Combat & Casualty Care

Q2 2016

Military Magazines in the United States and Canada, Covering Combat and Casualty Care, first responders, rescue and medical products programs and news\Tactical Defense Media

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Page 7 of 39 6 | Combat & Casualty Care | Summer 2016 Prolonged Field Care Hemorrhage and TBI By Geoffrey P. Dobson. PhD, FAHA and Hayley Letson, MSc PhD I magine the following scenario: you are far forward leading your team on patrol in pursuit of enemy insurgents in low light conditions and step onto a pressure plate buried beneath the surface. The explosion is massive. You hit the ground hard with one leg blown off. After the dust and smoke clears, help arrives. The combat medic sees your body rapidly bleeding out, going into shock, and notices no helmet and a gaping hole in your abdomen. The new enemy is time. Point-of-Injury and Prolonged Field Care In scenarios like these, tourniquet use has saved thousands of lives in the recent Iraq and Afghanistan conflicts. However, there are few options preventing internal blood loss from penetrating foreign objects, gunshots or explosive fragments. In severe exsanguinating cases with suspected traumatic brain injury (TBI), the only option is resuscitative surgery and rapid evacuation. Saving lives in this fast-closing window is unique and challenging. Currently, there is no effective fluid treatment for a casualty suffering severe internal blood loss and/or suspected TBI. We are working with U.S. Special Operations Command (USSOCOM) to develop a new intravenous (IV) or intraosseous (IO) ultra-small volume 3% NaCl adenosine, lidocaine, Mg 2+ (ALM) fluid therapy to fill these capability gaps. Our idea is different than most because it focuses more on bolstering the combatant's response to trauma, rather than treating the trauma "stressor" itself, which may explain why the therapy confers such broad-spectrum protection against hemorrhagic shock, cardiac arrest, regional myocardial ischemia, arrhythmias, endotoxemia, infection, and sepsis. Addressing Three Key Gaps in Forward Combat Medicine: What is the Solution? Unfortunately no fluid exists that addresses all of the unique requirements of what is required in forward environments. The choice of fluid remains controversial, however, for hemorrhagic shock, donor blood or blood products are preferred. Two to four liters of normal saline, as was common in the Vietnam war, or one liter of colloidal Hextend, as recommended in the current Tactical Combat Casualty Care (TCCC) guidelines (if blood or blood products are not available), does not work. In 2013 the U.S. Federal Drug Administration (FDA) placed a 'black box warning' on the clinical use of Hextend in critically ill patients. Our USSOCOM-funded study examined the effect of small- volume 3% NaCl ALM bolus and 0.9% NaCl ALM 'drip' (3-4 hours) (termed ALM therapy) on resuscitation, cardiac function, inflammation, coagulopathy and survivablity in three different rat models to address the three capability gaps: 1) Non-compressible (internal) (60% liver resection) and shock 2) Mild-to-moderate TBI 3) The lethal combination of TBI and internal hemorrhage The treatments for each model were identical; an IV single bolus (0.7 ml/kg body wt) administered 15 min after injury, wait 60 min (Phase 1), then begin a 'stabilization' IV drip (0.5 ml/kg/hour) which was continued for 3 to 4 hours (Phase 2). In our first model, ALM therapy reduced uncontrolled blood loss by up to 60% after 4 hours, and improved blood flow to the gut and kidney compared to saline controls. In contrast, Hextend administered according to TCCC guidelines, promoted internal bleeding, inflammation, coagulopathy, organ failure and early death. ALM's ability to significantly reduce blood loss may arise from its unique ability to improve cardiac function, correct coagulopathy, blunt systemic inflammation and improve tissue oxygenation. With respect to blood loss, the therapy is not a foam or synthetic compound like those used to plug a flat tyre, it is a drug that rapidly restores normal clotting allowing the system to form a viable clot. The ALM drug therapy acted like a "pharmacological tourniquet" which may have significant potential to save countless lives in forward and civilian prehospital settings. In our second study, the same ALM therapy protected against mild-moderate TBI and reduced secondary 'hit' complications with improved cardiac function over 4 hours. Mortality was 25% in saline controls and 0% in the ALM group. During Phase 2 (drip), saline controls continued to decline functionally, and after 3 hours they had 60-70% falls in cardiac output (CO), stroke volume and contractility, right heart dilatation, severe arrhythmias (VT/VF), and could not form a viable clot. In direct contrast, ALM-treated animals had significantly higher CO and contractility at lower heart rates, no arrhythmias, correction of coagulation towards baseline, ADDRESSING THE TRAUMATIC BRAIN INJURY AND HEMORRHAGE LINK

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