Validation of Laboratory Animal and Surrogate Human Models in Primary Blast Injury Studies

Blast-induced neurotrauma has affected more than 300,000 service members. It is important to understand the effect of single and repeated shock-blast wave exposures on the neuropsychological behavior of soldiers, to offer them better protection, diagnostics, and treatment. Preclinical animal models and helmet design studies on human surrogate models have relied on the use of compression gas-driven shock tubes. Traditional shock tubes are so simple that if not carefully designed and operated, the test results can easily introduce detrimental artifacts clouding the conclusions. In this work, we present live-fire test results of an instrumented human surrogate head-neck model and compare with the data obtained in a carefully designed shock tube. We present various features incorporated in the shock tube design that led to better fidelity between live-fire and laboratory shock-blast conditions. The effect of specimen placement, choice of driver gas, pressure and volume of driver, end-plate conditions, and measurement techniques all determine the successful replication of live-fire loading conditions. These parameters become more important when conducting animal testing as the totality of loading will dictate the injury severity and type which ultimately will determine the mechanisms of blast-induced neurotrauma and hence their prevention and treatment strategies.