The influence of air bags and restraining devices on extremity injuries inmotor vehicle collisions

The influence of air bags and other restraining devices an injury after mot or vehicle collisions is not well defined. This study examined the relation ship between the use of restraining devices and the incidence of extremity injuries in motor vehicle collisions. A retrospective analysis was performe d on motor vehicle collision data submitted to the Pennsylvania Trauma Outc ome Study database from 1990 through 1995. Criteria for submission included trauma patients who were admitted to the intensive care unit, who died dur ing hospitalization, who were hospitalized for more than 72 hours, or who w ere transferred in or out of the receiving hospital. A total of 21,875 pati ents met these criteria. These patients were analyzed for the presence or a bsence of upper and lower extremity injuries and were compared based on the ir use of restraining devices. Restraining devices were categorized into fo ur groups: air bag alone, air bag and seat belt, seat belt or carseat witho ut air bag, and no restraining device. Statistical analysis was performed u sing the chi-squared test of association. For contingency tables with small expected frequencies, Fisher's exact test was used. Study participants inc luded 11,688 men and 10,185 women with a mean age of 38 +/- 20 years. There were 16,033 drivers and 5,842 passengers. Air bags were deployed in 472 in stances. In 297 of these cases, additional restraint was provided with a se at belt. In 6,632 cases, air bags were not deployed; however, patients were restrained with either a seat belt or a carseat. In 14,771 cases, patients were not restrained. When comparing restraining devices as a group vs, no restraint, there was a significant decrease in the incidence of upper (p = 0.018) and lower (p < 0.001) extremity injuries. Air bags, however, were as sociated with an increased incidence of both upper (p = 0.033) and lower (p = 0.002) extremity injuries when compared with no restraint or when compar ed among patients who were restrained. As a group, restraining devices decr ease the incidence of upper and lower extremity trauma sustained by patient s injured in motor vehicle collisions. Air bags, however, are associated wi th an increased incidence of upper and lower extremity injuries when compar ed with seat belts alone or when no restraining devices are used.