Along with changes in damage control surgery and resuscitation, changes in transfusion management for trauma hemorrhage over the past 20 years have led to significant reductions in mortality rates.1,2 However, uncontrolled bleeding or its consequences still cause up to 40% of injury-related deaths.3
In a review published in the British Journal of Haematology, Nicola S Curry, MD, of the department of haematology at Oxford University Hospitals NHS Trust in the United Kingdom, and Ross Davenport, PhD, senior lecturer in trauma sciences at the Centre for Trauma Science at Queen Mary University of London in the United Kingdom, summarized current transfusion practices for trauma hemorrhage and examined the evidence supporting these practices.
“The approach to transfusion now, particularly in trauma but also in other instances of massive blood loss, is much more proactive and empiric,” Dr Davenport told Hematology Advisor.
“Blood products that used to be stored in a laboratory as frozen products are now prethawed, and in some instances, they are kept in the emergency department, so that they’re easier to access. The protocols in hospitals are also more streamlined.”
When trauma teams manage significant hemorrhage after injury, they employ a management strategy called damage control resuscitation. This strategy integrates damage control surgery, permissive hypotension, and hemostatic resuscitation. Hemostatic resuscitation is characterized by avoidance of crystalloids, such as normal saline, that may induce dilutional coagulopathy and empiric resuscitation of blood and blood components following a major hemorrhage protocol (MHP; also called massive transfusion protocol in the United States and other countries).
MHPs are implemented to coordinate the large multidisciplinary team that must act rapidly to stop bleeding and restore blood volume in patients with traumatic injuries. Observational studies have demonstrated improved outcomes including increased survival when MHPs are implemented in these emergency situations.
Despite this evidence, a 2015 survey of 6 large European trauma centers uncovered substantial variation in transfusion practices.4 Drs Curry and Davenport argued that this reflects the uncertainty that remains surrounding best practices and suggested a move toward personalized or targeted hemorrhage therapy, including conducting more studies on the effects of different transfusion therapies on clinical outcomes and seeking an increased understanding of the mechanisms underlying trauma-induced coagulopathy.
Trauma-induced coagulopathy, described by Drs Curry and Davenport as an “overall failure of the coagulation system to sustain hemostasis after major injury,” is a process that can be induced by suboptimal resuscitation (dilutional coagulopathy) or by endogenous activation of protein C (acute traumatic coagulopathy). The latter can lead to fibrinolysis and continued bleeding.
“Most of the literature over the last 10 years has suggested up to 25% [of patients with bleeding] develop TIC,” Dr Davenport explained. “In reality, it’s less than that now that we’ve completely changed the practice.”
One of the first steps in an MHP is coagulation testing, including prothrombin time and rotational thromboelastometry or thromboelastography. However, these tests are insensitive to fibrinolytic activity.
“Instead of waiting for a laboratory test to show that there is a derangement in clotting and then responding to that, we now assume that a bleeding patient who presents with evidence of shock is coagulopathic, and, therefore, we will empirically start trying to correct their coagulation,” said Dr Davenport.