Internal Jugular Vein Compression: A Novel Approach to Mitigate Blast Induced Hearing Injury.

HYPOTHESIS: Internal jugular vein (IJV) compression before blast injury will lead to reduced risk of traumatic hearing injury following exposure to a blast injury.

BACKGROUND: IJV compression and its effects on not only intracranial, but also intracochlear pressure may potentiate blast induced hearing injury, therefore, precluding its use as a prophylactic therapy for blast induced traumatic brain injury.

METHODS: Twenty Sprague Dawley rats were exposed to a 17.9 ± 0.4 PSI (195.8 dB SPL) right sided shock wave in which 10 had application of a custom IJV compression collar before injury. All rodents received baseline and post blast injury otoacoustic emission (OAE) and auditory brainstem response (ABR) testing followed by cochlear histology.

RESULTS: IJV compression was shown to significantly reduce ABR and OAE threshold shifts in comparison to the non-intervention group by: 14.9 ± 4.8 dB (right ear ABR 0.5 kHz Day 1 post blast, p = 0.01), 13.1 ± 4.9 dB (right ear ABR 4 kHz Day 1 post blast, p = 0.04), 16.5 ± 4.5 dB (right ear ABR click Day 1 post blast, p = 0.003), 12.1 ± 4.6 dB (right ear ABR click Day 6 post blast, p = 0.04), and 14.0 ± 3.2 dB (both ears OAE 3.2-10 kHz, p < 0.0001). Also, those animals with collar application had a greater number of total hair cells per mm from 70 to 100% distance from the cochlear apex following blast injury in comparison to those without intervention (blast: 211.8 ± 27.5 versus blast+collar: 355.5 ± 39.5 [p = 0.0002]).

CONCLUSION: This study supports the use of IJV compression in a pre-clinical model as a new prophylactic mechanism to combat blast induced hearing injury.