RESUMEN
Measurements of the saturation of arterial blood with oxygen (SaO2) were compared in 24 children during sickle cell crises. Simultaneous pulse oximetry (Nellcor N-100 pulse oximeter) and arterial blood analysis showed that SaO2 measured by pulse oximetry overestimated cooximeter-measured SaO2 (mean bias, 6.9%; p < 0.001). The blood gas machine-calculated SaO2 also overestimated cooximeter-measured SaO2 (p < 0.001). The bias increased with increasing age (p = 0.002) and carboxyhemoglobin level (p = 0.005) but was not related to methemoglobin, total hemoglobin, percentage of hemoglobin S, or percentage of hemoglobin F.
Asunto(s)
Anemia de Células Falciformes/sangre , Oxígeno/sangre , Adolescente , Niño , Preescolar , Humanos , Lactante , Modelos Lineales , OximetríaRESUMEN
To assess the effects of decreased erythrocyte production on the levels of serum erythropoietin in children, we measured simultaneous hemoglobin concentrations and erythropoietin in 18 children with iron deficiency anemia, 17 children with transient erythroblastopenia of childhood (TEC), and 7 children with aplastic anemia. In all but two patients (one with TEC; one with aplastic anemia), erythropoietin was measured at diagnosis, before institution of specific therapy for the anemia. There was a statistically significant inverse linear correlation between log10 erythropoietin and hemoglobin values for all patient groups (r = 0.904 to 0.912; p less than 0.005). A comparison of the slopes of the regressions for each patient group by analysis of covariance revealed a significantly steeper slope for the iron deficiency group (-0.553) versus the TEC (-0.287) and aplastic anemia (-0.256) groups (p = 0.0001). The difference in erythropoietin levels appeared greatest in patients whose presenting hemoglobin level was greater than 5 gm/dl. Decline in serum erythropoietin levels was more precipitous in the less severely anemic patients with iron deficiency anemia than in the patients with TEC or aplastic anemia. These data reveal quantitative and qualitative differences in the relationship between serum erythropoietin and hemoglobin levels when children with severe iron deficiency anemia versus those with TEC or aplastic anemia are considered, even though all three conditions are characterized by hypoproliferation of erythrocytes.