Special Interest Group Update

In each issue, one of NANN’s special interest groups shares information in their area of focus.

Neonatal Transfusion Therapy

Julie Williams, DNP CRNP NNP-BC

Introduction

The administration of blood products is a common practice in the neonatal intensive care unit (NICU). The younger the gestational age, the greater the infant's chance of requiring a blood transfusion during their hospitalization.

The need for blood products often can be attributed to various factors, including sepsis, iatrogenic blood loss, hematologic problems, and surgery. There are a number of blood products available, and the product of choice is related to the infant's physiologic needs. Understanding the hematologic system and blood product options can help nurses understand the reasoning behind various transfusions.

Pathophysiology

Hematopoiesis, or the formation, production, and maintenance of blood cells, begins during the embryonic period and continues across the life span. Blood cells arise from the embryonic mesoderm. By 21 days' gestation, a fetal circulatory system is evident and primitive erythroblasts are detectable (Verklan & Walden, 2021; Akpan et al., 2019). All cellular components originate from hematopoietic stem cells (HSC). Embryonic HSCs, or pluripotent cells, can differentiate into various blood cell lineages, including erythroid (RBCs), lymphoid (T-cells and B-cells), and myeloid (granulocytes and platelets) (Akpan et al., 2019). Physiologic stressors, including oxidative stress, hypoxia, and bacterial infections, can influence the differentiation rate of these pluripotent cells.

Red blood cell production occurs through a process called erythropoiesis. Fetal erythropoiesis occurs in the yolk sac, liver, bone marrow, spleen, and thymus at varying times throughout gestation (Letterio, Ahuja, Pateva, & Petrosiute, 2020; Verklan & Walden, 2021). Postnatally, erythropoiesis occurs primarily in the bone marrow (Akpan et al., 2019). Erythropoiesis is regulated by the hormone erythropoietin, which is produced in the fetal liver prenatally and in the kidney postnatally. Erythropoietin production is increased in cases of hypoxia and anemia and decreased in response to hypertransfusion. Elevated levels can be seen in infants with Down syndrome, intrauterine growth restriction, and infants born to mothers with diabetes or pregnancy-induced hypertension (Verklan & Walden, 2021).

After birth, there is a decrease in the production of erythropoietin due to higher levels of tissue oxygenation. This postnatal decrease in erythropoietin production results in physiologic anemia of infancy, yielding an average hemoglobin concentration of 11 g/dl at 2–3 months of age in a healthy term infant. Due to the shorter RBC life span, the preterm infant's nadir is approximately 6 weeks of age with ranges from 7 to 10 g/dl.

Megakaryocytopoiesis is the process through which mature megakaryocytes (platelet precursors) are produced. Megakaryocytes are present by 5 weeks' gestation, and the first platelets can be seen at 8–9 weeks' gestation. Several cytokines stimulate the development of megakaryocytes, including thrombopoietin (TPO). TPO is primarily produced in the liver throughout the life span. There is no correlation between TPO levels and platelet count (Akpan et al., 2019). Fetal megakaryocytes are smaller in size, less mature, and exist in lower ploidy than adults (Akpan et al., 2019). These factors may account for the tendency toward neonatal thrombocytopenia. Platelets are the first cells to respond to vascular endothelium injury. The number of available platelets is dependent on the size and number of megakaryocytes. It can take approximately 5 days from megakaryocyte maturation to release of platelets.

The fetus produces coagulation proteins, and most clotting factors are present by 10 weeks' gestation (Akpan et al., 2019). The concentration of these clotting factors relative to adult values vary. For example, vitamin K–dependent factors are approximately 50% of the average adult values at birth (Akpan et al., 2019). In contrast, fibrinogen is present in concentrations similar to adults at birth. Clot formation occurs via the intrinsic or extrinsic coagulation pathways. The intrinsic pathway is activated by cell trauma, and the extrinsic pathway is activated by vascular endothelium or tissue trauma.

Transfusion therapies

Transfusion therapy should be tailored to the infant's demonstrated needs. Unit criteria to administer blood products should be developed to promote safe administration and consistent practices.

Parents should be informed of the risks and benefits, and written consent should be obtained.

Whole Blood

Whole blood products contain red cells, white cells, and platelets suspended in blood plasma. The blood plasma makes up about 55% of whole blood, while red cells, white cells, and platelets make up about 45% of the volume. Whole blood is commonly used for patients with massive hemorrhage associated with trauma, pediatric open-heart surgery, and non-trauma-related hemorrhages (American Red Cross, n.d.). Whole blood has a shelf life of 21–35 days based on the anticoagulant type (American National Red Cross, 2020). Whole blood must be ABO compatible with the recipient (American Red Cross, n.d.). Whole blood can increase hematocrit by approximately 35% (Verklan & Walden, 2021).

Packed Red Blood Cells (PRBCs)

RBCs are responsible for transporting oxygen to the body and carbon dioxide back to the lungs to be exhaled. There are approximately 1 billion RBCs in 2–3 drops of blood (American National Red Cross, 2020). A 10–15 ml/kg transfusion volume can increase the hemoglobin by about 3 g/dl in neonates (American Red Cross, n.d.). PRBCs are commonly used for patients experiencing trauma, surgery, anemia, and blood disorders. The shelf life is up to 42 days, depending on the anticoagulant used. They also can be treated and frozen for 10 years or more (American National Red Cross, 2020). PRBCs must be ABO/RH compatible.

Leukocyte-reduced RBCs undergo filtration to reduce the number of leukocytes, or white blood cells, present in the sample. This process is completed before RBCs are stored because, over time, the leukocytes can fragment, deteriorate, and release cytokines, triggering adverse reactions in patients. The administration of PRBCs with compatible solutions is essential to the cells' integrity and the infant's response. PRBCs should not be administered with glucose-containing solutions because they can cause sludge and decrease RBC survival. Calcium-containing solutions also are incompatible because they can cause clot formation (Kulkarni & Gera, 1999).

Platelets

Platelets have the primary function of adhering to the lining of blood vessels to stop or prevent bleeding. They are made in the bone marrow and have a shelf life of 5 days. Platelets often are suspended in a small amount of plasma. Donor plasma should be ABO compatible with the recipient's RBCs to avoid exposure to potentially hemolyzing isoagglutinins (anti-A or anti-B) (American Red Cross, n.d.). Platelets often are used to treat thrombocytopenia, platelet function abnormalities in patients undergoing cancer treatment or organ transplant, and surgery (American National Red Cross, 2020). One unit of platelets can increase platelet count by 50,000–100,000 mm³ (Verklan & Walden, 2021).

Fresh Frozen Plasma

Blood plasma is approximately 92% water; 7% protein (including albumin, gamma globulin, and anti-hemophilia factor); and 1% mineral salts, sugars, fats, hormones, and vitamins (American National Red Cross, 2020). It is vital to the replacement of clotting factors and has a shelf life of 1 year (American National Red Cross, 2020; Verklan & Walden, 2021). For transfusion, plasma must be ABO compatible with the recipient's RBCs. For example, group B plasma can be transfused to group B and O patients. Group AB plasma can be transfused to patients of all blood types but should be reserved for patients with AB blood type (American Red Cross, n.d.). Plasma often is transfused to patients with trauma, bleeding disorders, burns, and shock.

Cryoprecipitate

Cryoprecipitate antihemophilic factors (cryo) is rich in clotting factors, including factor VII and fibrinogen. It is white and has a shelf life of 1 year. Cryo is considered to be acellular, thus it does not require compatibility testing. However, ABO-compatible cryo is preferred (American Red Cross, n.d.). Cryo is used to prevent or control bleeding in patients with hemophilia, Von Willebrand disease, and to provide fibrinogen. One cryo unit is composed of multiple donors to achieve a sufficient transfusion volume, therefore increasing the infant's exposure.

Conclusion

Blood component therapy has allowed for targeted treatment. A strong knowledge base of the products available and the infant's deficiency is important. Poised with an understanding of the pathophysiology of the hematopoietic system, nurses can advocate for the most beneficial treatment for their patients.

References:

Akpan, U., Orth, E., Moore, R., Timoney, P., Cavaliere, T., Davilla, R., & Calhoun, D. (2019). The Hematopoietic System. In A. Jnah & A. Trembath (Eds.), Fetal and neonatal physiology for the advanced practice nurse (pp. 191–238). Springer Publishing Company.
American Red Cross. (n.d.). A compendium of transfusion practice guidelines. https://www.redcrossblood.org/content/dam/redcrossblood/documents/249301_compendium_v03.pdf
Kulkarni, R., & Gera, R. (1999). Pediatric transfusion therapy: Practical considerations. Indian Journal of Pediatrics, 66(3):307–317. doi: 10.1007/BF02845512
Letterio, J., Ahuja, S., Pateva, I., & Petrosiute, A. (2020). Hematologic and oncologic problems in the fetus and neonate. In R. Martin, A. Fanaroff, & M. Walsh (Eds.), Fanaroff and Martin's neonatal-perinatal medicine (pp. 1416–1475). Elsevier.
American National Red Cross. (2020). Plasma, platelets, and whole blood | Red Cross Blood Services. American Red Cross. https://www.redcrossblood.org/donate-blood/how-to-donate/types-of-blood-donations/blood-components.html
Verklan, T., & Walden, M. (2021). Core curriculum for neonatal intensive care nursing. Elsevier.

Check out last issue's SIG Update on Bronchopulmonary Dysplasia