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Introduction: Despite the advancement of eye-tracking technology for smooth pursuit (SP) eye movement evaluation, qualitative observation offers much information that is not captured by computers; hence, both objective and qualitative information should be utilized to evaluate SP. This study examined the consistency among our clinicians when evaluating SP using normal (N), grossly normal (GN), mildly abnormal (MA), and abnormal (AB) as classifications. We then evaluated the effect of combining GN and MA into a single subclinical (SUBC) category. We also evaluated the computerized percent saccade (PS) metric by determining its sensitivity and specificity in classifying SP., Materials and Methods: Retrospective horizontal and vertical SP test videos and numerical data for 70 participants were obtained from the Neuro Kinetics Neuro-Otologic Test Center and de-identified. From this, eye-tracking videos, time plots of eye-tracking positional data, and tables of SP eye-tracking performance data were generated for 0.1, 0.3, and 0.5 Hz in both horizontal and vertical planes, totaling 6 tests per subject. Three clinicians rated each subject's SP performance as N, GN, MA, or AB for a total of 6 ratings (3 frequencies, horizontal and vertical). This process was repeated using N, SUBC, and AB as rating categories. Clinicians also provided an overall SP rating for each plane as follows: AB if the results were abnormal for 2 or more frequencies tested. Alternatively, if fewer than 2 frequencies presented with a rating of AB, then an overall rating of MA, GN, or N was determined at the respective clinician's discretion., Results: When the 3 clinicians were tasked with classifying SP videos using 4 clinical categories, fair overall agreement was demonstrated. However, when MA and GN categories were combined into an SUBC category, the overall agreement for the 3 clinicians improved slightly for both horizontal SP (HSP) and vertical SP (VSP). This pattern of agreement did not differ considerably when comparing HSP versus VSP, and good consistency and reliability was observed across clinicians. Again, inter-rater consistency was smaller for VSP versus HSP despite the reduction in clinical categories. Cut-off values were generated for the PS metric and demonstrated good specificity and sensitivity when they were exceeded for 2 or more frequencies in a particular plane when evaluating a subject's SP test., (Published by Oxford University Press on behalf of the Association of Military Surgeons of the United States 2024. This work is written by (a) US Government employee(s) and is in the public domain in the US.)

Introduction: Presently, traumatic brain injury (TBI) triage in field settings relies on symptom-based screening tools such as the updated Military Acute Concussion Evaluation. Objective eye-tracking may provide an alternative means of neurotrauma screening due to sensitivity to neurotrauma brain-health changes. Previously, the US Army Medical Research and Development Command Non-Invasive NeuroAssessment Devices (NINAD) Integrated Product Team identified 3 commercially available eye-tracking devices (SyncThink EYE-SYNC, Oculogica EyeBOX, NeuroKinetics IPAS) as meeting criteria toward being operationally effective in the detection of TBI in service members. We compared these devices to assess their relative performance in the classification of mild traumatic brain injury (mTBI) subjects versus normal healthy controls., Materials and Methods: Participants 18 to 45 years of age were assigned to Acute mTBI, Chronic mTBI, or Control group per study criteria. Each completed a TBI assessment protocol with all 3 devices counterbalanced across participants. Acute mTBI participants were tested within 72 hours following injury whereas time since last injury for the Chronic mTBI group ranged from months to years. Discriminant analysis was undertaken to determine device classification performance in separating TBI subjects from controls. Area Under the Curves (AUCs) were calculated and used to compare the accuracy of device performance. Device-related factors including data quality, the need to repeat tests, and technical issues experienced were aggregated for reporting., Results: A total of 63 participants were recruited as Acute mTBI subjects, 34 as Chronic mTBI subjects, and 119 participants without history of TBI as controls. To maximize outcomes, poorer quality data were excluded from analysis using specific criteria where possible. Final analysis utilized 49 (43 male/6 female, mean [x̅] age = 24.3 years, SD [s] = 5.1) Acute mTBI subjects, and 34 (33 male/1 female, x̅ age = 38.8 years, s = 3.9) Chronic mTBI subjects were age- and gender-matched as closely as possible with Control subjects. AUCs obtained with 80% of total dataset ranged from 0.690 to 0.950 for the Acute Group and from 0.753 to 0.811 for the Chronic mTBI group. Validation with the remaining 20% of dataset produced AUCs ranging from 0.600 to 0.750 for Acute mTBI group and 0.490 to 0.571 for the Chronic mTBI group., Conclusions: Potential eye-tracking detection of mTBI, per training model outcomes, ranged from acceptable to excellent for the Acute mTBI group; however, it was less consistent for the Chronic mTBI group. The self-imposed targeted performance (AUC of 0.850) appears achievable, but further device improvements and research are necessary. Discriminant analysis models differed for the Acute versus Chronic mTBI groups, suggesting performance differences in eye-tracking. Although eye-tracking demonstrated sensitivity in the Chronic group, a more rigorous and/or longitudinal study design is required to evaluate this observation. mTBI injuries were not controlled for this study, potentially reducing eye-tracking assessment sensitivity. Overall, these findings indicate that while eye-tracking remains a viable means of mTBI screening, device-specific variability in data quality, length of testing, and ease of use must be addressed to achieve NINAD objectives and DoD implementation., (Published by Oxford University Press on behalf of the Association of Military Surgeons of the United States 2024. This work is written by (a) US Government employee(s) and is in the public domain in the US.)

Introduction: Extensive trauma, commonly seen in wounded military Service Members, often leads to a severe sterile inflammation termed systemic inflammatory response syndrome (SIRS), which can progress to multiple organ dysfunction syndrome (MODS) and death. MODS is a serious threat to wounded Service Members, historically causing 10% of all deaths in trauma admissions at a forward deployed combat hospital. The importance of this problem will be exacerbated in large-scale combat operations, in which evacuation will be delayed and care of complex injuries at lower echelons of care may be prolonged. The main goal of this study was to optimize an existing mouse model of lethal SIRS/MODS as a therapeutic screening platform for the evaluation of immunomodulatory drugs., Materials and Methods: Male C57BL/6 mice were euthanized, and the bones and muscles were collected and blended into a paste termed tissue-bone matrix (TBX). The TBX at 12.5%-20% relative to body weight of each recipient mouse was implanted into subcutaneous pouches created on the dorsum of anesthetized animals. Mice were observed for clinical scores for up to 48 hours postimplantation and euthanized at the preset point of moribundity. To test effects of anesthetics on TBX-induced mortality, animals received isoflurane or ketamine/xylazine (K/X). In a separate set of studies, mice received TBX followed by intraperitoneal injection with 20 mg/kg or 40 mg/kg Eritoran or a placebo carrier. All Eritoran studies were performed in a blinded fashion., Results: We observed that K/X anesthesia significantly increased the lethality of the implanted TBX in comparison to inhaled anesthetics. Although all the mice anesthetized with isoflurane and implanted with 12.5% TBX survived for 24 hours, 60% of mice anesthetized with K/X were moribund by 24 hours postimplantation. To mimic more closely the timing of lethal SIRS/MODS following polytrauma in human patients, we extended observation to 48 hours. We performed TBX dose-response studies and found that as low as 15%, 17.5%, and 20% TBX caused moribundity/mortality in 50%, 80%, and 100% mice, respectively, over a 48-hour time period. With 17.5% TBX, we tested if moribundity/mortality could be rescued by anti-inflammatory drug Eritoran, a toll-like receptor 4 antagonist. Neither 20 mg/kg nor 40 mg/kg doses of Eritoran were found to be effective in this model., Conclusions: We optimized a TBX mouse model of SIRS/MODS for the purpose of evaluating novel therapeutic interventions to prevent trauma-related pathophysiologies in wounded Service Members. Negative effects of K/X on lethality of TBX should be further evaluated, particularly in the light of widespread use of ketamine in treatment of pain. By mimicking muscle crush, bone fracture, and necrosis, the TBX model has pleiotropic effects on physiology and immunology that make it uniquely valuable as a screening tool for the evaluation of novel therapeutics against trauma-induced SIRS/MODS., (Published by Oxford University Press on behalf of the Association of Military Surgeons of the United States 2024. This work is written by (a) US Government employee(s) and is in the public domain in the US.)

Introduction: Bloodstream infections are a significant threat to soldiers wounded in combat and contribute to preventable deaths. Novel and combination therapies that can be delivered on the battlefield or in lower roles of care are urgently needed to address the threat of bloodstream infection among military personnel. In this manuscript, we tested the antibacterial capability of silver ions (Ag+), with long-appreciated antibacterial properties, against ESKAPEE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter species, and Escherichia coli) pathogens., Materials and Methods: We used the GENESYS (RAIN LLC) device to deliver Ag+ to Gram-positive and Gram-negative ESKAPEE organisms grown in broth, human blood, and serum. Following the Ag+ treatment, we quantified the antibacterial effects by quantifying colony-forming units., Results: We found that Ag+ was bactericidal against 5 Gram-negative organisms, K pneumoniae, A baumannii, P aeruginosa, E cloacae, and E coli, and bacteriostatic against 2 Gram-positive organisms, E faecium and S aureus. The whole blood and serum inhibited the bactericidal activity of Ag+ against a common agent of bloodstream infection, P aeruginosa. Finally, when Ag+ was added in conjunction with antibiotic in the presence of whole blood, there was no significant effect of Ag+ over antibiotic alone., Conclusions: Our results confirmed that Ag+ has broad-spectrum antibacterial properties. However, the therapeutic value of Ag+ may not extend to the treatment of bloodstream infections because of the inhibition of Ag+ activity in blood and serum., (Published by Oxford University Press on behalf of the Association of Military Surgeons of the United States 2024. This work is written by (a) US Government employee(s) and is in the public domain in the US.)

Introduction: Considering the potential of weaponized opioids, evaluating how prophylactic countermeasures affect military-relevant performance is necessary. Naltrexone is a commercially available Food and Drug Administration-approved medication that blocks the effects of opioids with minimal side effects. However, the effects of naltrexone on the health and performance of non-substance abusing military personnel are not well described in the existing literature., Methods: Active duty U.S. Army Soldiers (n = 16, mean ± SD, age: 23.1 ± 5.3 y) completed a series of physical, cognitive, and marksmanship tasks during a 4-day pretrial, a 7-day active trial, and a 4-day post-trial phase. During the active trial, participants were administered 50 mg of oral naltrexone daily. Physiological and biological processes were monitored with a daily review of systems, sleep monitoring, biochemistry, and hematology blood panels., Results: Naltrexone did not negatively affect physical performance, cognitive functioning, marksmanship, or sleep duration (P > 0.05). Improvements were observed during the active trial compared to the pretrial phase in cognitive tasks measuring logical relations (P = 0.05), matching to sample (P = 0.04), math speed (P < 0.01), math percent correct (P = 0.04), and spatial processing (P < 0.01). Results from biochemistry and hematology blood panels remained within clinically normative ranges throughout all phases of the study. No participants were medically withdrawn; however, one participant voluntarily withdrew due to nausea and reduced appetite., Conclusions: Temporary (7-day) daily use of naltrexone was safe and did not negatively affect physical performance, cognitive functioning, marksmanship ability, or sleep in a healthy cohort of U.S. Army Soldiers., (Published by Oxford University Press on behalf of the Association of Military Surgeons of the United States 2023. This work is written by (a) US Government employee(s) and is in the public domain in the US.)

Introduction: Use of wearable impact sensor devices to quantitatively measure head impact exposure remains largely unstudied in military-style martial arts training and combat sports, particularly at the beginner levels. The baseline frequency and severity of head impact exposure during introductory military-style martial arts trainings, such as combatives training, is valuable information for developing future programs of instruction and exposure monitoring programs. The purpose of this study was to describe head impact exposures experienced during introductory combatives training (a boxing course) at U.S. Military Academy., Methods: This study used instrumented mouthguards to measure head impact exposure in U.S. Military Academy cadets during a compulsory boxing course. Summary exposures from a preliminary dataset are presented., Results: Twenty-two male subjects (19.9 ± 1.1 years, 86.6 ± 11.7 kg) participated in 205 analyzed player-bouts (full contact sparring sessions) with 809 video verified impacts (average 3.9 impacts per player-bout). The mean peak linear acceleration was 16.5 ±7.1 G, with a maximum of 70.8 G. There was a right-skewed distribution, with 640/809 (79.1%) events falling between 10 and 20 G. The mean peak angular acceleration was 1.52 ± 0.96 krad/s2, with a maximum of 8.85 krad/s2., Conclusions: Compared to other high-risk sports at Service Academies, head impacts from beginner boxing were of similar magnitude to those reported for Service Academy football and slightly lower than those reported for Service Academy rugby. Based on these preliminary data, the risk profile for introductory military-style martial arts training, such as boxing or combatives, may be similar to other contact sports like football and rugby, but further research is required to confirm these findings and understand the effects of the exposures in a shorter duration., (Published by Oxford University Press on behalf of the Association of Military Surgeons of the United States 2023. This work is written by (a) US Government employee(s) and is in the public domain in the US.)

Background: Service members experience unique circumstances when providing medical care in austere environments. Some challenges include supply shortages and the need to perform surgery in extreme temperatures. As such, methods for the sanitization of medical tools are sought and efficacy of existing materiel sourced to austere medical facilities should be examined for this purpose. This study tested the efficacy of commercially available, FDA-approved wound cleansers for alternative use as a potential sanitizer of stainless-steel medical devices and instruments found at improvised medical facilities., Methods: Escherichia coli and Staphylococcus aureus cultures were inoculated onto sterile stainless-steel carriers. After cleanser treatment, samples were held for 2 h, 24 h, or 7 days to represent different turn-around times between uses at ambient (25 °C), cold (-20 °C) and hot (50 °C) temperatures. Additional ex vivo challenges were performed using slurry harvested from porcine cecum. Colony-forming units and log reduction were calculated. Significance was determined using one-way ANOVA and multiple comparisons between treatment groups were calculated using Tukey's multiple comparison test., Results: All wound cleansers demonstrated statistically significant bactericidal activity against lab bacteria and ex vivo cecal slurry. E. coli and S. aureus resulted in approximately a 5-6 log reduction on average, resulting in no growth after treatment for all cleaners at 2  and 24 h. Similarly, 7-day post exposure results in a 6-log reduction after treatment for all groups at 25 °C and -25 °C. While treatment of ex vivo samples did not result in total kill, significant reductions in bacterial load were observed in all groups., Conclusions: Wound cleansers cleared for use in surgical settings demonstrated antimicrobial effects against bacteria deposited on metal surfaces. These cleansers decreased bacterial viability when challenged against extreme temperatures and few bacteria were harvested from treated surfaces even after 7 days. FDA-approved wound cleaners show promise as a potential sanitizer in resource limited environments., (Published by Oxford University Press on behalf of the Association of Military Surgeons of the United States 2023. This work is written by (a) US Government employee(s) and is in the public domain in the US.)

Introduction: The helmet is an ideal platform to mount technology that gives U.S. Soldiers an advantage over the enemy; the total system is recognized quantitatively as head-supported mass (HSM). The stress placed on the head and neck is magnified by adding mass and increasing the center of mass offset away from the atlanto-occipital complex, the head's pivot point on the spine. Previous research has focused on HSM-related spinal degeneration and performance decrement in mounted environments. The increased capabilities and protection provided by helmet systems for dismounted Soldiers have made it necessary to determine the boundaries of HSM and center of mass offset unique to dismounted operations., Materials and Methods: A human subject volunteer study was conducted to characterize the head and neck exposures and assess the impact of HSM on performance in a simulated field-dismounted operating environment. Data were analyzed from 21 subjects who completed the Load Effects Assessment Program-Army obstacle course at Fort Benning, GA, while wearing three different experimental HSM configurations. Four variable groups (physiologic/biomechanical, performance, kinematic, and subjective) were evaluated as performance assessments. Weight moments (WMs) corresponding to specific performance decrement levels were calculated using the quantitative relationships developed between each metric and the study HSM configurations. Data collected were used to develop the performance decrement HSM threshold criteria based on an average of 10% total performance decrement of dismounted Soldier performance responses., Results: A WM of 134 N-cm about the atlanto-occipital complex was determined as the preliminary threshold criteria for an average of 10% total performance decrement. A WM of 164 N-cm was calculated for a corresponding 25% average total performance decrement., Conclusions: The presented work is the first of its kind specifically for dismounted Soldiers. Research is underway to validate these limits and develop dismounted injury risk guidance., (Published by Oxford University Press on behalf of the Association of Military Surgeons of the United States 2023. This work is written by (a) US Government employee(s) and is in the public domain in the US.)

Introduction: In aircraft crashes, injuries to the head and upper torso are frequently reported, with head injury reported most frequently of all body regions. Because preventing flail of the head and body is of utmost importance for occupant survival, the Aircraft Crash Survival Design Guide (ACSDG), the guide to crashworthy aircraft design, published flail envelopes. However, the ACSDG flail envelopes are based on a single test with an anthropomorphic test device subjected to a frontal acceleration. In this article, human research volunteer (HRV) response data are used to calculate head flail corridors and evaluate the ACSDG flail envelopes., Materials and Methods: Data from HRV sled tests were obtained from the historical Naval Biodynamics Laboratory collection of the Biodynamics Data Resource. Digitized high-speed film for each test was tracked and processed to represent the head flail response in a format amenable to corridor development. Time-based and position-based head flail corridors were developed for groups of exposure-matched tests and then compared to the ACSDG flail envelopes., Results: A collection of 714 HRV sled tests conducted in six different impact directions ranging from 3 to 15 g was used to develop time-based and position-based head flail corridors for 39 match groups. The ACSDG vertical limit and anteroposterior limit and curve were not exceeded by the flail corridors, but the lateral limit and curve were exceeded by 4.6 cm to 15.8 cm., Conclusions: The flail corridors provide a useful baseline for representing the well-restrained occupant response at lower, non-injurious exposure levels and across multiple impact directions. Under these conditions, the ACSDG lateral limit and curve are not adequate. At higher exposure levels or with modified restraints, seating, or equipment, the ACSDG vertical limit and anteroposterior limit and curves may also be inadequate., (Published by Oxford University Press on behalf of the Association of Military Surgeons of the United States 2023. This work is written by (a) US Government employee(s) and is in the public domain in the US.)

Introduction: Combat injuries are complex and multimodal. Most injuries to the extremities occur because of explosive devices such as improvised explosive devices. Blast exposure dramatically increases the risk of infection in combat wounds, and there is limited available information on the best antibiotic treatments for these injuries. We previously demonstrated that mice exposed to blast displayed a delayed clearance of cefazolin from the plasma and liver; further semi-mechanistic modeling determined that cefazolin concentrations in the skin of these mice were reduced. Our objective was to investigate the effects of blast on the pharmacokinetics of antibiotics of different types used for the treatment of combat wounds in the rat model., Materials and Methods: Male Sprague Dawley rats were exposed to blast overpressure followed by injection of a bolus of animal equivalent doses of an antibiotic (cefazolin, cefepime, ertapenem, or clindamycin) into the tail vein at 1-hour post-blast exposure. Blood was collected at predetermined time points via repeated sampling from the tail vein. Animals were also euthanized at predetermined time points, at which time liver, kidney, skin, and blood via cardiac puncture were collected. Antibiotic concentrations were determined by ultra-performance liquid chromatography-tandem mass spectrometry., Results: Blast-exposed rats exhibited a similar rate of clearance compared to non-blasted rats in the blood, liver, kidney, and skin, which is inconsistent with the data regarding cefazolin in blast-exposed mice., Conclusions: Our results in rats do not recapitulate our previous observation of delayed cefazolin clearance in mice following the blast overpressure exposure. Although using rats permitted us to collect multiple blood samples from the same animals, rats may not be a suitable model for measuring the pharmacokinetics of antibiotics following blast. The interpretation of the results may be challenging because of variation in data among rat subjects in the same sample groups., (Published by Oxford University Press on behalf of the Association of Military Surgeons of the United States 2023. This work is written by (a) US Government employee(s) and is in the public domain in the US.)

Introduction: Emergency departments (EDs) have continued to struggle with overcrowding, causing delays in patient care and increasing stress on the medical staff and resources. This was further illustrated during the recent coronavirus disease 2019 pandemic, where we saw large unpredictable surges to the ED as hospitals tried to meet the medical needs of patients while trying to minimize the spread of coronavirus disease. A previous study from the Department of Emergency at the Brooke Army Medical Center (BAMC) found that nearly half of the patients presenting to the ED could have been managed in a primary care setting. We sought to pilot an alternate appointment scheduling system, Acute Care Clinic Easy Scheduling System, to allow patients to see and book available appointments while waiting in the ED waiting room., Materials and Methods: Our appointment display system was created through collaboration with the BAMC Information Management Division. A Tableau data interface connects to the Composite Health Care System to view available primary appointments across the San Antonio Military Health Care System. These are displayed in real-time on multiple TV screens outside the ED and in the ED waiting room. Patients were provided signage that provides a way to call or use a World Wide Web-based interface to immediately schedule the open appointments within the next 48 hours. Patients voluntarily opted to use this system and may opt to leave the ED if another appointment became available within an acceptable time frame to them., Results: This section is not applicable to this article., Conclusions: Expansion of the Acute Care Clinic Easy Scheduling System within the Military Health Care System may (1) help reduce ED crowding, (2) improve access to care through a live-tracking system that patients can review and select from, and (3) reduce the number of unfilled primary care appointments. The system in place in the BAMC ED serves as a template for other MTFs to use., (Published by Oxford University Press on behalf of the Association of Military Surgeons of the United States 2022. This work is written by (a) US Government employee(s) and is in the public domain in the US.)

The U.S. Army employs over 470,000 active duty soldiers throughout the world. Although the Army also employs hundreds of public health professionals, public health recommendations are often not framed in ways that are readily actionable to senior Army leaders. This case study shows how public health findings were translated into actionable recommendations using the Army Design Methodology (ADM) and subsequently implemented by installation leadership. Following a perceived increase in suicides at Fort Wainwright, Alaska, in 2019, installation leadership requested that the U.S. Army Public Health Center conduct an epidemiological consultation. A mixed-methods approach was used to gather qualitative and quantitative data. The ADM was used to translate the findings and provide actionable recommendations for senior Army leaders. Many recommendations were implemented within a year of the report's release and included modifications to gym facilities, dining halls, and sleeping areas. Key improvements included the installation of $900,000 worth of new gym equipment in existing physical fitness facilities, increasing the basic daily food allowance by 44% to facilitate the purchase of healthy options, and the installation of blackout blinds in all barracks to ensure more restful sleep during times of peak sunlight. The ADM is well understood by senior Army leaders. Use of the ADM in future military-specific public health studies could ensure a more effective uptake and implementation of public health recommendations., (Published by Oxford University Press on behalf of the Association of Military Surgeons of the United States 2021. This work is written by (a) US Government employee(s) and is in the public domain in the US.)

Background: Emergency departments (EDs) continue to struggle with overcrowding, increasing wait times, and a surge in patients with non-urgent conditions. Patients frequently choose the ED for non-emergent medical issues or injuries that could readily be handled in a primary care setting. We analyzed encounters in the ED at the Brooke Army Medical Center-the largest hospital in the Department of Defense-to determine the percentage of visits that could potentially be managed in a lower cost, appointment-based setting., Materials and Methods: We conducted a retrospective chart review of patients within our electronic medical record system from September 2019 to August 2020, which represented equidistance from the start of the COVID-19 pandemic, resulting in a shift in ED used based on previously published data. Our study also compared the number of ED visits pre-covid vs. post-covid. We defined visits to be primary care eligible if they were discharged home and received no computed tomography imaging, ultrasound, magnetic resonance imaging, intravenous medications, or intramuscular-controlled substances., Results: During the 12 month period, we queried data on 75,205 patient charts. We categorized 56.7% (n = 42,647) of visits as primary care eligible within our chart review. Most primary-care-eligible visits were ESI level 4 (59.2%). The largest proportion of primary-care-eligible patients (28.3%) was seen in our fast-track area followed by our pediatric pod (21.9%). The total number of ED visits decreased from 7,477 pre-covid to 5,057 post-covid visits. However, the proportion of patient visits that qualified as primary care eligible was generally consistent., Conclusions: Over half of all ED visits in our dataset could be primary care eligible. Our findings suggest that our patient population may benefit from other on-demand and appointment-based healthcare delivery to decompress the ED., (Published by Oxford University Press on behalf of the Association of Military Surgeons of the United States 2022. This work is written by (a) US Government employee(s) and is in the public domain in the US.)

Introduction: The U.S. Army conducts airborne operations in order to insert soldiers into combat. Military airborne operations are physically demanding activities with a unique loading environment compared with normal duties. A significant amount of research surrounding airborne operations has focused on assessing the incidence and type of associated injuries as well as the potential risk factors for injuries. During parachute opening shock and other high-acceleration events (e.g., fixed wing flight or vehicle crashes), the neck may be vulnerable to injury if inertial loads overcome the voluntary muscular control of the cervical spine and soft tissue structures. A recent epidemiological survey of sport skydivers showed that the neck, shoulders, and back were the most frequently reported sites of musculoskeletal pain. In addition, the survey indicated that wing loading (a measure of the jumper's weight divided by the size of the parachute canopy) was a potential contributing factor for developing musculoskeletal pain. Recently, there have been efforts to measure the severity of parachute opening shock as an additional potential risk factor for injury; however, no studies have measured both head and body accelerations and no studies have measured head or body angular rate during parachute opening shock. The purpose of this study was to measure and characterize the accelerations and angular rates of both the head and body during parachute opening shock as well as investigate potential factors contributing to higher severity opening shock, which may link to the development of musculoskeletal pain or injury., Materials and Methods: Data were collected from the U.S. Army Parachute Team, The Golden Knights, under an approved Medical Research and Material Command Institutional Review Board protocol. Subjects were instrumented with a helmet- and body-mounted sensor package, which included three angular rate sensors and three single-axis accelerometers each. Data were collected at 2,500 samples per second. Kruskal-Wallis tests were used to determine if helmet-mounted equipment (e.g., cameras), neck length, neck circumference, or wing loading (the ratio of jump weight to the size of the main parachute canopy) affected the accelerations or angular rates of the head or body., Results: A total of 54 jumps conducted by 19 experienced free-fall jumpers were analyzed. For the head, the mean (± SD) resultant accelerations and angular rates were 5.8 (± 1.6) g and 255.9 (± 74.2) degrees per second (deg/s), respectively. For the body, the resultant accelerations and angular rates were 4.3 (± 1.5) g and 181.3 (± 61.2) deg/s, respectively. A wing loading above 1.4 pounds per square foot (lb/ft2) was found to have a significant effect on head (P = .001) and body (P = .001) resultant acceleration as well as body angular rate about the Y-axis (P = .001)., Conclusions: There is evidence to suggest that wing loading has an influence on individual head and body resultant accelerations. However, no significant effects were found for the other variables (e.g., neck length and circumference, helmet-mounted equipment, etc.). Future research should focus on identifying additional factors that result in changes in accelerations and angular rates of the head and body during parachute opening shock events., (Published by Oxford University Press on behalf of the Association of Military Surgeons of the United States 2021. This work is written by (a) US Government employee(s) and is in the public domain in the US.)

Introduction: An anonymous online survey was presented to active duty U.S. Army, Reserve, and National Guard Soldiers with experience as en route care medical providers with the intent of identifying factors which contribute to musculoskeletal disorders in U.S. Army en route care medical providers. The survey looked at transport vehicle design, equipment, and awkward postures that could play a role in causing injuries., Materials and Methods: Survey responses were received from 60 en route care providers regarding postures assumed during administration of en route critical care tasks, routine medical transport scenarios, and patient loading. Care providers reported gender, height, weight, experience, tasks, and awkward postures experienced. They also reported occupational injuries that occurred as a result of performing job duties, such as back, neck, and joint pain, injuries, and discomfort., Results: The survey was answered by 56 (93.3%) males and 4 females (6.7%) with an average of 7.34 years of experience as en route care personnel. Lower back injuries were suffered by 87% of respondents. The most common causes were awkward positions and lifting patients. There are statistically significant relationships between shoulder injuries and overextending, lower back injuries and overextending, and lower back injuries and reaching backwards, ankle injuries and care provider height, and knee injuries and the frequency at which care providers utilized the postures of kneeling, squatting, reaching behind themselves, and straining to lift a heavy weight. Loading and unloading patients from evacuation platforms was among the top causes of all awkward postures among respondents., Conclusion: Results of this survey emphasize the need for injury mitigation and prevention strategies to reduce impacts on soldier health and readiness., (© Association of Military Surgeons of the United States 2020. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Introduction: Accelerative events commonly expose military pilots to potentially injurious + Gz (axial, caudal to cranial) accelerations. The Naval Biodynamics Laboratory exposed nonhuman primates (NHPs) to + Gz loading in two subject orientations (supine or upright) to assess the effect of orientation and accelerations associated with injury at accelerations unsafe for human participation., Materials and Methods: Archived care records, run records, and necropsy and pathology reports were used to identify acceleration-related injuries. Injuries were categorized as central nervous system (CNS), musculoskeletal (MSK) system, or thoracic (THR). The occurrence of injuries relative to corresponding peak sled acceleration (PSA) and subject orientation were compared. A t-test was applied within each injury category to test for a significant difference in mean PSA between orientations., Results: For all 63 + Gz runs conducted, PSA ranged between 6 and 86 G. Of these runs, 17 (6 supine, 11 upright) resulted in acceleration-related injury. The lowest PSAs associated with injury for supine and upright were 69.8 G and 39.6 G, respectively. Individual injury occurrences for supine runs (CNS [n = 5], MSK [n = 6], and THR [n = 6]) occurred at/above 75.7 G, 69.8 G, and 69.8 G, respectively. For upright runs, injury occurrences (CNS [n = 3], MSK injuries [n = 9], and THR injuries [n = 6]) occurred at/above 60.1 G, 39.6 G, and 50.5 G, respectively. The applied t-test showed significant difference between the mean orientation accelerations within each category. Injuries to supine NHPs included compression fracture, organ damage, brain hemorrhage, spinal cord hemorrhage, cervical hemorrhage, paresis/paraplegia, and THR bruising, whereas injuries to upright NHPs included compression fracture, organ damage, spinal cord hemorrhage, paresis/paraplegia, THR bruising, and difficulty breathing., Conclusions: Axial loading to supine occupants produced more CNS injuries, whereas upright produced more MSK injuries. Both orientations produced equal THR injuries. NHP injuries reported reflected those reported following human + Gz acceleration events, highlighting the importance of orientation during acceleration to mitigate injury for next generation equipment design and testing., (© The Association of Military Surgeons of the United States 2021. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Introduction: Noncombat injuries ("injuries") threaten soldier health and United States (U.S.) Army medical readiness, accounting for more than twice as many outpatient medical encounters among active component (AC) soldiers as behavioral health conditions (the second leading cause of outpatient visits). Noncombat musculoskeletal injuries (MSKIs) account for more than 80% of soldiers' injuries and 65% of medically nondeployable AC soldiers. This review focuses on MSKI risk reduction initiatives, management, and reporting challenges within the Army. The authors will summarize MSKI risk reduction efforts and challenges affecting MSKI management and reporting within the U.S. Army., Materials/methods: This review focuses on (1) initiatives to reduce the impact of MSKIs and risk for chronic injury/pain or long-term disability and (2) MSKI reporting challenges. This review excludes combat or battle injuries., Results: Primary risk reduction Adherence to standardized exercise programming has reduced injury risk among trainees. Preaccession physical fitness screening may identify individuals at risk for injury or attrition during initial entry training. Forward-based strength and conditioning coaching (provided in the unit footprint) and nutritional supplementation initiatives are promising, but results are currently inconclusive concerning injury risk reduction., Secondary Risk Reduction: Forward-based access to MSKI care provided by embedded athletic trainers and physical therapists within military units or primary care clinics holds promise for reducing MSKI-related limited duty days and nondeployability among AC soldiers. Early point-of-care screening for psychosocial risk factors affecting responsiveness to MSKI intervention may reduce risk for progression to chronic pain or long-term disability., Tertiary Risk Reduction: Operational MSKI metrics enable commanders and clinicians to readily identify soldiers with nonresolving MSKIs. Monthly injury reports to Army leadership increase command focus on soldiers with nonresolving MSKIs., Conclusions: Standardized exercise programming has reduced trainee MSKI rates. Secondary risk reduction initiatives show promise for reducing MSKI-related duty limitations and nondeployability among AC soldiers; timely identification/evaluation and appropriate, early management of MSKIs are essential. Tertiary risk reduction initiatives show promise for identifying soldiers whose chronic musculoskeletal conditions may render them unfit for continued military service.Clinicians must document MSKI care with sufficient specificity (including diagnosis and external cause coding) to enable large-scale systematic MSKI surveillance and analysis informing focused MSKI risk reduction efforts. Historical changes in surveillance methods and injury definitions make it difficult to compare injury rates and trends over time. However, the U.S. Army's standardized injury taxonomy will enable consistent classification of current and future injuries by mechanism of energy transfer and diagnosis. The Army's electronic physical profiling system further enablesstandardized documentation of MSKI-related duty/work restrictions and mechanisms of injury. These evolving surveillance tools ideally ensure continual advancement of military injury surveillance and serve as models for other military and civilian health care organizations., (Published by Oxford University Press on behalf of the Association of Military Surgeons of the United States 2020. This work is written by US Government employees and is in the public domain in the US.)

Introduction: Brooke Army Medical Center (BAMC), the largest military hospital and the only level 1 trauma center in the DoD, cares for active duty, retired uniformed services personnel, and beneficiaries. In addition, BAMC works in collaboration with the Southwest Texas Regional Advisory Council (STRAC) and University Hospital (UH), San Antonio's other level 1 trauma center, to provide trauma care to residents of the city and 22 counties in southwest Texas from San Antonio to Mexico (26,000 square mile area). Civilian-military partnerships are shown to benefit the training of military medical personnel; however, to date, there are no published reports specific to military personnel experiences within emergency care. The purpose of the current study was to describe and compare the emergency department trauma patient populations of two level 1 trauma centers in one metropolitan city (BAMC and UH) as well as determine if DoD level 1 trauma cases were representative of patients treated in OEF/OIF emergency department settings., Materials and Methods: We obtained a nonhuman subjects research determination for de-identified data from the US Air Force 59th Medical Wing and the University of Texas Health Science Center at San Antonio Institutional Review Boards. Data on emergency department patients treated between the years 2015 and 2017 were obtained from the two level 1 trauma centers (BAMC and UH, located in San Antonio, Texas); data included injury descriptors, ICU and hospital days, and department procedures., Results: Two-proportion Z-tests indicated that trauma patients were similar across trauma centers on injury type, injury severity, and discharge status; yet trauma patients differed significantly in terms of mechanism of injury and regions of injury. BAMC received significantly greater proportions of patients injured from falls, firearms and with facial and head injuries than UH, which received significantly greater proportion of patients with thorax and abdominal injuries. In addition, a significantly greater proportion of patients spent more than 2 days in the ICU and greater than two total hospital days at BAMC than in UH. In comparison to military emergency departments in combat zones, BAMC had significantly lower rates of blood product administration and endotracheal intubations., Conclusions: The trauma patients treated at a military level 1 trauma center were similar to those treated in the civilian level 1 trauma center in the same city, indicating the effectiveness of the only DoD Level 1 trauma center to provide experience comparable to that provided in civilian trauma centers. However, further research is needed to determine if the exposure rates to specific procedures are adequate to meet predeployment readiness requirements., (Published by Oxford University Press on behalf of Association of Military Surgeons of the United States 2020. This work is written by (a) US Government employee(s) and is in the public domain in the US.)

Introduction: Noncombat injuries ("injuries") greatly impact soldier health and United States (U.S.) Army readiness; they are the leading cause of outpatient medical encounters (more than two million annually) among active component (AC) soldiers. Noncombat musculoskeletal injuries ("MSKIs") may account for nearly 60% of soldiers' limited duty days and 65% of soldiers who cannot deploy for medical reasons. Injuries primarily affect readiness through increased limited duty days, decreased deployability rates, and increased medical separation rates. MSKIs are also responsible for exorbitant medical costs to the U.S. government, including service-connected disability compensation. A significant subset of soldiers develops chronic pain or long-term disability after injury; this may increase their risk for chronic disease or secondary health deficits potentially associated with MSKIs. The authors will review trends in U.S. Army MSKI rates, summarize MSKI readiness-related impacts, and highlight the importance of standardizing surveillance approaches, including injury definitions used in injury surveillance., Materials/methods: This review summarizes current reports and U.S. Department of Defense internal policy documents. MSKIs are defined as musculoskeletal disorders resulting from mechanical energy transfer, including traumatic and overuse injuries, which may cause pain and/or limit function. This review focuses on various U.S. Army populations, based on setting, sex, and age; the review excludes combat or battle injuries., Results: More than half of all AC soldiers sustained at least one injury (MSKI or non-MSKI) in 2017. Overuse injuries comprise at least 70% of all injuries among AC soldiers. Female soldiers are at greater risk for MSKI than men. Female soldiers' aerobic and muscular fitness performances are typically lower than men's performances, which could account for their higher injury rates. Older soldiers are at greater injury risk than younger soldiers. Soldiers in noncombat arms units tend to have higher incidences of reported MSKIs, more limited duty days, and higher rates of limited duty days for chronic MSKIs than soldiers in combat arms units. MSKIs account for 65% of medically nondeployable AC soldiers. At any time, 4% of AC soldiers cannot deploy because of MSKIs. Once deployed, nonbattle injuries accounted for approximately 30% of all medical evacuations, and were the largest category of soldier evacuations from both recent major combat theaters (Iraq and Afghanistan). More than 85% of service members medically evacuated for MSKIs failed to return to the theater. MSKIs factored into (1) nearly 70% of medical disability discharges across the Army from 2011 through 2016 and (2) more than 90% of disability discharges within enlisted soldiers' first year of service from 2010 to 2015. MSKI-related, service-connected (SC) disabilities account for 44% of all SC disabilities (more than any other body system) among compensated U.S. Global War on Terrorism veterans., Conclusions: MSKIs significantly impact soldier health and U.S. Army readiness. MSKIs also figure prominently in medical disability discharges and long-term, service-connected disability costs. MSKI patterns and trends vary between trainees and soldiers in operational units and among military occupations and types of operational units. Coordinated injury surveillance efforts are needed to provide standardized metrics and accurately measure temporal changes in injury rates., (Published by Oxford University Press on behalf of the Association of Military Surgeons of the United States 2020. This work is written by US Government employees and is in the public domain in the US.)

Introduction: High altitude missions pose significant challenges to Warfighter medical readiness and performance. Decreased circulating oxygen levels cause a decrease in exercise performance and can cause debilitating symptoms associated with acute mountain sickness, especially with rapid ascent. Acetazolamide (AZ) is known to minimize symptoms of acute mountain sickness, but it is unknown whether this medication alters hand strength and manual dexterity during altitude exposure., Materials and Methods: Ten male volunteers (22 ± 4 yr, 75.9 ± 13.7 kg, 174.9 ± 9.3 cm) participated in two separate 30 h simulated altitude exposures (496 mmHg, equivalent to 3,500 m, 20°C, 20% RH) in a hypobaric chamber. Participants were given either a placebo or 250 mg of AZ twice daily for 3.5 d (2 sea-level [SL] days + the 30 h altitude exposure) in a randomized, single-blind, crossover design. During SL and both altitude (ALT) exposures, hand function tests were performed, including hand grip and finger pinch strength tests, as well as the Purdue Pegboard (PP) and magazine loading tests to assess manual dexterity. Paired T tests and two-way repeated measure analysis of variance were used as appropriate to evaluate the effects of AZ and ALT. The value of p < 0.05 was accepted for statistical significance., Results: There were no influences of acute ALT exposure or AZ treatment on hand strength (eg, grip strength; SL: 39.2 ± 5.5 kg vs. ALT: 41.5 ± 6.9 kg, p > 0.05) or dexterity (eg, PPassembly; placebo: 35.5 ± 5.3 vs. AZ: 34.3 ± 4.6, p > 0.05) in our volunteers. Two dexterity tests (PPsum and magazine loading) showed improvements over time at ALT, regardless of treatment, where scores were improved after 10 h of exposure compared to at 1 h (eg, magazine loading: 56 ± 12 vs. 48 ± 10, p < 0.001). This pattern was not seen in the PPassembly test or any strength measurements., Conclusions: Our results suggest that 500 mg/d of AZ does not influence hand strength or manual dexterity during a 30 h exposure to 3,500 m simulated ALT. Acute ALT exposure (1 h) did not influence dexterity or strength, although some measures of dexterity showed improvements as exposure time increased. We conclude that use of AZ to optimize medical readiness at ALT is unlikely to impair the Warfighter's ability to complete mission tasks that depend on hand function., (Published by Oxford University Press on behalf of the Association of Military Surgeons of the United States 2020. This work is written by (a) US Government employee(s) and is in the public domain in the US.)

Introduction: Transcranial electrical stimulation (tES) as a method of cognitive enhancement in both diseased and healthy individuals has gained popularity. Its potential for enhancing cognition in healthy individuals has gained the interest of the military. However, before it being implemented into military training or operational settings, further work is needed to determine its efficacy and safety. Although a considerable amount of literature exists, few studies have specifically evaluated its use in enhancing cognition relative to operational, military tasks. Therefore, in a first step to evaluate its efficacy, we completed a systematic literature review of studies using transcranial direct current stimulation (tDCS), a type of tES, to enhance cognitive processes in healthy individuals., Methods: A systematic literature review was conducted to identify literature published between 2008 and 2018 that used a method of tES for cognitive enhancement. As part of a larger literature review effort, 282 articles were initially retrieved. These were then screened to identify articles meeting predetermined criteria, to include those using various methods of tES, resulting in 44 articles. Next, the articles were screened for those using tDCS or high-definition tDCS, resulting in 34 articles for review and information extraction., Results: Of the 34 articles reviewed, 28 reported some degree of enhancement (eg, improved accuracy on tasks and reduced reaction times). Areas of cognitive enhancements included executive functioning, creativity/cognitive flexibility, attention/perception, decision-making, memory, and working memory. However, the precise outcomes of enhancement varied given the range in tasks that were used to assess the constructs. Additionally, the stimulation parameters in terms of intensity applied, duration of stimulation, and brain region targeted for stimulation varied., Conclusions: The conclusions to be drawn from this systematic literature review include the identification of a brain region for targeting with stimulation to enhance a broad range of cognitive constructs applicable to military tasks, as well as stimulation parameters for duration and intensity. The dorsolateral prefrontal cortex was most frequently targeted in the studies that found enhanced performance across several cognitive constructs. Stimulation intensities of 2 mA and durations of 20 minutes or longer appeared frequently as well. Although several parameters were identified, further work is required before this type of technology can be recommended for operational use., (Published by Oxford University Press on behalf of the Association of Military Surgeons of the United States 2019. This work is written by (a) US Government employee(s) and is in the public domain in the US.)

Introduction: Excessive alcohol consumption continues to be a significant concern to overall military readiness; each year, it results in non-deployable active duty service members and service members separated from service. In 2009, The Community Preventive Services Task Force recommended limiting the hours of alcohol sales as an evidence-based and effective intervention to reduce alcohol-related harms. In June 2014, partnerships at an Army Installation in the Midwestern United States implemented a policy to reduce excessive alcohol consumption and associated alcohol-related harms. Although community-based interventions have been shown to successfully reduce alcohol-related negative consequences, little research has explored the effects of these interventions in military communities., Materials and Methods: The intervention reduced the retail sale of alcoholic beverages by eight hours daily (11:01 pm to 6:59 am) within the installation community. The U.S. Army Public Health Review Board approved this study as public health practice. The quantitative assessment from a mixed-methods evaluation implemented an interrupted time series design to assess changes in the community resulting from the intervention. Revenue and crime data were collected 11 months and 12 months prior to and after the onset of the intervention, respectively, to quantify the adherence to and effectiveness of the policy. The outcome variables measured in the evaluation were Serious Incident Reports (SIRs) and Driving Under the Influence/Driving While Intoxicated (DUI/DWI) citations. A Wilcoxon Signed-Rank Test of significance was used to measure changes in crime outcomes post-policy., Results: The results indicated that pre-policy rates of overall DUI/DWI citations, and DUI/DWI citations on-post were significantly higher than post-policy DUI/DWI citations (p < 0.05). The results also indicated that pre-policy rates of overall SIRS, alcohol-related SIRs, and SIRs occurring at night were not statistically higher than post-policy rates (p ≥ 0.05). The pre-policy DUI/DWI citations occurring off-post and DUI/DWI citations occurring at night did not reach statistical significance (p > 0.05). Policy adherence was good and total alcohol sales revenue remained stable before and after policy implementation., Conclusions: This was the first known evaluation within a military community to report improvements in crime statistics following an eight hour reduction in daily retail sale hours of alcohol. The reduction in alcohol-related harms presented in this evaluation are typical for small communities implementing alcohol-related policies; however, the effect sizes reported here are larger than those reported in the current literature, suggesting that the policy positively impacted the installation community in decreasing alcohol-related harms. Evaluation data did not show statistically significant reductions in DUI/DWI citations and SIRs occurring during night hours. Further, the evaluation design disallows the ability to draw a causal relationship between the intervention and measured outcomes. Additional installations should consider implementing similar policies to determine if observed effects are replicable. Future studies should include a longitudinal design that would allow for long-lasting changes to be observed within the population, measurement of additional proximal outcomes (e.g., reported alcohol consumption), and investigating social and health outcomes both inside and outside the confines of the installation community., (© Association of Military Surgeons of the United States 2019. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Introduction: Many epidemiologic studies have been performed in military recruit populations, but little is known about the health of those who conduct the training. This study aims to characterize the physical and mental health of a military trainer cohort., Materials and Methods: All US Air Force military training instructors (MTIs) who served between 1 October 2011 and 30 September 2016 were included in this retrospective descriptive study. All International Classification of Diseases, Ninth or Tenth Revision codes received by MTIs as inpatients or outpatients in the TRICARE system were obtained and mapped to Clinical Classifications Software levels. After excluding routine and administrative codes, the relative burden of disease by diagnostic category and subcategory was calculated, with further classification of musculoskeletal conditions by anatomic site. For all conditions accounting for at least 1.0% of the burden of care, incidence density rates and incidence rate ratios (IRRs) with 95% confidence intervals (CIs) were calculated to compare males and females., Results: A total of 1,269 MTIs received 32,601 non-administrative, non-routine diagnoses while accumulating 50,376 person-months of exposure during the surveillance period. Musculoskeletal conditions were the greatest contributor to overall disease burden, accounting for 39.1% of all diagnoses, followed by mental health (10.4%), respiratory (10.1%), and neurologic and sensory (9.8%). The burden attributed to mental health conditions decreased by 54% over the 5-year period. Twenty-three conditions accounted for at least 1.0% of the healthcare burden. The highest incidence conditions were connective tissue disease (27.18 per 1,000 person-months), non-traumatic joint disorders (25.74), upper respiratory infections (25.14), and back pain (23.70). As compared to males, females had a higher incidence of several conditions, including adjustment disorders (IRR: 2.57; 95% CI: 1.61, 4.11) and anxiety disorders (IRR: 2.24; 95% CI: 1.33, 3.77)., Conclusions: Musculoskeletal conditions are the leading contributor to burden of care among US Air Force MTIs, followed by mental health, respiratory, and neurologic and sensory conditions. The burden of healthcare among US Air Force MTIs more closely resembles active component service members than recruit trainees., (Published by Oxford University Press on behalf of the Association of Military Surgeons of the United States 2019.)

Concussion biomarkers are important guides for diagnosis and return-to-duty decisions. Recent literature describes the King-Devick (KD) test as a sensitive sports-related concussion screener. This test involves timing an individual reading aloud 120 digits printed on three test cards. The test is commonly considered to evaluate the effects of concussion and other factors on reading-related eye movements (EMs). However, the extent to which the KD test reflects EMs remains a matter of conjecture since the test reports only reading speed and number of errors. An off-the-shelf, computerized KD with eye tracking system recently became commercially available. Two early model KD with eye tracking systems were purchased in 2015 and evaluated before deploying them for research. The evaluation consisted of two studies; one with 20 volunteers assessing the comparability of the two systems and the other with 5 volunteers to quantify the systems' stability and repeatability over 5 successive days. The results showed that several of the systems' reported EM response parameters lacked face validity; consequently, the systems could not be used for scientific research. This conclusion emphasizes the importance of systematic test and evaluation of new equipment before it is used for research., (Published by Oxford University Press on behalf of the Association of Military Surgeons of the United States 2019.)

Introduction: Dismounted military operations often involve prolonged load carriage over complex terrain, which can result in excessive metabolic costs that can directly impair soldiers' performance. Although estimating these demands is a critical interest for mission planning purposes, it is unclear whether existing estimation equations developed from controlled laboratory- and field-based studies accurately account for energy costs of traveling over complex terrain. This study investigated the accuracy of the following equations for military populations when applied to data collected over complex terrain with two different levels of load carriage: American College of Sports Medicine (2002), Givoni and Goldman (1971), Jobe and White (2009), Minetti et al (2002), Pandolf et al (1977), and Santee et al (2003)., Materials and Methods: Nine active duty military personnel (age 21 ± 3 yr; height 1.72 ± 0.07 m; body mass 83.4 ± 12.9 kg; VO2 max 47.8 ± 3.9 mL/kg/min) were monitored during load carriage (with loads equal to 30% and 45% of body mass) over a 10-km mixed terrain course on two separate test days. The course was divided into four 2.5-km laps of 40 segments based on distance, grade, and/or surface factors. Timing gates and radio-frequency identification cards (SportIdent; Scarborough Orienteering, Huntington Beach, CA) were used to record completion times for each course segment. Breath-by-breath measures of energy expenditure were collected using portable oxygen exchange devices (COSMED Sri., Rome, Italy) and compared model estimates., Results: The Santee et al equation performed best, demonstrating the smallest estimation bias (-13 ± 87 W) and lowest root mean square error (99 W)., Conclusion: Current predictive equations underestimate the metabolic cost of load carriage by military personnel over complex terrain. Applying the Santee et al correction factor to the Pandolf et al equation may be the most suitable approach for estimating metabolic demands in these circumstances. However, this work also outlines the need for improvements to these methods, new method development and validation, or the use of a multi-model approach to account for mixed terrain., (Published by Oxford University Press on behalf of Association of Military Surgeons of the United States 2018.)

Purpose: To assess uncorrected and corrected distance and near binocular visual acuity (VA) and the use of corrective lenses in U.S. Army Active Duty, Guard, and Reserve Soldiers., Methods: A descriptive statistical analysis of VA group data from the U.S. Army Vision Readiness Classification Screening system was performed. Data pulls from June 2012 to January 2015 were compared., Results: In January 2015, 62.3% of Soldiers had an uncorrected binocular distance VA of 20/20, 21.2% of Soldiers were worse than 20/40, and 41.4% of Soldiers wore corrective eyewear for distance vision. With correction, 92.5% had a binocular distance VA of 20/20 and 1.4% were worse than 20/40. In January 2015, 32.6% of Soldiers age >45 had an uncorrected binocular near VA of 20/20, 28.4% of Soldiers age >45 were worse than 20/40, and 61.9% of Soldiers age >45 wore corrective eyewear for near vision. With correction, 74.6% had a binocular near VA of 20/20 and 3.0% were worse than 20/40. Data for both years were similar, although there were differences between individual service components., Conclusions: In comparison to the U.S. adult population, U.S. Army Soldiers have better uncorrected and corrected vision and are less likely to wear vision correction., (Reprint & Copyright © 2016 Association of Military Surgeons of the U.S.)