The Clemedson Blast Tube

Abstract

Traumatic brain injuries (TBI) because of detonations have become a significant problem in military medicine. Partly because the use of modern body protection has increased the survival of victims subjected to detonations from landmines or improvised explosive devices. Detonations commonly expose these victims to pressure waves, high speed fragments, and bodily accelerations. The pressure wave itself may result in a mild TBI, commonly referred to as primary blast, while penetration of fragments into the brain and head rotations resulting from body accelerations can lead to more severe forms of TBI. The details of the cellular injury mechanisms of primary blast are still debated and studies are needed to understand the propagation and effects of the pressure waves inside the skull. Laboratory experiments with good control for physical parameters can provide information that is difficult to retrieve from real-life cases of blast injury. This study focused on head kinematics and pressure propagation into the animal brain cavity during simulated blast trauma (part 1) and the behavioral outcome (part 2). The rat blast model presented here produced maximum intracranial pressure increases of 6 bar while minimal pressure drops. Violent head-to-head restraint contact occurred at approximately 1.7 ms after the pressure pulse reached the head; this contact did not produce any high intracranial pressures. Working memory error was not significantly changed between the exposed and controls at 1 week after blast while significantly more reference memory errors at 5 days and 2 weeks following injury compared to sham after blast.