Brain injury risk from primary blast

Abstract

The first primary blast brain injury risk assessments for mild and moderate/severe injuries in a gyrencephalic animal model were determined. The blast level needed to cause a mild/moderate brain injury may be similar to or less than that needed for pulmonary injury. The risk functions can be used in future research for blast brain injury by providing realistic injury risks to guide the design of protection or evaluate injury.

On the prospective contributions of the shock physics community to outstanding issues concerning blast-induced traumatic brain injury

“…The limited amount of research on bTBI across a range of different species has prevented the establishment of robust scaling laws that would allow extrapolation to humans. Owing to its successful use for thoracic primary blast injuries and for automotive blunt impacts, scaling based on body weight ratio has been proposed for bTBI [2,14,24,29]. It has, however, been acknowledged that the scaling approach should be based on head/brain-specific anatomical and physiological considerations [2,30,31].…”

“…In contrast to the existing body of work defining injury criteria (injury risk functions) for thoracic primary blast injuries [19][20][21][22][23][24], studies addressing the definition of injury risk functions for blast TBI applicable to humans are very limited [14,25,26]. Shock tube experiments involving rabbits [25] and ferrets [14] were used by Rafaels et al to propose injury functions from linear logistic regressions for the risk of mild bleeding, moderate to severe bleeding, and fatality.…”

“…In a response to Nyein et al [12], who had chosen a very close exposure to a 3.16-g TNT charge to simulate a blast threat, Moss et al [13] mentioned that 2.2 kg of TNT was a more relevant military threat. Rafaels et al [14] stated that relevant scenarios including terrorist attacks may consist in the explosion of 1-800 kg of TNT equivalent, at various distances. Sundaramurthy et al [15] chose a range of conditions, based on various sources, using C4 explosives between 1 and 100 kg and standoff distances between 2 and 10 m to represent operational scenarios, which yielded peak overpressures between 60 and 450 kPa and a range of duration between 2 and 8 ms.…”

“…Shock tube experiments involving rabbits [25] and ferrets [14] were used by Rafaels et al to propose injury functions from linear logistic regressions for the risk of mild bleeding, moderate to severe bleeding, and fatality. Although it was recognized that common scaling approaches may not apply to brain blast injury, the functions were scaled to a 70-kg man using a mass scaling approach similar to that used previously by Bowen et al [19] in the study of other blast injuries.…”

“…Fig. 2 Reduction of the bTBI problem space using injury risk functions for fatality and mild bleeding in the brain (adapted from [14]) as the upper and lower bound…”