The combined use of air bags and seat belts significantly reduces injuries to the brain, face, spine and chest during a vehicle crash and also lowers in-hospital death rates, injury severity and hospital-acquired infections among crash patients, says a U.S. study.

It also suggests that optimal use of air bags could reduce the use of resources at trauma centers, and thus lower costs, The researchers calculated that if all the unrestrained crash victims in the study had used both an air bag and a seat belt, the estimated cost savings would be more than $60 million over 11 years.

“Using both a seat belt and an air bag can substantially reduce the severity of injury for motor vehicle crash victims. For hospitals, the use of an air bag can mean tremendous cost savings due to reduced length of hospital stay and fewer hospital-acquired infections,” Dr. Regan F. Williams, resident physician in the department of surgery at the University of Tennessee Health Science Center in Memphis, said in a prepared statement.

Williams and colleagues evaluated 14,390 crash patients admitted to a Level 1 trauma center. The patients were classified as unrestrained (7,881); air bag only (692); seat belt only (4,909); or air bag and seat belt (908).

Compared to unrestrained patients, those who used both air bags and seat belts were less likely to suffer severe injuries to the brain, face, spine and chest. Patients in the air bag only group were less likely to have abdominal injuries, but were more likely to suffer injuries to the extremities. This same association was also seen in patients in the air bag/seat belt group.

Rates of ventilator-associated pneumonia and bacteremia were 2.9 percent and 2.3, respectively, for air bag-seat belt patients, 5.2 percent and 5.8 percent for air bag-only patients, and 8.3 percent and 5.8 percent for unrestrained patients.

In-hospital death rates were 3.4 percent for seat belt-only patients, 3.8 percent for air bag-seat belt patients, 4.6 percent for air bag-only patients, and 6.8 percent for unrestrained patients.

Patients in the air bag-seat belt group had an average of 2 days in the intensive care unit and 6.4 total hospital days, compared with 2.8 days and 7.1 days for patients in the air bag-only group, and 3.7 days and 8.6 days for unrestrained patients.

(Source: Journal of the American College of Surgeons / National Highway Traffic Safety Administration)