Determinants of hemoglobin concentration in cyanotic heart disease

Children with cyanotic heart disease were studied to determine the effects of chronic hypoxemia, iron stores, and age on hemoglobin. Red cell mean corpuscular volume greater than 90th percentile was found in 72% of children and hemoglobin was higher in this group than in patients with a mean corpuscular volume in the 10-90th percentile or less than 10th percentile (p less than 0.05). In children presumed iron sufficient and with oxygen saturation greater than 75%, multiple regression analysis showed that age (p less than 0.0001) and oxygen saturation (p less than 0.0001) were associated with hemoglobin. Significant correlations between hemoglobin and oxygen saturation were present for children less than 2 years (r = -0.50) and 2-11 years (-0.48), but not for patients greater than 11 years. We conclude that variables other than oxygen saturation, including age and iron stores, are important in determining hemoglobin concentration in cyanotic heart disease.