Pulmonary injury risk assessment for short-duration blasts.

BACKGROUND Blast injuries are becoming more common in modern war and terrorist action. This increasing threat underscores the importance of understanding and evaluating blast effects. METHODS For this study, data on more than 2,550 large animal experiments were collected from more than 50 experimental studies on blast. From this dataset, over 1,100 large animal experiments were selected with positive phase overpressure durations of 30 milliseconds or less. A two variable nonlinear logistic regression was performed on the experimental data for threshold injury and lethality in terms of pressure and duration. The effects of mass, pressure, and duration scaling were all evaluated. RESULTS New injury risk assessment curves were analyzed for both incident and reflected pressure conditions. Position dependent injury risk curves were also analyzed and were found to be unnecessary, at least for prone and side on conditions. CONCLUSIONS The injury risk assessment showed good correlation to some of the existing injury assessments. It also showed good correspondence to a reported human case of blast exposure. Pressure scaling was analyzed to be unnecessary for these short duration exposures. Recommended injury assessments for various orientations relative to the incoming blast wave are included.