Massive Transfusion in Pediatric Patients

Massive transfusion in pediatric patients is infrequent but associated with much higher mortality than in adults. Blood transfusion and hematology has conceptualized ideas such as blood failure and the interplay of the blood-endothelium interface to understand coagulopathy in the context of hemorrhagic shock. Researchers are still searching for an appropriate definition of what constitutes a pediatric massive transfusion. There is no universally accepted protocol for massive transfusion and how to address the many complications that can arise. Pharmacologic adjuncts to resuscitation may prove beneficial in reducing coagulopathy during pediatric massive transfusion, but high-quality evidence has not yet emerged.

Key points

• A universal definition of massive transfusion in children remains elusive. The definitions are typically based on the volume of blood products transfused as a function of the estimated total blood volume of a child given over a given period of time.
• Pediatric transfusions carry a spectrum of risks similar to adult transfusions. These risks include metabolic derangements, coagulation dysregulation, immunologic reactions, volume disturbances, or any combination of effects.
• The optimal ratio of blood products transfused in pediatric patients has its basis in the adult trauma literature. Several studies have evaluated the benefit of a balanced resuscitation in children without a clear survival advantage, but more investigation is needed.
• The resurgence of whole blood for adult trauma resuscitation has renewed interests in its application in the pediatric realm. The primary concerns are its possible allogeneic reactions and its overall availability. More evidence showing its safety and effectiveness is emerging.
• Pharmacologic adjuncts to resuscitation (eg, tranexamic acid and recombinant factor VIIa) should be considered in severely bleeding children. Thromboelastography and rotational thromboelastometry are two tests that can be used at the point of care to guide treatment of coagulopathy.

Introduction

Life-threatening hemorrhage (LTH) in children is a rare but potentially catastrophic event. The timely delivery of blood products can mean the difference between life and death. Although the term massive transfusion has been used to describe the phenomenon of large-volume delivery of blood products to an exsanguinating child, an accurate definition that is clearly linked to outcomes remains elusive. Moreover, the term massive can be misleading in children for whom small absolute volumes of blood loss can invoke significant physiologic derangements. This article focuses on the pathophysiology of hemorrhagic shock from injury and the current practice of hemostatic resuscitation in children.

Epidemiology of life-threatening hemorrhage in children

Injury is the leading cause of death in children and adolescents, with falls and motor vehicle accidents as the two leading mechanisms of injury. 1 , 2 Bleeding from these mechanisms can be severe enough to warrant massive transfusion protocol activations. Additional causes of LTH include surgical bleeding and gastrointestinal bleeding. 3456 Despite these varied reasons for hemorrhage, traumatic injury accounts for most activations of pediatric massive transfusion protocols. This subset of patients with trauma is generally older, more hypothermic, and has a higher injury severity score compared with other pediatric patients with trauma who were transfused but did not meet the criteria for pediatric massive transfusion. 7