The Golden Hour of Casualty Care: Rapid Handoff to Surgical Team is Associated With Improved Survival in War-injured US Service Members.

OBJECTIVE: To examine time from injury to initiation of surgical care and association with survival in US military casualties. BACKGROUND: Although the advantage of trauma care within the "golden hour" after an injury is generally accepted, evidence is scarce. METHODS: This retrospective, population-based cohort study included US military casualties injured in Afghanistan and Iraq, January 2007 to December 2015, alive at initial request for evacuation with maximum abbreviated injury scale scores ≥2 and documented 30-day survival status after injury. Interventions: (1) handoff alive to the surgical team, and (2) initiation of first surgery were analyzed as time-dependent covariates (elapsed time from injury) using sequential Cox proportional hazards regression to assess how intervention timing might affect mortality. Covariates included age, injury year, and injury severity. RESULTS: Among 5269 patients (median age, 24 years; 97% males; and 68% battle-injured), 728 died within 30 days of injury, 68% within 1 hour, and 90% within 4 hours. Only handoffs within 1 hour of injury and the resultant timely initiation of emergency surgery (adjusted also for prior advanced resuscitative interventions) were significantly associated with reduced 24-hour mortality compared with more delayed surgical care (adjusted hazard ratios: 0.34; 95% CI: 0.14-0.82; P = 0.02; and 0.40; 95% CI: 0.20-0.81; P = 0.01, respectively). In-hospital waits for surgery (mean: 1.1 hours; 95% CI; 1.0-1.2) scarcely contributed ( P = 0.67). CONCLUSIONS: Rapid handoff to the surgical team within 1 hour of injury may reduce mortality by 66% in US military casualties. In the subgroup of casualties with indications for emergency surgery, rapid handoff with timely surgical intervention may reduce mortality by 60%. To inform future research and trauma system planning, findings are pivotal.

Therapeutic Interventions and Outcomes in Civilian and Military Isolated Gunshot Wounds to the Head: A Department of Defense Trauma Registry and ACS TQIP-matched Study.

OBJECTIVE: The purpose of this study was to compare therapeutic strategies and outcomes, following isolated gunshot wounds of the head, between military and civilian populations. BACKGROUND: Recent military conflicts introduced new concepts in trauma care, including aggressive surgical intervention in severe head trauma. METHODS: This was a cohort-matched study, using the civilian Trauma Quality Improvement Program (TQIP) database of the American College of Surgeons (ACS) and the Department of Defense Trauma Registry (DoDTR), during the period 2013 to 2016. Included in the study were patients with isolated gunshots to the head. Exclusion criteria were dead on arrival, civilians transferred from other hospitals, and patients with major extracranial associated injuries (body area Abbreviated Injury Scale >3). Patients in the military database were propensity score-matched 1:3 with patients in the civilian database. RESULTS: A total of 136 patients in the DoDTR database were matched for age, sex, year of injury, and head Abbreviated Injury Scale with 408 patients from TQIP. Utilization of blood products was significantly higher in the military population ( P <0.001). In the military group, patients were significantly more likely to have intracranial pressure monitoring (17% vs 6%, P <0.001) and more likely to undergo craniotomy or craniectomy (34% vs 13%, P <0.001) than in the civilian group. Mortality in the military population was significantly lower (27% vs 38%, P =0.013). CONCLUSIONS: Military patients are more likely to receive blood products, have intracranial pressure monitoring and undergo craniectomy or craniotomy than their civilian counterparts after isolated head gunshot wounds. Mortality is significantly lower in the military population. LEVEL OF EVIDENCE: Level III-therapeutic.

Evidence-Based and Clinically Relevant Outcomes for Hemorrhage Control Trauma Trials.

OBJECTIVE: To address the clinical and regulatory challenges of optimal primary endpoints for bleeding patients by developing consensus-based recommendations for primary clinical outcomes for pivotal trials in patients within 6 categories of significant bleeding, (1) traumatic injury, (2) intracranial hemorrhage, (3) cardiac surgery, (4) gastrointestinal hemorrhage, (5) inherited bleeding disorders, and (6) hypoproliferative thrombocytopenia. BACKGROUND: A standardized primary outcome in clinical trials evaluating hemostatic products and strategies for the treatment of clinically significant bleeding will facilitate the conduct, interpretation, and translation into clinical practice of hemostasis research and support alignment among funders, investigators, clinicians, and regulators. METHODS: An international panel of experts was convened by the National Heart Lung and Blood Institute and the United States Department of Defense on September 23 and 24, 2019. For patients suffering hemorrhagic shock, the 26 trauma working-group members met for almost a year, utilizing biweekly phone conferences and then an in-person meeting, evaluating the strengths and weaknesses of previous high quality studies. The selection of the recommended primary outcome was guided by goals of patient-centeredness, expected or demonstrated sensitivity to beneficial treatment effects, biologic plausibility, clinical and logistical feasibility, and broad applicability. CONCLUSIONS: For patients suffering hemorrhagic shock, and especially from truncal hemorrhage, the recommended primary outcome was 3 to 6-hour all-cause mortality, chosen to coincide with the physiology of hemorrhagic death and to avoid bias from competing risks. Particular attention was recommended to injury and treatment time, as well as robust assessments of multiple safety related outcomes.

Joint Trauma System, Defense Committee on Trauma, and Armed Services Blood Program consensus statement on whole blood.

Hemorrhage is the most common mechanism of death in battlefield casualties with potentially survivable injuries. There is evidence that early blood product transfusion saves lives among combat casualties. When compared to component therapy, fresh whole blood transfusion improves outcomes in military settings. Cold-stored whole blood also improves outcomes in trauma patients. Whole blood has the advantage of providing red cells, plasma, and platelets together in a single unit, which simplifies and speeds the process of resuscitation, particularly in austere environments. The Joint Trauma System, the Defense Committee on Trauma, and the Armed Services Blood Program endorse the following: (1) whole blood should be used to treat hemorrhagic shock; (2) low-titer group O whole blood is the resuscitation product of choice for the treatment of hemorrhagic shock for all casualties at all roles of care; (3) whole blood should be available within 30 min of casualty wounding, on all medical evacuation platforms, and at all resuscitation and surgical team locations; (4) when whole blood is not available, component therapy should be available within 30 min of casualty wounding; (5) all prehospital medical providers should be trained and logistically supported to screen donors, collect fresh whole blood from designated donors, transfuse blood products, recognize and treat transfusion reactions, and complete the minimum documentation requirements; (6) all deploying military personnel should undergo walking blood bank prescreen laboratory testing for transfusion transmitted disease immediately prior to deployment. Those who are blood group O should undergo anti-A/anti-B antibody titer testing.

The diamond of death: Hypocalcemia in trauma and resuscitation.

INTRODUCTION: Early recognition and management of hemorrhage, damage control resuscitation, and blood product administration have optimized management of severe trauma. Recent data suggest hypocalcemia exacerbates the ensuing effects of coagulopathy in trauma. OBJECTIVE: This narrative review of available literature describes the physiology and role of calcium in trauma resuscitation. Authors did not perform a systematic review or meta-analysis. DISCUSSION: Calcium is a divalent cation found in various physiologic forms, specifically the bound, inactive state and the unbound, physiologically active state. While calcium plays several important physiologic roles in multiple organ systems, the negative hemodynamic effects of hypocalcemia are crucial to address in trauma patients. The negative ramifications of hypocalcemia are intrinsically linked to components of the lethal triad of acidosis, coagulopathy, and hypothermia. Hypocalcemia has direct and indirect effects on each portion of the lethal triad, supporting calcium's potential position as a fourth component in this proposed lethal diamond. Trauma patients often present hypocalcemic in the setting of severe hemorrhage secondary to trauma, which can be worsened by necessary transfusion and resuscitation. The critical consequences of hypocalcemia in the trauma patient have been repeatedly demonstrated with the associated morbidity and mortality. It remains poorly defined when to administer calcium, though current data suggest that earlier administration may be advantageous. CONCLUSIONS: Calcium is a key component of trauma resuscitation and the coagulation cascade. Recent data portray the intricate physiologic reverberations of hypocalcemia in the traumatically injured patient; however, future research is needed to further guide the management of these patients.

Development of prehospital assessment findings associated with massive transfusion.

BACKGROUND: Massive transfusion is frequently a component of the resuscitation of combat casualties. Because blood supplies may be limited, activation of a walking blood bank and mobilization of necessary resources must occur in a timely fashion. The development of a risk prediction model to guide clinicians for early transfusion in the prehospital setting was sought. STUDY DESIGN AND METHODS: This is a secondary analysis of a previously described data set from the Department of Defense Trauma Registry from January 2007 to August 2016 focusing on casualties undergoing massive transfusion. Serious injury was defined based on an Abbreviated Injury Scale score of 3 or greater by body region. The authors constructed multiple imputations of the model for risk prediction development. Efforts were made to internally validate the model. RESULTS: Within the data set, there were 15540 patients, of which 1238 (7.9%) underwent massive transfusion. In the body region injury scale model, explosive injuries (odds ratio [OR], 3.78), serious extremity injuries (OR, 6.59), and tachycardia >120/min (OR, 5.61) were most strongly associated with receiving a massive transfusion. In the simplified model, major amputations (OR, 17.02), tourniquet application (OR, 6.66), and tachycardia >120 beats/min (OR, 8.72) were associated with massive transfusion. Both models had area under the curve receiver operating characteristic values of greater than 0.9 for the model and bootstrap forest analysis. CONCLUSION: In the body region injury scale model, explosive mechanisms, serious extremity injuries, and tachycardia were most strongly associated with massive transfusion. In the simplified model, major amputations, tourniquet application, and tachycardia were most strongly associated.

The need for dried plasma - a national issue.

Recent studies have demonstrated that early transfusion of plasma or RBCs improves survival in patients with severe trauma and hemorrhagic shock. Time to initiate transfusion is the critical factor. It is essential that transfusion begin in the prehospital environment when transport times are longer than approximately 15 to 20 minutes. Unfortunately, logistic constraints severely limit the use of blood products in the prehospital setting, especially in military, remote civilian, and mass disaster circumstances, where the need can be most acute. US military requirements for logistically supportable blood products are projected to increase dramatically in future conflicts. Although dried plasma products have been available and safely used in a number of countries for over 20 years, there is no dried plasma product commercially available in the United States. A US Food and Drug Administration-approved dried plasma is urgently needed. Considering the US military, disaster preparedness, and remote civilian trauma perspectives, this is an urgent national health care issue.

Association of time to craniectomy with survival in patients with severe combat-related brain injury.

OBJECTIVEIn combat and austere environments, evacuation to a location with neurosurgery capability is challenging. A planning target in terms of time to neurosurgery is paramount to inform prepositioning of neurosurgical and transport resources to support a population at risk. This study sought to examine the association of wait time to craniectomy with mortality in patients with severe combat-related brain injury who received decompressive craniectomy.METHODSPatients with combat-related brain injury sustained between 2005 and 2015 who underwent craniectomy at deployed surgical facilities were identified from the Department of Defense Trauma Registry and Joint Trauma System Role 2 Registry. Eligible patients survived transport to a hospital capable of diagnosing the need for craniectomy and performing surgery. Statistical analyses included unadjusted comparisons of postoperative mortality by elapsed time from injury to start of craniectomy, and Cox proportional hazards modeling adjusting for potential confounders. Time from injury to craniectomy was divided into quintiles, and explored in Cox models as a binary variable comparing early versus delayed craniectomy with cutoffs determined by the maximum value of each quintile (quintile 1 vs 2-5, quintiles 1-2 vs 3-5, etc.). Covariates included location of the facility at which the craniectomy was performed (limited-resource role 2 facility vs neurosurgically capable role 3 facility), use of head CT scan, US military status, age, head Abbreviated Injury Scale score, Injury Severity Score, and injury year. To reduce immortal time bias, time from injury to hospital arrival was included as a covariate, entry into the survival analysis cohort was defined as hospital arrival time, and early versus delayed craniectomy was modeled as a time-dependent covariate. Follow-up for survival ended at death, hospital discharge, or hospital day 16, whichever occurred first.RESULTSOf 486 patients identified as having undergone craniectomy, 213 (44%) had complete date/time values. Unadjusted postoperative mortality was 23% for quintile 1 (n = 43, time from injury to start of craniectomy 30-152 minutes); 7% for quintile 2 (n = 42, 154-210 minutes); 7% for quintile 3 (n = 43, 212-320 minutes); 19% for quintile 4 (n = 42, 325-639 minutes); and 14% for quintile 5 (n = 43, 665-3885 minutes). In Cox models adjusted for potential confounders and immortal time bias, postoperative mortality was significantly lower when time to craniectomy was within 5.33 hours of injury (quintiles 1-3) relative to longer delays (quintiles 4-5), with an adjusted hazard ratio of 0.28, 95% CI 0.10-0.76 (p = 0.012).CONCLUSIONSPostoperative mortality was significantly lower when craniectomy was initiated within 5.33 hours of injury. Further research to optimize craniectomy timing and mitigate delays is needed. Functional outcomes should also be evaluated.

Association of Prehospital Blood Product Transfusion During Medical Evacuation of Combat Casualties in Afghanistan With Acute and 30-Day Survival.

IMPORTANCE: Prehospital blood product transfusion in trauma care remains controversial due to poor-quality evidence and cost. Sequential expansion of blood transfusion capability after 2012 to deployed military medical evacuation (MEDEVAC) units enabled a concurrent cohort study to focus on the timing as well as the location of the initial transfusion. OBJECTIVE: To examine the association of prehospital transfusion and time to initial transfusion with injury survival. DESIGN, SETTING, AND PARTICIPANTS: Retrospective cohort study of US military combat casualties in Afghanistan between April 1, 2012, and August 7, 2015. Eligible patients were rescued alive by MEDEVAC from point of injury with either (1) a traumatic limb amputation at or above the knee or elbow or (2) shock defined as a systolic blood pressure of less than 90 mm Hg or a heart rate greater than 120 beats per minute. EXPOSURES: Initiation of prehospital transfusion and time from MEDEVAC rescue to first transfusion, regardless of location (ie, prior to or during hospitalization). Transfusion recipients were compared with nonrecipients (unexposed) for whom transfusion was delayed or not given. MAIN OUTCOMES AND MEASURES: Mortality at 24 hours and 30 days after MEDEVAC rescue were coprimary outcomes. To balance injury severity, nonrecipients of prehospital transfusion were frequency matched to recipients by mechanism of injury, prehospital shock, severity of limb amputation, head injury, and torso hemorrhage. Cox regression was stratified by matched groups and also adjusted for age, injury year, transport team, tourniquet use, and time to MEDEVAC rescue. RESULTS: Of 502 patients (median age, 25 years [interquartile range, 22 to 29 years]; 98% male), 3 of 55 prehospital transfusion recipients (5%) and 85 of 447 nonrecipients (19%) died within 24 hours of MEDEVAC rescue (between-group difference, -14% [95% CI, -21% to -6%]; P = .01). By day 30, 6 recipients (11%) and 102 nonrecipients (23%) died (between-group difference, -12% [95% CI, -21% to -2%]; P = .04). For the 386 patients without missing covariate data among the 400 patients within the matched groups, the adjusted hazard ratio for mortality associated with prehospital transfusion was 0.26 (95% CI, 0.08 to 0.84, P = .02) over 24 hours (3 deaths among 54 recipients vs 67 deaths among 332 matched nonrecipients) and 0.39 (95% CI, 0.16 to 0.92, P = .03) over 30 days (6 vs 76 deaths, respectively). Time to initial transfusion, regardless of location (prehospital or during hospitalization), was associated with reduced 24-hour mortality only up to 15 minutes after MEDEVAC rescue (median, 36 minutes after injury; adjusted hazard ratio, 0.17 [95% CI, 0.04 to 0.73], P = .02; there were 2 deaths among 62 recipients vs 68 deaths among 324 delayed transfusion recipients or nonrecipients). CONCLUSIONS AND RELEVANCE: 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.

Perception does not equal reality for resident vascular trauma skills.

BACKGROUND: Experience with the management of vascular trauma by senior surgical residents is increasingly limited. When queried about their understanding of anatomy and ability to perform specific vascular exposures, residents express a moderately high level of confidence. We hypothesized that this perception does not equal reality. METHODS: A total of 42 senior surgical residents participating in an ongoing validation study of the Advanced Surgical Skills for Exposures in Trauma course were asked to self-assess their baseline (precourse) confidence of their understanding of the anatomy required to perform and their ability to perform exposure and control of the axillary, brachial, and femoral arteries, as well as lower extremity fasciotomy using a 5-point Likert scale. Residents then performed the four procedures on a fresh cadaver model and were scored in real time by experts using a global assessment of anatomic knowledge and readiness to perform." The Student t-test was used with α set at P < 0.05. RESULTS: Residents consistently rated their understanding of anatomy and their ability to perform the procedures significantly higher than expert evaluator ultimately scored them. Evaluators also deemed that residents would be unable to perform without help 65%-86% of the time. CONCLUSIONS: Senior residents are ill-prepared to perform the procedures studied and have an unwarranted confidence in their knowledge and abilities. Perception clearly does not equal reality in preparing these trainees to perform as advertized. The low global scores for anatomy and performance should be a wake-up call for surgical educators prompting curricular reform and evaluation.

Risk management analysis of air ambulance blood product administration in combat operations.

BACKGROUND: Between June-October 2012, 61 flight-medic-directed transfusions took place aboard U.S. Army Medical Evacuation (medevac) helicopters in Afghanistan. This represents the initial experience for pre-hospital blood product transfusion by U.S. Army flight medics. METHODS: We performed a retrospective review of clinical records, operating guidelines, after-action reviews, decision and information briefs, bimonthly medical conferences, and medevac-related medical records. RESULTS: A successful program was administered at 10 locations across Afghanistan. Adherence to protocol transfusion indications was 97%. There were 61 casualties who were transfused without any known instance of adverse reaction or local blood product wastage. Shock index (heart rate/systolic blood pressure) improved significantly en route, with a median shock index of 1.6 (IQR 1.2-2.0) pre-transfusion and 1.1 (IQR 1.0-1.5) post-transfusion (P < 0.0001). Blood resupply, training, and clinical procedures were standardized across each of the 10 areas of medevac operations. DISCUSSION: Potential risks of medical complications, reverse propaganda, adherence to protocol, and diversion and/or wastage of limited resources were important considerations in the development of the pilot program. Aviation-specific risk mitigation strategies were important to ensure mission success in terms of wastage prevention, standardized operations at multiple locations, and prevention of adverse clinical outcomes. Consideration of aviation risk mitigation strategies may help enable other helicopter emergency medical systems to develop remote pre-hospital transfusion capability. This pilot program provides preliminary evidence that blood product administration by medevac is safe.

Advancing Combat Casualty Care Statistics and Other Battlefield Care Metrics.

Aggregate statistics can provide intra-conflict and inter-conflict mortality comparisons and trends within and between U.S. combat operations. However, capturing individual-level data to evaluate medical and non-medical factors that influence combat casualty mortality has historically proven difficult. The Department of Defense (DoD) Trauma Registry, developed as an integral component of the Joint Trauma System during recent conflicts in Afghanistan and Iraq, has amassed individual-level data that have afforded greater opportunity for a variety of analyses and comparisons. Although aggregate statistics are easily calculated and commonly used across the DoD, other issues that require consideration include the impact of individual medical interventions, non-medical factors, non-battle-injured casualties, and incomplete or missing medical data, especially for prehospital care and forward surgical team care. Needed are novel methods to address these issues in order to provide a clearer interpretation of aggregate statistics and to highlight solutions that will ultimately increase survival and eliminate preventable death on the battlefield. Although many U.S. military combat fatalities sustain injuries deemed non-survivable, survival among these casualties might be improved using primary and secondary prevention strategies that prevent injury or reduce injury severity. The current commentary proposes adjustments to traditional aggregate combat casualty care statistics by integrating statistics from the DoD Military Trauma Mortality Review process as conducted by the Joint Trauma System and Armed Forces Medical Examiner System.

Analysis of the U.S. Military Trauma System in Accordance With Doctrinal Levels of Warfare.

INTRODUCTION: In recent conflicts, the Joint Theater Trauma System (JTTS) led the systematic approach to improve battlefield trauma care, substantially contributing to the unprecedented survival of combat casualties. The Joint Trauma System (JTS) was codified in 2016 to preserve the lessons learned and functions of the JTTS, including the Department of Defense Trauma Registry. Concurrently, Combatant Commands (CCMD) were directed to establish CCMD Trauma Systems (CTS) "modeled after the JTTS" and to maintain a baseline of core functions intended to rapidly scale as needed. The complex nature of both CCMDs and the military trauma system has challenged the full implementation of the CTS. Analyzing the historical experiences of the JTTS, JTS, and CTS within a military doctrinal framework might enable the further success of the military trauma system. METHODS: The strategic, operational, and tactical levels of warfare, in accordance with Joint Publication 1-0, Doctrine of the Armed Forces of the United States, and Joint Publication 3-0, Joint Operations, established the analytic framework for this study. The literature regarding the JTTS, CTS, and JTS was reviewed for relevant information concerning organizational structure and functions of trauma system performance improvement (PI) capabilities. A comprehensive analysis was performed using a thematic approach to evaluating descriptive data contained within the collected data set. Deployed trauma system PI tasks, functions, and responsibilities were identified, defined, and correlated according to the respective levels of warfare. RESULTS: The comprehensive analysis revealed both discrete and overlapping tasks, functions, and responsibilities of the trauma system PI capabilities at each of the three levels of warfare. Strategic-level actions were categorized according to 12 distinct themes: reduce mortality; strategic reporting; centralized trauma registry; strategic communications; centralized organization; direct support to CCMDs; Department of Defense policy and doctrine; strategic-level PI; clinical practice guidelines; training and readiness standards; force structure, standardization, and interoperability; and research and development. Operational-level actions were categorized according to seven distinct themes: theater trauma system policies and requirements; theater trauma system leadership; stakeholder coordination; theater communication; theater standards for readiness and skill sustainment; trauma system planning; and medical logistics support. Tactical-level actions were categorized according to seven distinct themes: trauma system personnel; PI; documentation enforcement and patient care data collection; tactical planning recommendations for employing medical assets; research support; communication and reporting; and training and skills sustainment. CONCLUSION: The deployed U.S. military trauma system requires a robust PI capability to optimize combat casualty care. Policy updates, a joint military trauma system doctrine, and force design updates are necessary for deployed military trauma system PI capabilities to function optimally across all levels of warfare.

United States Military Fatalities During Operation Inherent Resolve and Operation Freedom's Sentinel.

BACKGROUND: Military operations provide a unified action and strategic approach to achieve national goals and objectives. Mortality reviews from military operations can guide injury prevention and casualty care efforts. METHODS: A retrospective study was conducted on all U.S. military fatalities from Operation Inherent Resolve (OIR) in Iraq (2014-2021) and Operation Freedom's Sentinel (OFS) in Afghanistan (2015-2021). Data were obtained from autopsy reports and other existing records. Fatalities were evaluated for population characteristics; manner, cause, and location of death; and underlying atherosclerosis. Non-suicide trauma fatalities were also evaluated for injury severity, mechanism of death, injury survivability, death preventability, and opportunities for improvement. RESULTS: Of 213 U.S. military fatalities (median age, 29 years; male, 93.0%; prehospital, 89.2%), 49.8% were from OIR, and 50.2% were from OFS. More OIR fatalities were Reserve and National Guard forces (OIR 22.6%; OFS 5.6%), conventional forces (OIR 82.1%; OFS 65.4%), and support personnel (OIR 61.3%; OFS 33.6%). More OIR fatalities also resulted from disease and non-battle injury (OIR 83.0%; OFS 28.0%). The leading cause of death was injury (OIR 81.1%; OFS 98.1%). Manner of death differed as more homicides (OIR 18.9%; OFS 72.9%) were seen in OFS, and more deaths from natural causes (OIR 18.9%; OFS 1.9%) and suicides (OIR 29.2%; OFS 6.5%) were seen in OIR. The prevalence of underlying atherosclerosis was 14.2% in OIR and 18.7% in OFS. Of 146 non-suicide trauma fatalities, most multiple/blunt force injury deaths (62.2%) occurred in OIR, and most blast injury deaths (77.8%) and gunshot wound deaths (76.6%) occurred in OFS. The leading mechanism of death was catastrophic tissue destruction (80.8%). Most fatalities had non-survivable injuries (80.8%) and non-preventable deaths (97.3%). CONCLUSIONS: Comprehensive mortality reviews should routinely be conducted for all military operation deaths. Understanding death from both injury and disease can guide preemptive and responsive efforts to reduce death among military forces.

Clinical Assessment of Low Calcium In traUMa (CALCIUM).

Major trauma frequently occurs in the deployed, combat setting and is especially applicable in the recent conflicts with explosives dominating the combat wounded. In future near-peer conflicts, we will likely face even more profound weapons including mortars and artillery. As such, the number of severely wounded will likely increase. Hypocalcemia frequently occurs after blood transfusions, secondary to the preservatives in the blood products; however, recent data suggests major trauma in and of itself is a risk factor for hypocalcemia. Calcium is a major ion involved in heart contractility; thus, hypocalcemia can lead to poor contractility. Smaller studies have linked hypocalcemia to worse outcomes, but it remains unclear what causes hypocalcemia and if intervening could potentially save lives. The objective of this study is to determine the incidence of hypocalcemia on hospital arrival and the association with survival. We are seeking to address the following scientific questions, (1) Is hypocalcemia present following traumatic injury prior to transfusion during resuscitation? (2) Does hypocalcemia influence the amount of blood products transfused? (3) To what extent is hypocalcemia further exacerbated by transfusion? (4) What is the relationship between hypocalcemia following traumatic injury and mortality? We will conduct a multicenter, prospective, observational study. We will gather ionized calcium levels at 0, 3, 6, 12, 18, and 24 hours as part of scheduled calcium measurements. This will ensure we have accurate data to assess the early and late effects of hypocalcemia throughout the course of resuscitation and hemorrhage control. These data will be captured by a trained study team at every site. Our findings will inform clinical practice guidelines and optimize the care delivered in the combat and civilian trauma setting. We are seeking 391 patients with complete data to meet our a priori inclusion criteria. Our study will have major immediate short-term findings including risk prediction modeling to assess who is at risk for hypocalcemia, data assessing interventions associated with the incidence of hypocalcemia, and outcome data including mortality and its link to early hypocalcemia.

Evidence-based principles of time, triage and treatment: Refining the initial medical response to massive casualty incidents.

BACKGROUND: The overall approach to massive casualty triage has changed little in the past 200 years. As the military and civilian organizations prepare for the possibility of future large-scale combat operations, terrorist attacks and natural disasters, potentially involving hundreds or even thousands of casualties, a modified approach is needed to conduct effective triage, initiate treatment, and save as many lives as possible. METHODS: Military experience and review of analyses from the Department of Defense Trauma Registry are combined to introduce new concepts in triage and initial casualty management. RESULTS: The classification of the scale of massive casualty (MASCAL) incidents, timeline of life-saving interventions, immediate first pass actions prior to formal triage decisions during the first hour after injury, simplification of triage decisions, and the understanding that ultra-MASCAL will primarily require casualty movement and survival needs with few prehospital life-saving medical interventions are discussed. CONCLUSION: Self aid, bystander, and first responder interventions are paramount and should be trained and planned extensively. Military and disaster planning should not only train these concepts, but should seek innovations to extend the timelines of effectiveness and to deliver novel capabilities within the timelines to the greatest extent possible.