Evidence-Based Practice of Transfusion Medicine

By Eleftherios C. Vamvakas, 360 pp, with illus, Bethesda, Md, American Association of Blood Banks, 2001.Evidence-Based Practice of Transfusion Medicine, the first text written to elucidate some of the evidence upon which modern transfusion medicine is based and to provide a succinct guide to the mathematical tools by which to analyze the same, is easily readable and factually correct in the data presented. In this one volume, the novice and experienced practitioner have a ready reference with all of the common definitions and formulae needed to evaluate published scientific claims related to the practice of transfusion medicine. As stated by the author, this book is intended to “present the rationale of clinical research methods, as well as describe the application of such clinical research methods in the field of transfusion methods” (p 1). Dr Vamvakas has organized the book so that the reader who is familiar with statistical methods and definitions can easily move directly into the later chapters, in which these methods are applied to such diverse topics as risk of transfusion-transmitted viral infections or the epidemiology of blood transfusion or long-term survival after blood transfusion, while the novice has an introduction to the statistical methods themselves as well. The material included in this book is thoughtfully handled.Chapters 1 through 3 provide thoughtful definitions of commonly used statistical terms, with illustrations based on published transfusion medicine-related studies. Having this information organized and presented in such a lucid manner in one book is of benefit in and of itself. However, the author then adds to this benefit by applying the concepts to risk analysis of transfusion-transmitted viral diseases in chapters 4 through 6. These chapters, which are well written and pertinent in the limited arena of viral and some other agents, are, however, incomplete regarding known risks for infection. There is no reference to the much more frequent risks of transfusion-related acute lung injury, bacterial contamination, or ABO mistransfusion. The selective exclusion of these more commonly encountered hazards of transfusion is not addressed anywhere in the book, so their absence might be incorrectly construed as an indication that they are of lesser importance than the viruses and other agents that are discussed.Chapter 7, while of interest for the broad-based data and analysis provided, suggests a much broader handling of transfusion than just the red blood cell (RBC) data included. Without any discussion of the use of other blood components, this book fails to address the essential information needed in day-to-day decisions for transfusion. The very different approach (from that used for RBCs) to both the collection and transfusion of platelets, for example, would have been a welcome addition to this chapter.Chapter 8 attempts to look at outcomes of blood transfusion, but focuses much of the discussion on data from a single county in Minnesota, raising the question of whether the information is applicable to other settings or locations. Furthermore, although long-term survival is clearly one outcome marker of great interest, this topic is not closely linked to the discussion of outcome measures handled in chapter 12, which describes the concept and provides some analytical information. Chapter 9, “Applications of Meta-Analysis in Transfusion Medicine,” is another statistical methods chapter that is inexplicably inserted after discussion of long-term survival, in which such methods are used.Chapter 10, the only chapter to specifically address “Deleterious Clinical Effects” of transfusion, limits the discussion to a very controversial topic, that of transfusion-associated immunomodulation (generally referred to in the text and other publications as transfusion-related immunomodulation [TRIM]). None of the more commonly observed adverse or deleterious effects of transfusion, for example, death, hemolysis, and fever, are considered. Nor does the author provide any explanation of their omission.Thus, for the average practicing transfusion medicine physician, the fundamental questions are not satisfactorily addressed. Although there are discussions of RBC utilization, there is no mention of the frequent and increasing use of platelets, plasma, cryoprecipitate, or any of the factor concentrates. The practice of transfusion medicine clearly encompasses decisions surrounding the administration of blood components besides RBCs. Even the data presented are of limited practical applicability. For example, in chapter 7, “Epidemiology of Blood Transfusion and Forecasts of the Demand for Blood,” after a summary of published epidemiological studies, the author states, “the overall variation in RBC use is [due to] limited medical consensus regarding the proper indications for use, and instances of inappropriate use of blood transfusion” (p 194). Perhaps this self-evident conclusion needed to be documented with the referenced studies, but no one who practices or has practiced in more than one institution is unaware of this problem.The strength of this book lies in its explanation of mathematical tools and in the selected examples of their applicability in some aspects of transfusion medicine. Clearly, the author is knowledgeable and experienced in these methods and their application. Perhaps if this book had been entitled “Some” Evidence-Based Practices in Transfusion Medicine, my expectations would have been met. Nevertheless, this is a valuable addition to the literature of transfusion medicine, and I look forward to future editions in which some of the aforementioned omissions may well be addressed. This publication is particularly useful to the resident in any clinical discipline, including pathology and hematology, and to fellows in transfusion medicine who are interested in extending their knowledge base in our field.