EFFECT OF ERYTHROCYTAPHERESIS ON ARTERIAL OXYGEN-SATURATION AND HEMOGLOBIN OXYGEN-AFFINITY IN PATIENTS WITH SICKLE-CELL DISEASE

An important purpose of blood transfusion in patients with sickle cell disease is to improve arterial oxygen saturation (SaO(2)) and thereby reduce red cell sickling. To investigate the degree of improvement in SaO(2) by blood transfusion, we determined the hemoglobin oxygen affi nity, transcutaneous oxygen saturation (Tc-SO2), and pulse rate before and after automated partial exchange transfusion (erythrocytapheresis ). In 13 patients with sickle cell disease who underwent 24 erythrocyt apheresis procedures, the mean oxygen tension at half saturation (P50) was significantly reduced from 30.4 +/- 2.2 to 26.0 +/- 1.6 mm Hg (P < 0.01) immediately after exchange transfusion. Mean Tc-SO2 values inc reased from 96.2 +/- 2.8 to 98.5 +/- 2.1% (P < 0.01), Approximately 50 % of the increase in Tc-SO2 after erythrocytapheresis could be explain ed by the increase in hemoglobin oxygen affinity. An increase in arter ial oxygen pressure (PaO2) following erythrocytapheresis, suggested by the calculated PaO2 in this study, may explain some of the increase i n Tc-SO2. We conclude that improvement in Tc-SO2 in patients with sick le cell disease resulted from changes in hemoglobin oxygen affinity as well as blood oxygen pressure following erythrocytapheresis. (C) 1998 Wiley-Liss, Inc.