Airbags not only protect people from head and chest injuries during car accidents, they may also protect individual organs - particularly the kidneys.

In a new study that reviews data collected from people injured during serious crashes, researchers found that those with front airbags were 45 percent less likely to suffer severe kidney trauma.

Specifically, among those injured during car accidents, 3.4 percent of people with front airbags experienced kidney trauma, versus 7.5 percent of those without front airbags, Dr. Bryan Voelzke and colleagues report in the Journal of the American College of Surgeons.

“The paper does an admirable job of proving airbags decrease the chance of significant kidney injury in a motor vehicle accident,” said Dr. Richard A. Santucci of the Detroit Medical Center and Michigan State College of Medicine, who was not involved in the study.

Voelzke and his team from the Harborview Injury Prevention and Research Center, Harborview Medical Center at the University of Washington in Seattle reviewed data collected from 2,864 people injured during serious car accidents between 1996 and 2008, 139 of whom had experienced kidney trauma. Indeed, crashes are a major source of this life-threatening injury, responsible for up to two-thirds of all cases.

While front airbags were the most effective at shielding the kidneys, side airbags also appeared to offer some protection - a somewhat surprising finding, given that side airbags are known to increase the risk of abdominal injuries.

“We were unsure what the data would reveal for the relationship of side impact (accidents) and renal injuries,” Voelzke said. “Despite this, we did find an association between side impact airbags and a reduced rate of renal injury.”

“The mechanism of kidney injury is incursion by the armrest and door panel, which wouldn’t necessarily be mitigated by a side curtain airbag - yet they still work to protect the kidneys from injury,” Santucci told Reuters Health in an e-mail.

Airbags also reduced the risk of kidney injuries regardless of the intensity of the collision, Voelzke and his team found.

There are many factors that can influence how well airbags protect the kidneys, Santucci noted. Only 33 percent of people injured in car accidents were wearing seatbelts, and the benefits of airbags might increase or decrease if more people wore seatbelts, he noted. In addition, a significant number of side airbags fail to deploy during accidents, “which might artificially decrease the benefit seen in this study,” Santucci added.

There were too few accidents involving seatbelts in this study to determine whether seatbelts have any impact on airbags’ protective effect on the kidney, said Voelzke.

In addition, the results are taken from a database of serious accidents only involving newer vehicles, so the study was “weighted toward vehicles that have airbags,” he told Reuters Health in an e-mail. “A study with larger numbers would be ideal to validate our findings.”

SOURCE:  Journal of the American College of Surgeons, September 2010.