Brain injury risk from primary blast

BACKGROUND: Military service members are often exposed to at least one explosive event, and many blast-exposed veterans present with symptoms of traumatic brain injury. However, there is little information on the intensity and duration of blast necessary to cause brain injury. METHODS: Varying intensity shock tube blasts were focused on the head of anesthetized ferrets, whose thorax and abdomen were protected. Injury evaluations included physiologic consequences, gross necropsy, and histologic diagnosis. The resulting apnea, meningeal bleeding, and fatality were analyzed using logistic regressions to determine injury risk functions. RESULTS: Increasing severity of blast exposure demonstrated increasing apnea immediately after the blast. Gross necropsy revealed hemorrhages, frequently near the brain stem, at the highest blast intensities. Apnea, bleeding, and fatality risk functions from blast exposure to the head were determined for peak overpressure and positive-phase duration. The 50% risk of apnea and moderate hemorrhage were similar, whereas the 50% risk of mild hemorrhage was independent of duration and required lower overpressures (144 kPa). Another fatality risk function was determined with existing data for scaled positive-phase durations from 1 millisecond to 20 milliseconds. CONCLUSION: The first primary blast brain injury risk assessments for mild and moderate/severe injuries in a gyrencephalic animal model were determined. The blast level needed to cause a mild/moderate brain injury may be similar to or less than that needed for pulmonary injury. The risk functions can be used in future research for blast brain injury by providing realistic injury risks to guide the design of protection or evaluate injury. (J Trauma Acute Care Surg. 2012;73: 895-901. Copyright ? 2012 by Lippincott Williams & Wilkins).     

原发肺冲击伤动物实验研究概况

肺脏是爆炸冲击伤最易受累的脏器之一,是冲击伤实验研究的重点.过去通过将多种动物暴露于冲击波致伤,在肺损伤后的病理生理学表现、安全性阈值和预测模型等方面,获得了大量的实验研究结果.近些年来,研究重点转向冲击伤的分子机制方面.本文从肺冲击伤的细胞因子活性变化、氧化应激反应及治疗等方面综述其主要研究概况.     

Disaster preparedness,pediatric considerations in primary blast injury,chemical, and biological terrorism

Both domestic and foreign terror incidents are an unfortunate outgrowth of our modern times from the Oklahoma City bombings, Sarin gas attacks in Japan, the Madrid train bombing, anthrax spores in the mail, to the World Trade Center on September 11^th, 2001. The modalities used to perpetrate these terrorist acts range from conventional weapons to high explosives, chemical weapons, and biological weapons all of which have been used in the recent past. While these weapons platforms can cause significant injury requiring critical care the mechanism of injury, pathophysiology and treatment of these injuries are unfamiliar to many critical care providers. Additionally the pediatric population is particularly vulnerable to these types of attacks. In the event of a mass casualty incident both adult and pediatric critical care practitioners will likely be called upon to care for children and adults alike. We will review the presentation, pathophysiology, and treatment of victims of blast injury, chemical weapons, and biological weapons. The focus will be on those injuries not commonly encountered in critical care practice, primary blast injuries, category A pathogens likely to be used in terrorist incidents, and chemical weapons including nerve agents, vesicants, pulmonary agents, cyanide, and riot control agents with special attention paid to pediatric specific considerations.     

肺爆震伤的超声显像实验研究

目的 探讨兔肺部爆震伤的超声显像特征。方法 建立轻、中、重度三组实验兔肺部爆震伤模型,爆震前后应用超声显像技术观察各组肺部及胸腔变化情况、测定各组肿瘤坏死因子(TNF-α),并与病理结果对照分析。结果 1.超声显示：轻度致伤组少部分肺区见少许彗星尾征(同一切面小于3处);中度致伤组大部分肺区见彗星尾征(同一切面彗星尾征占据整个切面1/2及以上) ;重度致伤组主要表现为大面积的“白瀑布”征,少数合并气胸及胸腔积液。2.各组爆震后即刻TNF-α均较爆震前增大(P<0.05),爆震后三组间TNF-α有明显差异(P<0.05)。3.病理显示肺出血、肺淤血及肺水肿改变在轻、中、重度三组实验兔中依次加重。结论 肺爆震伤具有显著的超声声像图特征,超声显像能较准确地评判肺爆震伤的范围和程度,为伤情判断奠定了较好的基础,可为临床早期诊断和后期救治提供重要的参考价值。     

肺泡中肺表面活性蛋白A反映冲击伤复合缺氧的肺损伤程度

目的 研究冲击伤及冲击伤复合缺氧时支气管肺泡灌洗液(BALF)中肺表面活性蛋白A(SP-A)含量变化与肺损伤的关系及意义.方法 Wistar大鼠131只(野战外科研究所实验动物中心提供),随机分为4组:冲击伤(BI)组47只,冲击伤复合缺氧Ⅰ组(BAⅠ)36只,冲击伤复合缺氧Ⅱ组(BAⅡ)40只,正常对照(Nc)组8只.用BST-Ⅰ型生物激波管致冲击伤,BAⅠ、BAⅡ组伤后立即置入低氧舱内,分别通入含12.5%和10%的O2的混合气体,并分别保持舱内氧的体积分数稳定在12.5%和10%.NC组大鼠不做任何处理.动物分别于伤后1、3、6 h活杀,行大体解剖、光镜和电镜病理观察、肺含水量测定,Western blot法测定BALF中SP-A含量.计量资料数据以均数±标准差(x±s)表示,采用组间比较q检验和相关分析;计数资料采用x2检验.结果 大鼠冲击伤后呼吸加快,BA Ⅰ组和BA Ⅱ组有烦躁不安、呼吸急促,BAⅡ组可见明显口鼻发绀;致伤各组肺含水率明显高于正常大鼠(P<0.05).肺大体解剖主要表现为肺出血、肺水肿,光镜下见肺泡壁增厚、肺泡腔出血、间质水肿;电镜下可见肺泡壁断裂,Ⅱ型上皮细胞板层体减少;这些改变均以 BAⅡ组最重、BA Ⅰ次之、BI再次,6 h的死亡率分别为37.5%、11.1%和2.1%(P<0.01).伤后BALF中SP-A浓度显著降低(P<0.01),并与肺含水率呈显著负相关(r=-0.796,P<0.01).结论 冲击伤复合缺氧显著加重肺部的损伤,缺氧越重、时间越长,则肺损伤越重、死亡率越高;BALF中SP-A含量的显著减少与肺水肿程度有关,BALF中SP-A含量可作为判断冲击伤及其复合伤肺损伤严重程度的观察指标.     

冲击伤的历史沿革与精准诊断

冲击伤是在冲击波作用下,机体所发生的各种损伤。战争冲突、意外伤害是冲击伤发生的主要原因。进入二十一世纪以来,中国社会进步和经济发展为世界瞩目。然而,在社会安全领域,特别是在全球区域性矛盾和局部冲突加剧的背景下,爆炸事故渐增且呈多样化趋势,并在伤情和转归方面表现出与战时冲击伤不尽相同的新特点。为此,深入了解人类对爆炸冲击伤认识的历史变迁,洞悉其精准诊治原则,对于突破冲击伤研究的理论和技术瓶颈,切实提升我国冲击伤的预防、诊断和治疗水平,具有重要的临床价值和深远的社会意义。     

救治突发爆震伤的组织管理与效果

目的探讨突发爆震伤救治过程中的护理组织与管理。方法由护理部统一指挥、统筹安排,建立快速有效的应急管理机制。结果24例患者抢救成功并治愈。结论科学有效的护理组织与管理,是争取抢救时间、提高突发爆震伤救治成功率的重要保证。     

小鼠肺爆震伤蛋白质组学研究

目的:通过检测不同时间点肺爆震伤小鼠肺蛋白质组学变化,探究肺爆震伤损伤机制。方法:60只健康雄性C57BL/6小鼠,随机（随机数字法）分为对照组、爆震后12 h组、24 h组、48 h组、72 h组及1周组（每组10只）。在北部战区总医院动物实验室进行实验,利用自主研发的精准爆震装置建立小鼠肺爆震伤模型;通过大体观察和...     

Explosions and human health: the long-term effects of blast injury

The immediate patterns of injury from explosions are well documented, from both military and civil experience. However, few studies have focused on less immediately apparent health consequences and latent effects of explosions in survivors, emergency responders and the surrounding community. This review aimed to analyze the risks to health following an explosion in a civil setting. A comprehensive review of the open literature was conducted, and data on 10 relevant military, civilian and industrial events were collected. Events were selected according to availability of published studies and involvement of large numbers of people injured. In addition, structured interviews with experts in the field were conducted, and existing national guidelines reviewed. The review revealed significant and potentially long-term health implications affecting various body systems and psychological well-being following exposure to an explosion. An awareness of the short- and long-term health effects of explosions is essential in screening for blast injuries, and identifying latent pathologies that could otherwise be overlooked in stressful situations with other visually distracting injuries and, often, mass casualties. Such knowledge would guide responsible medical staff in implementing early appropriate interventions to reduce the burden of long-term sequelae. Effective planning and response strategies would ensure accessibility of appropriate health care resources and evidence-based information in the aftermath of an explosion.     

点爆源爆炸伤模型建立及颌面部损伤特点

目的：建立实验室条件下的点爆源爆炸伤模型，并探讨颌面部致伤特点，方法：采用不同TNT当量的球形炸药作爆炸源，建立点爆源爆炸致伤模型，检测爆炸时不同距离下的各向冲击波压力。用1．0gTNT当量的炸药在不同距离下对新鲜羊头颌面部致伤，观察致伤效果。结果：冲击波压力峰值具有各向同性，其随爆距增大呈急剧减小，颌面部组织损伤亦随之显著减轻，爆炸伤远重于一般损伤，并且具有自身特点，尤其爆距1．0cm时，可见下颌骨放射状多线性骨折及下颌角附近内外侧骨板的“层裂”。结论：点爆源爆炸伤模型简单，安全，可靠，适用于实验室条件下的爆炸伤研究，冲击波的致伤方式，下颌骨的特殊解剖结构构成了颌骨特异性的骨折。     

Mechanisms and pathophysiology of the low-level blast brain injury in animal models

The symptoms of primary blast-induced mTBI, posttraumatic stress disorder and depression overlap. Evidence of an organic basis for these entities has been scarce and controversial. We present a review of animal studies demonstrating that low-level blast causes pathophysiological and functional changes in the brain. We monitor a time period from minutes to approximately 1 week after blast exposure from multiple modes (air, underwater, localized and whole body). The most salient findings observed were (1) the peak pressures (P_max) in the brain, elicited from the blast from the firing of military weapons (P_max 23–45 kPa), have a similar magnitude as that registered in air close to the head. Corresponding measurements during the detonation pulse from explosives under water show a P_max in the brain, which is only 10% of that in water outside the head. (2) The rise time of the pressure curve is 10 times longer in the brain as compared with the blast in air outside the head during firing of military weapons. (3) The lower frequencies in the blast wave appear to be transmitted more readily to the brain than the higher frequencies. (4) When animals are exposed to low levels of blast, the blast wave appears mostly transmitted directly to the brain during air exposure, not via the thorax or abdomen. (5) Low levels of blast cause brain edema, as indicated by increased bioelectrical impedance, an increase in the intracranial pressure, small brain hemorrhages and impaired cognitive function.     

Evidence of disrupted functional connectivity in the brain after combat-related blast injury

Non-impact blast-related mild traumatic brain injury (mTBI) appears to be present in soldiers returning from deployments to Afghanistan and Iraq. Although mTBI typically results in cognitive deficits that last less than a month, there is evidence that disrupted coordination of brain activity can persist for at least several months following injury (Thatcher et al., 1989, Thatcher et al., 2001). In the present study we examined whether neural communication may be affected in soldiers months after blast-related mTBI, and whether coordination of neural function is associated with underlying white matter integrity. The investigation included an application of a new time–frequency based method for measuring electroencephalogram (EEG) phase synchronization (Aviyente et al., 2010) as well as fractional anisotropy measures of axonal tracts derived from diffusion tensor imaging (DTI). Nine soldiers who incurred a blast-related mTBI during deployments to Afghanistan or Iraq were compared with eight demographically similar control subjects. Despite an absence of cognitive deficits, the blast-related mTBI group exhibited diminished EEG phase synchrony of lateral frontal sites with contralateral frontal brain regions suggesting diminished interhemispheric coordination of brain activity as a result of blast injury. For blast injured (i.e., blast-related mTBI) soldiers we found that EEG phase synchrony was associated with the structural integrity of white matter tracts of the frontal lobe (left anterior thalamic radiations and the forceps minor including the anterior corpus callosum). Analyses revealed that diminished EEG phase synchrony was not the consequence of combat-stress symptoms (e.g., post-traumatic stress and depression) and commonly prescribed medications. Results provide evidence for poor coordination of frontal neural function after blast injury that may be the consequence of damaged anterior white matter tracts.     

爆炸冲击波所致轻度颅脑损伤的诊断与处理

爆炸冲击波引起的创伤性颅脑损伤(bTBI)是战场上最常见的损伤,大多数患者是轻度的颅脑创伤(mTBI)。常规的临床影像技术如CT不能检测出mTBI的脑部变化,并且这类损伤的功能意义目前还有争议,最近几年出现的新技术能敏感地检测出脑组织的细微异常,因此在mTBI的诊断中起非常中的作用。笔者主要综述爆炸冲击波所致mTBI诊断的相关进展。