Obstetric hemorrhage remains one of the leading causes of maternal death in the United States, often necessitating the transfusion of blood products as a lifesaving measure. More commonly, the practitioner encounters less acute situations and must decide which blood products, if any, are appropriate for the patient. In this chapter, we will address the blood products currently available for transfusion, the indications for their use, and potential risks. This chapter is not intended to be an exhaustive reference but will highlight practical concerns and issues for the clinician. We will also discuss some alternatives and techniques to avoid transfusion, including available colloid solutions, use of the “autologous transfusion device,” and acute normovolemic hemodilution (ANH).
In modern obstetric practice, transfusion of whole blood is uncommon. Typically, whole blood is separated into its components [red blood cells (RBCs), platelets, fibrinogen, and other clotting factors] and stored. Blood component therapy allows treatment of specific derangements in the patient’s blood. The potential benefits of administering blood products must be weighed against the potential risks, both short and long term.
Transfusion risks are typically categorized into infectious and noninfectious complications. Adverse events are reported to complicate approximately 10% of the 14.2 million red cell units administered annually in the United States. Fortunately, less than 0.5% of these are serious reactions. Nevertheless, death related to transfusion may be significantly underreported.1 Patient concerns regarding transfusion risks have traditionally focused on the spread of viral infectious diseases. However, 40% to 50% of deaths related to transfusion result from noninfectious complications and bacterial contamination of platelets.2 The leading causes of allogeneic blood transfusion-related mortality in the United States in the order of number of reported deaths are transfusion-related acute lung injury (TRALI), transfusion associated cardiac overload (TACO), acute hemolytic transfusion reactions (AHTR), transfusion-associated sepsis (TAS), and anaphylaxis.3
Infectious Transfusion Risks
Improvements in screening strategies for prospective donors and testing of donated blood products have significantly reduced the likelihood of viral infection from contaminated blood. In the United States, each unit of donated blood is tested for HIV-1 and HIV-2, human T-lymphotropic virus (HTLV)-I and HTLV-II, hepatitis C virus (HCV), hepatitis B virus (HBV), West Nile virus (WNV), Treponema pallidum (syphilis), Trypanosoma cruzi (Chagas disease), and Zika virus. Cytomegalovirus (CMV) testing is not done on all units, only on enough units to ensure adequate supply of CMV negative blood when needed.
Table 2-1 outlines infectious risks from transfusion and their estimated frequency. Composite risk for HIV, hepatitis B and C, and HTLV infection from transfusion is estimated to be less than 1 in 30,000.
TABLE 2-1Infectious Risks From Transfusion and Their Estimated Frequency4,5