Airbags
Introduced in the early seventies, rare until the late eighties, today's vehicle contains from two to ten airbags.
- General precautions include avoiding the path of any undeployed airbag
- Consider the position of your patient(s) and reposition away from the potential airbag path if practical
- Effort should be made to locate and disconnect the battery
- For deployed airbag incident, use caution handling products of combustion (always wear personal protective equipment including eye and hand protection)
- Carefully assess patient for possible airbag interaction injuries including abrasions, lacerations, contusions, thermal or chemical burns, nasal fractures, cervical sprain/fracture
- Always follow your SOP's/SOG's regarding patient handling/stabilization
Specific airbags
Driver/passenger front airbags
- Designed to deploy at impact speeds of 8-14 MPH, recently allowable low end threshold increased to near 20 MPH, depending on manufacturer
- Deploy in 30-50 milliseconds (1,000'ths of a second) with a forward speed of 100 - 210 MPH
- Driver bags deployed volume average 35-70 liters
- No standard size or shape for passenger bag. Deployed volume ranges from 60 to 160 liters
- Variety of gas generators including sodium azide, temperature compensated stored gas (Argon) and cobalt/copper
- Solid propellants generate very hot gasses (1,200° to 2,400° F); compressed gas generators are cooler.
- Avoid pulling steering wheel column when it contains an undeployed airbag
- Dual deployment bags introduced recently, one side may remain live after collision
- Some systems are designed to sense unoccupied seat or child in seat, eliminating passenger bag deployment in the crash.
Side impact airbags
- Introduced by Volvo in 1995, are now available in over 120 models from 27 manufacturers.
- Most common location is seat side mount, some located in doors (see Holmatro's
Rescuer's Guide to Vehicle Safety Systems for specific models and locations).
- Deploy in 12-15 milliseconds (more than twice as fast as front airbags).
- Large variety of sizes/shapes (see Holmatro's New Vehicle Safety Systems for the Rescuer video for images of deploying side bags).
- Gas generators include nitro-cellulose, sodium azide and temperature compensated stored gas.
- Potential deployment path should be avoided, with extra care taken during door removal.
- Avoid cutting or pinching areas that you suspect contain live airbags (seat sides, door panels).
- Removed doors containing undeployed airbags should be placed on the ground with the interior of the door facing up.
- Consider alternate access methods such as roof removal.
- Identification for side impact airbags varies widely. Some typical areas to check are the door panel, upper seat side, lower edge of seat, tab sewn into seat seam, tab on lower seat edge, and windshield. When in doubt, refer to Rescuer's Guide to Vehicle Safety Systems.
Head protection airbags
- Introduced in BMW 1997, Mercedes and Volvo 1998, Audi 1999
- Dedicated head protection (i.e. not head/thorax which are mounted in seat) bags located in the roof rail and covered by the headliner. There are 2 styles. The first is tubular in shape, (used by BMW, referred to as HPS or Head Protection System) and protects front seat occupants. The second is a curtain style (known as Window Curtain by Mercedes, Inflatable Curtain by Volvo, and Sideguard by Audi), which covers both front and rear seat occupants. Refer to New Vehicle Safety Systems for the Rescuer video for additional information on these systems (relative size, deployment zones etc.)
- Inflators for the curtain style airbags are compressed gas cylinders, located in the "C" pillars. To avoid cutting into these cylinders during roof removal cut at the very top of the "C" pillar or use a rear roof flap. Always use extra caution when working near this device.
- BMW introduced an additional head protection airbag for the rear seat occupant in the 7-series for 2000
- Designed to deploy on side of impact only, threshold of deployment varies widely between manufacturers. Typically side impact sensors are highly sensitive due to need for rapid deployment (side of vehicle much narrower than front mass)
- Avoid the potential deployment path of head protection systems by accessing the patient through the rear window
- Cervical immobilization should be performed from behind the patient when live head protection airbags are present
- Identification of these systems vary. BMW uses "HPS" lettering on the "A" pillar trim, Volvo uses IC on a plastic tab near the top of the "C" pillar, Mercedes uses SRS on a plastic tab at the top of the "B" pillar. When in doubt, refer to Rescuer's Guide to Vehicle Safety Systems.
Knee airbag
- Deploys from dashboard area below steering column, designed to reduce injuries to the knee region
- Triggered by frontal impact
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