Limb trauma
Ian Greaves in Military Medicine in Iraq and Afghanistan, 2018
The term blast injury is given to the various effects that an explosion has on the human body.8 This subject is covered in detail in Chapter 10; therefore, only a brief summary is given here. Following detonation of an explosive in air, a shock front (a wave travelling in excess of the speed of sound in that medium) travels away from the centre of the charge. The initial shock wave following an explosion is a special form of high-pressure stress wave, with an effectively instantaneous wave front.9 The surrounding atmosphere is heated by the passage of this shock wave and then forced outwards and compressed by the expansion of gases formed within the explosion: the blast wave. Behind this blast wave are the products of the explosion; gas and fragments of debris. The blast wave travels supersonically before decaying into an acoustic wave as it loses velocity and magnitude. If the explosion is in the open and unconfined, then a simple waveform is produced. This simple wave has an almost instantaneous rise to peak overpressure, which then declines exponentially through ambient pressure to sub-atmospheric pressure, corresponding to the rarefied zone behind the blast front. Overpressure lasts for approximately 10 milliseconds, with the sub-atmospheric pressure zone lasting for considerably longer. Confinement of the explosion within a building or underwater produces a complex blast wave pattern containing multiple overpressure peaks, due to reflections of the blast wave. The biological effects of the blast wave depend on the peak overpressure and its duration.
Mechanism of injury
Ian Greaves, Keith Porter, Chris Wright in Trauma Care Pre-Hospital Manual, 2018
Blast injury is covered in detail in Chapter 21 and only an overview is given here. Tissue damage due to blast injury combines blunt trauma (from kinetic energy transfer) and penetrating injury from fragments. Conventional explosions involve a solid or liquid undergoing a chemical reaction, generating gaseous by-products and releasing a large amount of stored energy. It must be remembered that the majority of explosions are caused not by bombs, but by chemical reactions and release of flammable materials in an industrial or domestic context. The release of energy compresses the surrounding air, producing a spherical wave of compressed gas known as the blast wave (with increased temperature, pressure and density). The movement of the air and explosive products produce the blast wind. The blast overpressure is defined as the difference between the wave front pressure and atmospheric pressure. It is related to the amount of energy released in the blast and the distance from the blast (falling away exponentially with increasing distance). Following this overpressure is a small period of negative pressure. When the blast wave hits an object, kinetic energy is converted to work done causing deformation and injury. Tissue damage as a result of blast can be divided into primary, secondary, tertiary and other effects (13). This classification is summarised in Box 5.2.
Neurobehavioral consequences of mild traumatic brain injury in military service members and veterans
Mark J. Ashley, David A. Hovda in Traumatic Brain Injury, 2017
Signs and symptoms of TBI that typically emerge within 48 hours of injury (or sooner) can include headaches or neck pain; lightheadedness, dizziness, or loss of balance; nausea; insomnia; tinnitus or ringing in the ears; sensitivity to light or sound; difficulty remembering, concentrating, or making decisions; slowness in thinking, speaking, acting, or reading; getting lost or easily confused; feeling irritable; or experiencing changes in mood or personality. The interviewing clinician is encouraged to systematically assess for the presence of these symptoms in the days following the blast injury. Related to this, the interviewing clinician should also inquire about any medical attention that was sought and the outcome of that effort as well as any other behaviors that were required to cope with symptoms. For example, inquire about use of over-the-counter medication, the need for extra rest, the need for any compensatory strategies that were identified, and any feedback from superiors or other service members. The clinician is also advised to ask about the effect of the injury on the service member’s ability to perform his or her duties in the days or weeks after the event, recognizing that, even though rest or other postconcussion treatment measures may have been indicated medically, these may not have been realistically available options in the combat zone.
Utilization of Outpatient Social Work Services Among Veterans with Combat-Related Polytrauma: A Review and Case Analysis
Published in Military Behavioral Health, 2019
David L. Albright, Bruce A. Thyer, Raymond J. Waller
A blast injury is a trauma that results from an explosion. Sources include improvised explosive devices, land mines, roadside bombs, and rocket and mortar shells (DePalma, Burris, Champion, & Hodgson, 2005). Blast sequelae can result in complex, polytrauma injuries. The Veterans Administration (VA) defines polytrauma (PT) as “two or more injuries to physical regions or organ systems, one of which may be life threatening, resulting in physical, cognitive, psychological, or psychosocial impairments and functional disability” (US Department of Veterans Affairs, 2018, polytrauma). Polytrauma injuries can include bone fractures, burns, loss of limbs, posttraumatic stress disorder (PTSD), spinal cord injury, and traumatic brain injury (TBI; Friedemann-Sanchez, Sayer, & Pickett, 2008).
Quantitative analysis of the global proteome in lung from mice with blast injury
Published in Experimental Lung Research, 2020
Ying Liu, Yunen Liu, Changci Tong, Peifang Cong, Xiuyun Shi, Lin Shi, Mingxiao Hou, Hongxu Jin, Yongli Bao
Blast injury is mainly caused by the primary shock wave. The internal organs present at the gas-liquid interface can be severely damaged.13 Although proteomic analysis following low-intensity blast-induced mild traumatic brain injury has been reported, the critical players involved in blast-induced acute lung injury is not clear. The significance of this study is highlighted by an urgent need to identify mice responses to lung injury at the molecular level.14,15 Based on the proteomic profiles of mouse lung exposed to blast, we are exploring novel targets and candidate proteins linked to acute lung injury. Biological process enrichment shown that the disruption of key canonical pathways. Enrichment pathways found these changes included multiple proteins associated with thermogenesis, complement and coagulation cascades, amino sugar metabolism, nucleotide sugar metabolism, oxidative phosphorylation and so on. These dysfunctions are related to the relevant enzyme activities. Thus, it is important to obtain the proteomic profiles of lung from mice suffered blast, these will provide a basis for the diagnosis and treatment.
Numerical assessment of the human body response to a ground-level explosion
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2019
Piotr W. Sielicki, Tomasz Gajewski
Depending on the blast injury cause, the world literature classifies injuries as primary, secondary, tertiary and quaternary (Yeh and Schecter, 2012; Mathews and Koyfman, 2015). Primary injuries are caused directly by a blast wave propagated in a gas; therefore, organs containing air, such as the tympanic membranes (eardrums), lungs, and bowels are vulnerable to this type of injury (Tan et al., 2015; Gupta and Przekwas, 2015; Unified Facilities Criteria, 2008). It should be stated that body armour does not protect against this type of injury (Dionne et al., 2018). Secondary injuries are caused by flying objects in the surrounding environment, such as glass or metal pieces (bolts and nails) (Szymczyk et al., 2017). Stab and gunshot types of wounds are usually classified as secondary injuries. Tertiary injuries include the effects of human body translation due to collisions with hard objects, such as walls, furniture, cars, and so on (Eskridge et al., 2012). Structural collapse injuries also belong to this group. Quaternary injuries are classified as effects not categorised previously, such as burns, psychological trauma, or harmful radiation (Gupta and Przekwas, 2015). To conclude, primary injuries are the most detrimental to human health. Thus, this article focuses on the numerical analysis of the human body and corresponding harmful over-pressures and accelerations resulting from a blast wave on eardrums, lungs, and the pelvis.
Related Knowledge Centers
- Auditory System
- Cochlea
- Deflagration
- Gastrointestinal Tract
- Hair Cell
- Hearing Loss
- Tinnitus
- Eardrum
- Injury
- Total Body Disruption