Use of Recombinant Factor VIIa for Control of Combat-Related Hemorrhage
- Saturday, 01 May 2010
Recombinant rFVIIa may have a damage-control role, quickly arresting blood loss until the casualty can be evacuated to a hospital.Blood loss is a major cause of death among combat casualties, accounting for nearly half of all deaths on the battlefield. The great majority of these deaths is due to intracavitary hemorrhage that cannot be controlled by traditional methods such as tourniquets or pressure dressings. Surgery remains the best method for controlling this type of hemorrhage and preventing death, although methods are needed to control bleeding until patients can get surgical intervention. Recombinant activated human coagulation factor VII (rFVIIa) is a serine protease that was originally developed for use in hemophiliac patients who developed antibodies that inhibit or neutralize standard replacement treatment with clotting factor VIII. Because of its pro-coagulant properties, the use of rFVIIa has been expanded to other types of patients to overcome a variety of coagulation and platelet disorders. It may slow down and even control massive bleeding in trauma, and possibly prolong survival and reduce mortality.
Animal studies and civilian efficacy and safety data suggest that use of rFVIIa in the combat setting may widen the survival window of hemorrhaging casualties. Recombinant rFVIIa promotes coagulation at the site of the injury, and has other advantages that lend themselves to battlefield trauma, such as a rapid onset, short half-life, and ease of administration. However, there may be potential drawbacks to using rFVIIa that should be considered, including complications such as unwanted thrombosis, and the considerable expense of rFVIIa.
This work presents data from the Navy-Marine Corps Combat Trauma Registry (CTR) to describe the initial experiences with rFVIIa at Navy-Marine Corps medical treatment facilities (MTFs) near the front line. Data for this work came from the CTR, a deployment health database comprising trauma data captured from (1) Levels 1 and 2 Navy and Marine Corps MTFs, and (2) the Joint Theatre Trauma Registry. In addition, the CTR contains non-battle injury data, disease data, psychiatric data, and routine day-to-day sick-call encounters.
One purpose of the CTR is to analyze combat injury patterns (particularly near the point of injury) and inform casualty management for wounded personnel throughout the medical chain of evacuation. Medical encounter data from the CTR were reviewed to identify all battle-injured patients documented as having received rFVIIa. Those patients suffering a head/brain trauma exclusively were excluded from the study because they may require different treatment considerations and less is known about the safety of rFVIIa for these types of patients. Primarily young Marines, these patients typically had penetrating injuries from improvised explosive devices and gunshot wounds. The primary significant injury was often an abdominal type of injury that is not conducive to compression/tourniquet.
No differences were found in survival outcomes between the rFVIIa group and a control group matched for injury severity and age. Over two-thirds (68%) of the rFVIIa patients and the control group survived; a notable overall percentage given that severely injured civilian trauma patients have up to a 50% mortality rate. The data did not show rFVIIa to be superior to standard care, although methodological difficulties and a small sample size preclude drawing conclusions about the relative effectiveness of rFVIIa.
Additional combat studies with more complete clinical data and a larger sample are needed to evaluate the impact of rFVIIa and the conditions under which it is most effective. The military surgeon has limited resources and the potential for being overwhelmed by many casualties, and, as a
result, rFVIIa may make an important contribution to combat casualty care. Recombinant rFVIIa may have a damage-control role, quickly arresting blood loss until the casualty can be evacuated to a higher-echelon hospital for more definitive care. Potentially, rFVIIa could even be administered immediately after the injury by firstline medics/corpsmen, prolonging survival until surgical control of bleeding can be conducted.
This work was done by Susan I. Woodruff of San Diego State University; Amber L. Dougherty, Judy L. Dye, and Charlene R. Mohrle of Science Applications International Corp.; and Michael R. Galarneau of the Naval Health Research Center. For more information, download the Technical Support Package (free white paper) at www.medicaldesignbriefs.com/briefs. NRL-0043
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