AUTHOR AND EDITOR INFORMATION

Section 1 of 11  

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• Medication
• Follow-up
• Miscellaneous
• Multimedia
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INTRODUCTION

Section 2 of 11  

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• Introduction
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• Differentials
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• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
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Background

Explosions have the capability to cause multisystem, life-threatening injuries in single or multiple victims simultaneously. These types of events present complex triage, diagnostic, and management challenges for the health care provider. Explosions can produce classic injury patterns from blunt and penetrating mechanisms to several organ systems, but they can also result in unique injury patterns to specific organs including the lungs and the central nervous system. Understanding these crucial differences is critical to managing these situations.

The extent and pattern of injuries produced by an explosion are a direct result of several factors including the amount and composition of the explosive material (eg, the presence of shrapnel or loose material that can be propelled, radiological or biological contamination), the surrounding environment (eg, the presence of intervening protective barriers), the distance between the victim and the blast, the delivery method if a bomb is involved, and any other environmental hazards. No two events are identical, and the spectrum and extent of injuries produced varies widely.

Between 1991 and 2000, 93 terrorist attacks worldwide produced more than 30 casualties, with 885 of these incidents involving explosions. The 2005 London subway bombings, the 1995 bombing of the Murrah Federal Building in Oklahoma City, and the catastrophic explosions of aircraft into 3 buildings on September 11, 2001 in New York City and Washington DC reminded health care workers of the magnitude of injuries and death that can result from a blast mechanism. Internationally, explosive devices directed against both civilian and military targets are frequently used in war or acts of terrorism. Although the United States has been spared the majority of these events, the potential exists for use of explosive weapons in the United States in the future.

As the risk of terrorist bombings in the United States increases, emergency physicians and Emergency Medical Services (EMS) personnel should be especially concerned about radiation and/or chemical contamination of explosion victims. Careful observation for signs and symptoms of exposure to poisonous chemicals, screening for radiation contamination, and decontamination of patients as needed are important steps in the management of victims of nonaccidental explosions. In addition to deliberately set explosions, incidents also occur as a result of industrial accidents (eg, factory and mining operations, fuel transportation and storage, grain elevator explosions).

In many parts of the world, undetonated military incendiary devices such as land mines and hand grenades contaminate the sites of abandoned battlefields. Such devices cause significant numbers of civilian casualties years and even decades after local hostilities cease. During wartime, injuries arising from explosions frequently outnumber those from gunshots with many innocent civilians becoming victims.

Much of the challenge facing the care providers is the potential for the sudden creation of large numbers of patients who require extensive medical resources. This scenario can overwhelm local EMS and hospital resources. Emergency physicians must remain attentive to the possibility and consequences of blast injuries.

Once notified of a possible bombing or explosion, hospital-based physicians should consider immediately activating hospital disaster and contingency plans, including preparations to care for anywhere from a handful to hundreds of victims.

Pathophysiology

Blast injuries traditionally are divided into 4 categories: primary, secondary, tertiary, and quaternary (or miscellaneous) injuries. A patient may be injured by more than one of these mechanisms.

• A primary blast injury is caused solely by the direct effect of blast overpressure on tissue. Air is easily compressible, unlike water. As a result, a primary blast injury almost always affects air-filled structures such as the lung, ear, and gastrointestinal (GI) tract.
• A secondary blast injury is caused by flying objects that strike people.
• A tertiary blast injury is a feature of high-energy explosions. This type of injury occurs when people fly through the air and strike other objects.
• Miscellaneous blast-related injuries encompass all other injuries caused by explosions, such as burns, crush injuries, and toxic inhalations. For example, the crash of two jet airplanes into the World Trade Center only created a relatively low-order pressure wave, but the resulting fire and building collapse killed thousands.

Frequency

United States

Incidence is sporadic and infrequent. Cases tend to be grouped several (up to hundreds) at a time and have the ability to temporarily overwhelm a local health care system.

International

Incidence is sporadic. Frequency depends on the political (terrorism, military) and economic (occupational health and safety priorities) stability of the region.

Mortality/Morbidity

• Mortality rates vary widely between incidents. An analysis of 29 large terrorist bombing events between 1966 and 2002 showed 8,364 casualties, including 903 immediate deaths and 7,461 immediately surviving injured.¹ Immediate death/injury rates were higher for bombings involving structural collapse (25%) than for confined space (8%) and open air detonations (4%).
• Unique patterns of injury are found in all bombing types. Injury is caused both by direct blast overpressure (primary blast injury) and by a variety of associated factors. Enclosed-space explosions, including those occurring in busses, and in-water explosions produce more primary blast injury. Explosions leading to structure collapse produce more orthopedic injuries. Land mine injuries are associated with a high risk of below- and above-the-knee amputations. Fireworks-related injuries prompt an estimated 10,000-12,000 ED visits in the United States annually, with 20-25% involving either the eye or hand.
• Presence of tympanic membrane (TM) rupture indicates that a high-pressure wave (at least 40 kilopascal [kPa], 6 psi) was present and may correlate with more dangerous organ injury. Theoretically, at an overpressure of 100 kPa (15 psi), the threshold for lung injury, TM routinely ruptures; however, a recent Israeli case series of 640 civilian victims of terrorist bombings contradicts traditional beliefs about a clear correlation between the presence of TM injury and coincidence organ damage. Of 137 patients initially diagnosed as having isolated eardrum perforation who were well enough to be discharged, none later developed manifestations of pulmonary or intestinal blast injury. Furthermore, 18 patients with pulmonary blast injuries had no eardrum perforation.

CLINICAL

Section 3 of 11  

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History

• If possible, determine what material caused the explosion.
• • High-order explosives (HEs) undergo detonation, an almost instantaneous transformation of the original explosive material into gases occupying the same volume of space under extremely high pressure. These high-pressure gases rapidly expand, compress the surrounding medium, and produce a defining supersonic, overpressurization blast wave. Examples of HEs include materials such as TNT, ammonium nitrate fuel oil, dynamite, and C-4 "plastic" explosives. In general, only HE explosions produce severe primary blast injury.
  • Low-order explosives (LEs) are composed of propellants, such as black powder, and pyrotechnics, such as fireworks. LEs undergo deflagration rather than detonation and release energy relatively slowly compared with HEs. This results in a subsonic explosion lacking the overpressurization blast wave that characterizes HEs. Although LE explosions can be deadly, LE explosions very uncommonly cause the pulmonary and central nervous system injuries unique to primary blast injury.
• If possible, determine the patient's location relative to the center of the explosion.
• • An explosion that occurs in an enclosed space (including a building, a mine, or a relatively lightly constructed enclosed space such as a bus) or in water tends to cause more serious injury.
  • Intensity of an explosion pressure wave declines with the cubed root of the distance from the explosion. A person 3 m (10 ft) from an explosion experiences 9 times more overpressure than a person 6 m (20 ft) away. Proximity of the person to the explosion is an important factor in a primary blast injury.
  • Blast waves are reflected by solid surfaces; thus, a person standing next to a wall may suffer increased primary blast injury.
• Because explosions often cause multiple casualties, anticipate activating the hospital or regional disaster plan.
• Another ominous consideration is the tactic of setting dual explosions. The initial explosion is intended to injure civilians and to attract law enforcement and rescue personnel, followed by a delayed explosion designed to injure rescuers. Hospital disaster plans should include tight security at all hospital entrances in the event of a terrorist explosion in the community. All hospital personnel should be alert for unattended packages.
• • In addition to protecting hospital patients and staff, sealing entrances helps control the chaotic flow of patients and visitors.
  • Industrial accidents and terrorist explosions may be associated with the release of toxic and/or radioactive materials. The Federal Bureau of Investigation (FBI) is particularly concerned about the possibility that a terrorist could attach a radioactive substance (eg, a radiopharmaceutical or part of an old radiography machine) to a conventional explosive device, causing radiation contamination of the scene and casualties. In the 1993 attack on the World Trade Center, terrorists attached cyanide to a bomb placed in the underground parking garage. Fortunately, in that incident the cyanide was destroyed by the combustion. Physicians and EMS personnel must diligently search for evidence of radiation and/or chemical contamination in persons with blast injuries.
  • Question plant managers, fire department officials, EMS personnel, and law enforcement personnel about these possibilities.
  • EMS agencies should check for radiation contamination at the scene of a deliberately caused explosion. In addition, hospital personnel should screen persons who have been exposed to deliberate explosions for radioactivity with a Geiger counter or similar radiation dosimeter. Each hospital has a radiation safety officer (usually a radiology technician) who can assist with this task.

Physical

• Examine lungs for evidence of pulmonary contusion and pneumothorax.
• • Assume that a patient's wheezing associated with a blast injury is from pulmonary contusion.
  • Other causes of wheezing in this setting may include inhalation of irritant gases or dusts, pulmonary edema from myocardial contusion, and adult respiratory distress syndrome (ARDS).
• Many experts recommend obtaining a chest radiograph in the presence of isolated tympanic membrane (TM) rupture since this may indicate exposure to significant overpressure. In a large series of victims of terrorist bombings, mostly involving closed spaces, 22% of patients with eardrum perforation had other significant injuries.
• • However, a patient with isolated TM perforation, but no other immediately identified injuries, does not automatically require an extended period of observation. In the above study, none of the 137 patients initially identified as having isolated TM rupture and well enough to be discharged developed later manifestation of pulmonary or intestinal blast injury.
  • Intact TMs do not imply the absence of serious injury, especially if the patient was wearing some type of hearing protection as is common in certain types of military or law enforcement operations.
• Abdominal injuries from explosions may be occult, and serial examinations are often required.
• • A recent large Israeli case series found that abdominal injuries occurred only as a result of massive trauma. This finding may be the result of selection bias, as all the explosions in their series occurred in open air. Air is a poor conductor of blast-wave energy, thus those who were subjected to enough energy to damage abdominal organs probably were situated near the explosive devices.
  • Other authors have reported occult injuries to both solid and hollow abdominal organs in people injured by closed-space explosions and blast injuries occurring in water.

Causes

• Primary blast injury
• • Primary blast injury (PBI) is organ and tissue damage caused solely by the blast wave associated with HEs.
    • The leading edge of a blast wave is called the blast front. When a blast front reaches a victim, it causes an enormous, almost instantaneous rise in ambient pressure. For example, C4 explosions can create initial pressures of over 4 million pounds per square inch (30GPa).
    • Because explosive gases continue to expand from their point of origin, a longer negative underpressure (relative vacuum) follows the peak positive overpressure. Both the positive overpressure and the negative underpressure are capable of causing significant PBI.
  • Since air is easily compressible by pressure while water is not, gas-containing organs, especially the lungs, bowel, and middle ear, are most susceptible to PBI.
  • Pulmonary barotrauma is the most common fatal primary blast injury. This includes pulmonary contusion, systemic air embolism, and free radical–associated injuries such as thrombosis, lipoxygenation, and disseminated intravascular coagulation (DIC). ARDS may be a result of direct lung injury or of shock from other body injuries.
  • Thoracic PBI produces a unique cardiovascular response, observed nowhere else in medicine, that which is sufficient to cause death in the absence of any demonstrable physical injury. The immediate cardiovascular response to pulmonary blast injury is a decrease in heart rate, stroke volume, and cardiac index. The normal reflex increase in systemic vascular resistance does not occur, so blood pressure falls. This effect occurs within seconds. If this response is not fatal, recovery usually occurs within 15 minutes to 3 hours. However, even nonlethal PBI can impair pulmonary performance for hours to days.
  • Acute gas embolism (AGE), a form of pulmonary barotrauma, requires special attention. Air emboli most commonly occlude blood vessels in the brain or spinal cord. Resulting neurologic symptoms must be differentiated from the direct effect of trauma.
  • Intestinal barotrauma is more common with underwater than air blast injuries. Although the colon usually is affected most, any portion of the GI tract may be injured.
  • The ear is the organ most susceptible to primary blast injury. Acoustic barotrauma commonly consists of TM rupture. Hemotympanum without perforation also has been reported. Ossicle fracture or dislocation may occur with very high-energy explosions.
• Secondary blast injury
• • Secondary blast injuries (SBIs) are caused by flying objects striking individuals.
  • This mechanism is responsible for the majority of casualties in many explosions. Penetrating thoracic trauma, including lacerations of the heart and great vessels, is a common cause of death in the setting of SBIs. For example, the glass facade of the Alfred P. Murrah Federal Building in Oklahoma City shattered into thousands of heavy glass chunks that were propelled through occupied areas of the building with devastating results. During the 1998 terrorist bombing of the US Embassy in Nairobi, flying glass wounded people up to 2 km away.
  • Military explosive casings (eg, hand grenades) are specifically designed to fragment and to maximize damage from flying debris (shrapnel).
  • Civilian terrorist bombers (eg, Olympic Park in Atlanta) often deliberately place screws or other small metal objects around their weapons to increase secondary blast injuries.
• Tertiary blast injury
• • Tertiary blast injuries are caused by individuals flying through the air and striking other objects, generally from high-energy explosions.
  • Unless the explosion is of extremely high energy or focused in some way (eg, through a door or hatch), a person with tertiary blast injury usually is very close to the explosion source.
  • Together with SBIs, this category accounted for most of the pediatric casualties in the Oklahoma City bombing. A high incidence of skull fractures (including 17 children with open brain injuries) and long-bone injuries including traumatic amputations occurred.²
• Miscellaneous blast-related injuries, sometimes termed quaternary blast injury, include burns (chemical or thermal); injury from falling objects; crush injuries from collapsed structures and displaced heavy objects; falls resulting from the explosion; and toxic dust, gas, or radiation exposure.

DIFFERENTIALS

Section 4 of 11  

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Other Problems to be Considered

Cardiac tamponade
Flail chest

WORKUP

Section 5 of 11  

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Lab Studies

• Judicious use of the laboratory is essential for accurate diagnosis in the mass-casualty situation. Do not overwhelm the laboratory with screening or protocol laboratory tests of little clinical benefit.
• Most patients injured by significant explosions should have a screening urinalysis.
• If the explosion occurred in an enclosed space or was accompanied by fire, test carboxyhemoglobin (HbCO) and electrolytes to assess acid/base status.
• • Pulse oximetry readings may be misleading in cases of CO poisoning. When in doubt, apply 100% oxygen by tight-fitting face mask until CO levels can be measured.
  • Exposure to cyanide (CN), a product of incomplete combustion of plastics, is difficult to measure directly. CN exposure often accompanies CO poisoning. Consider CN poisoning in patients exposed to combustion in an enclosed space who have an anion gap metabolic acidosis. Treatment for CN poisoning should be started for significantly ill patients while awaiting confirmatory test results. Sodium thiosulfate or hydroxocobalamin are safe and appropriate empiric therapies.
• Victims of major trauma should have baseline hemoglobin determinations, crossmatching for potential blood transfusion, and screening for DIC.
• • If significant crush injury, compartment syndrome, or severe burns have occurred, emergency physicians should be attentive to the possibility of rhabdomyolysis with resulting hyperkalemia and myoglobinuric renal failure.
  • Useful tests for DIC include the following:
    • Protime
    • Activated partial thromboplastin time (aPTT)
    • Thrombin time
    • Fibrinogen
    • Fibrin split products
    • D-dimer levels
    • Serial CBC determinations, to include platelet counts
  • Patients with burns from military white phosphorous (WP) munitions are at risk for hypocalcemia and hyperphosphatemia; follow serial levels of these ions. WP is a metal that ignites on contact with air, creating intense heat and releasing phosphorous pentoxide, a severe pulmonary irritant. WP is a widely used component of military munitions, including hand grenades.

Imaging Studies

• Perform chest radiography in patients who have been exposed to high overpressure and are therefore at high risk for primary blast injury. This group of patients may include all patients with TM rupture from blast injury. Chest radiographs should be performed on all patients who exhibit respiratory symptoms, have abnormal findings on auscultation, or have visible external signs of thoracic trauma.
• If significant abdominal pain is present, consider an immediate abdominal radiographic series (flat and upright films) or abdominal CT to detect pneumoperitoneum from enteric rupture. The Focused Abdominal Sonography for Trauma (FAST) examination is a potentially useful tool for rapidly screening patients, especially in the setting of multiple seriously injured victims. A positive FAST examination in an unstable patient is an indication for surgical exploration of the abdomen in the operating room. In stable patients, a positive FAST examination can facilitate prioritization for CT imaging. A negative FAST examination is unreliable in the setting of penetrating trauma to the abdomen, flank, buttocks, or back, and it should be followed up with CT examination of the abdomen and pelvis.
• No practical, sensitive test exists for intestinal hematoma. The diagnosis is often missed even when performing the best available test—abdominal CT. Because intestinal hematoma can take 12-36 hours to develop, symptoms such as increased pain or vomiting should determine decisions about testing.

Other Tests

• If there is any question of radiation or chemical contamination, arrange to test and decontaminate patients and equipment.
• • Most fire departments' hazardous materials teams have the training and equipment to perform this task.
  • Notify the hospital's radiation safety officer (often the chief technician for the radiology department's nuclear medicine section) for assistance screening victims for radiation contamination. Contact hospital public relations to work with the press.

TREATMENT

Section 6 of 11  

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Prehospital Care

EMS personnel should attempt to determine and report any information regarding the nature and size of the explosion; the time of occurrence; the proximity of the victim to the epicenter of the blast; victim displacement by the blast wind if any; the presence of secondary fires, smoke, dust, or chemical or radioactive contamination; and history of entrapment in collapsed structures. EMS personnel are responsible for activating appropriate disaster and/or hazardous material responses as early as possible.

• Analysis of blast incidents indicates that "upside-down" triage is common; less injured patients typically arrive at the hospital, via ambulance or private vehicle, before the most severely injured victims.
• Screening for radioactive contamination with a hand-held Geiger counter is a prudent precaution for any explosion that may involve radioactive material, including any explosion that may have been deliberately set. If radioactive material is detected, decontamination of personnel and equipment as well as notification of the receiving hospital is required. The Radiation Emergency Action Center and Training Site (REAC/TS) provides advice and assistance; their 24-hour emergency telephone number is +1 (865) 576-1005.
• Significant extremity trauma and associated death from exsanguination is a major cause of preventable death. EMS personnel should rapidly identify patients with life-threatening external hemorrhage and control bleeding. Early use of tourniquets may be life-saving, especially in the setting of multiple seriously injured casualties. 
• High-flow oxygen should be administered to all patients with respiratory distress, abnormal findings on auscultation, and evidence of significant thoracic trauma. 
• EMS personnel should avoid administration of large quantities of intravenous fluid in patients with a high suspicion of ongoing internal hemorrhage. Judicious fluid boluses may be required if patients exhibit signs and symptoms of inadequate perfusion, such as deteriorating mental status, in this setting. Recent experiences on the battlefield suggest that Hextend is the preferred resuscitation fluid for the prehospital setting. 
• EMS personnel should initiate measures to reduce heat loss and prevent hypothermia in the trauma patient since this condition is associated with increased mortality.

Emergency Department Care

• Examine the lungs, abdomen, and TMs of all patients exposed to a significant explosion.
• Penetrating wounds (secondary blast injury), blunt trauma (tertiary/secondary blast injury), and burns receive standard treatment.
• Shrapnel wounds (secondary blast injury) are treated as low-velocity gunshot wounds.
• Hemodynamically unstable patients with significant trauma may benefit from early use of packed red blood cells (PRBC), fresh frozen plasma (FFP), and platelets in a 1:1 ratio. Recent battlefield experience suggests a benefit to the early use of fresh whole blood if available. Additionally, cryoprecipitate and recombinant factor VIIa should be considered in the severe trauma patient, especially in the setting of massive transfusion requirements.
• Because pulmonary contusion tends to evolve over several hours, a period of observation and repeat radiography may be necessary if indicated. Definitive airway management and ventilatory support may be required.
• If abdominal pain persists or vomiting develops, consider admitting the patient for observation. Intestinal hematoma may be difficult to detect in the ED.
• White phosphorus (WP) burns require unique management.
• • Initial management of WP-contaminated burns consists of copious lavage of the area, removing identifiable particles (which should be placed in water to prevent further combustion), and covering the area with saline-soaked gauze to prevent further combustion.
  • Use of a Wood lamp in a darkened resuscitation suite or operating room may help identify WP particles in the wound.
  • Definitive treatment consists of a rinse using 1% copper sulfate (CuSO₄) solution and removing the WP particles. Copper sulfate combines with phosphorous particles to create a blue-black cupric phosphide coating. This impedes further WP combustion and makes particles easier to find.
  • Rinse the contaminated burn with copper sulfate solution, remove WP particles, and then use copious saline lavage to rinse off the copper sulfate.
  • Never apply copper sulfate as a dressing. Excess copper sulfate absorption can cause intravascular hemolysis and renal failure.
  • WP injury can lead to hypokalemia and hyperphosphatemia with ECG changes, cardiac arrhythmias, and death. Place the patient on a cardiac monitor and closely track serum calcium levels. Intravenous (IV) calcium may be required.
  • Moistened face masks and good ventilation help protect patients and medical personnel from the pulmonary effects of phosphorous pentoxide gas.
  • Naturally, avoid the use of flammable anesthetic agents and excessive oxygen around WP.

Consultations

• Consult a trauma surgeon, otolaryngologist, pulmonary medicine specialist, critical care specialist, orthopedic surgeon, plastic surgeon, urologist, and toxicologist, as required.

MEDICATION

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Research into the pathophysiology of primary blast injury (PBI) continues. On a cellular level, shock waves produce an inflammatory response. Interleukin 8 is released, causing mobilization of polymorphonuclear leukocytes (PMNs) into the systemic circulation. The release of proinflammatory cytokines induces the expression of the CD11b receptor complex on the PMN surface, leading to adhesion at the site of injury. Select free-radical scavengers and inhibitors of inflammatory pathways are promising in phase I animal trials. In addition, blast injury to the lungs causes levels of inducible nitric oxygen synthase (iNOS) to increase in the brain, causing brain injury. The iNOS inhibitor aminoguanidine appears to be effective when administered to mice either before or 1 hour after the blast, but human data are lacking.

Although animal models suggest that bradycardia and hypotension observed in primary blast injury may be vagally mediated, it would be premature to recommend atropine at this time.

Use of copper sulfate solution for management of burns contaminated with the military munition WP is described in Emergency Department Care.

FOLLOW-UP

Section 8 of 11  

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Further Inpatient Care

• Limited data prevent establishing the optimal duration of observation. Consider the following guidelines:
• • Persons who are exposed to open-space explosions and who have no apparent significant injury and normal vital signs and unremarkable lung and abdominal examinations generally can be discharged after 4 hours of observation. Return instructions should include shortness of breath, abdominal pain, vomiting, or other symptoms occur.
  • Persons exposed to significant closed-space explosions, in-water explosions, and those who incur TM rupture are at higher risk of delayed complications. All these patients should have chest radiography, and selected patients should have imaging of other organs. Even if no injury is identified, these patients should receive more intensive observation over a longer period. Motivated, reliable, and completely asymptomatic patients may be sent home after 4 hours of observation.
  • Admit to the hospital all patients with significant burns, suspected air embolism, radiation or WP contamination, abnormal vital signs, abnormal lung examination findings, clinical or radiographic evidence of pulmonary contusion or pneumothorax, abdominal pain, vomiting, evidence of renal contusion/hypoxia, or penetrating injuries to the thorax, abdomen, neck or cranial cavity.
• Patients thought to have arterial gas embolism (AGE) or cerebral AGE
• • Positive pressure ventilation (PPV) and positive end expiratory pressures (PEEP) should be avoided whenever possible in the setting of pulmonary blast injury due to the risk of pulmonary alveolar rupture and subsequent formation of air emboli. However, mechanical ventilation often cannot be avoided. Due to the nonhomogeneous pulmonary compliance that characterizes the blast lung, localized overinflation of the more compliant lung segments occurs when high ventilatory pressures are used. Whenever possible, reduce the tidal volume to limit peak inspiratory pressure (PIP) and minimize ventilator-induced lung barotrauma injury. If necessary, consider permissive hypercapnia ventilation: reduce the tidal volume to maintain PIP less than 35-40 cm H₂O; make no attempts to control PaCO₂ levels until the arterial pH falls below 7.20. When respiratory acidosis becomes too severe, increase the respiratory rate until the arterial pH rises above 7.25.
  • Patients thought to have AGE require recompression treatment. Place patients on 100% oxygen by tight-fitting face mask and, if possible, place them in the left lateral recumbent position to minimize the risk of travel of the air embolism out of the heart. Trendelenburg (head down) position is no longer recommended. If the side of the lung responsible for the AGE can be identified, unilateral lung ventilation may prevent further introduction of air into the vascular system during positive pressure ventilation.
  • In the setting of acute mental status, cerebral AGE should be considered as well as other causes of symptoms (eg, traumatic CNS injury).
  • Hyperbaric oxygen (HBO) treatment is the definitive procedure for AGE and cerebral AGE. Transfer of the patient to a facility with HBO therapy may be required.
  • Research suggests that aspirin is helpful in AGE. Aspirin may reduce inflammation-mediated injury in pulmonary barotrauma as well. However, it may be unwise to give an antiplatelet agent to a patient with acute trauma.

Further Outpatient Care

• As symptoms of pulmonary contusion and intestinal hematoma may take 12-48 hours to develop, instruct all discharged patients to return for reevaluation if they develop breathing problems, increasing abdominal pain, or vomiting.
• Outpatient treatments for blast-related lacerations, burns, contusions, fractures, and other injuries are the same as for these injuries from other causes.
• TM rupture
• • TM rupture by itself does not require specific treatment or hospitalization. Patients should be instructed not to put anything in the affected ear and should be referred to ENT for follow-up care. Remember that neomycin (a component of otic solutions and suspensions) is ototoxic and theoretically contraindicated in cases of TM perforation.
  • Most cases of TM perforation heal spontaneously; however, complications such as ossicle disruption, cholesteatoma formation, and development of perilymphatic fistulae are possible. About one third of patients with TM perforation have permanent hearing loss.
  • All patients noted to have a TM rupture due to PBI should have chest radiography performed.

Deterrence/Prevention

• Garments designed to protect against both PBIs and SBIs have proven very effective in the military setting. However, except for use by bomb squad technicians, these garments have little applicability in the civilian setting.

Complications

• Various sequelae of traumatic injuries may occur.

Prognosis

• The prognosis varies based on the injury.

MISCELLANEOUS

Section 9 of 11  

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Special Concerns

• Pregnancy
• • Pregnant patients with blast injuries warrant special consideration. Because the fetus is surrounded by relatively incompressible amniotic fluid, direct injury to the fetus should be uncommon. Injuries to the placenta, however, are probably more common and must be detected. After life-threatening conditions have been stabilized, patients in the second or third trimester of pregnancy who have been exposed to blast injury should be admitted to the labor and delivery area for continuous fetal monitoring and possible further testing and evaluation.
  • The placental attachment is at risk for primary blast injury because of the effect of spalling, which occurs when a blast wave passing from a higher-density medium (endometrial muscle) to a lower-density medium (placenta) is partially reflected, damaging tissues at the interface. In addition, tissues of different densities are accelerated by the blast wave at different rates, causing shearing injuries and placental abruption.
  • Obtain a Kleihauer-Betke assay (screening test for fetal-maternal hemorrhage) on all women in the second or third trimester of pregnancy. A positive test (detection of fetal cells in the maternal bloodstream) requires mandatory pelvic ultrasound, fetal nonstress test monitoring, and obstetrics/gynecology (OB/GYN) consultation. In addition, Rh immune globulin is administered at a dose of 300 mcg (1 vial) SC per 15 mL of calculated fetal-maternal hemorrhage if the mother's blood type is Rh negative.

MULTIMEDIA

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Media file 1:  Blast injuries. Idealized graph of a blast pressure wave over time. Courtesy of Bowen TE and Bellamy RF, eds, Emergency War Surgery. Washington, DC: United States Government Printing Office, 1988.
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Media type:  Graph

Media file 2:  Blast injuries. Estimated human tolerances for single, sharp, rising blast waves. Courtesy of Bowen TE and Bellamy RF, eds, Emergency War Surgery. Washington, DC: United States Government Printing Office, 1988.
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Media type:  Graph

REFERENCES

Section 11 of 11

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1. Arnold JL, Halpern P, Tsai MC, Smithline H. Mass casualty terrorist bombings: a comparison of outcomes by bombing type. Ann Emerg Med. Feb 2004;43(2):263-73. [Medline].
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5. Almogy G, Rivkind AI. Surgical lessons learned from suicide bombing attacks. J Am Coll Surg. Feb 2006;202(2):313-9. [Medline].
6. Argyros GJ. Management of primary blast injury. Toxicology. Jul 25 1997;121(1):105-15. [Medline].
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Article Last Updated: Dec 19, 2007