Chapter 21: Blood Product Replacements

INTRODUCTION

In the general patient population, 10% receive a transfusion during their inpatient stay.^1,2 Among obstetric patients, fewer than 2% of patients require transfusion from birth through 6 weeks’ postpartum.³ Postpartum hemorrhage (PPH), defined as blood loss of ≥750 mL after cesarean delivery or ≥500 mL after vaginal birth,⁴ may complicate 3% to 7% of deliveries and accounts for nearly 20% of all in-hospital deaths following delivery.^5-7 The rate of severe PPH (defined as PPH accompanied by transfusion, hysterectomy, or surgical repair of the uterus) per 1000 deliveries has increased between 2001 and 2008, from 1.9 to 4.2.⁷ In addition to red blood cell (RBC) transfusion, obstetric transfusion may involve transfusion of platelets, plasma, and cryoprecipitate (CRYO).⁸ Massive transfusion protocols (MTPs) are increasingly used in the obstetric hemorrhage setting.^9-13 This chapter will therefore familiarize the OB/GYN hospitalist with pretransfusion testing as well as principles of blood component therapy in the obstetrics patient.

TRANSFUSION SAFETY AND RELATED RISKS

TRANSFUSION SAFETY PRACTICES

Specimen Labeling and Type Checks

Improper identification of the patient or mislabeling of the tube results in wrong blood in tube (WBIT) errors, which are detected at rates of 1.2 to 17 per 1000 specimens.^14,15 WBIT errors, the rates of which rise during urgent transfusion scenarios, place patients at risk for potentially fatal ABO-incompatible transfusion events.^16,17 Type checks enhance patient safety by providing a second opportunity to verify the patient's ABO type prior to transfusion of non–Group O red cells.¹⁸ Type checks are triggered when non–Group O patients have never previously had their blood group confirmed. Type checks are also performed to enable electronic crossmatch.

RISKS OF TRANSFUSION

Infectious and Noninfectious Transfusion Risks

Blood component therapy has witnessed an era of increasing safety.¹⁹ Infectious risks are quite low,^20-23 and far surpassed by noninfectious risks^24-31 (see Table 21-1). Zika virus, an arbovirus in the flaviviridae family³² causes infections with mild or asymptomatic disease in affected individuals but bears serious implications to the fetus.³³ Centers are currently complying with a recent US Food and Drug Administration (FDA) guidance³⁴ on Zika by testing of donor samples using one of two nucleic acid amplification-based ZIKV testing platforms: Procleix Zika Virus Assay—codeveloped by Hologic (Hologic, Inc, Marlborough, MA) and Grifols (Grifols Biologics Inc., Barcelona, Spain), and the Cobas Zika Test (Roche Diagnostics, Basel, Switzerland). Units testing positive are discarded and donors deferred for 120 days following a positive test or resolution of symptoms, ...