Hematological and hemorheological determinants of resting and exercise-induced hemoglobin oxygen desaturation in children with sickle cell disease

The aim of the study was to determine the factors associated with resting and exerciseinduced hemoglobin oxygen desaturation. The well-established 6-minute-walk test was conducted in 107 sickle cell children (50 with sickle hemoglobin C disease and 57 with sickle cell anemia) at steady state. Hemoglobin oxygen saturation was measured before and immediately after the 6-minute-walk test. Blood samples were obtained on the same day to measure hematological and hemorheological parameters. Exercise-induced hemoglobin oxygen desaturation was defined as a drop in hemoglobin oxygen saturation ≥3% at the end of the 6-minute-walk test compared to resting levels. No children with sickle hemoglobin C disease, but ~50% of children with sickle cell anemia exhibited mild or moderate oxygen desaturation at rest, which was independently associated with the percent reticulocytes. Exercise-induced hemoglobin oxygen desaturation was observed in 18% of children with sickle hemoglobin C disease and 34% of children with sickle cell anemia, and was independently associated with the 6-minute-walk test, acute chest syndrome rate and the strength of red blood cell aggregates in children with sickle cell anemia. No association was found in children with sickle hemoglobin C disease between exercise-induced hemoglobin oxygen desaturation and the measured parameters. Hemoglobin oxygen desaturation at rest was common in children with sickle cell anemia but not in children with sickle hemoglobin C disease, and was mainly associated with greater hemolysis. Physiological strain during exercise and red blood cell aggregation properties, may predict the occurrence of exerciseinduced hemoglobin oxygen desaturation in children with sickle cell anemia. in se rm -0 08 38 98 9, v er si on 1 26 J un 2 01 3