BACKGROUND

Damage Control Resuscitation (DCR) is generally accepted as a complementary strategy usually paired with Damage Control Surgery (DCS), which focuses surgical interventions to those which address life-threatening injuries and delays all other surgical care until metabolic and physiologic derangements have been treated.8 Recognizing that this approach saved lives, DCR was developed to work synergistically with DCS and prioritize non-surgical interventions which may reduce morbidity and mortality from trauma and hemorrhage.9 The major principle of DCR is to restore homeostasis, prevent or mitigate the development of tissue hypoxia, oxygen debt and burden of shock, as well as coagulopathy.10,11 This amounts to preventing ‘blood failure,’ specifically with a goal of restoring blood functionality (improving oxygen delivery and tissue perfusion, reducing acidosis, preventing fibrinolysis, reducing coagulopathy, protecting the endothelium, and reducing platelet dysfunction). This is best accomplished through aggressive hemorrhage control and a blood product-based resuscitation, which restores tissue oxygenation, avoids platelet and coagulation factor dilution, and also replaces lost hemostatic potential. DCR is most effective when resuscitation replaces lost blood with whole blood, whether ideally transfused as units of whole blood (WB), or blood product components transfused in a ratio approximating whole blood (i.e. 1:1:1 ratio of FFP:Plt:RBC). Additional goals of DCR are avoidance or limiting of the use of crystalloids to avoid dilutional coagulopathy, selective use of hypotensive resuscitation (SBP of 100 or SBP of 110, if TBI suspected until surgical control is achieved, correction of coagulopathy and acidosis, maintenance of normothermia, empiric administration of Tranexamic Acid in appropriate patient populations, and expeditious evacuation to damage control and definitive surgical capabilities.

Advanced Trauma Life Support (ATLS) guidelines historically advocated a linear resuscitation strategy beginning with an emphasis on crystalloid infusion, particularly during the pre-hospital phase, followed by the addition of red blood cells (RBCs), and finally plasma. Platelets were delayed until a low platelet count was documented and reserved either for severe thrombocytopenia or thrombocytopenia in the presence of active hemorrhage. As documented in retrospective reports from the civilian trauma literature, this approach resulted in excessive crystalloid use and is associated with a risk of dilutional coagulopathy, abdominal compartment syndrome, multiple organ failure, and death12. Although selection bias may have contributed to these findings, it should be noted that the ATLS 10th edition identifies that resuscitation with greater than 1.5L of crystalloid is associated with increased mortality, and suggests limiting crystalloid use to no more than one liter during the initial resuscitation. Instead, current ATLS recommendations for bleeding patients are for early administration of blood products, including plasma and platelets, while focusing on rapidly achieving hemorrhage control.13

During the conflicts in Iraq and Afghanistan between 2003 and 2012 14% of patients admitted to Role 3 military treatment facilities (e.g., combat support hospitals) received a transfusion of at least one blood product. Of these, 35% received MT. (MT is defined as ≥ 10 units of RBCs and/or WB in 24 hours. The proportion of transfused patients receiving MT reached approximately 50% by 2011 in parallel with increasing injury severity scores, use of blood resuscitation, and decreased use of crystalloid and colloid use.14 During this period mortality fell as military clinicians became experts in the treatment of very severe multisystem trauma accompanied by massive hemorrhage. Civilian ATLS-based practice gave way to a hemostatic resuscitation approach designed to mimic WB functionality.

There is now strong retrospective evidence in both civilian and military trauma populations that patients requiring MT benefit from a higher ratio of plasma and platelets to red cells (e.g., 1 unit plasma: 1 unit platelets: 1 unit RBCs). MT at a 1:1:1 ratio is associated with improved survival.9, 15-18 Recently, prospective randomized data from the Pragmatic Randomized Optimal Platelet and Plasma Ratios (PROPPR) trial revealed that mortality at 3 hours after injury due to exsanguination was lower in patients resuscitated with a 1:1:1 ratio compared to 1:1:2.13 These were important findings given that the differences between resuscitation strategies were small—and probably best characterized by an early vs. late platelet approach. There was no difference in overall mortality at 24 hours or 30 days, likely due to the confounding effect of head injury. Balanced resuscitation was not associated with increased complication rates.19,20

Although physicians continue to debate the lessons of the PROPPR trial and the relative benefits of specific blood component ratios, the practice of giving large amounts of crystalloid or RBCs alone during the initial resuscitation is no longer standard practice. As stated above, in combat casualties with bleeding, EARLY blood product resuscitation (ideally within 36 minutes of injury) provides the lowest early and late mortality rates.2 Available data on balanced resuscitation comes from component based resuscitation. We know that any blood product combination represents an advantage over salt based crystalloids for the bleeding casualty. However, LTOWB represents the best way to deliver a functional resuscitation early, clinically as well as logistically.