Reduction in Temporary and Permanent Audiological Injury Through Internal Jugular Vein Compression in a Rodent Blast Injury Model.

HYPOTHESIS: Internal jugular vein (IJV) compression influences not only intracranial but also intracochlear physiology and has demonstrated preclinical effectiveness in reducing acute audiological injury in a rodent blast model. However, the long-term effects in this model are unknown.

BACKGROUND: Blast wave-induced audiological injury from an improvised explosive device is a leading cause of morbidity among service members in theater but there are limitations to the current protective measures.

METHODS: For this study, we exposed 20 Sprague Dawley rats to a 16.8 ± 0.3 PSI (195.3 dB SPL) right-sided shock wave in which 10 had application of a custom IJV compression collar in place at the time of injury.

RESULTS: IJV compression at the time of injury was shown acutely to significantly reduce the incidence of tympanic membrane rupture and the initial temporary threshold shift on otoacoustic emissions in both the right and left ears of animals who had collar application immediately after and 7 days post injury. At 28 days from injury, collared animals demonstrated a return to baseline of otoacoustic emission values while the noncollared animals had persistent threshold shifts, signifying the presence of a permanent threshold shift only in those animals without collar application. IJV compression was also found to significantly reduce hair cell loss at the base of the cochlea secondary to mechanical trauma from the blast wind.

CONCLUSION: Previously observed acute protective effects of IJV compression are sustained at chronic time points. IJV compression can potentially be used to reduce long-term permanent morbidity from blast-induced audiological trauma.