P re-hospital whole blood programs implemented by ground and air EMS systems are game changers in survival for hemorrhagic shock patients. Optimize field damage control resuscitation (DCR) by understanding the importance of preventing the lethal triad and early warmed whole blood administration at the point of injury. While MEDEVAC and select military units operating in the prehospital environment have carried cold stored blood products for several years, recent advances have expanded the use of cold stored blood products throughout military and civilian EMS systems. In 2016 military units began carrying and administering Cold Stored – Low Titer O Whole Blood (CS-LTOWB) with several civilian EMS agencies following suit shortly after. Initiated in 2018, the large scale San Antonio, TX regional prehospital CS-LTOWB program is proving whole blood can be safely fielded by urban, suburban, and rural EMS systems. Lives are being saved with ground EMS forward carried whole blood administered immediately at the point of injury. A recent study examined the association of prehospital transfusion and the time to initial transfusion with injury survival. 1 Among medically evacuated US military combat causalities in Afghanistan, blood product transfusion prehospital, or within minutes of injury, was associated with greater 24-hour and 30-day survival than delayed transfusion or no transfusion. The findings support prehospital transfusion in this setting. (Fig. 1) In this study, the most significant survival advantage was when a transfusion was given less than 15 minutes after the arrival of the MEDEVAC team. The danger of not warming blood or IV solutions in trauma patients While improved outcomes have already been shown with early administration of blood products, administration of any cold fluids into a trauma patient carries a significant risk of inducing or worsening hypothermia leading to a synergistic effect of hypothermia on Trauma Induced Coagulopathy(TIC). In addition, the delivery of warmed fluids and whole blood is crucial for a number of reasons, but many medics don’t fully appreciate the implications of the mantra beyond preventing hypothermia. As part of the lethal triad (fig. 2), hypothermia can have a detrimental effect to trauma patients, especially those suffering from catastrophic hemorrhage, by affecting the coagulation pathways. A decrease in core body temperature has been demonstrated to increase mortality in patients suffering hemorrhagic shock. Mortality increases predictably with successive increases in lactate levels and the detrimental effects of acidemia are compounded while survival is markedly reduced by hypothermia with a core temperature <93°F. Coagulation factor activity is reduced approximately 10%– 15% for each 2°F drop in temperature, which is exacerbated by factor depletion secondary to dilution, leading to increased mortality. Patient temperature and its effect on oxygen delivery The above graph (fig. 3) depicts oxygens affinity for heme molecules in blood cells - the Oxygen-Hemoglobin dissociation curve. Several factors can adjust the curve left (which results in a decrease in oxygen unloading at the tissues) or right (which results in an increase in oxygen unloading at the tissues). As patient temperature decreases, the curve shifts to the left which decreases oxygen delivery at the tissues and thus worsening shock. As patient temperature increases Pre-hospital Whole Blood Optimizing survival for hemorrhagic shock patients Fig. 3 Fig. 1 Fig. 2 1 JAMA. 2017 Oct 24;318(16):1581-1591. doi: 10.1001/jama.2017.15097. Association of Prehospital Blood Product Transfusion During Medical Evacuation of Combat Casualties in Afghanistan With Acute and 30-Day Survival. Shackelford SA, Del Junco DJ, Powell-Dunford N, Mazuchowski EL, Howard JT, Kotwal RS1 Gurney J, Butler FK Jr, Gross K, Stockinger ZT.