Why is there a need to reduce the use of blood?The quality and safety of blood in the UK are among the best in the world but, like all other clinical procedures, the transfusion of donor blood is not risk free. The most logical approach to reducing the risk of transfusion is to use blood only when strictly clinically necessary and where there are no alternatives. There have been recent, essentially unfunded, initiatives to promote the appropriate use of blood and the avoidance of transfusion, 1,2 and the Chief Medical Officer made a number of practical recommendations in his 2003 annual report (Table 1). 3 It appears that these efforts are having some effect: the demand for blood in England and North Wales, which steadily increased during the 1990s, has successively reduced by 1%, 1% and 6% over the last three years.However, it is likely that blood usage could be further reduced without compromising patient safety.High quality evidence about clinical outcomes associated with blood transfusion has only recently been provided. Recent randomised controlled trials have shown that using less blood neither impairs nor improves patient outcome. 4,5 Current practice in surgery and critical care has been strongly influenced by one of these trials which found that a 'restrictive' transfusion strategy using a haemoglobin (Hb) concentration trigger of 7 g/dl showed a trend towards better clinical outcome than a 'liberal' strategy with an Hb trigger of 10 g/dl. 4 Data from over 24,000 patients with acute coronary syndromes demonstrated an association between transfusion and higher 30-day mortality for patients with a nadir haematocrit greater than 25%, suggesting that a haematocrit as low as 25% may be tolerated in otherwise stable patients with ischaemic heart disease. 6
The safety of blood transfusionThe risk of transfusion-transmitted infection (TTI) by donor blood transfusion has never been lower. During the period 1996-2003, data from the UK haemovigilance scheme (Serious Hazards of Transfusion (SHOT)) show that the incidence of death and major morbidity associated with transfusion was 0.39 and 1 per 100,000 units, respectively. 7 The most frequent causes of death were non-infectious complications (Table 2). Major morbidity due to TTI was mostly due to bacterial contamination associated with stored platelet concentrates. The chance that donor transfusion will transmit one of the viruses for which blood is currently tested is very low. The incidence of viral transmission of HIV, HBV and HCV is 4.58, 0.41 and 22.09 per million blood donations, respectively (K Davison; personal communication).Two of the 50 recipients of blood from blood donors known to have developed variant Creutzfeldt-Jakob disease (vCJD) have themselves become infected; one recipient died of vCJD, 8 and the other died of unrelated causes but with histological evidence of vCJD. 9 The cost of providing blood in the UK has greatly increased since 1995, mostly due to measures to reduce the risk of transmission of vCJD and to new microbiological tests. Furth...