Regular reinfusion of ascites during haemodialysis in a patient with amyloidosis.

patients with sickle cell anaemia was shown promptly to decrease the incorporation of radioactive iron into red cells and cause reticulocytopenia and rapid worsening of the anaemia. These events reversed rapidly when administration of oxygen was stopped.2 The haematological events in our patient are identical to those observed in that study, which also showed that patients with pernicious anaemia exposed to similar concentrations of oxygen during treatment with vitamin B12 had a suboptimal reticulocyte response. A brief period of red cell hypoplasia is of little consequence to an individual with red cells with a normal life span but will cause a rapid decrease in the packed cell volume in the patient with haemolytic anaemia of any cause. Failure to recognise this iatrogenic cause of aplastic crisis may lead to unwarranted diagnostic procedures and treatment. In the patient with a nutritional anaemia hyperoxia may retard the reticulocyte response to the administration of the deficient nutrient and thereby mislead the physician. Finally, studies of haematological changes during vaso-occlusive crises in patients with sickle cell disease should take account of the potential contribution of hyperoxygenation.