot of serum transferrin saturation on admission to the intensive care unit against drop in renal function. Drop in renal function measured by change in estimated glomerular filtration rate from preoperative to lowest value during the first postoperative week. Two patients in the control arm had missing transferrin saturation values and are not included; they had 0% and 34% drops in estimated glomerular filtration rate. Circles represent patients in the control arm; triangles represent patients in the intervention arm treated according to protocol; squares represent the two patients in the intervention arm who did not complete their prophylactic transfusions until about 2 h before the start of their surgery. ICU = intensive care unit.