Anaemia is extremely common amongst critically ill patients, whether as a direct result of their admission diagnosis, as a complication of their stay in intensive care or, indeed, from iatrogenic causes:

• In the multicentre European ABC study (Anaemia and Blood transfusion in Critical care), 29% of patients were anaemic at some point in their stay (defined as an Hb (haemoglobin) concentration < 10 g/dl [1]).

• In non-bleeding ICU patients the average fall in Hb concentration has been shown in one study [2] to be 0.52 g/dl/day. The decline was larger for the 1st 3 days than later days and was greater in septic patients.

Aetiology of anaemia on adult intensive care unit

Many factors are involved in the aetiology of anaemia in the critically ill:

• Surgical and traumatic blood loss.

• There is a blunted erythropoietin (EPO) response in critical illness [3]. EPO production will be further reduced if renal failure develops.

• Gastrointestinal blood loss; either as the admission diagnosis or occurring as a complication of critical illness. Even without overt melaena and despite the use of pharmacological prophylaxis a slow but continuous G-I mucosal blood loss may well be a major contributing factor to the anaemia seen on Intensive Care Unit (ICU). For example, an endoscopic study [4] performed at the time of ICU admission found that the frequency of acute gastric erosions was 21.7%. By the third day of admission the frequency had increased to 37.5% in patients receiving prophylaxis with Sucralfate and 88.9% in patients with no prophylaxis.

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