Military Standard Testing of Commercially Available Supraglottic Airway Devices for Use in a Military Combat Setting.

INTRODUCTION: Airway obstruction is the second leading cause of death on the battlefield. The harsh conditions of the military combat setting require that devices be able to withstand extreme circumstances. Military standards (MIL-STD) testing is necessary before devices are fielded. We sought to determine the ability of supraglottic airway (SGA) devices to withstand MIL-STD testing. METHODS: We tested 10 SGA models according to nine MIL-STD-810H test methods. We selected these tests by polling five military and civilian emergency-medicine subject matter experts (SMEs), who weighed the relevance of each test. We performed tests on three devices for each model, with operational and visual examinations, to assign a score (1 to 10) for each device after each test. We calculated the final score of each SGA model by averaging the score of each device and multiplying that by the weight for each test, for a possible final score of 2.6 to 26.3. RESULTS: The scores for the SGA models were LMA Classic Airway, 25.9; AuraGain Disposable Laryngeal Mask, 25.5; i-gel Supraglottic Airway, 25.2; Solus Laryngeal Mask Airway, 24.4; LMA Fastrach Airway, 24.4; AuraStraight Disposable Laryngeal Mask, 24.1; King LTS-D Disposable Laryngeal Tube, 22.1; LMA Supreme Airway, 21.0; air-Q Disposable Intubating Laryngeal Airway, 20.1; and Baska Mask Supraglottic Airway, 18.1. The limited (one to three) samples available for testing provide adequate preliminary information but restrict the range of failures that could be discovered. CONCLUSIONS: Lower scoring SGA models may not be optimal for military field use. Models scoring sufficiently close to the top performers (LMA Classic, AuraGain, i-gel, Solus, LMA Fastrach, AuraStraight) may be viable for use in the military setting. The findings of our testing should help guide device procurement appropriate for different battlefield conditions.

A Comparison of Injury Patterns and Interventions among US Military Special Operations Versus Conventional Forces Combatants.

BACKGROUND: Over the course of the US' Global War on Terrorism, its military has utilized both conventional and special operations forces (SOF). These entities have sustained and treated battlefield casualties in the prehospital, Role 1 setting, while also making efforts to mitigate risks to the force and pursuing improved interventions. The goal of this study is to compare outcomes and prehospital medical interventions between SOF and conventional military combat casualties. METHODS: This is a secondary analysis of previously published data from the Department of Defense Trauma Registry. The casualties were categorized as special operations if they were 18-series, Navy SEAL, Pararescue Jumper, Tactical Air Control Party, Combat Controller, and Marine Corps Force Reconnaissance. The remainder with a documented military occupational specialty (MOS) were classified as conventional forces. RESULTS: Within our dataset, a MOS was categorizable for 1806 conventional and 130 special operations. Conventional forces were younger age (24 versus 30, p is less than 0.001). Conventional forces had a higher proportion of explosive injuries (61% versus 44%) but a lower proportion of firearm injuries (22% versus 42%, p is less than 0.001). The median injury severity scores were similar between the groups. Conventional forces had lower rates of documentation for all metrics: pulse, respiratory rate, blood pressure, oxygen saturation, Glasgow Coma Scale, and pain score. On adjusted analyses, SOF had higher odds of receiving an extremity splint, packed red blood cells, whole blood, tranexamic acid, ketamine, and fentanyl. CONCLUSION: SOF had consistently better medical documentation rates, more use of ketamine and fentanyl, less morphine administration, and lower threshold for use of blood products in both unadjusted and adjusted analyses. Our findings suggest lessons learned from the SOF medics should be extrapolated to the conventional forces for improved medical care.

The Battalion Aid Station-The Forgotten Frontier of the Army Health System During the Global War on Terrorism.

BACKGROUND: The battalion aid station (BAS) has historically served as the first stop during which combat casualties would receive care beyond a combat medic. Since the conflicts in Iraq and Afghanistan, many combat casualties have bypassed the BAS for treatment facilities capable of surgery. We describe the care provided at these treatment facilities during 2007-2020. METHODS: This is a secondary analysis of previously described data from the Department of Defense Trauma Registry. We included encounters with the documentation of an assessment or intervention at a BAS or forward operating base from January 1, 2007 to March 17, 2020. We utilized descriptive statistics to characterize these encounters. RESULTS: There were 28,950 encounters in our original dataset, of which 3.1% (884) had the documentation of a prehospital visit to a BAS. The BAS cohort was older (25 vs. 24, P < .001) The non-BAS cohort saw a larger portion of pediatric (<18 years) patients (10.7% vs. 5.7%, P < .001). A higher proportion of BAS patients had nonbattle injuries (40% vs. 20.7%, P < .001). The mean injury severity score was higher in the non-BAS cohort (9 vs. 5, P < .001). A higher proportion of the non-BAS cohort had more serious extremity injuries (25.1% vs. 18.4%, P < .001), although the non-BAS cohort had a trend toward serious injuries to the abdomen (P = .051) and thorax (P = .069). There was no difference in survival. CONCLUSIONS: The BAS was once a critical point in casualty evacuation and treatment. Within our dataset, the overall number of encounters that involved a stop at a BAS facility was low. For both the asymmetric battlefield and multidomain operations/large-scale combat operations, the current model would benefit from a more robust capability to include storage of blood, ventilators, and monitoring and hold patients for an undetermined amount of time.

Incidence of Airway Interventions in the Setting of Serious Facial Trauma.

BACKGROUND: Airway obstruction is the second leading cause of preventable death on the battlefield. Most airway obstruction occurs secondary to traumatic disruptions of the airway anatomical structures. Facial trauma is frequently cited as rationale for maintaining cricothyrotomy in the medics' skill set over the supraglottic airways more commonly used in the civilian setting. METHODS: We used a series of emergency department procedure codes to identify patients within the Department of Defense Trauma Registry (DoDTR) from January 2007 to August 2016. This is a sub-group analysis of casualties with documented serious facial trauma based on an abbreviated injury scale of 3 or greater for the facial body region. RESULTS: Our predefined search codes captured 28,222 DoDTR casualties, of which we identified 136 (0.5%) casualties with serious facial trauma, of which 19 of the 136 had documentation of an airway intervention (13.9%). No casualties with serious facial trauma underwent nasopharyngeal airway (NPA) placement, 0.04% underwent cricothyrotomy (n = 10), 0.03% underwent intubation (n = 9), and a single subject underwent supraglottic airway (SGA) placement (<0.01%). We only identified four casualties (0.01% of total dataset) with an isolated injury to the face. CONCLUSIONS: Serious injury to the face rarely occurred among trauma casualties within the DoDTR. In this subgroup analysis of casualties with serious facial trauma, the incidence of airway interventions to include cricothyrotomy was exceedingly low. However, within this small subset the mortality rate is high and thus better methods for airway management need to be developed.

Battle Injury Patterns Sustained Noncombatant Military Occupational Specialty Service Members.

BACKGROUND: The US military has been engaged in the Global War on Terrorism for nearly 2 decades. This asymmetric warfare has exposed many noncombat military occupational specialties (MOS) personnel to combat. We assessed what proportion of casualties were combat versus noncombat MOS personnel. METHODS: This is a secondary analysis of a previously described dataset from the Department of Defense Trauma Registry (DODTR). We included US military casualties sustaining battle injuries from January 2007 to March 2020 with a documented MOS. We classified each casualty as combat versus noncombat MOS personnel. RESULTS: There were 2,037 casualties who met inclusion for this analysis. Within these groups, there were 1,554 (76%) combat and 483 (24%) noncombat personnel. The median ages were 24 and 25, with more males among the combat MOS personnel (99% versus 93%). Army personnel comprised the largest proportion of both groups (78% versus 75%) with most injured by explosive (73% versus 78%). Median injury severity scores were similar (9 in both groups) as was survival (98% versus 98%). The annual proportion of battle injuries comprised of noncombat MOS personnel fluctuated year-to-year. The proportion of noncombat personnel with a medic in their chain of care was similar to combat personnel (25% versus 26%), as was the proportion undergoing medical evacuation by ground (11% versus 11%) or air (87% versus 86%). All prehospital interventions occurred in similar proportions except for ketamine administration (8% combat versus 3% noncombat MOS personnel). CONCLUSIONS: Our study showed noncombat MOS personnel comprised nearly one in four casualties. Injury patterns were similar between combat and noncombat MOS personnel with nearly identical consumption of resources except for ketamine. More data is necessary on noncombatant MOS personnel battle injury patterns to guide commanders and medical leaders for future mission planning in resource constrained environments.

Analysis of the Effects of a Texas State-Wide Mask Mandate (Executive Order GA-29) on Case Load, Hospitalizations, and Mortality.

OBJECTIVES: The coronavirus disease 2019 (COVID-19) pandemic has resulted in unprecedented hospitalizations, ventilator use, and deaths. Because of concerns for resource utilization and surges in hospital capacity use, Texas Executive Order GA-29 required statewide mask wear beginning July 3, 2020. Our objective was to compare COVID-19 case load, hospital bed use, and deaths before and after implementation of this mask order. METHODS: This was a retrospective observational study using publicly reported statewide data to perform a mixed-methods interrupted time series analysis. We compared outcomes before and after the statewide mask wear mandate per Executive Order GA-29. The preorder period was from June 19 to July 2, 2020. The postorder period was July 17 to September 17, 2020. Outcomes included daily COVID-19 case load, hospitalizations, and mortality. RESULTS: The daily case load before the mask order per 100,000 individuals was 187.5 (95% confidence interval [CI] 157.0-217.0) versus 200.7 (95% CI 179.8-221.6) after GA-29. The number of daily hospitalized patients with COVID-19 was 171.4 (95% CI 143.8-199.0) before GA-29 versus 225.1 (95% CI 202.9-247.3) after. Daily mortality was 2.4 (95% CI 1.9-2.9) before GA-29 versus 5.2 (95% CI 4.6-5.8). There was no material impact on our results after controlling for economic activity. CONCLUSIONS: In both adjusted and unadjusted analyses, we were unable to detect a reduction in case load, hospitalization rates, or mortality associated with the implementation of an executive order requiring a statewide mask order. These results suggest that during a period of rapid virus spread, additional public health measures may be necessary to mitigate transmission at the population level.

An Analysis of 13 Years of Prehospital Combat Casualty Care: Implications for Maintaining a Ready Medical Force.

Background: Most potentially preventable deaths occur in the prehospital setting before reaching a military treatment facility with surgical capabilities. Thus, optimizing the care we deliver in the prehospital combat setting represents a ripe target for reducing mortality. We sought to analyze prehospital data within the Department of Defense Trauma Registry (DODTR). Materials and methods: We requested all encounters with any prehospital activity (e.g., interventions, transportation, vital signs) documented within the DODTR from January 2007 to March 2020 along with all hospital-based data that was available. We excluded from our search casualties that had no prehospital activity documented. Results: There were 28,950 encounters that met inclusion criteria. Of these, 25,897 (89.5%) were adults and 3053 were children (10.5%). There was a steady decline in the number of casualties encountered with the most notable decline occurring in 2014. U.S. military casualties comprised the largest proportion (n = 10,182) of subjects followed by host nation civilians (n = 9637). The median age was 24 years (interquartile range/IQR 21-29). Most were battle injuries (78.6%) and part of Operation ENDURING FREEDOM (61.8%) and Operation IRAQI FREEDOM (24.4%). Most sustained injuries from explosives (52.1%) followed by firearms (28.1%), with serious injury to the extremities (24.9%) occurring most frequently. The median injury severity score was 9 (IQR 4-16) with most surviving to discharge (95.0%). A minority had a documented medic or combat lifesaver (27.9%) in their chain of care, nor did they pass through an aid station (3.0%). Air evacuation predominated (77.9%). Conclusions: Within our dataset, the deployed U.S. military medical system provided prehospital medical care to at least 28,950 combat casualties consisting mostly of U.S. military personnel and host nation civilian care. There was a rapid decline in combat casualty volumes since 2014, however, on a per-encounter basis there was no apparent drop in procedural volume.

An Analysis of Prolonged, Continuous Ketamine Infusions.

INTRODUCTION: Opioids carry high risk of dependence, and patients can rapidly build tolerance after repetitive dosing. Low-dose ketamine is an analgesic agent alternative that provides more hemodynamic stability. We sought to describe the effects of prolonged ketamine use in non-burn patients. MATERIALS AND METHODS: We queried the electronic health system at the Brooke Army Medical Center for patient encounters with ketamine infusions lasting >72 hours. We abstracted data describing demographics, vital signs, ketamine infusion dose and duration, and discharge diagnoses potentially relevant to ketamine side effects. RESULTS: We identified 194 subjects who met the study inclusion criteria. The median age was 39 years, most were male (67.0%), and most were primarily admitted for a non-trauma reason (59.2%). The mean ketamine drip strength was 43.9 mg/h (95% CI, 36.7-51.1; range 0.1-341.6) and the mean drip length was 130.8 hours (95% CI, 120.3-141.2; range 71-493). Most subjects underwent mechanical ventilation (56.1%) at some point during the infusion and most survived to hospital discharge (83.5%). On a per-day basis, the average heart rate was 93 beats per minute, systolic blood pressure was 128 mmHg, diastolic blood pressure was 71 mmHg, oxygen saturation was 96%, and respiratory rate was 22 respirations per minute. CONCLUSIONS: We demonstrate that continuous ketamine infusions provide a useful adjunct for analgesia and/or sedation. Further development of this adjunct modality may serve as an alternative agent to opioids.

An Analysis of Conflicts Across Role 1 Guidelines.

INTRODUCTION: Role 1 care is vital to patient survival and includes many echelons of care from point-of-injury first aid to medical attention at battalion aid stations. Many guidelines are written for Role 1 care providers to optimize care for different scenarios. Differences in the guidelines lead to confusion and discrepancies between the types of treatment medical care providers provide. Although the guidelines were written for different areas of care, uniformity between the guidelines is needed and will lead to a reduced mortality rate. MATERIALS AND METHODS: It was determined that the Tactical Combat Casualty Care Guidelines, Prolonged Field Care Guidelines, Joint Trauma System Clinical Practice Guidelines, and Standard Medical Operating Guidelines from medical evacuation were the military medical guidelines most relevant to Role 1 care. These Guidelines were compared side by side to determine the differences between them. RESULTS: Although the guidelines were largely similar, many major differences were found between them. Our online tables contain large inconsistences between guidelines including direct contradictions in conversion of junctional tourniquets and the administration of tranexamic acid. CONCLUSIONS: Role 1 care is vital to patient survival, including care from point of injury to battalion aid stations, but the guidelines available to instruct this care and the guidance on which personnel should provide this care are conflicting. This lack of clarity and consistency may adversely impact treatment outcomes. The reduction or elimination of conflicting information across the various guidelines, augmentation of guidance for pediatric care, more specific guidance for unique levels of care, and clearer delineation of the Role 1 phases of care (as well as which guidelines are most appropriate to each) should be considered as urgent priorities within the military medical community.

Battlefield Vital Sign Monitoring in Role 1 Military Treatment Facilities: A Thematic Analysis of After-Action Reviews from the Prehospital Trauma Registry.

INTRODUCTION: The Prehospital Trauma Registry (PHTR) captures after-action reviews (AARs) as part of a continuous performance improvement cycle and to provide commanders real-time feedback of Role 1 care. We have previously described overall challenges noted within the AARs. We now performed a focused assessment of challenges with regard to hemodynamic monitoring to improve casualty monitoring systems. MATERIALS AND METHODS: We performed a review of AARs within the PHTR in Afghanistan from January 2013 to September 2014 as previously described. In this analysis, we focus on AARs specific to challenges with hemodynamic monitoring of combat casualties. RESULTS: Of the 705 PHTR casualties, 592 had available AAR data; 86 of those described challenges with hemodynamic monitoring. Most were identified as male (97%) and having sustained battle injuries (93%), typically from an explosion (48%). Most were urgent evacuation status (85%) and had a medical officer in their chain of care (65%). The most common vital sign mentioned in AAR comments was blood pressure (62%), and nearly one-quarter of comments stated that arterial palpation was used in place of blood pressure cuff measurements. CONCLUSIONS: Our qualitative methods study highlights the challenges with obtaining vital signs-both training and equipment. We also highlight the challenges regarding ongoing monitoring to prevent hemodynamic collapse in severely injured casualties. The U.S. military needs to develop better methods for casualty monitoring for the subset of casualties that are critically injured.

A Prospective Assessment of a Novel, Disposable Video Laryngoscope With Physician Assistant Trainees Using a Synthetic Cadaver Model.

BACKGROUND: Airway obstruction is the second leading cause of preventable death on the battlefield. Video laryngoscopy has improved airway management in the emergency setting for several decades, and technology continues to improve. Current technology in the supply chain is cost-prohibitive to incorporate at Role 1 facilities, which is where many intubations occur by novice intubators. The i-view is a novel video laryngoscopy device that is handheld, inexpensive, and disposable. The aim of this study was to determine if the i-view is suitable based on performance assessments by physician assistant trainees and survey feedback. MATERIALS AND METHODS: We prospectively enrolled physician assistant students at the Interservice Physician Assistant Program at Joint Base San Antonio-Fort Sam Houston. We provided them structured training on how to use the device, and then, a board-certified emergency medicine physician or certified registered nurse anesthetist assessed their intubations performed on a SynDaver mannequin model. We surveyed the participants afterward. RESULTS: We enrolled 60 Interservice Physician Assistant Program students. Most participants were male (75%) with a median age of 32 years. Service affiliations included Army (50%), Navy (23%), Air Force (18%), and Coast Guard (8%). Most (70%) had previous deployment experience. All the participants successfully cannulated the mannequins and 98% achieved first-attempt success. Most participants (78%) reported a grade 1 view. On postprocedure survey, 91% strongly agreed with using this device in the deployed setting and 89% strongly agreed with finding it easy to use. CONCLUSIONS: All physician assistant trainees successfully and rapidly performed endotracheal intubation using the disposable i-view video laryngoscope. Study participants rated the device as easy to use and desirable for deployment. Further research is necessary to validate this novel device in the clinical setting before recommending dissemination to the deployed military medical force sets, kits, and outfits.

Analysis of the Effects of COVID-19 Mask Mandates on Hospital Resource Consumption and Mortality at the County Level.

OBJECTIVES: Coronavirus disease 2019 (COVID-19) threatens vulnerable patient populations, resulting in immense pressures at the local, regional, national, and international levels to contain the virus. Laboratory-based studies demonstrate that masks may offer benefit in reducing the spread of droplet-based illnesses, but few data are available to assess mask effects via executive order on a population basis. We assess the effects of a county-wide mask order on per-population mortality, intensive care unit (ICU) utilization, and ventilator utilization in Bexar County, Texas. METHODS: We used publicly reported county-level data to perform a mixed-methods before-and-after analysis along with other sources of public data for analyses of covariance. We used a least-squares regression analysis to adjust for confounders. A Texas state-level mask order was issued on July 3, 2020, followed by a Bexar County-level order on July 15, 2020. We defined the control period as June 2 to July 2 and the postmask order period as July 8, 2020-August 12, 2020, with a 5-day gap to account for the median incubation period for cases; longer periods of 7 and 10 days were used for hospitalization and ICU admission/death, respectively. Data are reported on a per-100,000 population basis using respective US Census Bureau-reported populations. RESULTS: From June 2, 2020 through August 12, 2020, there were 40,771 reported cases of COVID-19 within Bexar County, with 470 total deaths. The average number of new cases per day within the county was 565.4 (95% confidence interval [CI] 394.6-736.2). The average number of positive hospitalized patients was 754.1 (95% CI 657.2-851.0), in the ICU was 273.1 (95% CI 238.2-308.0), and on a ventilator was 170.5 (95% CI 146.4-194.6). The average deaths per day was 6.5 (95% CI 4.4-8.6). All of the measured outcomes were higher on average in the postmask period as were covariables included in the adjusted model. When adjusting for traffic activity, total statewide caseload, public health complaints, and mean temperature, the daily caseload, hospital bed occupancy, ICU bed occupancy, ventilator occupancy, and daily mortality remained higher in the postmask period. CONCLUSIONS: There was no reduction in per-population daily mortality, hospital bed, ICU bed, or ventilator occupancy of COVID-19-positive patients attributable to the implementation of a mask-wearing mandate.

Blood Product Administration During Transport Throughout the US Africa Command Theater of Operation.

BACKGROUND: United States Africa Command (US AFRICOM) is one of six US Defense Department's geographic combatant commands and is responsible to the Secretary of Defense for military relations with African nations, the African Union, and African regional security organizations. A full-spectrum combatant command, US AFRICOM is responsible for all US Department of Defense operations, exercises, and security cooperation on the African continent, its island nations, and surrounding waters. We seek to characterize blood product administration within AFRICOM using the in-transit visibility tracking tool known as TRAC2ES (TRANSCOM Regulating and Command & Control Evacuation System). METHODS: We performed a retrospective review of TRAC2ES medical evacuations from the AFRICOM theater of operations conducted between 1 January 2008 and 31 December 2018. RESULTS: During this time, there were 963 cases recorded in TRAC2ES originating within AFRICOM, of which 10 (1%) cases received blood products. All patients were males. One was a Department of State employee, one was a military working dog, and the remainder were military personnel. Of the ten humans, seven were the result of trauma, most by way of gunshot wound, and three were due to medical causes. Among human subjects receiving blood products for traumatic injuries, a total of 5 units of type O negative whole blood, 29 units of packed red blood cells (pRBCs), and 9 units of fresh frozen plasma (FFP) were transfused. No subjects underwent massive transfusion of blood products, and only one subject received pRBCs and FFP in 1:1 fashion. All subjects survived until evacuation. CONCLUSIONS: Within the TRAC2ES database, blood product administration within AFRICOM was infrequent, with some cases highlighting lack of access to adequate blood products. Furthermore, the limitations within this database highlight the need for systems designed to capture medical care performance improvement, as this database is not designed to support such analyses. A mandate for performance improvement within AFRICOM that is similar to that of the US Central Command would be beneficial if major improvements are to occur.

Combat Medic eFAST with Novel and Conventional Portable Ultrasound Devices: A Prospective, Randomized, Crossover Trial.

BACKGROUND: Extended Focused Assessment with Ultrasonography in Trauma (eFAST) reliably identifies noncompressible torso hemorrhage (NCTH), a major cause of battlefield death. Increased portability of ultrasound enables eFAST far forward on the battlefield, and published data demonstrate combat medics can learn and reliably perform ultrasound exams. One medical company developed an ultrasound device with an intuitive graphical user interface (GUI) and novel, finger-worn transducer with built-in linear and phased arrays, referred to as the novel device. We evaluated combat medic eFAST performance between the novel and conventional device. METHODS: This was a prospective, randomized, crossover trial completed at a single US military installation. Subjects were US Army combat medics with no previous ultrasound experience. Subjects performed an eFAST on a live human and a simulation model with both devices after a brief training intervention. Our primary outcome was time in seconds for eFAST completion, limited to 600 seconds. Secondary outcomes included diagnostic accuracy, technical adequacy using a validated task-specific checklist, and end-user appraisal of device ease-of-use with 5-point Likert items. This study was approved by the local institutional review board. RESULTS: Forty subjects volunteered, most were male (67.5%), less than 36 years old (95.0%), and grade E-4 or below (75.0%). Subjects performed a total of 160 eFAST scans (80 novel, 80 conventional). We found no significant difference in time for eFAST completion between the novel and conventional devices (391 seconds [95% CI 364, 417] versus 352 seconds [95% CI 325, 379]; p = 0.71). We also found no significant differences between the novel and conventional devices with respect to diagnostic accuracy (91.5% versus 89.2%; p = 0.28) and technical adequacy (75.0% versus 72.5%; p = 0.28). However, we did find that subjects favored the image quality of the novel device (4.3 versus 3.6; p is less than 0.01), while favoring the conventional transducer (3.8 versus 4.3; p = 0.04). CONCLUSION: Combat medic eFAST performance utilizing both devices did not differ with respect to time to completion, diagnostic accuracy, and technical adequacy. Medics with limited ultrasound experience performed diagnostically accurate eFAST after a brief training intervention. Future research should assess learning gaps and skill retention in order to guide development of US military ultrasound training programs for combat medics.

16 Years of Role 1 Trauma Care: A Descriptive Analysis of Casualties within the Prehospital Trauma Registry.

BACKGROUND: Most battlefield deaths occur in the prehospital setting prior to reaching surgical and hospital care. Described are casualties captured by the Joint Trauma System (JTS) in the Prehospital Trauma Registry (PHTR) module of the Department of Defense Trauma Registry (DoDTR), from inception through May 2019. METHODS: The JTS was queried for all PHTR encounters and associated data from inception (January 2003) through May 2019. The PHTR captures data on Role 1 prehospital care which encompasses treatment prior to arrival at a Role 2 with or without forward surgical team or Role 3 combat support hospital. Two unique patient identifiers were used to link DODTR outcome data to each PHTR encounter. Descriptive statistics were used to analyze the data. RESULTS: We obtained a total of 1,357 encounters from the PHTR. Of these encounters, we successfully linked 52.2% (709/1357) to the DODTR for outcome data. Encounters spanned from 2003 to 2019, with most (69.5%) occurring from 2012 to 2014. Many casualties were in the 18-25 (25.5%) or 26-33 (27.0%) age ranges, male (99.2%), injured by explosive (47.1%) or firearm (34.8%), enlisted (44.8%), and US military conventional (24.1%) and special operations (23.9%) forces. Of those linked to the DODTR, demographics were similar, most casualties sustained battle injuries (87.1%), the majority of which survived (99.1%). CONCLUSIONS: We described 1,357 encounters within the PHTR, most of which were US casualties and casualties injured by explosives. This renewed effort by the JTS to capture more casualties for inclusion into the registry has nearly doubled the proportion of available encounters for analysis. This analysis lays the foundation for in-depth analyses targeting areas for optimizing Role 1 prehospital combat casualty care.

A Descriptive Analysis of Battlefield First Responder and Combat Lifesaver Interventions during the Role 1 Phase of Care.

BACKGROUND: Battlefield first responders (BFR) are the first non-medical personnel to render critical lifesaving interventions for combat casualties, especially for massive hemorrhage where rapid control will improve survival. Soldiers receive medical instruction during initial entry training (IET) and unit-dependent medical training, and by attending the Combat Lifesaver (CLS) course. We seek to describe the interventions performed by BFRs on casualties with only BFRs listed in their chain of care within the Prehospital Trauma Registry (PHTR). METHODS: This is a secondary analysis of a dataset from the PHTR from 2003-2019. We excluded encounters with a documented medical officer, medic, or unknown prehospital provider at any time in their chain of care during the Role 1 phase to isolate only casualties with BFR medical care. RESULTS: Of the 1,357 encounters in our initial dataset, we identified 29 casualties that met inclusion criteria. Pressure dressing was the most common intervention (n=12), followed by limb tourniquets (n=4), IV fluids (n=3), hemostatic gauze (n=2), and wound packing (n=2). Bag-valve-masks, chest seals, extremity splints, and nasopharyngeal airways (NPA) were also used (n=1 each). Notably absent were backboards, blizzard blankets, cervical collars, eye shields, pelvic splints, hypothermia kits, chest tubes, supraglottic airways (SGA), intraosseous (I/O) lines, and needle decompression (NDC). CONCLUSIONS: Despite limited training, BFRs employ vital medical skills in the prehospital setting. Our data show that BFRs largely perform medical interventions within the scope of their medical knowledge and training. Better datasets with efficacy and complication data are needed.

New Versus Old, The i-View Video Laryngoscope Versus the GlideScope: A Prospective, Randomized, Crossover Trial.

BACKGROUND: A novel video laryngoscope device, the i-view, may extend intubation capability to the lowest echelons of deployed military medicine. The i-view is a one-time use, disposable laryngoscope. We compared time to completion of endotracheal intubation (ETI) between the i-view and GlideScope among military emergency medicine providers in a simulation setting. METHODS: We conducted a prospective, randomized, crossover trial. We randomized participants to i-view or GlideScope first before they performed 2 ETI-1 with each device. The primary outcome was time to completion of ETI. Secondary outcomes included first-pass success, optimal glottic view, and end-user appraisal. We used a Laerdal Airway Management Trainer for all intubations. RESULTS: Thirty-three emergency medicine providers participated. ETI time was less with GlideScope than i-view (22.2 +/- 9.0 seconds versus 30.2 +/- 24.0 seconds; p=0.048). Optimal glottic views, using the Cormack-Lehan scale, also favored the GlideScope (2 [1,2] versus 2[2,2]; p=0.044). There was no difference in first-pass success rates (100% versus 100%). More participants preferred the GlideScope (24 versus 9; p=0.165); however, participants agreed that the i-view would be easier to use than the GlideScope in an austere environment (4[4,5]). CONCLUSIONS: We found the GlideScope outperformed the i-view with respect to procedural completion time. Participants preferred the GlideScope over i-view, but indicated the i-view would be easier to use than the GlideScope in an austere setting. Our findings suggest the i-view may be a suitable alternative to GlideScope for US military providers, especially for those in the prehospital setting.

Warfighter Personal Protective Equipment and Combat Wounds.

BACKGROUND: Personal protective equipment (PPE) is crucial to force protection and preservation. Innovation in PPE has shifted injury patterns, with protected body regions accounting for decreased proportions of battlefield trauma relative to unprotected regions. Little is known regarding the PPE in use by warfighters at the time of injury. METHODS: We queried the Prehospital Trauma Registry (PHTR) for all encounters from 2003-2019. This is a sub-analysis of casualties with documented PPE at the time of medical encounter. When possible, encounters were linked to the Department of Defense Trauma Registry (DODTR) for outcome data. Serious injuries are defined as an abbreviated injury scale of 3 or greater. RESULTS: Of 1,357 total casualty encounters in the PHTR, 83 were US military with documented PPE. We link 62 of this cohort to DODTR. The median composite Injury Severity Score (ISS) was 6 (Interquartile range (IQR) 4-21), and 11 casualties (18%) had an ISS >25. The most seriously injured body regions were the extremities (21%), head/neck (16%), thorax (16%), and abdomen (10%). PPE worn at time of injury included helmet (91%), eye protection (73%), front (75%) and rear plates (77%), left/right plates (65%), tactical vest (46%), groin protection (12%), neck protection (6%), pelvic shield (3%), and deltoid protection (3%). CONCLUSION: Our data set demonstrates that the extremities were the most commonly injured body region, followed by head/neck, and thorax. PPE designed for the extremities and neck are also among the least commonly worn protective equipment.

Vital sign thresholds predictive of death in the combat setting.

INTRODUCTION: Identifying patients at imminent risk of death is a paramount priority in combat casualty care. This study measures the vital sign values predictive of mortality among combat casualties in Iraq and Afghanistan. METHODS: We used data from the Department of Defense Trauma Registry from January 2007 to August 2016. We used the highest documented heart rate and the lowest documented systolic pressure in the emergency department for each casualty. We constructed receiver operator curves (ROCs) to assess the accuracy of these variables for predicting survival to hospital discharge. RESULTS: There were 38,769 encounters of which our dataset included 15,540 (40.1%). The median age of these patients was 25 years and 97.5% were male. The most common mechanisms of injury were explosives (n = 9481, 61.0%) followed by gunshot wounds (n = 2393, 15.3%). The survival rate to hospital discharge was 97.5%. The median heart rate was 94 beats per minute (bpm) with area under the ROC of 0.631 with an optimal threshold to predict mortality of 110 bpm (sensitivity 52.2%, specificity 79.2%). The median systolic blood pressure was 128 mmHg with area under the ROC of 0.790 with an optimal threshold to predict mortality of 112 mmHg (sensitivity 68.5%, specificity 81.5%). CONCLUSIONS: Casualties with a systolic blood pressure <112 mmHg, are at high risk of mortality, a value significantly higher than the traditional 90 mmHg threshold. Our dataset highlights the need for better methods to guide resuscitation as vital sign measurements have limited accuracy in predicting mortality.

An Analysis of Airway Interventions in the Setting of Smoke Inhalation Injury on the Battlefield.

INTRODUCTION: The Committee on Tactical Combat Casualty Care and Capabilities Development and Integration Directorate cite airway burn injuries as an indication for prehospital cricothyrotomy. We sought to build on previously published data by describing for the first time the incidence of prehospital airway interventions in combat casualties who received airway management in the setting of inhalational injuries.15,26 We hypothesized that (1) airway interventions in combat casualties who suffered inhalational injury would have a higher mortality rate than those without airway intervention and (2) prehospital cricothyrotomy was used with greater incidence than endotracheal intubation. MATERIALS AND METHODS: Using a previously described Department of Defense Trauma Registry dataset from January 2007 to August 2016, unique casualties with documented inhalational injury were identified. RESULTS: Our predefined search codes captured 28,222 (72.8% of all encounters in the registry) of those subjects. A total of 347 (1.2%) casualties had a documented inhalational injury, 27 (7.8%) of those with at least 1 prehospital airway intervention inhalational injuries (0.09% of our dataset [n = 28,222]). Within the subset of patients with an inhalation injury, 23 underwent intubation, 2 underwent cricothyrotomy, 3 had placement of an airway adjunct not otherwise specifically listed, and 1 casualty had both a cricothyrotomy and intubation documented. No casualties had a supraglottic, nasopharyngeal, or oropharyngeal airway listed. Contrary to our hypotheses, of those with an airway intervention, 74.0% survived to hospital discharge. In multivariable regression models, when adjusting for confounders, there was no difference in survival to discharge in those with an airway intervention compared to those without. CONCLUSIONS: Casualties undergoing airway intervention for inhalation injuries had similar survival adjusting for injury severity, supporting its role when indicated. Without case-specific data on airway status and interventions, it is challenging to determine if the low rate of cricothyrotomy in this population was a result of rapid transport to a more advanced provider capable of performing intubation or cricothyrotomy may not be meeting the needs of the medics.