Chapter 54: Blood Products

INTRODUCTION

The purpose of this chapter is to describe the components of various blood products, indications for transfusions, and complications of transfusion.

TRANSFUSION OF PACKED RED BLOOD CELLS (pRBCs) IN CRITICALLY ILL CHILDREN

OVERVIEW

• pRBCs are red blood cells obtained from donation of whole blood. Most of the plasma and platelets are removed prior to storage, and units of blood are further processed to either reduce or remove leukocytes to decrease the likelihood of leukocyte alloimmunization causing febrile nonhemolytic transfusion reactions (FNHTRs).

• Preservatives, nutrients, and anticoagulants are added to units of pRBCs to ensure a long shelf-life (up to 42–45 days).

TRANSFUSION

• The average pediatric blood volume is estimated to be approximately 80 cc/kg body weight.

• The amount of blood to be given in acute anemia can be calculated using the following formula; for example, assuming that the hematocrit of the unit of pRBCs is 60% or 0.6, the volume to be transfused is:

  $VolumeofpRBCs=Weight(kg)×incrementdesired(g/dLhemoglobin)×3/0.6$

• In general, transfusion of 1 unit of pRBCs is expected to raise the hemoglobin by approximately 1 g/dL and the hematocrit by 3% in adult patients.

• Special preparations of pRBCs

  • Irradiated blood – to prevent transfusion-associated graft versus host disease (TA-GVHD), a life-threatening condition caused by donor leukocytes. Consider using irradiated blood in immunocompromised states or if directed donor blood (blood donated from relative), such as when transfusing a neonate, in stem cell transplant patients, patients with leukemia, lymphoma, T-cell immunodeficiency, aplastic anemia, or myelodysplastic syndromes. Irradiated blood will have a shorter shelf-life.

  • Washed pRBCs – use if patient has hyperkalemia or renal failure (to reduce potassium levels) or if known allergic reaction to blood for additional leukocyte and plasma protein reduction (not including febrile reactions to transfusion).

• Indications for transfusion of pRBCs:

  • Anemia

    • Severe anemia is defined by a hemoglobin less than 5 g/dL even if the patient is asymptomatic and would likely benefit from transfusion.

    • If symptomatic anemia but stable hemodynamics (defined as not having a need for inotropic support, fluid resuscitation, or a mean arterial pressure less than 2 SD below the normal mean for age), consider transfusing prior to reaching a hemoglobin of 5 g/dL. There is no standard threshold at which to transfuse, however one randomized controlled trial performed in 19 tertiary care PICUs, the TRIPICU study, demonstrated that outcomes such as new or progressive organ dysfunction, transfusion reactions, or ICU length of stay were not worse in symptomatic, anemic patients if transfusion was held until the patient had a hemoglobin of 7 g/dL or less.

    • If symptomatic anemia and unstable hemodynamics, consider transfusion earlier.

    • If transfusing for severe, chronic anemia, consider transfusing in small aliquots (for example, if a hemoglobin of 4 g/dL, some centers transfuse 4 ...