A Multi-Mode Shock Tube for Investigation of Blast-Induced Traumatic Brain Injury

Abstract

Blast-induced mild traumatic brain injury (bTBI) has become increasingly common in recent military conflicts. The mechanisms by which non-impact blast exposure results in bTBI are incompletely understood. Current small animal bTBI models predominantly utilize compressed air-driven membrane rupture as their blast wave source, while large animal models use chemical explosives. The pressure-time signature of each blast mode is unique, making it difficult to evaluate the contributions of the different components of the blast wave to bTBI when using a single blast source. We utilized a multi-mode shock tube, the McMillan blast device, capable of utilizing compressed air- and compressed helium-driven membrane rupture, and the explosives oxyhydrogen and cyclotrimethylenetrinitramine (RDX, the primary component of C-4 plastic explosives) as the driving source. At similar maximal blast overpressures, the positive pressure phase of compressed air-driven blasts was longer, and the positive impulse was greater, than those observed for shockwaves produced by other driving sources. Helium-driven shockwaves more closely resembled RDX blasts, but by displacing air created a hypoxic environment within the shock tube. Pressure-time traces from oxyhydrogen-driven shockwaves were very similar those produced by RDX, although they resulted in elevated carbon monoxide levels due to combustion of the polyethylene bag used to contain the gases within the shock tube prior to detonation. Rats exposed to compressed air-driven blasts had more pronounced vascular damage than those exposed to oxyhydrogen-driven blasts of the same peak overpressure, indicating that differences in blast wave characteristics other than peak overpressure may influence the extent of bTBI. Use of this multi-mode shock tube in small animal models will enable comparison of the extent of brain injury with the pressure-time signature produced using each blast mode, facilitating evaluation of the blast wave components contributing to bTBI.

Department(s)

Mining Engineering

Keywords and Phrases

Carbon Monoxide; Cyclonite; Explosive; Helium; Hydrogen; Polyethylene; Animal Experiment; Animal Tissue; Army; Article; Blast Injury; Blood Vessel Injury; Combustion; Comparative Study; Compressed Air; Conflict; Device; Environment; Exposure; Gas; Hyperbarism; Hypoxia; Male; Membrane Rupture; Multi Mode Shock Tube; Nonhuman; Rat; Shock; Shock Wave; Traumatic Brain Injury; Animals; Blast Injuries; Brain Injuries; Compressed Air; Disease Models, Animal; Explosions; High-Energy Shock Waves; Laboratory Techniques and Procedures; Male; Rats; Rats, Sprague-Dawley; Helium; Overpressure; Oxyhydrogen; Pressure-Time Signature; RDX

International Standard Serial Number (ISSN)

0897-7151

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2011 Mary Ann Liebert Inc., All rights reserved.

Publication Date

01 Jan 2011

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