ICU Management of Trauma Patients

Samuel A. Tisherman, MD, FCCM; Deborah M. Stein, MD, MPH, FCCM

Disclosures

Crit Care Med. 2018;46(12):1991-1997. 

In This Article

Hemorrhage, Massive Transfusions, and Coagulopathy

The most common cause of hypotension in trauma patients is hemorrhage. Significant tissue trauma, however, adds to the hemorrhagic shock state by eliciting immunologic and inflammatory responses.[25] Thus, there is more to "traumatic shock" than just blood loss and tissue ischemia. Nonetheless, biomarkers of tissue ischemia or "oxygen debt" such as lactate or base deficit are useful to trend. Elevation of these variables, or failure to normalize them, is associated with increased mortality.[26]

Trauma patients with severe hemorrhagic shock often require a massive transfusion, usually defined by requiring at least 10 units of packed RBCs (PRBCs) within 24 hours. The optimal fluid for resuscitation of a trauma patient in severe hemorrhagic shock would likely be whole blood. In civilian practice, however, whole blood is not widely available. Consequently, PRBCs are used. Fresh frozen plasma (FFP), platelets, and cryoprecipitate can be administered to essentially reconstitute whole blood. Although the optimal ratios of these blood components remain unclear, early administration of FFP and platelets as part of "damage control resuscitation" seems to be beneficial.[27] A ratio of 1:1:1 may improve outcomes in terms of achieving hemostasis and preventing early death from exsanguination compared with higher ratios of PRBCs.[28,29] Small studies of banked whole blood are underway. Administration of crystalloids, colloids, or hypertonic solutions (in the absence of concomitant TBI) is to be minimized.[30,31]

For patients who have active hemorrhage, novel approaches include permissive hypotension, although optimal mean arterial pressure (MAP) has not been determined,[32–35] and Resuscitative Endovascular Balloon Occlusion of the Aorta for selected patients with abdominal or pelvic hemorrhage.[36–39]

Severe hemorrhage and resuscitation leads to a vicious cycle of deterioration from the "lethal triad" of coagulopathy, metabolic acidosis, and hypothermia. The coagulopathy of trauma includes dilution of clotting factors, consumption of factors at the site of bleeding, intravascular coagulation, fibrinolysis, hypothermia, acidosis, inflammation, and other factors.[40] Although prothrombin time, activated partial thromboplastin time, and platelet counts are typically used to monitor coagulation status, many trauma centers have turned to thromboelastography or rotational thromboelastometry which may better represent overall clotting function and allow for more targeted therapy.[41–43]

A number of adjuncts to blood product administration to decrease coagulopathy have been studied. Lyophilized plasma, for example, shows promise.[44] Trauma patients often develop hypofibrinogenemia, which has typically been managed with cryoprecipitate, although fibrinogen products are available in some countries and may have benefits.[45–48] Recombinant activated Factor VII initially showed promise but has mainly gone out of favor because of cost and lack of clear benefit.[49] Prothrombin complex concentrates are sometimes used, although data on efficacy in the absence of warfarin-induced coagulopathy are variable.[50–52]

Both hyperfibrinolysis and fibrinolysis shutdown, at the time of presentation, compared with normal levels of fibrinolysis, are associated with worse outcomes from major trauma.[53–55] Patients with hyperfibrinolysis may benefit from the use of tranexamic acid.[56] Conversely, patients with physiologic levels of fibrinolysis or with fibrinolysis shutdown could be harmed.[57] Monitoring fibrinolysis seems prudent.[58–60]

With a better understanding of the coagulopathy of trauma and evidence that a more aggressive approach to normalizing hemostatic mechanisms can improve outcomes, the concept of damage control resuscitation has been established and recommended.[61] For the moment, point of care viscoelastic testing seems to be the best way to guide therapy.[62]

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