Autologous Transfusion in Children: Blood-Saving Techniques

Abstract

It is uncontested that blood-saving strategies should also be applied in children. However, in the past, blood-saving techniques saw limited use in children although they are well-established in adults. This is due to technical and methodical problems but also to the physiologically limited compensatory mechanisms for diminished oxygen delivery in this age group. For this reason, the various blood-saving techniques cannot be universally applied to all age groups. During the first year of life most perioperative techniques are of only limited benefit: Even a small amount of blood loss in relation to total blood volume makes a transfusion of allogeneic blood necessary, which is far before enough shed blood can be recovered for re-transfusion. Preoperative autologous donation of blood calls for a high degree of cooperation by the child and the parents and is equally demanding in terms of organization and skills. Therefore, this procedure is used mainly in school-age children and in adolescents. Intraoperative blood salvage, by contrast, is already worthwhile in children of at least 1 year with an expected blood loss of 20% of blood volume. Acute normovolemic hemodilution and deliberate hypotension should be recommended only in an age group where cardiovascular compensatory mechanisms are given. Supporting procedures aimed at avoiding the need for allogeneic blood include perioperative administration of erythropoietin, iron supplementation, blood-saving surgical techniques and careful hemostasis. These prerequisites, the combination of various techniques as well as the definition of an age-specific low transfusion trigger have contributed to a marked decrease in the need for allogeneic blood products in children over the recent years.

Processing of small volumes in blood salvage devices

“…But especially the first filling is of clinical relevance, as the decision for the transfusion of allogeneic blood often is dependent on that first availability of autologous blood. An estimation based on the volumes of the separation chamber is of limited use because of RBC loss in dead spaces such as reservoir and wash system especially during the first filling and because of the discontinuous collection of wound blood with varying Hct . Therefore, tested and produced volumes are given in milliliters of RBCs in this study.…”

“…For C.A.T.S previous calculations of the minimum blood amount based on the volume of the separation chamber proposed that 30 mL of wound blood or 15 mL of RBCs would be sufficient, assuming a separation chamber volume of 30 mL. Thus, 72 mL of wound blood would be necessary for an effective IBS .…”