Hearing loss and automobile airbag deployments

Sensorineural Hearing Loss due to Air Bag Deployment

Deployment of the air bag in a passenger vehicle accident rarely causes otologic injuries. However, sensorineural hearing loss induced by air bag deployment is extremely rare, with only a few cases reported in the English literature. A 38-year-old man involved in a traffic accident while driving his car at 40 km/hour presented with right sensorineural hearing loss and tinnitus, without associated vertigo. Pure-tone audiometry demonstrated elevated thresholds of 30 dB and 25 dB at 4 kHz and 8 kHz, respectively, on the right side. Air bag deployment in car accidents is associated with the risk of development of sensorineural hearing loss.

Validation of the auditory hazard assessment algorithm for the human with impulse noise data

Predicting auditory hazard from intense acoustic impulses, such as weapons fire or airbags, has been an intractable problem. The U.S. Army developed a theoretically based mathematical model of the ear designed to predict such hazards [the Auditory Hazard Assessment Algorithm for the Human (AHAAH)]. To validate it as a predictor of hazard, data from the literature (wave forms and changes in hearing sensitivity) were processed with the model in order to predict the onset of unacceptable threshold shift (25 dB or more) in the 95th percentile human ear. For comparison, alternate standards MIL-STD-1747D and A-weighted energy were also used to compute hazards for the same data. The primary dataset was that of the US Army's "Albuquerque studies" (53 different cases) and other impulses from the literature (19 additional predictions). The AHAAH model predicted correctly in over 95% of the cases, the MIL-STD-1474D was correct in 42% of the cases, and A-weighted energy was correct in 25% of the cases. Errors for all methods tended to be in the direction of overprediction of hazard. In addition to greatly increased accuracy, the AHAAH model also has the advantage of being theoretically based and including novel diagnostic features.

Effects of airbag deployment: lesions, epidemiology, and management

Airbags are restraining safety devices, but their activation may sometimes induce injuries during road accidents. Rapid deceleration due to an impact causes the ignition of a sodium azide cartridge, which releases nitrogen gas to inflate the nylon rubber bag. Numerous high-temperature gases, sodium hydroxide, carbon dioxide, and various other metallic oxides are also released producing a corrosive alkaline aerosol. Cutaneous and extracutaneous injuries due to airbag deployment may occur. Cutaneous injuries are frequent, and consist of irritant dermatitis, and chemical and thermal burns. Furthermore, numerous kinds of traumatic lesions (abrasions, friction burns, and lacerations) may be observed. Extracutaneous damage may involve the eyes, ears, cardiovascular system, nerves, joints, and bones. The nature of airbag lesions, their frequency, and management are reported. Even though the majority of airbag lesions are minor and do not require hospitalization, correct diagnosis and the choice of the most suitable treatment are necessary.