Fresh frozen plasma reduces edema in skeletal muscle following combined limb ischemia-reperfusion injury and hemorrhagic shock in rats.

BACKGROUND: Exsanguination from extremity vascular injuries is the most common potentially survivable injury on the battlefield. Advances in treatment have dramatically improved survival, increasing the need to address associated morbidities including ischemia-reperfusion injury and extremity compartment syndrome. Despite advances, hemorrhagic shock (HS) requiring fluid resuscitation is common. Plasma-based resuscitation for the treatment of HS has been shown to reduce edema and injury in tissues other than muscle. The objective of this study was to determine if fresh frozen plasma (FFP) resuscitation offered protection in a rat model of combined HS and skeletal muscle ischemia-reperfusion injury. METHODS: Anesthetized Sprague-Dawley rats underwent 37.5% arterial hemorrhage, producing HS, followed by 3 hours of tourniquet application. Animals were not resuscitated or resuscitated with either FFP (equal to the shed blood volume) or lactated Ringer's solution (three times shed volume) after 30 minutes of ischemia. They were euthanized 24 hours later, and their muscles were analyzed for edema (wet weight-dry weight). Routine histology was performed on muscle cross-sections stained with hematoxylin and eosin and graded using a semiquantitative grading system. RESULTS: All animals developed HS; the mortality rate was 50% in no resuscitation rats. FFP reduced edema by 13% (p = 0.02) compared with lactated Ringer's solution. Pathology scores were not different between treatment groups. CONCLUSION: FFP resuscitation reduces edema following muscle injury, decreasing the risk of developing extremity compartment syndrome.

Predictors of early acute lung injury at a combat support hospital: a prospective observational study.

BACKGROUND: Acute lung injury (ALI) is a syndrome consisting of noncardiogenic acute hypoxemic respiratory failure with the presence of bilateral pulmonary infiltrates and occurs in up to 33% of critically ill trauma patients. Retrospective and observational studies have suggested that a blood component resuscitation strategy using equal ratios of packed red blood cells (PRBCs) and fresh frozen plasma (FFP) may have a survival benefit in combat casualties. The purpose of this study was to determine whether this strategy is associated with an increased incidence of ALI. METHODS: We performed a prospective observational study of all injured patients admitted to an intensive care unit (ICU) at a combat support hospital who required >5 units of blood transfusion within the first 24 hours of admission. Baseline demographic data along with Injury Severity Score (ISS), pulmonary injury, presence of long bone fracture, blood products transfused, mechanical ventilation data, and arterial blood gas analysis were collected. The primary endpoint of the study was the development of ALI at 48 hours after injury. Those who did not survive to ICU admission were excluded from analysis. Follow-up (including mortality) longer than 48 hours was unavailable secondary to rapid transfer out of our facility. A multivariate logistic regression was performed to determine the independent effects of variables on the incidence of early ALI. RESULTS: During a 12-month period (from January 2008 to December 2008), 87 subjects were studied; of these, 66 patients met inclusion criteria, and 22 patients developed ALI at 48 hours (33%). Overall, the ratio of FFP to PRBC was 1:1.1. Those who developed ALI had a higher ISS (32 +/- 15 vs. 26 +/- 11; p = 0.04) and received more units of FFP (22 +/- 15 vs. 12 +/- 7; p < 0.001), PRBCs (22 +/- 16 vs. 13 +/- 7; p = 0.008), and platelets (5 +/- 11 vs. 1 +/- 2; p = 0.004) compared with those who did not develop ALI. Multivariate logistic regression analysis revealed that presence of pulmonary injury (odds ratio, 5.4; 95% confidence interval, 1.3-21.9) and volume of FFP transfused (odds ratio, 1.2; 95% confidence interval, 1.1-1.3) had independent effects on ALI at 48 hours. CONCLUSION: On the basis of this small, prospective, descriptive study of severely injured patients admitted to the ICU, we determined that the presence of pulmonary injury had the greatest impact on the incidence of early ALI. There was also an independent relationship between the amount of FFP transfused and the incidence of early ALI. Further studies are required to determine the effects of the development of early ALI from FFP transfusion on short- and long-term survival.

Fatal airway injuries during Operation Enduring Freedom and Operation Iraqi Freedom.

INTRODUCTION: Airway compromise is the third leading cause of potentially preventable death on the battlefield. An understanding of the injuries associated with fatal airway compromise is necessary to develop improvements in equipment, training, and prehospital management strategies in order to maximize survival. OBJECTIVE: To determine injury patters resulting in airway compromise in the combat setting. METHODS: This was a subgroup analysis of cases previously examined by Kelly and colleagues, who reviewed autopsies of military personnel who died in combat in Iraq and Afghanistan between 2003 and 2006. Casualties with potentially survivable (PS) injuries and deaths related to airway compromise previously identified by Kelly et al. were reviewed in depth by a second panel of military physicians. RESULTS: There were 982 cases that met the inclusion criteria. Of these, 232 cases had PS injuries. Eighteen (1.8%) cases were found to have airway compromise as the likely cause of primary death. All had penetrating injuries to the face or neck. Twelve deaths (67%) were caused by gunshot wounds, while six deaths (33%) were caused by explosions. Nine cases had concomitant injury to major vascular structures, and eight had significant airway hemorrhage. Cricothyroidotomy was attempted in five cases; all were unsuccessful. CONCLUSION: Airway compromise from battlefield trauma results in a small number of PS fatalities. Penetrating trauma to the face or neck may be accompanied by significant hemorrhage, severe and multiple facial fractures, and airway disruption, leading to death from airway compromise. Cricothyroidotomy may be required to salvage these patients, but the procedure failed in all instances in this series of cases. Further studies are warranted to determine the appropriate algorithm of airway management in combat casualties sustaining traumatic airway injuries.

Longterm outcomes after combat casualty emergency department thoracotomy.

BACKGROUND: The incidence, survival, and blood product use after emergency department thoracotomy (EDT) in combat casualties is unknown. STUDY DESIGN: We performed a prospective and retrospective observational study of EDT at a combat support hospital in Iraq, evaluating the impact of injury mechanisms, blood product use, mortality, and longterm neurologic outcomes of survivors. RESULTS: From November 2003 to December 2007, 12,536 trauma admissions resulted in 101 EDTs (0.01%). In patients undergoing EDT, penetrating trauma from explosions and firearms accounted for the majority of injuries (93%). There were no survivors after EDT for blunt trauma (n=7). The areas of primary penetrating injury were the abdomen (30%), thorax (40%), and extremities (22%). Twelve percent (12 of 101) of all patients survived until evacuation, with the overall survival rate (8 to 26 months) of US casualties at 11% (6 of 53). There was no difference in survival seen in either injury mechanism or primary injury location. Signs of life were present in all overall survivors. Cardiopulmonary resuscitation (CPR) was performed in 92% (93 of 101) of all patients, and in 75% (9 of 12) of those evacuated. Mean (+/-SD) transfusion requirements for all patients were 15.0+/-12.7 U of RBC and 7.3+/-8.7 U of fresh frozen plasma during the initial resuscitation. Survivors demonstrated higher fresh frozen plasma:RBC ratios. All survivors were neurologically intact. CONCLUSIONS: In the combat casualty with penetrating injury, arriving with signs of life, receiving CPR, and undergoing EDT, longterm survival with normal neurologic outcomes is possible. CPR is not a contraindication to performance of EDT in penetrating injuries if signs of life are present. A large amount of blood products are used in the resuscitation of EDT patients.

Comparison of new hemostatic granules/powders with currently deployed hemostatic products in a lethal model of extremity arterial hemorrhage in swine.

BACKGROUND: HemCon bandage (HC) and QuikClot granules (QC) have been deployed for the past 5 years for treating external hemorrhage in combat casualties. We examined efficacy and initial safety of three new hemostatic granules/powders in a swine extremity arterial hemorrhage model that was 100% fatal with army standard gauze treatment. The new products were compared with the most advanced forms of HC and QC products. METHODS: Anesthetized pigs (37 kg, n = 46) were instrumented, splenectomized, and their femoral arteries were isolated and injured (6 mm arteriotomy). After 45 seconds free bleeding, a test agent [WoundStat (WS), super quick relief (SQR), Celox (CX)] or a control product [HC or QC bead bags (advanced clotting sponge plus)] was applied to the wounds and compressed with a large gauze for 2 minutes. Fluid resuscitation (colloid and crystalloid) was given and titrated to a mean arterial pressure of 65 mm Hg. Animals were observed for 180 minutes or until death. Computed tomography angiography was performed on survivors and tissue samples were collected form wounds for histologic examination. RESULTS: No differences were found in baseline measurements and pretreatment blood loss (17.4 mL/kg +/- 0.5 mL/kg, mean +/- SEM) among groups. Advanced clotting sponge plus testing was halted after six unsuccessful attempts (no hemostasis observed) whereas other agents were tested each in 10 animals. Stable hemostasis was achieved in 10 (WS), 7 (SQR), 6 (CX), and 1 (HC) subjects in each group, resulting in the recovery of mean arterial pressure and survival of the animals for 3 hours (p < 0.05, SQR or WS vs. HC). Posttreatment blood loss was significantly reduced with the use of the new agents (CX = 40 +/- 16.6, SQR = 34.5 +/- 16.3, WS = 9.5 mL/kg +/- 5.2 mL/kg) as compared with HC (85.6 mL/kg +/- 10 mL/kg, p < 0.05). The granular treated animals lived for 180 (WS), 164 +/- 8.2 (SQR) and 138 +/- 17.7 (CX) minutes, significantly (p < 0.05) longer than the HC (83.3 +/- 12 minutes) group. A significant (p < 0.05) rise in temperature (53.5 degrees C +/- 1.8 degrees C) over baseline (36.5 degrees C +/- 0.3 degrees C) was measured only in the wounds treated with SQR. Computed tomography images showed no blood flow through treated vessels. Histologic evidence indicated the least tissue damage with HC, moderate damage with WS and CX, and most damage including axonal necrosis with SQR. CONCLUSION: The new hemostatic agents are significantly more effective in treating arterial hemorrhage than currently deployed products. Among them, WS granules appear to be most efficacious, followed by SQR and CX powders. The clinical significance of tissue damage caused by these agents and any potential risk of embolism with procoagulant granular/powder products are unknown and warrant survival studies.