3. Internationales Symposium „Autologe Transfusion - Von der Euphorie zur Ratio: Praktisches Handeln aus wissenschaftlicher Sicht” (Teil I)

Autologous Transfusion - from Euphoria to Reason: Clinical Practice Based on Scientific Knowledge

”Your own blood is the safest blood” - this is the statement of the American Association of Blood Banks (AABB) on its official ”Autologous Blood Poster” [1]. It is made for lays in order to promote preoperative autologous blood donation (PABD), and to demonstrate its potential advantages. Autologous transfusion has become an established component of the patient’s blood supply. However, after having done the emotional difficult step ”from euphoria to reason” the next logical step of autologous blood management should be done; namely ”from reason to quality management and quality securing”.

In Germany, quality management concerning both autologous and allogeneic blood transfusion has been given by the German Transfusion Act (Transfusionsgesetz - TFG) from 1998 [2]. Concerning autologous transfusion, quality management was of minor importance to the clinician, so far, and stood far behind routine autologous clinical practice. Due to the continuous increase in safety of allogeneic blood, the total risk of autologous blood donation/intra-operative blood salvage plus re-transfusion of the appropriate autologous blood products should be smaller than with allogeneic blood transfusion [3]. This, however, means that autologous blood conservation measures have to achieve given quality standards. Therefore, the 3^rd International CAT-Symposium that was held on January 16 - 17, 2004 in Nottwil, Switzerland, intensively dealt with quality and safety perspectives of autologous transfusion.

Under legal perspectives, PABD - which describes both preoperative blood collection and its haemoseparation into autologous packed RBC and fresh frozen plasma - represents a pharmaceutical procedure comparable to manufacturing of a drug. It has to be made known to the appropriate official local authority and needs its approval for production [4]. German guidelines [5] by the ”Bundesärztekammer” and the ”Paul-Ehrlich-Institut” describe both the appropriate minimal prerequisites with respect to PABD and the corresponding autologous products, and the transfusion-specific education for physicians in charge of an autologous blood bank and autologous manufactoring. These guidelines primarily aim at quality measures concerning the safety of the blood products. However, concerning the patient’s benefit from autologous transfusion, it is also important to consider efficacy of autologous transfusion measures, too; i. e. increase in total RBC-mass is an additional and clinical important quality parameter. Since PABD per se represents nothing else but the transfer of patient’s RBC from his/her body into a plastic bag, availability of a given number of autologous units does not represent an appropriate or even identical increase in total RBC-mass. Only, if the decisive determinants of the efficacy of PABD are considered, PABD will result in an additional increase in RBC-mass, and PABD may be associated by a decrease of need for allogeneic blood supply.

Under legal perspectives, and in contrast to PABD, both perioperative blood salvage and its mechanical processing by sophisticated technology (PBS), autologous direct re-transfusion of salvaged but unwashed wound blood (ADR), and acute normovolaemic haemodilution (ANH) does not represent manufacturing of a drug. Due to their timely close relation to the surgical intervention, these measures are considered an integrated part of a patient’s medical treatment, and, therefore, do not need the approval by the local health authority [4]. However, with respect to these autologous measures, quality perspectives referring to product safety and efficacy have to be considered and established, too [6]. In addition, concerning PBS in patients undergoing tumor surgery, medical and legal perspectives are to be discussed with respect to irradiation of the processed blood product before its re-transfusion. Intense discussion on this topic at this symposium resulted in an amendment of the German Transfusion Act (TFG) to legally enable application of PBS, irradiation of the processed blood product, and its re-transfusion to this special group of patients.

ADR is mainly applied in cardiac and orthopaedic surgery patients. However, this measure is discussed controversely with respect to its efficacy, effectiveness, cost-effectiveness, and the potential risks of adverse events. It seems impossible to establish given quality standards for this measure comparable to those of PABD, PBS, and allogeneic RBC-units, respectively, regarding haematocrit, plasma-haemoglobin, unwanted by-products being released either from platelets and white blood cells, or resulting from blood coagulation/fibrinolysis. Measures to improve the quality of this procedure and the appropriate blood product may be of scientific interest to the clinician interested; however, a reasonable relation between efficacy, effectiveness, cost-effectiveness and clinical benefit to the patient is to be questioned.

The discussion on the effectiveness of ANH as a blood-/RBC conservation measure is as old as this measure is clinically applied; i. e. older than twenty years. However, this discussion does not consider the so-called dilution-coagulopathy that represents both a quantitative problem of volume replacement applied and a qualitative problem of the type of volume substitute administered. The lower the ”transfusion trigger” accepted, the more important becomes the topic of dilution-coagulopathy. With respect to blood coagulation neither cristalloids nor colloids, neither HES- nor gelatine-solution are ”inert”.

Another perspective very often neglected, is application of autologous transfusion measures in children. Although these techniques might be limited to special centres, exclusively, both anaesthesiologists and clinically interested transfusion specialists should be aware of the basics of this special topic.

Artificial oxygen carriers of different chemical nature are under discussion and have undergone clinical trials for years. Despite broad clinical interest and expectations, they are still not approved by the governmental authorities, and, thus, are not available for routine clinical usage, at least in Western Europe. While this makes to critically question whether artificial oxygen carriers can stand for what they are promising and we are expecting from them, another group of haemoglobin based oxygen carriers, the so-called haemoglobin-polymers, represent another experimental drug; however, it is in its very early experimental beginnings and has still a long way to go until possibly tested in clinical trials.

An ”autologous symposium” without a fundamental discussion on the rational procedure and individual clinical management and acceptance of the ”transfusion trigger” could be considered ”incomplete”; especially before the background of clinical studies dealing with tolerance of ”low” anaemic haemoglobin-levels by healthy volunteers and various groups of patients, and the clinical experience gathered from acceptance of dilution-anaemia during the last decade. Last but not least, this topic - like the preceeding ones - also stands for the basic idea of this symposium - ”clinical practice based on scientific knowledge”.

By the agreement of the editors of the below named journals it is possible to publish the lectures presented on this international/interdisciplinary symposium both in German in ”Anästhesiologie, Intensivmedizin, Notfallmedizin, Schmerztherapie” (Thieme Inc., Stuttgart), and in English in ”Transfusion Medicine and Hemotherapy” (Karger Inc., Basel). The topic of autologous transfusion covers the interest both of anaesthesiologists and transfusion specialists. Therefore, this kind of publication in two different languages and journals representing two different medical specialities was chosen by the guest-editors, in order to enable the presentation of the papers to the broad public of the two different clinical specialities interested and concerned. As the papers appear in two different languages, they are not considered a so-called ”double-publication” on the corresponding topic. The organisers of this symposium/guest-editors are very grateful both to the editors of these scientific journals for the opportunity to present the papers of this meeting and the authors for their highly appreciated contributions.

Literatur

• 1 .Autologous Blood Poster.  Am Assoc Blood Banks Bethesda, MD (E-mail: [e-mail]);
• 2 .Gesetz zur Regelung des Transfusionswesens (Transfusionsgesetz) vom 1. Juli 1998. BGBl. I, S. 1752, 1998
• 3 Karger R, Weippert-Kretschmer M, Kretschmer V. Preoperative autologous and plasma donation and retransfusion. In: Kretschmer V, Blauhut B (eds) Bailliere’s Clinical Anaesthesiology. Vol 11, Blood, Blood Products, Blood Saving Techniques. London; Bailliere Tindall 1997: 319-333
• 4 Deutsch E, Bender A W, Eckstein R, Zimmermann R. Transfusionsrecht. Stuttgart; Wiss. Verlagsges 2001
• 5 Wissenschaftlicher Beirat der Bundesärztekammer und vom Paul-Ehrlich-Institut .Richtlinien zur Gewinnung von Blut und Blutbestandteilen und zur Anwendung von Blutprodukten (Hämotherapie). Köln; Deutscher Ärzte-Verlag 2000
• 6 Hansen E, Dietrich G, Kasper S M, Leidinger W, Singbartl G, Wollinsky K H. Vorschläge zum internen Qualitätsmanagement bei der Retransfusion von intra- oder postoperativ gewonnenem Wund-/Drainageblut.  Anästhesiologie & Intensivmedizin. 2002;  43 81-84