The Efficacy of Whole Blood Resuscitation During Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) to Mitigate Post-occlusion Circulatory Collapse: A Translational Model in Large Swine.

INTRODUCTION: Uncontrolled torso hemorrhage is the primary cause of potentially survivable deaths on the battlefield. Zone 1 Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA), in conjunction with damage control resuscitation, may be an effective management strategy for these patients in the prehospital or austere phase of their care. However, the effect of whole blood (WB) transfusion during REBOA on post-occlusion circulatory collapse is not fully understood. MATERIALS AND METHODS: Yorkshire male swine (n = 6 per group, 70-90 kg) underwent a 40% volume-controlled hemorrhage. After a 10-minute hemorrhagic shock period, a REBOA balloon was inflated in Zone 1. Fifteen minutes after inflation, 0, 1, or 3 units (450 mL/unit) of autologous WB was infused through the left jugular vein. Thirty minutes after initial balloon inflation, the balloon was deflated slowly over 3 minutes. Following deflation, normal saline was administered (up to 3,000 mL) and swine were observed for 2 hours. Survival (primary outcome), hemodynamics, and blood gas values were compared among groups. Statistical significance was determined by log-rank test, one-way ANOVA, and repeated measures ANOVA. RESULTS: Survival rates were comparable between groups (P = .345) with 66% of control, 33% of the one-unit animals, and 50% of the 3-unit animals survived until the end of the study. Following WB infusion, both the 1-unit and the 3-unit groups had significantly higher blood pressure (P < .01), pulmonary artery pressure (P < .01), and carotid artery flow (P < .01) compared to the control group. CONCLUSIONS: WB transfusion during Zone 1 REBOA was not associated with increased short-term survival in this large animal model of severe hemorrhage. We observed no signal that WB transfusion may mitigate post-occlusion circulatory collapse. However, there was evidence of supra-normal blood pressures during WB transfusion.

Ketamine Administration by Special Operations Medical Personnel During Training Mishaps.

BACKGROUND: Opioids can have adverse effects on casualties in hemorrhagic shock. In 2014, the Committee on Tactical Combat Casualty Care (CoTCCC) recommended the use of ketamine at the point of injury (POI). Despite these recommendations the adherence is moderate at best. Poor use may stem from a lack of access to use ketamine during training. The United States Special Operations Command (USSOCOM) is often in a unique position, they maintain narcotics for use during all training events and operations. The goal of this work is to demonstrate that ketamine is safe and effective in both training and operational environments. METHODS: This was a retrospective, observational performance improvement project within United States Special Operations Command and Air Combat Command that included the US Army's 75th Ranger Regiment, 160th Special Operations Aviation Regiment, and US Air Force Pararescue. Descriptive statistics were used to calculate the doses per administration to include the interquartile range (IQR), standard deviation (SD) and the range of likely doses using a 95% confidence interval (CI). A Wilcoxon signed-rank test was used to compare the mean pre-ketamine pain scores to the mean post-ketamine on a 0-to-10 pain scale. RESULTS: From July 2010 to October 2017, there was a total of 34 patients; all were male. A total of 22 (64.7%) received intravenous ketamine and 12 (35.3%) received intramuscular ketamine and 8 (23.5%) received intranasal ketamine. The mean number of ketamine doses via all routes administered to patients was 1.88 (SD 1.094) and the mean total dose of all ketamine administration was 90.29mg (95% CI, 70.09-110.49). The mean initial dose of all ketamine administration was 47.35mg (95% CI, 38.52-56.18). The median preketamine pain scale for casualties was noted to be 8.0 (IQR 3) and the median post-ketamine pain scale was 0.0 (IQR 3). CONCLUSION: Ketamine appears to be safe and effective for use during military training accidents. Military units should consider allowing their medics to carry and use as needed.

Interventions Performed on Multipurpose Military Working Dogs in the Prehospital Combat Setting: A Comprehensive Case Series Report.

INTRODUCTION: The military working dog (MWD) has been essential in military operations such as Operation Iraqi Freedom (OIF) and Operation Enduring Freedom (OEF). MWDs sustain traumatic injuries that require point of injury and en route clinical interventions. The objective of this study was to describe the injuries and treatment military working dogs received on the battlefield and report their final disposition. METHODS: This was a convenience sample of 11 injury and treatment reports of US MWDs from February 2008 to December 2014. We obtained clinical data regarding battlefield treatment from the 160th Special Operations Aviation Regiment (SOAR) database and supplemental operational sources. A single individual collected the data and maintained the dataset. The data collected included mechanism of injury, clinical interventions, and outcomes. We reported findings as frequencies. RESULTS: Of the 11 MWD casualties identified in this dataset, 10 reports had documented injuries secondary to trauma. Eighty percent of the cases sustained gunshot wounds. The hindlegs were the most common site of injury (50%); however, 80% sustained injuries at more than one anatomical location. Seventy percent of cases received at least one clinical intervention before arrival at their first treatment facility. The most common interventions included trauma dressing (30%), gauze (30%), chest seal (30%), and pain medication (30%). The survival rate was 50%. CONCLUSION: The majority of the MWD cases in this dataset sustained traumatic injuries, with gunshot being the most common mechanism of injury. Most MWDs received at least one clinical intervention. Fifty percent did not survive their traumatic injuries.

A Novel Expeditionary Perfused Cadaver Model for Trauma Training in the Out-of-Hospital Setting.

BACKGROUND: Cadaver training for prehospital surgical procedures is a valid training model. The limitation to date has been that perfused cadavers have only been used in wet laboratories in hospitals or university centers. We endeavor to describe a transportable central-perfused cadaver model suitable for training in the battlefield environment. Goals of design were to create a simple, easily reproducible, and realistic model to simulate procedures in field and austere conditions. METHODS: We conducted a review of the published literature on cadaver models, conducted virtual-reality simulator training, performed interviews with subject matter experts, and visited the laboratories at the Centre for Emergency Health Sciences in Spring Branch, TX, the Basic Endovascular Skills in Trauma laboratory in Baltimore, MD, and the Fresh Tissue Dissection Laboratory at Los Angeles County and University of Southern California, Keck School of Medicine, Los Angeles, CA. PROCEDURE: This article will describe a five-step procedure that utilizes extremity tourniquets, right common carotid intra-arterial and distal femur intraosseous (IO) access for perfusion, and oropharynx preparation for airway procedures. The model will then be ready for all tactical combat casualty care procedures, including nasopharyngeal airway, endotracheal intubation, cricothyroidotomy, central-line access, needle decompression, finger and tube thoracostomy, resuscitative endovascular balloon occlusion of the aorta, junctional tourniquets, IO lines, and field amputations. CONCLUSIONS: This model has been used in the laboratory, field, ground ambulance, and military air ambulance (UH-60) settings with good results. The model described can be used in the field setting with minimal resources and accurately simulates the critical skills for all combat trauma procedures.

Survey of Casualty Evacuation Missions Conducted by the 160th Special Operations Aviation Regiment During the Afghanistan Conflict.

BACKGROUND: Historically, documentation of prehospital combat casualty care has been relatively nonexistent. Without documentation, performance improvement of prehospital care and evacuation through data collection, consolidation, and scientific analyses cannot be adequately accomplished. During recent conflicts, prehospital documentation has received increased attention for point-of-injury care as well as for care provided en route on medical evacuation platforms. However, documentation on casualty evacuation (CASEVAC) platforms is still lacking. Thus, a CASEVAC dataset was developed and maintained by the 160th Special Operations Aviation Regiment (SOAR), a nonmedical, rotary-wing aviation unit, to evaluate and review CASEVAC missions conducted by their organization. METHODS: A retrospective review and descriptive analysis were performed on data from all documented CASEVAC missions conducted in Afghanistan by the 160th SOAR from January 2008 to May 2015. Documentation of care was originally performed in a narrative after-action review (AAR) format. Unclassified, nonpersonally identifiable data were extracted and transferred from these AARs into a database for detailed analysis. Data points included demographics, flight time, provider number and type, injury and outcome details, and medical interventions provided by ground forces and CASEVAC personnel. RESULTS: There were 227 patients transported during 129 CASEVAC missions conducted by the 160th SOAR. Three patients had unavailable data, four had unknown injuries or illnesses, and eight were military working dogs. Remaining were 207 trauma casualties (96%) and five medical patients (2%). The mean and median times of flight from the injury scene to hospital arrival were less than 20 minutes. Of trauma casualties, most were male US and coalition forces (n = 178; 86%). From this population, injuries to the extremities (n = 139; 67%) were seen most commonly. The primary mechanisms of injury were gunshot wound (n = 89; 43%) and blast injury (n = 82; 40%). The survival rate was 85% (n = 176) for those who incurred trauma. Of those who did not survive, most died before reaching surgical care (26 of 31; 84%). CONCLUSION: Performance improvement efforts directed toward prehospital combat casualty care can ameliorate survival on the battlefield. Because documentation of care is essential for conducting performance improvement, medical and nonmedical units must dedicate time and efforts accordingly. Capturing and analyzing data from combat missions can help refine tactics, techniques, and procedures and more accurately define wartime personnel, training, and equipment requirements. This study is an example of how performance improvement can be initiated by a nonmedical unit conducting CASEVAC missions.

Comparison of zone 3 Resuscitative Endovascular Balloon Occlusion of the Aorta and the Abdominal Aortic and Junctional Tourniquet in a model of junctional hemorrhage in swine.

BACKGROUND: Traumatic injuries to the pelvis and high junctional injuries are difficult to treat in the field; however, Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) and the Abdominal Aortic and Junctional Tourniquet (AAJT) constitute two promising treatment modalities. The aim of this study is to use a large animal model of pelvic hemorrhage to compare the survival, hemostatic, hemodynamic, and metabolic profile of both techniques. METHODS: Yorkshire swine (n = 10, 70-90 kg) underwent general anesthesia, instrumentation, and surgical isolation of the femoral artery. Uncontrolled hemorrhage was initiated by an arteriotomy. Animals were randomly allocated to either REBOA or AAJT. Following completion of device application, both groups received a 500 mL Hextend bolus. After 1 hour, the injured femoral artery was ligated to simulate definitive hemostasis followed by a second Hextend bolus and device removal. Animals were observed for two more hours. Physiological data were collected throughout the experiments and compared between groups. RESULTS: Both techniques achieved 100% hemostasis, and all animals survived the entire experiment except one in the REBOA group. During the hour treatment phase, the AAJT group had a higher mean arterial pressure than the REBOA group (59.9 ± 16.1 versus 44.6 ± 9.8 mm Hg, respectively; P < 0.05). The AAJT-treated group had higher lactate levels than the REBOA-treated group (4.5 ± 2.0 versus 3.2 ± 1.3 mg/dL, respectively; P < 0.05). CONCLUSIONS: Despite their mechanistic differences, both techniques achieved a similar hemostatic, hemodynamic, and metabolic profile. Some differences do exist including lactate levels and blood pressure.

Feasibility and Proposed Training Pathway for Austere Application of Resuscitative Balloon Occlusion of the Aorta.

BACKGROUND: Noncompressible junctional and truncal hemorrhage remains a significant cause of combat casualty death. Resuscitative endovascular balloon occlusion of the aorta (REBOA) is an effective treatment for many junctional and noncompressible hemorrhages. The current hospital standard for time of placement of REBOA is approximately 6 minutes. This study examined the training process and the ability of nonsurgical physicians to apply REBOA therapy in an austere field environment. METHODS: This was a skill acquisition and feasibility study. The participants for this experiment were two board-certified military emergency medicine physicians with no prior endovascular surgery exposure. Both providers attended two nationally recognized REBOA courses for training. A perfused cadaver model was developed for the study. Each provider then performed REBOA during different phases of prehospital care. Time points were recorded for each procedure. RESULTS: There were 28 REBOA catheter placement attempts in 14 perfused cadaver models in the nonhospital setting: eight placements in a field setting, eight placements in a static ambulance, four placements in a moving ambulance, and eight placements inflight on a UH-60 aircraft. No statistically significant differences with regard to balloon inflation time were found between the two providers, the side where the catheter was placed, or individual cadaver models. Successful placement was accomplished in 85.7% of the models. Percutaneous access was successful 53.6% of the time. The overall average time for REBOA placement was 543 seconds (i.e., approximately 9 minutes; median, 439 seconds; 95% confidence interval [CI], 429-657) and the average placement time for percutaneous catheters was 376 seconds (i.e., 6.3 minutes; 95% CI, 311-44 seconds) versus those requiring vascular cutdown (821 seconds; 95% CI, 655-986). Importantly, the time from the decision to convert to open cutdown until REBOA placement was 455 seconds (95% CI, 285-625). CONCLUSION: This study demonstrated that, with proper training, nonsurgical providers can properly place REBOA catheters in austere prehospital settings at speeds.

Stop the Bleed: The Effect of Hemorrhage Control Education on Laypersons' Willingness to Respond During a Traumatic Medical Emergency.

BACKGROUND: The "Stop the Bleed" campaign advocates for non-medical personnel to be trained in basic hemorrhage control. However, it is not clear what type of education or the duration of instruction needed to meet that requirement. The objective of this study was to determine the impact of a brief hemorrhage control educational curriculum on the willingness of laypersons to respond during a traumatic emergency. METHODS: This "Stop the Bleed" education initiative was conducted by the University of Texas Health San Antonio Office of the Medical Director (San Antonio, Texas USA) between September 2016 and March 2017. Individuals with formal medical certification were excluded from this analysis. Trainers used a pre-event questionnaire to assess participants knowledge and attitudes about tourniquets and responding to traumatic emergencies. Each training course included an individual evaluation of tourniquet placement, 20 minutes of didactic instruction on hemorrhage control techniques, and hands-on instruction with tourniquet application on both adult and child mannequins. The primary outcome in this study was the willingness to use a tourniquet in response to a traumatic medical emergency. RESULTS: Of 236 participants, 218 met the eligibility criteria. When initially asked if they would use a tourniquet in real life, 64.2% (140/218) responded "Yes." Following training, 95.6% (194/203) of participants responded that they would use a tourniquet in real life. When participants were asked about their comfort level with using a tourniquet in real life, there was a statistically significant improvement between their initial response and their response post training (2.5 versus 4.0, based on 5-point Likert scale; P<.001). CONCLUSION: In this hemorrhage control education study, it was found that a short educational intervention can improve laypersons' self-efficacy and reported willingness to use a tourniquet in an emergency. Identified barriers to act should be addressed when designing future hemorrhage control public health education campaigns. Community education should continue to be a priority of the "Stop the Bleed" campaign. Ross EM , Redman TT , Mapp JG , Brown DJ , Tanaka K , Cooley CW , Kharod CU , Wampler DA . Stop the bleed: the effect of hemorrhage control education on laypersons' willingness to respond during a traumatic medical emergency. Prehosp Disaster Med. 2018;33(2):127-132.

The Tourniquet Gap: A Pilot Study of the Intuitive Placement of Three Tourniquet Types by Laypersons.

BACKGROUND: The "Stop the Bleed" campaign in the United States advocates for nonmedical personnel to be trained in basic hemorrhage control and that "bleeding control kits" be available in high-risk areas. However, it is not clear which tourniquets are most effective in the hands of laypersons. OBJECTIVES: The objective of this pilot study was to determine which tourniquet type was the most intuitive for a layperson to apply correctly. METHODS: This project is a randomized study derived from a "Stop the Bleed" education initiative conducted between September 2016 and March 2017. Novice tourniquet users were randomized to apply one of three commercially available tourniquets (Combat Action Tourniquet [CAT; North American Rescue, LLC, Greer, SC], Ratcheting Medical Tourniquet [RMT; m2 Inc., Winooski, VT], or Stretch Wrap and Tuck Tourniquet [SWAT-T; TEMS Solutions, LLC, Salida, CO]) in a controlled setting. Individuals with formal medical certification, prior military service, or prior training with tourniquets were excluded. The primary outcome of this study was successful tourniquet placement. RESULTS: Of 236 possible participants, 198 met the eligibility criteria. Demographics were similar across groups. The rates of successful tourniquet application for the CAT, RMT, and SWAT-T were 16.9%, 23.4%, and 10.6%, respectively (p = 0.149). The most common causes of application failure were: inadequate tightness (74.1%), improper placement technique (44.4%), and incorrect positioning (16.7%). CONCLUSION: Our pilot study on the intuitive nature of applying commercially available tourniquets found unacceptably high rates of failure. Large-scale community education efforts and manufacturer improvements of tourniquet usability by the lay public must be made before the widespread dissemination of tourniquets will have a significant public health effect.

Dual defibrillation in out-of-hospital cardiac arrest: A retrospective cohort analysis.

STUDY OBJECTIVES: The goal of our study is to determine if prehospital dual defibrillation (DD) is associated with better neurologically intact survival in out-of-hospital cardiac arrest. METHODS: This study is a retrospective cohort analysis of prospectively collected Quality Assurance/Quality Improvement data from a large urban fire based EMS system out-of-hospital cardiac arrest (OHCA) database between Jan 2013 and Dec 2015. Our inclusion criteria were administration of DD or at least four conventional 200J defibrillations for cases of recurrent and refractory ventricular fibrillation (VF). We excluded any case with incomplete data. The primary outcome for our study was neurologically intact survival (defined as Cerebral Performance Category 1 and 2). RESULTS: A total of 3470 cases of OHCA were treated during the time period of Jan 2013 to Dec 2015. There were 302 cases of recurrent and refractory VF identified. Twenty-three cases had incomplete data. Of the remaining 279 cases, 50 were treated with DD and 229 received standard single shock 200J defibrillations. There was no statistically significant difference in the primary outcome of neurologically intact survival between the DD group (6%) and the standard defibrillation group (11.4%) (p=0.317) (OR 0.50, 95% CI 0.15-1.72). CONCLUSION: Our retrospective cohort analysis on the prehospital use of DD in OHCA found no association with neurologically intact survival. Case-control studies are needed to further evaluate the efficacy of DD in the prehospital setting.

Use of the LMA Supreme in the Special Operations Environment: A Retrospective Comparison of the LMA Supreme and King LT-D.

The purpose of this study is to evaluate the use of the LMA Supreme® (LAM) as a combat supraglottic airway for U.S. Special Operations Forces (SOF). It is imperative to continuously evaluate and compare existing management options for airway control as requirements and technologies change. Providing our Special Operators with the most advanced and reliable medical equipment is of the utmost importance, and it is our intention here to compare the LMA Supreme with the currently fielded King LT-D® (King Systems) to determine whether the LMA Supreme may be a viable alternative supraglottic airway.