Survival risk assessment for primary blast exposures to the head.

Published

Journal Article

Many soldiers returning from the current conflicts in Iraq and Afghanistan have had at least one exposure to an explosive event and a significant number have symptoms consistent with traumatic brain injury. Although blast injury risk functions have been determined and validated for pulmonary injury, there is little information on the blast levels necessary to cause blast brain injury. Anesthetized male New Zealand White rabbits were exposed to varying levels of shock tube blast exposure focused on the head, while their thoraces were protected. The specimens were euthanized and evaluated when the blast resulted in respiratory arrest that was non-responsive to resuscitation or at 4?h post-exposure. Injury was evaluated by gross examination and histological evaluation. The fatality data from brain injury were then analyzed using Fisher's exact test to determine a brain fatality risk function. Greater blast intensity was associated with post-blast apnea and the need for mechanical ventilation. Gross examination revealed multifocal subdural hemorrhages, most often near the brainstem, at more intense levels of exposure. Histological evaluation revealed subdural and subarachnoid hemorrhages in the non-responsive respiratory-arrested specimens. A fatality risk function from blast exposure to the head was determined for the rabbit specimens with an LD(50) at a peak overpressure of 750?kPa. Scaling techniques were used to predict injury risk at other blast overpressure/duration combinations. The fatality risk function showed that the blast level needed to cause fatality from an overpressure wave exposure to the head was greater than the peak overpressure needed to cause fatality from pulmonary injury. This risk function can be used to guide future research for blast brain injury by providing a realistic fatality risk to guide the design of protection or to evaluate injury.

Full Text

Duke Authors

Cited Authors

  • Rafaels, K; Bass, CRD; Salzar, RS; Panzer, MB; Woods, W; Feldman, S; Cummings, T; Capehart, B

Published Date

  • November 2011

Published In

Volume / Issue

  • 28 / 11

Start / End Page

  • 2319 - 2328

PubMed ID

  • 21463161

Pubmed Central ID

  • 21463161

Electronic International Standard Serial Number (EISSN)

  • 1557-9042

Digital Object Identifier (DOI)

  • 10.1089/neu.2009.1207

Language

  • eng

Conference Location

  • United States