In this study, seventy-one frontal impact sled tests were conducted using post-mortem human subjects in the driver's position in an effort to better understand thoracic trauma in frontal impacts. Various contemporary automotive restraint systems were used. The resulting injury from the impact was determined through radiography and detailed autopsy, and its severity was coded according to the Abbreviated Injury Scale (AIS). The measured mechanical responses were analyzed using statistical procedures. In particular, linear logistic regression was used to develop models which associate the measured mechanical parameters to the observed thoracic injury response. Univariate and multivariate models were developed taking into consideration potential confounders and effect modifiers. The risk factors used in the models were normalized concerning the size and weight of the specimen. The gender and age of specimen at time of death were found not to be confounders in this data set. A linear combination of the 3-msec clip value of maximum resultant spine acceleration and maximum normalized chest deflection from an array of five measurements provided the goodness of fit measure. This linear combination was found to have significantly better injury predictive ability, for thoracic trauma in human subjects under any restraint environment, than other existing injury criteria such as VCmax ( Maximum Viscous Criterion), chest deflection, or chest acceleration alone.
Abstract