Blood Products Used in the Newborn

Steven R. Sloan

I. WHOLE BLOOD AND BLOOD COMPONENT TRANSFUSIONS

General principles. Routine blood components consist of packed red blood cells (RBCs), platelets, frozen plasma, fresh frozen plasma, cryoprecipitate (CRYO), and granulocytes. In some cases, whole blood, usually in the form of reconstituted whole blood, can be used. However, in most cases, blood components are preferred because each component has specific optimal storage conditions, and component therapy maximizes the use of blood donations. Other blood products include those used for transplants, such as umbilical cord blood and derivatives purified from blood, such as intravenous immunoglobulin (IVIG).
Side effects
- Infectious diseases. A variety of infectious diseases can be transmitted by blood transfusion. HIV, Hepatitis B virus, Hepatitis C virus, Syphilis, human T-lymphotropic virus types I or II (HTLV I/II), and West Nile virus are screened by medical history questionnaires and laboratory tests. The risk of acquiring a transfusion-transmitted infectious disease is very low and too low to accurately measure but has been calculated in the United States and are shown in Table 42.1. The risks vary depending on the prevalence of the disease and the testing performed and thus differ in other countries.
  
  Cytomegalovirus (CMV) can also be transmitted by blood, but this is rare if the blood is leukoreduced and/or it tests negative for antibodies to CMV (3). Other diseases known to be capable of being transmitted by blood transfusions include malaria, babesiosis, and Chagas disease. Animal studies suggest that variant Creutzfeldt-Jakob disease (vCJD) can also be transmitted by blood transfusion, and some probable cases of transfusion-transmitted vCJD in humans have been reported.

Special considerations. Whole blood, platelets, and RBCs can be leukoreduced by filtration or irradiated to reduce the incidence of specific complications.

Leukoreduction filters remove approximately 99.9% of the white blood cells (WBCs) from RBCs and platelets. In addition, most platelets collected by apheresis are leukoreduced even without additional filtration. Benefits of leuko reduction include the following:

Decreased rate of febrile transfusion reactions.
Decreased rate of CMV transmission.

Minimization of a possible (and controversial) immunomodulatory effects of blood transfusions.

Table 42.1 Current Infectious Disease Risks from Blood Transfusions (2)

Pathogen	Risk per Unit
Human immunodeficiency virus (HIV)	1 in 2,135,000
Hepatitis C virus (HCV)	1 in 1,935,000
Hepatitis A virus	1 in 1,000,000
Hepatitis B virus (HBV)	1 in 205,000-488,000
West Nile virus (WNV)	none
Parvovirus B19	1 in 10,000

Decreased immunization to antigens on leukocytes such as human leukocyte antigen (HLA). This has only been shown for some oncology patients and its importance for neonates is unknown.

Although the first three indications are not essential for neonates, neonates often receive leukoreduced blood components to decrease CMV transmission.

Irradiation prevents transfusion-associated graft-versus-host disease (TAGVHD) from transfused leukocytes in cellular blood components. Among those at risk are premature infants and children with certain congenital immunodeficiencies. To ensure that nobody gets this fatal consequence of transfusion, all RBCs, platelets, and granulocytes are irradiated at Children’s Hospital Boston, unless blood is emergently needed.

Some people donate blood for specific patients, providing what is commonly known as directed or designated blood. Directed donations have a small increase in rate of infectious disease transmission. The difference is minimal and parents often want to donate for their children. Transfusion of paternal RBCs or platelets is contraindicated if the neonate’s plasma contains antibodies directed against antigens expressed on paternal erythrocytes or platelets, respectively. If a first-degree relative does donate blood, the cellular blood components must be irradiated since they are at increased risk for causing TA-GVHD.

II. PACKED RED BLOOD CELLS (RBC)

General principles

Mechanism. RBCs provide oxygen carrying capacity for patients whose blood lacks sufficient oxygen carrying capacity due to anemia, hemorrhage, or hemoglobinopathy. Transfusion for hemoglobinopathies is unusual in the neonatal period when most patients will have significant amounts of fetal hemoglobin.

Several types of RBC units are available that vary in the preservatives added. Chemical additives delay storage damage to RBCs allowing for extended storage times. The types of units that are currently available in the United States are:
- Anticoagulant-preservative solution units. These units contain approximately 250 mL of a concentrated solution of RBCs. The average hematocrit of
  these units is 70% to 80%. In addition, these units contain 62 mg of sodium, 222 mg of citrate, and 46 mg of phosphate. Three types of units are currently approved for use in the United States. These are:
  - CPD. This contains 773 mg of dextrose and has a 21-day shelf life.
  - CP2D. This contains 1,546 mg of dextrose and has a 21-day shelf life.
  - CPDA-1. This contains 965 mg of dextrose and 8.2 mg of adenine and has a 35-day shelf life. This is the most widely used of the anticoagulant-preservative solution units.
- Additive solution units. Most RBC units used in the United States are additive units. Three additive solutions are currently approved for use in the United States. Each of these units contains approximately 350 mL, has an average hematocrit of 50% to 60%, and has a 42-day shelf life. Contents of these units are shown in Table 42.2.
Several changes occur in PRBCs during storage:
- The pH decreases from 7.4—7.55 to pH 6.5—6.6 at the time of expiration.
- Potassium is released from the RBC. The initial plasma K+ concentration is 4.2 mM and increases to 78.5 mM in CPDA-1 units at day 35 and 45 to 50 mM in additive solution units on day 42. CPDA-1 units contain about onethird the plasma volume as additive units so the total amount of extracellular potassium is similar in all units of the same age.
- 2,3-diphosphoglycerol (2, 2,3-DPG) levels drop rapidly during the first 2 weeks of storage. This increases the affinity of the hemoglobin for oxygen and decreases its efficiency in delivering oxygen to tissue. The 2,3-DPG levels replenish over several hours after being transfused.
Toxicity. Although there are theoretical concerns that mannitol may cause a rapid diuresis and adenine may be a nephrotoxin in the premature infant, case reports and case series have found no risk associated with additive solution units. Hence, some hospitals transfuse additive solution units to neonates. In general, we prefer to use nonadditive solution units or washed additive solution units for larger transfusions such as exchange transfusions or transfusions for surgical procedures with substantial blood loss for young infants. For transfusions of 5 to 20 mL/kg, additive units can be used.