Margaret (Peg) A. Fitzgerald, MS, APRN, BC, NP-C, FAANP

Disclosures

August 21, 2001

Question

I work in an emergency department where I occasionally see injuries from airbags. Some of the physicians are referring to the injuries as "airbag syndrome." What should I be looking for and how should these injuries be treated?

Mary Lake, FNP

Response from Margaret (Peg) A. Fitzgerald, MS, APRN, BC, NP-C, FAANP

When collision occurs, the vehicle speed decelerates rapidly, with the motor vehicle absorbing the majority of the force of the crash. Without restraint, the passengers move forward at the original speed of the vehicle until stopped by the interior structure of the car, such as the steering wheel or dashboard. The forward motion of a passenger wearing a shoulder-lap belt is significantly reduced but not eliminated; contact with the interior structure of the vehicle remains possible.

Airbags are designed to work in conjunction with the shoulder-lap belt to help minimize body contact with the interior of the vehicle while helping to evenly distribute the force of the crash across the occupant's body. The airbag unit consists of a fabric bag, inflator, and sensing device. The driver-side airbag, about the size of a beach ball, is located in the steering wheel hub. The passenger-side airbag is located in the dashboard and is nearly triple the size of the driver unit, to compensate for the greater distance between the passenger and dashboard.

Airbags are intended to deploy during collision at a force equivalent to striking a solid barrier at a speed of at least 14 miles per hour. Since real-life crash situations involve collision at a variety of angles and the object struck by the moving car may absorb some of the energy of impact, the actual vehicle speed needed to deploy the airbag is typically much greater. Airbags will not activate with sudden braking, minor strike of the bumper, or while riding over a bumpy road. These safety devices are not a soft pillow to cushion a blow; they were developed to absorb the force of collision in the event of an automobile accident. In order to do this, an airbag must deploy rapidly, and do so in about 1/20th of a second at an average of 144 mph and as fast as 210 mph. Airbags installed prior to March 1997 likely use up to 1200 lb of pressure, while second-generation or lower-powered airbags generate 25% to 30% less. Once the airbag deploys, the unit begins to deflate immediately. This allows the driver to control the vehicle if still moving and prevents occupants from being trapped.

While a literature search fails to reveal reports of a specific airbag syndrome, a number of health problems, major and minor, can arise from airbag deployment. During deployment, the airbag is filled with nitrogen or argon, harmless gases that dissipate quickly. At the same time, a significant amount of dust or powder is released into the vehicle. The majority is talc or cornstarch, a part of the airbag unit that allows the bag to slip out of its storage space. A small amount of sodium hydroxide may also be released, quickly converted to baking soda upon exposure to ambient oxygen. Some units may release potassium chloride. These substances may cause irritation to the throat and eyes, most often when the automobile occupants are not able to quickly leave the vehicle. Vehicle occupants may benefit from gentle eye cleansing after airbag deployment. These substances have the potential to be airway irritants and can trigger bronchospasm in the person with asthma or other airway and lung disease, resolving with standard bronchospasm therapy.

Since the airbag must deploy rapidly and with great force to provide protection, injury from airbag contact can occur and is typically limited to minor abrasions and burns.

Although airbags have saved many lives, severe, even fatal injuries have been seen with airbag use. Most have been noted when the vehicle driver is seated in a zone of less than the recommended 10 or more inches from the center of the steering wheel, when the unconscious driver is slumped over the steering wheel, or when a shoulder-lap belt has not been used. This causes the body to absorb the force of the airbag deployment, rather than the airbag helping to diffuse this force.

The driver-side airbag module is covered with rigid material with an intentionally weakened point to allow splitting upon airbag deployment. Injuries from this cover splitting apart during airbag deployment have been reported. To avoid this type of injury, Dr. William Smock,[1,2] an emergency department physician who has written on airbag safety, recommends that drivers use caution not to have any portion of the arm, hand, or fingers over the airbag module at any time while driving; front-seat passengers are similarly warned to avoid placing any body part up against the dashboard. In particular, a maneuver to sound the car horn or brace against the steering wheel or dashboard just prior to an anticipated collision places the car occupants at particular injury risk.

In certain circumstances, airbag use can pose significant safety risk, and deactivation or the installation of on-off switch should be considered. Placement of a rear-facing infant automobile restraint in the front passenger seat poses extreme risk, allowing the baby and car seat to absorb the significant force with airbag deployment. The infant should only be placed in the front passenger seat if the vehicle has no back seat. Short-stature drivers (less than 4'6") who must sit within a few inches of the airbag are also at risk, as are children younger than 12 years who must sit in the front passenger seat in order to be monitored by the driver. If no other accommodation is possible, airbag deactivation or the installation of an on-off switch may be needed.

Nurse practitioners can play an important role in advising patients about the following National Highway Traffic Safety Administration recommendations. This will help reduce the frequency and severity of airbag injury:

  • Adjust the driver's seat so that there is a 10" margin of safety between the driver and the point where the airbag will deploy, usually the center of the steering wheel.

  • Make sure the driver and adult passengers are properly using car passenger restraints. Airbags are a supplemental safety device designed to work in conjunction with lap-shoulder belts.

  • Advise that front-seat passengers not place any body part on the dashboard.

  • Make sure children are in the proper location in the car and in the right car seat for age and weight. All children under 12 years of age should be seated in the back seat; proper child automobile restraints may also be needed. Infants should be placed in a rear-facing car seat until they reach at least 1 year and weigh up to 20 lb. After this, a forward-facing car seat can be used until the child reaches 40 lb. Beyond 40 lb, a belt-positioning booster seat is recommended until the child weighs 80 lb. Even when appropriately restrained, a child seated in the front passenger seat is at great risk of injury from a deployed airbag.

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