University of Extrication: Collision Damage and Patient Mechanisms of Injury

Topic: Occupant mechanism-of-injury potential

Objective: Understand how exterior and interior vehicle damage can serve as clues as to potential occupant injury

Task: “Read” a crash-damaged vehicle to create a mental list of potential occupant injury mechanisms that are based on these physical findings

The vast majority of responders to vehicle collisions have some degree of medical training (e.g., first responder, EMT-B or paramedic). As such, you must realize that you are exposed to a lot of physical “evidence” while on scene. If you proactively look for it—called “reading the wreck”—you can get clues about a patient’s injury potential even before you make patient contact. Exterior and interior images of several crash-damaged vehicles that are included below illustrate these size-up and assessment teaching points.

Figure 1. As you approach this sedan, you note an offset frontal crash and that the driver’s door already is open. Start thinking about potential mechanism of injury possibilities for at least the driver prior to making patient contact.

Airbag signals

In Figure 1, an Infiniti G35 sedan shows moderate off-set frontal crash damage. Upon approaching the vehicle, a wise rescuer already would be thinking about possible mechanisms of injury for any occupant who was involved in a frontal crash, particularly the driver.

From strictly safety, rescue and extrication points of view, concerns about the vehicle itself begin to be factored into the rescue size-up: Is the damaged vehicle in “Park”? Is the engine off? How will the vehicle be stabilized? Is anyone inside of the vehicle? Is there interior access, or are the occupants trapped? Is everyone out and ambulatory?

Figure 2. Your first view of the interior of this sedan provides more clues about your patient’s potential injuries.

Once you reach the driver’s side of the vehicle (Figure 2), a close look confirms that the door opens normally, the driver’s seat is empty and only three airbags deployed. However, you know that there are more than three airbags in this car—dual frontal bags, a side-impact bag in each front seat and a roof airbag on each side—so you start seriously thinking about powering down this vehicle by having the crew shut down the 12-volt power. (Plan on encountering six airbags in a typical vehicle today as a starting point for assessing airbags.) Also, with the passenger frontal bag still undeployed, proceed by anticipating that the front passenger’s seat—a so-called smart seat—was unoccupied at the moment of the crash. So, maybe you only have one patient from this car to account for and treat.

You also note a splattering of fresh blood on the deployed airbags, rocker area and base of the B-pillar. It isn’t a large quantity of blood, and it isn’t pooled in one spot; it just is scattered about on this side of the vehicle. Look to see whether any drops are on the roadway. The visual evidence indicates you that should be looking for an occupant who most likely was the driver. Your patient now most likely is ambulatory and has some degree of head or facial injury that’s enough to cause bleeding from the mouth or nose. Once this patient is located and assessed, his/her facial injuries will reinforce the clues that you observed from the vehicle itself.

Appearances can deceive

Rescuers must be careful about the exterior vehicle damage as it relates to patient injuries. Officers who are in charge of an incident must be keen not to judge a book by its cover—the exterior of the vehicle. Exterior appearances of vehicle damage or lack thereof no longer are reliable/telltale clues as to what occupants went through during the crash sequence. Outward appearances that the vehicle gives must be balanced with any supplemental restraint system use and the physical damage that’s inside of the vehicle, particularly within the front and rear seat occupant areas, to come up with an accurate prediction of an occupant’s potential mechanisms of injury.

Figure 3. Approach to this crash-damaged two-door convertible shows the “crumple zone” at the front of the vehicle.

Figure 3 shows a two-door PT Cruiser convertible that was involved in a head-on collision. Exterior damage, including the crumple to the front of the vehicle, is typical of a moderate head-on collision. However, looking at the driver’s seat and instrument panel area (Figure 4) reveals a different story altogether and serves as a general lesson that, if you look closely, the interior can show something that’s somewhat out of the ordinary but vitally important to your size-up process—clues that you don’t exactly expect when you see the frontal crash damage. In this case, the steering wheel airbag deployed as expected, but the steering wheel ring is bent severely, which isn’t the norm. Also, the steering wheel spokes are bent forward along the bottom side of the wheel. In addition, the entire steering column assembly broke off of its mount in the instrument panel and now lies on the floorboard. Wheel and column damage are one thing, but when coupled with the fact that the rest of the instrument panel essentially is intact, they indicate that there was a significant forward-direction force on just the steering wheel and column. What could have caused this? The column didn’t move toward the driver; you realize that the driver instead was flung toward and against the column enough to bend and break it.

Figure 4. The interior of the two-door convertible shows not only frontal airbag deployment but significant bending of the steering wheel ring and total failure of the steering column mounting bracket.

Your inside size-up of this car should lead you to anticipate that your medical personnel will encounter a driver who possibly was unrestrained and might now be in respiratory distress. Since this driver probably moved forward enough to bend and break the wheel and column during the impact, you’ll be looking for chest and abdominal injuries as well as potential hand and arm fractures that were caused by the driver trying to hold on as tightly as he/she could during the crash. Being out of position when the airbag deployed also might have resulted in airbag-induced facial or head/neck injuries.

Perspective from the passenger’s side of the sedan shows the three deployed airbags, the blood splatters and the lack of passenger-side airbag deployment.

Despite the fact that there isn’t any drastic outward collision damage, medical personnel should suspect internal injuries to this driver that might not be readily visible upon initial patient contact. Get good vitals early and monitor any changes in them. The interior wheel and column damage should be enough to trigger this into a trauma situation.

The sedan’s deployed driver’s-seat airbag clearly shows that the patient’s blood didn’t come from abrasion contact with the seat airbag as it deployed. Look further for clues, such as shattered window glass, loose flying objects that were inside of the vehicle or the patient’s eyeglasses or sunglasses, which might have factored into the injuries that you find when you locate the patient.

Thorough investigation

Whether a crash scene involves a vehicle that has severe damage or that has little or no outward appearances of damage, you must see and understand the meaning of both the exterior and interior clues to get the whole picture to effectively anticipate potential occupant mechanisms of injury. It’s like a giant puzzle. As a responder, you must understand that clues are everywhere at an incident scene. You must calm down and be in control enough mentally to take the time to be a good detective to read the wreck based on physical findings.