[Transfusion problems in surgery and anesthesiology. The causes, consequences, prevention and treatment of...

The classical indication for blood transfusion is the correction of oxygen delivery failure, and the elimination of tissue ischaemia. Such indications in the surgical and anesthesiological practice are the acute haemorrhagic states (trauma, acute gastrointestinal bleeding, intraoperative hemorrhage), as well as diseases associated with chronic blood loss (occult bleeding caused by malignancies, and ulcerating processes etc.). The traditional surgical and anesthesiological viewpoint has adopted a remarkably liberal approach to the indication of blood transfusion, and a whole range of its subtle, medium-long term adverse effects has been taken into account only recently. The purpose of this review was to analyze the causes and pathophysiological consequences of perioperative anemia and blood loss, as well as to reconsider the proper indications of blood transfusion in the view of immunological sequela. The most recent data on the transfusion related immuno-depression and immunomodulation are summarized. The authors wish to provide clues for the definition of "transfusion trigger", in addition, methods available for the clinical practice to reduce blood demand and to restore oxygen transport capacity during surgical and anesthesiological interventions are revisited. Based on the review of the literature and the personal experience of the authors the practical recommendations concerning the administration of blood and blood products should be summarized as follows: 1. Blood transfusion is rarely indicated if the hemoglobin level is above 10 g/dl, and in fact always necessary if it is less than 6 g/dl, especially, if the anemia developed acutely. 2. The "transfusion trigger" is subject to continued debate, and whether a particular patient with intermediary (6-10 g/dl) Hb levels should be transfused or not must be assessed in the perspective of the potential complications initiated by the inadequate oxygenation. 3. If major co-morbidity (e.g. emphysema, ischaemic heart disease) is present, 10 g/dl Hb, in case of respirator dependency 12 g/dl Hb levels justify the administration of transfusion. If feasible, the beneficial effects of allogenous blood sparing methodologies should be utilized.

Although the National Blood Supply Service is excellently organized in Hungary, the current clinical practice is not satisfactory. The use of up-to-date methods at the average surgical departments is suboptimal, and due to the lack of knowledge concerning the recent advances in immunology the clinicians are far too liberal in the indication of blood transfusion. The objective is to establish a modern surgical and anesthesiological transfusion practice based on the solid understanding of immunological facts, and to modernize the continued education, as well as to improve the financing of costly blood saving methodologies.