Shooting through windscreens: ballistic injury assessment using a surrogate head model-two case reports.

A synthetic head model developed to reproduce military injuries was assessed in two different scenarios involving shooting through intermediate targets (a laminated vehicle windscreen in scenario 1 and a military helicopter windscreen in scenario 2) with 7.62 × 39-mm mild steel core (MSC) ammunition. The injury patterns resulting from the two scenarios were assessed by a military radiologist and a forensic pathologist with combat injury experience and found to be clinically realistic.

The effect of helmet materials and simulated bone and tissue layers on bullet behaviour in a gelatine model of overmatch penetrating head injury.

The aim of this work was to simulate an overmatch ballistic event against a head wearing a helmet. The experiments were designed to understand how layers of bone (or synthetic bone), synthetic skin and currently used helmet materials influence the behaviour of full metal jacket mild steel core (FMJ MSC) 7.62 × 39 mm bullets, impacting on targets with a mean velocity of 650 m/s. Bullet behaviour within 10% (by mass) gelatine blocks was assessed by measurements made of the temporary cavity within the blocks using high-speed video and of the permanent cavity by dissecting blocks post firing. While ANOVA did not find significant difference at the 0.05 level in the mean values of most of the measurements, there was a significant difference in neck length within the gelatine blocks. The addition of material layers did produce greater variability in the temporary cavity measurements under some of the conditions. One of the synthetic bone polymers with a synthetic skin layer produced similar results within the gelatine blocks to the horse scapulae (with residual tissue) and may be suitable for future ballistic experiments.

Defining the essential anatomical coverage provided by military body armour against high energy projectiles.

INTRODUCTION: Body armour is a type of equipment worn by military personnel that aims to prevent or reduce the damage caused by ballistic projectiles to structures within the thorax and abdomen. Such injuries remain the leading cause of potentially survivable deaths on the modern battlefield. Recent developments in computer modelling in conjunction with a programme to procure the next generation of UK military body armour has provided the impetus to re-evaluate the optimal anatomical coverage provided by military body armour against high energy projectiles. METHODS: A systematic review of the literature was undertaken to identify those anatomical structures within the thorax and abdomen that if damaged were highly likely to result in death or significant long-term morbidity. These structures were superimposed upon two designs of ceramic plate used within representative body armour systems using a computerised representation of human anatomy. RESULTS AND CONCLUSIONS: Those structures requiring essential medical coverage by a plate were demonstrated to be the heart, great vessels, liver and spleen. For the 50th centile male anthropometric model used in this study, the front and rear plates from the Enhanced Combat Body Armour system only provide limited coverage, but do fulfil their original requirement. The plates from the current Mark 4a OSPREY system cover all of the structures identified in this study as requiring coverage except for the abdominal sections of the aorta and inferior vena cava. Further work on sizing of plates is recommended due to its potential to optimise essential medical coverage.

Repetitive, but Not Single, Mild Blast TBI Causes Persistent Neurological Impairments and Selective Cortical Neuronal Loss in Rats.

Exposure to repeated mild blast traumatic brain injury (mbTBI) is common in combat soldiers and the training of Special Forces. Evidence suggests that repeated exposure to a mild or subthreshold blast can cause serious and long-lasting impairments, but the mechanisms causing these symptoms are unclear. In this study, we characterise the effects of single and tightly coupled repeated mbTBI in Sprague-Dawley rats exposed to shockwaves generated using a shock tube. The primary outcomes are functional neurologic function (unconsciousness, neuroscore, weight loss, and RotaRod performance) and neuronal density in brain regions associated with sensorimotor function. Exposure to a single shockwave does not result in functional impairments or histologic injury, which is consistent with a mild or subthreshold injury. In contrast, exposure to three tightly coupled shockwaves results in unconsciousness, along with persistent neurologic impairments. Significant neuronal loss following repeated blast was observed in the motor cortex, somatosensory cortex, auditory cortex, and amygdala. Neuronal loss was not accompanied by changes in astrocyte reactivity. Our study identifies specific brain regions particularly sensitive to repeated mbTBI. The reasons for this sensitivity may include exposure to less attenuated shockwaves or proximity to tissue density transitions, and this merits further investigation. Our novel model will be useful in elucidating the mechanisms of sensitisation to injury, the temporal window of sensitivity and the evaluation of new treatments.

Impact of an acute pain service on pain outcomes with combat-injured soldiers at Camp Bastion, Afghanistan.

BACKGROUND: Few studies demonstrate the impact of early aggressive analgesia with acute pain service (APS) involvement at combat support hospitals (CSHs) using real-time data. Collaboration between the British and the United States (US) Army led to a 3-month deployment of a US Army APS to Camp Bastion, the main British military base in southern Afghanistan, from April to July 2009. METHODS: Pain outcomes data were collected at Camp Bastion from 71 soldiers sustaining major combat injuries followed by an APS. RESULTS: The sample was predominantly male (98.6%) and Caucasian (98.8%) with a mean age 25.4 years ± 5.4 (range 18-45). Regional nerve blocks were performed in 51 (71.8%) and epidurals placed in 11 (15.5%) of the cases. Repeated measures analysis of variance showed a statistically significant decreases in pain intensity (numeric rating scale from 0 for "none" to 10 for "as bad as you can imagine") over the three data collection points; first 3, 4-6, and 7-10 hours (F = 133.35; degrees of freedom [df; 1,68]; P < 0.001). Mean percent pain relief (0% "no relief" to 100% "complete relief") increased significantly over time (F = 193.12; df[1,69]; P < 0.001) with scores 31.29% ± 20.3 (initial 3 hours), 74.86% ± 27.5 (4-6 hours), and 83.14% ± 19.3 (7-24 hours). Overall, the perceived quality of pain control by soldiers was high. CONCLUSIONS: Findings from this quality of pain care study show that aggressive multimodal analgesia interventions by an APS in a CSH is associated with decreased pain intensity and increased pain relief.

A survey of military health professionals' perceptions of an acute pain service at Camp Bastion, Afghanistan.

OBJECTIVE: The primary goal of this investigation was to survey military health care professionals at a Camp Bastion, Afghanistan, regarding their perceptions of care delivered by an anesthesiologist-directed acute pain service (APS) at a British Combat Support Hospital (CSH)-Role 3. METHODS: The APS was directed by a U.S. Army anesthesiologist experienced in acute pain medicine who established an APS within a deployed British CSH. A brief 15-item survey was developed to assess impressions of outcomes, complexity of care, and satisfaction with the APS. Content validity was established through limited published surveys of APSs, expert review, and end user evaluation. RESULTS: The sample (N = 70, of which 61.4% were male) included 50% nurses, 15.8% surgeons, and 10% anesthesiologists who completed the survey at the end of the 3-month APS implementation period. Approximately 75% of the sample agreed or strongly agreed that injured soldiers managed by an APS obtained better pain relief than those who were not. With a 10-point scale, respondents rated how satisfied they were with the APS (mean 7.70 ± 1.7), how beneficial it was for patients (7.89 ± 2), and how important it would be to deploy an APS again to a level 3 facility (8.52 ± 1.7). Internal consistency reliability (Cronbach's alpha) for the 12-items measuring perceptions was acceptable, alpha = 0.82. CONCLUSIONS: Overall, the majority of military health care survey responders indicated support for an APS team as part of a CSH care, and confirmed its contributions to improving trauma care.

Primary Blast Lung Injury: The UK Military Experience.

INTRODUCTION: Primary blast lung injury occurs when an explosive shock wave passes through the thorax and transits through tissues of varying densities. It requires close proximity to an explosion and presents quick with respiratory distress in survivors. MATERIALS AND METHODS: The Joint Theatre Trauma Registry and the Defence Statistics (Health) Database were interrogated for casualties injured as a result of an explosion during the conflict in Afghanistan. The case notes and imaging of casualties meeting the criteria for diagnosis were reviewed. Demographic and clinical data on casualties with primary blast lung injury were analyzed. RESULTS: 848 blast-exposed casualties survived to discharge from intensive care, and 238 blast-exposed casualties were killed in action. Following exclusions, 111 case notes and all postmortem reports were reviewed in detail. About, 25 casualties had isolated primary blast lung injury (2.9% of casualties surviving to discharge from intensive care) and 31 nonsurvivors (13% of nonsurvivors) had the disease documented at postmortem. Severe cases of primary blast lung injury required an estimated average of 4.5 days of conventional mechanical ventilation. CONCLUSIONS: 8.1% of blast exposed casualties suffered primary blast lung injury. It was a less severe disease than other nontraumatic forms of acute lung injury and did not cause deaths once a casualty had reached a combat support hospital. It was well managed with a relatively brief period of conventional mechanical ventilation.

A Novel In Vitro Model of Blast Traumatic Brain Injury.

Traumatic brain injury is a leading cause of death and disability in military and civilian populations. Blast traumatic brain injury results from the detonation of explosive devices, however, the mechanisms that underlie the brain damage resulting from blast overpressure exposure are not entirely understood and are believed to be unique to this type of brain injury. Preclinical models are crucial tools that contribute to better understand blast-induced brain injury. A novel in vitro blast TBI model was developed using an open-ended shock tube to simulate real-life open-field blast waves modelled by the Friedlander waveform. C57BL/6N mouse organotypic hippocampal slice cultures were exposed to single shock waves and the development of injury was characterized up to 72 h using propidium iodide, a well-established fluorescent marker of cell damage that only penetrates cells with compromised cellular membranes. Propidium iodide fluorescence was significantly higher in the slices exposed to a blast wave when compared with sham slices throughout the duration of the protocol. The brain tissue injury is very reproducible and proportional to the peak overpressure of the shock wave applied.

Xenon Protects against Blast-Induced Traumatic Brain Injury in an In Vitro Model.

The aim of this study was to evaluate the neuroprotective efficacy of the inert gas xenon as a treatment for patients with blast-induced traumatic brain injury in an in vitro laboratory model. We developed a novel blast traumatic brain injury model using C57BL/6N mouse organotypic hippocampal brain-slice cultures exposed to a single shockwave, with the resulting injury quantified using propidium iodide fluorescence. A shock tube blast generator was used to simulate open field explosive blast shockwaves, modeled by the Friedlander waveform. Exposure to blast shockwave resulted in significant (p < 0.01) injury that increased with peak-overpressure and impulse of the shockwave, and which exhibited a secondary injury development up to 72 h after trauma. Blast-induced propidium iodide fluorescence overlapped with cleaved caspase-3 immunofluorescence, indicating that shock-wave-induced cell death involves apoptosis. Xenon (50% atm) applied 1 h after blast exposure reduced injury 24 h (p < 0.01), 48 h (p < 0.05), and 72 h (p < 0.001) later, compared with untreated control injury. Xenon-treated injured slices were not significantly different from uninjured sham slices at 24 h and 72 h. We demonstrate for the first time that xenon treatment after blast traumatic brain injury reduces initial injury and prevents subsequent injury development in vitro. Our findings support the idea that xenon may be a potential first-line treatment for those with blast-induced traumatic brain injury.

Targeted resuscitation improves coagulation and outcome.

BACKGROUND: Acute trauma coagulopathy in seriously injured casualties may be initiated by tissue hypoperfusion. A targeted (or novel hybrid [NH]) resuscitation strategy was developed to overcome poor tissue oxygen delivery associated with prolonged hypotension. METHODS: Under the Animals (Scientific Procedures) Act 1986, terminally anesthetized large white pigs were divided into four groups (n = 6). Groups 1 and 2 received blast injury and 3 and 4 no blast (sham). All were given a controlled hemorrhage (35% blood volume) and an uncompressed grade IV liver injury. Five minutes later, all were resuscitated with 0.9% saline to a systolic arterial pressure (SAP) of 80 mm Hg. After 60 minutes, the NH groups (1 and 3) were resuscitated to a SAP (110 mm Hg), whereas hypotensive groups (2 and 4) continued with SAP 80 mm Hg for up to 8 hours from onset of resuscitation. RESULTS: Mean survival time was shorter in group 2 (258 minutes) compared with groups 1, 3, and 4 (452 minutes, 448 minutes, and 369 minutes). By the end of the study, hypotension was associated with a significantly greater prothrombin time (1.73 ± 0.10 and 1.87 ± 0.15 times presurgery, groups 2 and 4) compared with NH (1.44 ± 0.09 and 1.36 ± 0.06, groups 1 and 3, p = 0.001). Blast versus sham had no significant effect on prothrombin time (p = 0.56). Peak levels of interleukin 6 were significantly lower in NH groups. Arterial base excess was significantly lower with hypotension (-18.4 mmol/L ± 2.7 mmol/L and -12.1 mmol/L ± 3.2 mmol/L) versus NH (-3.7 mmol/L ± 2.8 mmol/L and -1.8 mmol/L ± 1.8 mmol/L, p = 0.0001). Hematocrit was not significantly different between groups (p = 0.16). CONCLUSION: Targeted resuscitation (NH) attenuates the development of acute trauma coagulopathy and systemic inflammation with improved tissue perfusion and reduced metabolic acidosis in a model of complex injury. This emphasizes the challenge of choosing a resuscitation strategy for trauma patients where the needs of tissue perfusion must be balanced against the risk of rebleeding during resuscitation.

Outcomes following military traumatic cardiorespiratory arrest: A prospective observational study.

AIM: To determine the characteristics of military traumatic cardiorespiratory arrest (TCRA), and to identify factors associated with successful resuscitation. METHODS: Data was collected prospectively for adult casualties suffering TCRA presenting to a military field hospital in Helmand Province, Afghanistan between 29 November 2009 and 13 June 2010. RESULTS: Data was available for 52 patients meeting the inclusion criteria. The mean age (range) was 25 (18-36) years. The principal mechanism of injury was improvised explosive device (IED) explosion, the lower limbs were the most common sites of injury and exsanguination was the most common cause of arrest. Fourteen (27%) patients exhibited ROSC and four (8%) survived to discharge. All survivors achieved a good neurological recovery by Glasgow Outcome Scale. Three survivors had arrested due to exsanguination and one had arrested due to pericardial tamponade. All survivors had arrested after commencing transport to hospital and the longest duration of arrest associated with survival was 24 min. All survivors demonstrated PEA rhythms on ECG during arrest. When performed, 6/24 patients had ultrasound evidence of cardiac activity during arrest; all six with cardiac activity subsequently exhibited ROSC and two survived to hospital discharge. CONCLUSION: Overall rates of survival from military TCRA were similar to published civilian data, despite military TCRA victims presenting with high Injury Severity Scores and exsanguination due to blast and fragmentation injuries. Factors associated with successful resuscitation included arrest beginning after transport to hospital, the presence of electrical activity on ECG, and the presence of cardiac movement on ultrasound examination.