Mass Casualty Incidents, Terrorism & Active Shooter, Trauma

Improving Upon Blast Injury Response in Mass Casualty Scenarios

Issue 8 and Volume 41.

Several incidents involving explosions and mass casualty situations have occurred since we published the article “Detonation Station: Responding to scenes involving blast injury” in the July 2010 issue.1

It’s beneficial to review events such as the Boston Marathon bombing terrorist incident that occurred in April 2013, as well as the recent terrorist incidents in Paris and Brussels, to determine if there are areas within an organized response that can be improved upon.

Review

Because there are many variable factors behind explosions, it’s difficult to describe or predict a commonality to injury patterns outside of multiple, simultaneous casualties and, probably, a mass casualty scenario. However, as we described in the July 2010 article, there are specific types of injuries that are commonly encountered.

Although the first thing that usually comes to mind when discussing explosions are injuries associated with overpressures generated from the blast, the most frequently encountered immediate life threat is bleeding from penetrating injuries caused by flying debris and/or shrapnel. Blunt force trauma, crush injury, burns, inhalation, and toxic exposures may also add a level of complexity.

EMS blast injury response in MCIs
Loud, chaotic scenes, like this one at the Boston Marathon bombing in 2014, are dynamic challenges most providers working in fixed facilities don’t have to contend with. AP Photo/Charles Krupa

In an attempt to provide complete information regarding the kinematics of trauma, traditional education processes may inadvertently emphasize esoteric information that doesn’t contribute a great deal to actual casualty management by first responders.

Although it’s instructional to recognize that there are various types of injury processes attributed to an explosion, that recognition rarely changes immediate stabilization strategies. For example, does the immediate recognition and stabilization of a closed femur fracture change if the injury occurred due to flying debris as opposed to the casualty being thrown against a solid surface?

Likewise, it’s informative to know that tremendous overpressures that travel in waves are generated by explosive detonations. The dynamics of these pressure waves are highly variable due to a multitude of factors such as the amount of the explosive charge, height above ground, reflective surfaces or barriers between the blast, and the casualty. Even atmospheric conditions such as low-lying cloud cover can affect these blast waves.

Pressure waves have their greatest effects on organ systems that contain air (e.g., lungs, gastrointestinal tract, and sinus/middle ear cavities). Tympanic membrane rupture is frequently encountered but is clearly not life threatening. Ruptured or perforated intestines cause pain and may lead to peritonitis, but aren’t as immediately concerning as severe hemorrhage or respiratory difficulty. Keeping that in mind may influence triage/treatment strategies that we’ll discuss later.

Lung injuries may present a challenge for prehospital providers—especially in light of mass casualty scenarios and limited resource availability. Ventilation problems aren’t necessarily airway problems, so not every patient requires intubation. Pulmonary contusions, pulmonary edema/hemorrhage, and pneumothorax are all potential overpressure injuries.

For patients not stabilizing with simple supplemental oxygen, we often consider positive pressure ventilation. However, it’s extremely challenging in the noisy/chaotic prehospital mass casualty environment to determine if the addition of positive pressure is creating additional problems (i.e., expanding a pneumothorax). For example, think about how challenging it would be to manage a single heart failure patient with both pulmonary edema and a pneumothorax, and then imagine managing that same patient with too much noise to auscultate breath sounds and no ability to rapidly image the chest while 30 other patients are yelling for your immediate attention; this is a dynamic challenge that most providers working in fixed facilities don’t have to contend with.

Compounding isolated lung injuries, of course, is the potential for other environmental threats from toxic by-products from burning synthetic materials to dust/particulate matter generated from the explosion (recall the scenes from the dust generated from the structural collapse of the World Trade Center buildings).

EMS blast injury response in MCIs
A shrapnel injury from a secondary blast can be seen on the forehead as comet-like streak wounds. This patient also has frontal sinus fractures as part of his primary blast injuries. Photo Edward T. Dickinson

Theory vs. Reality

On April 15, 2013, two terrorists detonated two explosive devices near the finish line for the Boston Marathon. These homemade devices were concealed in backpacks that were left at ground level. The attack resulted in three people killed at the scene and another 243 wounded (152 of whom were either transported to local hospitals or sought care within the first 24 hours).2

Based on the type of explosive used combined with the ground-level location of the devices, most serious injuries resulted from penetrating debris or traumatic amputations.

In one review of the 152 patients presenting to the local EDs in that first 24-hour period, 66 had at least one extremity injury. Of those 66 patients, 15 had traumatic lower extremity amputations (two patients experienced bilateral amputations), 12 had injuries to a major artery, and 29 had life-threatening exsanguination from their extremities.2 Twenty-seven tourniquets were applied in the prehospital setting, all of which were improvised.

Tourniquets were applied to 16 of the 17 traumatic amputations. Only five of the 12 patients with major arterial injury had tourniquets applied, and six of seven patients with major soft tissue injuries had tourniquets applied.2 The after-action data suggests the vast majority of the 27 tourniquets applied were determined to be ineffective at controlling hemorrhage. In fact, improvised tourniquets are often ineffective as they generally create an initial venous hemostasis that’s followed by a worsening hemorrhage (when compared to using no tourniquet).2,3

Three reviews from radiological studies done on casualties of the Boston Marathon bombing showed that primary blast injury was relatively rare and not associated with life-threatening injuries.4–6

In a study reviewing patients who underwent head/neck imaging, only 12 of 115 patients had CT/MRI findings of injury: Eight were due to shrapnel and of the four not associated with shrapnel, two had subgaleal hematomas, one had a facial contusion and one had a mastoid injury.4

Two studies reviewed patients who underwent abdominal or pelvic imaging (one had 87 patients, the other 43): No pulmonary or gastrointestinal manifestations of primary blast injury were identified.5,6 In another study that reviewed ontological injuries, over 90% of the 94 patients had tympanic membrane ruptures that resulted in long-term hearing loss and tinnitus.7

The terrorists who planned and executed the attacks that killed 14 people and injured another 22 in San Bernardino in December 2015 had planted an explosive device at the scene—three pipe bomb-type devices linked together to a remote detonator. This device was probably intended to target first responders, but failed to detonate.8

On Nov.13, 2015, terrorists executed a coordinated attack that combined shootings and bombings at six locations in Paris that resulted in 129 deaths and 368 wounded.9 In March 2016, terrorists again executed a coordinated bombing—this time in Brussels, where two bombs detonated in the airport and a third at the metro station, killing 32 and injuring 340.10 Unfortunately, there isn’t much information that’s been published yet on the extent or nature of the injuries resulting from the bombings.

EMS blast injury response in MCIs
An injured man is escorted out of the Pulse nightclub after a shooting rampage, in Orlando, Fla., on June 12. Injured people aren’t going to wait for you to sort the situation out. If a victim perceives they have an injury and are otherwise capable of moving themselves, they will often self-evacuate. AP Photo/Steven Fernandez

First Responder Considerations

What useful information can we synthesize from these events? If history is any reputable teacher, the first lesson we should apply is that the likelihood of a future terrorist incident involving explosive devices is probable, but predicting where, when and why is astronomically difficult.

Mass casualty drills can help us plan and prepare, but if they’re not conducted in realistic fashions, we may get lulled into a false sense of security in our response capabilities.

One of the primary lessons is that perpetrators don’t play by any rulebook. They seek to strike targets that offer little security or resistance, and they have no qualms about targeting first responders. Scene security should always be a paramount concern. Additionally, if part of your plan calls for establishing a casualty collection point (CCP), you need to identify several alternative locations in case the primary location becomes compromised. What resources will be required to move non-ambulatory casualties? Are you protected from the environment? Does it provide easy access for ambulance or other vehicle traffic in order to move casualties to hospital facilities? Do you have a method to account for everyone within the CCP? Does it provide enough adequate shelter to provide short-term treatment?

We’re frequently asked to provide triage methods in mass casualty incident planning. The reality is that there isn’t a single method that will work flawlessly in all situations. The one thing that you can count on is chaos; your job is to rapidly gain control and bring some semblance of order to the chaos of the mass casualty situation. You need to locate victims, be able to rapidly identify life threats where you can actually intervene, begin to consolidate casualties for both treatment and evacuation priorities, coordinate with local resources to distribute casualties appropriately (otherwise you’re just changing the location of the mass casualty event from the site to the hospital), and prevent further injuries to the victims as well as to the rescuers.

In many cases, injured people aren’t going to wait for you to sort the situation out. Most local people know where the local hospitals are located. If a victim perceives they have an injury and are otherwise capable of moving themselves, they will often self-evacuate. Remember, the triage process is not the time to stop to provide definitive care. Stopping to render complex care means you’re not going to find everyone who needs medical attention. Generally, if it takes more than positioning someone in a recovery position to keep their airway open or quickly applying a tourniquet, then you’re consuming valuable time.

Consider how environmental conditions will impact your decisions. Does your process work at night? What about in rain, snow, ice or high winds? For example, having casualties laid out on a concrete parking lot at noon in Dallas is a good way to create heat injuries and thermal burns to exposed skin.

Does your plan rely on electronic devices? How will you address the situation if power isn’t readily available? What’s is your backup communication plan if cell towers are offline?

The Centers for Disease Control and Prevention produced a good online reference source titled “Interim planning guidance for preparedness and response to a mass casualty event resulting from terrorist use of explosives.”11 It’s definitely worth reviewing.

Historically, rapid hemorrhage control will be the priority medical intervention. Don’t allow people to be “bystanders”—someone who’s present but doesn’t take part. People want to help; they may simply not know what to do. Give them very clear and simple commands such as “put on these gloves and hold pressure right here until I get back.” You should have rapidly transportable bleeding control kits that are simple to use. At a minimum, each package should have a pair of gloves, a roll of gauze and an elastic bandage. Your department probably doesn’t have enough funding to procure all of the commercial tourniquets you’d like to have, but you need to stock many tourniquets and have them readily available.

Improvised tourniquets can be effective, but only if you routinely practice using them. For the initial entry missions into Afghanistan and Iraq, and in subsequent training missions with host nation military forces, U.S. military personnel used heavy-duty triangular bandages and pre-cut dowel rods as their primary tourniquets. They worked very well because they routinely practiced with them, including tightening them to the point of arterial occlusion.

There are several commercial tourniquet devices that are now available that are much more effective. If you don’t practice tightening tourniquets to the end point of abolishing distal pulses, you’ll never gain an appreciation for just how tight these devices need to be. Attempting to fashion a tourniquet from material scrounged during a mass casualty scenario will most likely result in either an ineffective tourniquet, or worse, a constricting band that actually increases bleeding. If a tourniquet has been applied, check it to make sure it’s tightened adequately.

When conducting mass casualty exercises, make your responses and interventions realistic. Protocols and algorithms intended to manage the single patient don’t always work for mass casualty scenarios. We’ve all witnessed the drill where the responder verbalizes, “I’m intubating the patient.” We actually ran one exercise where a responder verbalized intubating five victims simultaneously. (Some of us have mad skills, but even so, that was an unrealistic stretch.)

Under realistic conditions, the evaluator needs to hold the responder for the 2–3 minutes it will take to perform the skill. If you’re using paralytics, that requires IV or intraosseous access first, and afterward someone has to breathe for that patient. How many bag-valve masks (BVMs) do you have on hand? Are you going to ask or allow an untrained civilian to use the BVM, or even perform mouth to tube ventilations?

Another phenomenon we observe frequently in mass casualty exercises is what we call “trained first responder flocking.” We get so accustomed to working with our partners as a team during single patient encounters or scenarios with only a few casualties that in mass casualty scenarios, we revert to that same methodology. One first responder needs to be responsible for a designated number of casualties, and when they have adequately stabilized those, either start re-assessing or, more importantly, start looking for other unstable patients. Ask other responders if any of them requires assistance with their casualties. Work as an individual with a speed that’s fast enough to enable appropriate head-to-toe, front-to-back assessments and necessary immediate interventions, but not so fast that you’re missing things or cutting corners. In these situations, the maxim “slow is smooth, and smooth is fast” is extremely applicable. Don’t feel like you’re alone: Look for people looking for something purposeful to do and give them a task.

If language is an issue, try to locate someone who’s uninjured or minimally injured who can serve as an interpreter. In the U.S., we often find that when older children are present (4th grade and above), they often speak a common language with one of us and can assist in translating. If that situation presents itself, identify your translator, evaluate and treat them first, then put them to work.

Most civilians don’t routinely utilize personal protective equipment such as body armor, hearing protection or eye protection with ballistic lenses. However, penetrating eye injuries aren’t uncommon in explosions. If you suspect a penetrating eye injury, shield the eye with a rigid device that doesn’t put pressure on the eye itself. Never apply an eye patch that puts pressure on the eye.

Other Considerations

Although first responders generally become desensitized to a great deal of traumatic injuries, a mass casualty situation can be overwhelming and may create a considerable amount of distress. Having to tend to multiple casualties in various degrees of dismemberment, especially when the casualty array contains children, is difficult.

Don’t underestimate the power of a critical incident debriefing. Be vigilant for warning signs of post-traumatic stress for yourself and your teammates. Loss of appetite, insomnia, withdrawing from usual interactions/activities may all be early warning signs that a responder should seek counseling. Everyone deals with stressful situations in a different manner, but recognizing that you need to seek counsel is highly commendable, and most definitely not a sign of weakness.

References

1. Cain JS. Detonation station: Responding to scenes involving blast injury. JEMS. 2010; 35(8):64–69.

2. King DR, Larentzakis B, Rambly E. Tourniquet use at the Boston Marathon bombing: Lost in translation. J Trauma Acute Care Surg. 2015;78(3):594–599.

3. Kragh JF, Swan KG, Smith DC, et al. Historical review of tourniquet use to stop bleeding. Am J Surg. 2012;203(2):242–252.

4. Singh AK, Buch K, Sung E, et al. Head and neck injuries from the Boston Marathon bombing at four hospitals. Em Rad. 2015;22(5):527-532.

5. Singh AK, Sodickson A, Abujudeh H. Imaging of abdomen and pelvis injuries from the Boston Marathon bombing. Em Rad. 2015;23(1):35–39.

6. Singh AK, Gowalnick E, Velmahos C, et al. Radiological features from the Boston Marathon bombing at three hospitals. Am J Roent. 2014;203(2):235–239.

7. Remenschneider AK, Lookabaugh S, Alphus A, et al. Otologic outcomes after blast inuury: The Boston Marathon bombing experience. Oto Neur. 2014;35(10):1825–1834.

8. Domonoski C. (Dec. 3, 2015.) San Bernardino shootings: What we know, one day after. NPR. Retrieved June 15, 2016, from www.npr.org/sections/thetwo-way/2015/12/03/458277103/san-bernardino-shootings-what-we-know-one-day-after.

9. Marcus MB. (Nov. 19, 2015.) Injuries from Paris attacks will take long to heal. CBS. Retrieved June 15, 2016, from www.cbsnews.com/news/injuries-from-paris-attacks-will-take-long-to-heal/.

10. BBC. (April 9, 2016.) Brussels explosions: What we know about the airport and metro attacks. Retrieved June 15, 2016, from www.bbc.com/news/world-europe-35869985.

11. CDC. (2010.) Interim planning guidance for preparedness and response to a mass casualty event resulting from terrorist use of explosives. Retrieved June 15, 2016, from https://stacks.cdc.gov/view/cdc/5705.