Prevalence of hypoxemia among children with sickle cell anemia during steady state and crises: a cross-sectional study.

BACKGROUND Patients with sickle cell anemia (SCA) are prone to recurrent pain crises related to red blood cell sickling and vaso-occlusion with subsequent tissue hypoxia. Alveolar hypoxia has been shown to be associated with entrapment of sickle cells in the pulmonary microcirculation which may propagate a cycle of further hypoxemia and sickling. Pulmonary complications are common in sickle cell disease (SCD) and may exacerbate microvascular occlusive phenomena. Thus, detecting hypoxemia is of particular importance in SCD. OBJECTIVES This study was designed to determine the prevalence of hypoxemia among children with SCA and compare the oxygen saturation of those in crises with those in steady state. MATERIALS AND METHODS This is a prospective observational study involving 46 children with SCA in steady state, 42 with crises, and 42 with HbAA genotype carried out between August and December 2010. The study compared the oxygen saturation of sickle cell anaemic children in steady state and in crises with normal hemoglobin genotype using Nellcon pulse oximeter while the hemoglobin concentration was analyzed using automated Sysmex KX-21N model. RESULTS A total of 130 participants aged 6 months to 18 years were recruited. The overall prevalence of hypoxemia in this study was 13.8%. Hypoxemia was highest among SCA patients in the crisis state (23.8%) compared to 13% and 0% for those in the steady state and in those with normal hemoglobin genotype, respectively (χ² = 6.425, P = 0.04). Hypoxemia was higher among those with hemoglobin less than 5 g/dl (30%) and least among those whose hemoglobin levels were 10 g/dl and above. CONCLUSIONS Hypoxemia was significantly higher among children with SCA during Vaso-occlusion crises. We recommend that one should have a high index of suspicion and take prompt action in managing these individuals especially those with acute chest syndrome.