Читать книгу Transfusion Medicine - Jeffrey McCullough - Страница 124

Alesia Kaplan MD

Whole blood (WB) transfusion was a standard of care for military and civilian settings during the period between World War I and World War II. When the technology to manufacture the components became available and the need for transfusion component therapy grew with advancement of medicine, WB fell out of favor. WB had a limited use and mainly was used only for pediatric cardiothoracic surgery patients in the United States until recently [1–3]. In the past decade, a renewed interest in WB has emerged. This is due to a published military experience that showed successful use of blood products, including low titer O whole blood (LTOWB), for prehospital resuscitation [4, 5]. Military success was adapted for civilian trauma patients with severe, life‐threatening hemorrhage in prehospital and hospital settings. Retrospective data from military and civilian trauma patients indicates that LTOWB transfusion is associated with improved or noninferior survival compared with resuscitation with blood components [4–8]. Although secondary analysis of the prehospital air medical plasma trial showed that patients receiving red blood cells (RBCs) + plasma had the greatest mortality benefit [6], a prospective, randomized, controlled trial comparing mortality between LTOWB and standard therapy (1:1:1 component therapy) during air medical transport and through the early in‐hospital phase of care is being conducted [9]. Several authors pointed out that use of LTOWB in severely bleeding patients is associated with biological and logistical advantages (Table 5.1) [10–12]. WB has less anticoagulant preservative solution and higher hematocrit, number of platelets, and coagulation factors compared with a reconstituted unit of WB with three components (RBC, platelets, and plasma). Also, it provides more effective oxygen‐carrying capacity [10–12]. In addition, studies showed that WB stored at cold temperatures (1–6°C) has functional platelets that provide improved hemostasis [2, 13]. Logistically, WB simplifies resuscitation and accelerates the provision of all blood components needed for patients with severe hemorrhage. The future application of LTOWB in different phases of care and clinical indications are still being explored.

Interestingly, in less developed parts of the world, WB is usually used and not blood components because equipment to produce components may not be available. However, in these situations, given the kind of patients being transfused, WB may be the best use of limited blood transfusion resources. In addition, the use of rapid tests for human immunodeficiency virus (HIV), hepatitis C virus, hepatitis B virus, and syphilis make fresh WB available in those situations. Additional information on the current use of WB for transfusion is available in Chapter 11.

Table 5.1 Some advantages and disadvantages of whole blood versus blood component therapy used primarily for hemorrhagic shock resuscitation.

Whole blood

Component therapy

Advantages:Easy preparation, no additional separation is required byblood centerEasy to transport and store (room temperature or 1–6°C)Improved efficiency in preparation for issuing (no thawing plasma)Easy to administer during resuscitation (single product)Ensures 1:1:1 ratioHigher hematocrit, number of platelets, and coagulationfactors in WB unit compared with a reconstitutedunit of WBLess donor exposureLess anticoagulant‐preservative solution Disadvantages:Cannot be administered to patients with specifictransfusion requirements (e.g., low hemoglobin or lowplatelet count only)Requires maintaining dual inventoryNeed to titer anti‐A and anti‐B

Advantages:Blood components are provided for isolated deficit (e.g., RBC for anemia, platelets for thrombocytopenia)Provides blood components that can be used to supplement WB massive transfusion (e.g., cryoprecipitate, platelets)Provides some flexibility (can use O group RBC and A plasma)Guided by TEG and laboratory data, 1:1:1 ratio can be altered to meet needs of patientsProvides plasma for fractionation for manufacturing plasma concentrates Disadvantages:WB requires a separation step into componentsEach component requires different temperatures and conditions for transport and storage, and because of that a potential for a higher wastage1:1:1 ratio needs to be met during resuscitationDifficult to transport and provide needed ratio in the prehospital settingReconstituted WB yields lower hematocrit and less platelets and coagulation factorsMore donor exposureMore anticoagulant‐preservative solution and citrate toxicity

RBC, red blood cell; TEG, thromboelastography; WB, whole blood.

Despite growing use of WB in patients with severe hemorrhage, the majority of WB collected in the United States is separated into its components, and each component is stored under conditions optimal for that component. This makes it possible to retain all of the activities of the original unit of WB and results in a large number of different components being available for transfusion therapy (Tables 5.2 and 5.3).

This chapter describes the characteristics of blood products, their preparation, and storage. Clinical uses are described in Chapters 10 and 11.