Hypoxaemia, generalised or local, causes sickling of red cells in people with sickle cell disease and there is evidence that nocturnal hypoxaemia may be a cause of central nervous system complications and vaso-occlusive crises. Researchers in Philadelphia (BM Yamaja Setty and colleagues. Lancet2003;362:1450–5OpenUrlCrossRefPubMedWeb of Science) have shown that children with severe sickle cell disease may be hypoxaemic both …