The Utility of Seat Belt Signs to Predict Intra-Abdominal Injury Following Motor Vehicle Crashes

Abstract

Objective: Safety belts are the most important safety system in motor vehicles and should always be worn to prevent serious injury. The purpose of this study, using Crash Injury Research Engineering Network (CIREN) data, was to assess occupant and crash factors associated with minor contusions and abrasions caused by the safety belt (commonly referred to as seat belt signs) and their association with serious intra-abdominal trauma. Methods: CIREN data were used to determine which factors are associated with seat belt signs. Occupant variables (age, gender, body mass index, proper safety belt use, driver v. passenger status) and crash variables (crash type, crash severity, and airbag deployment) were compared for occupants with seat belt sign who had serious (AIS 3 or greater) intra-abdominal injury and those who did not have intra-abdominal injuries. Adjusted odds ratios were used to quantify the independent association between predictive factors for serious intra-abdominal injury for occupants with seat belt signs. Results: Of 1539 occupants included in this study, 419 had a positive seat belt signs. Of those 419 occupants, 100 had serious intra-abdominal injury and 319 did not. Being in the passenger seat position increased the odds, whereas front airbag deployment and frontal impact were associated with decreased odds of serious intra-abdominal injury for occupants with seat belt signs. However, multivariate analysis showed only that being a passenger increased the odds (OR = 2.64) of having serious intra-abdominal injury for occupants with seat belt signs when other factors, including crash severity and type of impact, were controlled for in the analysis. Conclusions: Seat belt signs remain an important physical finding in patients with intra-abdominal injury following motor vehicle crashes. Front seat passengers presenting with seat belt signs were more than twice as likely to sustain intra-abdominal injury; thus, emergency physicians and trauma surgeons should be aware of passenger position when evaluating a seat belt sign.