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 (Ask for REAC/TS).
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. 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.
In cases of life-threatening extremity trauma secondary to blast injuries, early use of tourniquets may prove lifesaving. In a study comparing combat application tourniquet (CAT) to the newer emergency and military tourniquet (EMT) pneumatic tourniquet, the CAT tourniquet proved ineffective in controlling arterial blood flow when applied at mid-thigh level while EMT was successful in a significantly larger number of patients. [27]
The FDA has approved an expandable, multi-sponge, temporary wound dressing (XSTAT) to control bleeding from certain types of wounds received in battle. The dressing, which can be used for up to 4 hours, consists of 3 syringe-style applicators with 92 compressed cellulose sponges that have an absorbent coating. These sponges expand and swell to fill the wound cavity, creating a temporary physical barrier to blood flow. Each tablet-shaped sponge measures 9.8 mm in diameter and 4-5 mm in height and can absorb 3 ml of blood or body fluid. [28]
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) and fresh frozen plasma (FFP) in a 1:1 ratio, as well as platelets. 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. One review of 3 mass casualty incidents following explosive events in Iraq suggested that this resuscitation strategy resulted in the transfusion of an average 3.5 units of PRBC and 3.8 units of plasma, as well as a mortality of 8%. [29]
The prevention of hypoxia and hypotension are critical in patients with traumatic brain injury to prevent significant increases in mortality. [22] 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 potentially death. Place the patient on a cardiac monitor and closely track serum calcium levels. 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.
A high rate of ICU admission and ventilator requirement should be anticipated. In a review of 3 mass casualty incidents, approximately 50% of surgical patients with injuries resulting from blasts required each of these. [29] 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.
-
Persons exposed to significant closed-space explosions or in-water explosions and those who incur tympanic membrane (TM) rupture are at higher risk of delayed complications. All these patients should have achest 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.
For patients thought to have arterial gas embolism (AGE) or cerebral AGE, note the following recommendations:
-
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 H 2O; make no attempts to control PaCO 2 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.
Medical 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.
Tympanic membrane (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 an ENT specialist 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.
Exposure to blasts may induce vestibular disorders that progress over time. Referral to a neurologist and ENT should be considered for follow-up care. [30] Physical therapy referral may be required for vestibular rehabilitation. [31]
Exposure to blasts may result in mild traumatic brain injury (mTBI) and predispose to posttraumatic stress disorder (PTSD). [32] Patients with residual symptoms should be referred to neurologists and mental health specialists as required. Although insufficient data exist to make a definitive recommendation, hyperbaric oxygen (HBO) may be of some benefit in the treatment of blast-related postconcussive symptoms. [33]
-
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.
-
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.
