| Sumario: | Background Acute haemorrhage may be of great risk for the patient. Fast and efficient treatment is of the utmost importance. Blood and plasma products are used in many parts of clinical medicine in the treatment of acute haemorrhage in hospitals in Norway and other industrialized countries. Jehovah's Witnesses refuse, based on their religious beliefs, to receive blood and blood product transfusion. Many major surgical interventions have been performed on these patients. The organisation of Jehovah's Witnesses contacted the health authorites and raised the question whether there was unnessary transfusion of blood in the Norwegian hospitals. This report is a result of this request. The Transfusion Service Quality Council has been contacted and supports the making of this HTA-report in order to optimize the use of blood products in clinical medicine in Norway. Purpose Indications for use of blood and plasma products are wide, and a total assessment of all use of haemotherapy was considered too extensive. The review team chose to limit the task to assess the evidence base for transfusion versus alternative treatment in acute haemorrhage, defined as treatment instituted within 24 hours after the start of the acute haemorrhage. The report concerns the effect of treatment in volume replacement, oxygen delivery to prevent tissue hypoxia and haemostasis to stop or reduce bleeding by drugs and other methods. The review team was also asked to give an overview of side effects associated with transfusion in addition to legal and ethical considerations related to haemotherapy. Search strategy and method The review team has performed a health technology assessment according to internationally appoved principles by doing a systematic review of the published literature. A systematic literature search was done to identify literature on acute haemorrhage in trauma and surgery within 24 hours after start of haemorrhage. The literature review was evaluated by three pairs of reviewers. The assessment was done stepwise starting with 2438 abstracts and ending with 81 studies approved as the evidence base. Information on legal aspects was given by the Norwegian Board of Health and the report includes a statement given by Jehovah's Witnesses. The literature search was done in the databases Medline, EMBASE and Cochrane. No groups of patients should be excluded. The studies should include interventions to replace lost blood volume, ensure sufficient oxygen delivery to the tissues or drugs or other methods that were used to achieve good haemostasis. Outcomes were length of hospital stay, survival, complications and use of blood products. An updated literature search was made 13.01.2005. Main results Volume replacement The only product derived from human blood, albumin, was not found to be more effective in fluid therapy in acute haemorrhage than colloids or crystalloids. No difference in effect between colloids and crystalloids was found. Whether volume resuscitation should be started prehospitally or not is still controversial, as well as to what degree the blood pressure should be normotensive or hypotensive in the acute phase. Oxygen transport There is strong evidence for young and healthy individuals to tolerate a reduced haemoglobin concentration down to 5 g/L provided that the patient is kept normovolemic. At very low haemoglobin concentrations, reduced muscle power, fatigue and lightly reduced cognitive function can be observed, but this is normalized soon after retransfusion of own blood. No research has shown that erythrocytes stored in blood bank have the same effect whether used immediately or after some hours storage. This distinction is important as considerable changes occur in the properties of the erythrocytes during storage in the blood bank. To what degree these changes actually are of relevance for the results of haemotherapy, is not known. It is possible, but has not been shown conclusively, that the reduced heart and lung capacity of older persons lead to a lower tolerance for acute anemia than in younger persons. It seems reasonable, therefore, to maintain a higher transfusion trigger level for the elderly and ill patients than the younger and healthier ones. The review team did not find good evidence, however, for this hypothesis. There is good evidence for being restrictive in using erythrocytes in intensive care, but reservations must be made regarding the use of erythrocyte concentrates containing leucocytes. Some studies indicate the need for a higher threshold value of haemoglobin in treatment of patients with unstable angine pectoris / myocardial infarction, but the evidence is not consistent. In Norway, leucocyte filtered erythrocyte concentrates are used and seem to be associated with less side effects. It is possible that a more liberal transfusion practice may be advantageous in elderly patients, but there is no good evidence for this view. Little evidence currently supports the replacement of transfusion of erythrocytes with artificial oxygen carriers. Haemostasis There is good evidence for fibrinolytic agents reducing the need of transfusion during acute haemorrhage. There is low evidence for the use of freshly frozen plasma / Octaplas(r) in reducing the need for transfusions. The same applies to the use of specific coagulation factors. The number of studies are few and they are generally small. It is unclear what clinical use recombinant factor VIIs will get in the future. The results of the published studies diverge, hence no firm conclusion about effect can be drawn. Only low evidence was found for the transfusion of thrombocytes used in acute haemorrhage. Conclusions by the review team With the exception of fibrinolytic drugs that reduce the need for transfusion there is generally a weak evidence base for haemotherapy. It is especially weak for the transfusion of erythrocytes and thrombocytes. There are several uncertainties about the quality of transfusion products stored in blood banks. No study results indicate that practice in Norway involves too high consumption of blood and blood products. The increasing mean age of the population and the increasing number of new therapeutic possibilities may indicate that the need for bloodproducts will remain stable over time. It is considered a high priority for the Norwegian and international field of transfusion medicine to improve the evidence base for haemotherapy.
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