Association of lactic acidosis with biguanide therapy.

To the Editor: In recent months an increasing number of patients have been referred to us by doctors from outside with a standard note: ' breathlessness ... tiredness anaemia (4 8 g/IOO mJ) blood transfusion given .. Hb now 12 g/IOO ml please see and treat'. Many of these patients have required urgent blood-leiting and dialysis for iatrogenic pulmonary oedema and renal failure. Few doctors realize the many disadvantages of, and the limited indications for, blood transfusion. The disadvantages are: (i) infection thrombophlebitis, hepatitis, etc. (ii) allergy, including renal shutdown; (iii) incompatibility reactions, including renal shutdown; (iv) sensitization, making future transfusions or transplants difficult; (v) volume overload and cardiac failure; (vi) worsening of uraemia; (vii) limited availability and enormous cost (R16 R20 per unit); and (most important) (viii) delay and confusion in diagnosis and treatment of the cause of the anaemia. Management of Anaemia Acute haemorrhage (e.g. obstetric, acute haemolysis, trauma, gut): Packed cells only should be given, to keep the Hb at 8 10 g/IOO mI (haematocrit ± 30%), or above 12 g/IOO ml in pregnancy. In massive, ongoing haemorrhage, fresh whole blood should be given after 6 units of packed cells. Chronic bleeding (e.g. slow gut losses, menorrhagia) or anaemia of any other cause: Blood transfusion is contraindicated, except (a) for urgent anaesthetic transfuse to Hb 8 g/IOO ml; (b) if Hb is below ±4 g/lOO ml or if there is frank high-output cardiac failure or cardiac or brain i chaemia 1 2 units only; (c) in severe trauma or sepsis transfuse to Hb 8 IO g/I 00 ml wi th packed cells. For example, the majority of anaemic patients require only iron replacement (oral, rarely intravenous) for chronic bleeding or frank iron deficiency; folic acid or vitamin B" for macrocytic anaemia; rarely, steroids for ongoing haemolysis; and diagnosis and treatment of other causative disease, e.g. infection, renal failure, cancer, leukaemia. In patients without obvious bleeding, a blood smear will how hypochromic microcytic anaemia in most in which case only iron replacement is needed. Other anaemic patients or those without an obvious cause should have a bone marrow examination and blood urea estimation done. o patient should have blood transfusion without regular checking of the urine, blood electrolytes and urea (Azostix is better than nothing). Diuretics should nor be given routinely. Although the Hb may rise by only I g/IOO mI per week, replacement of deficient iron, folate or vitamin B", etc., produces dramatic symptomatic improvement within a few hours.