The effect of noise and carbogen on cochlear vasculature.

Histological measures of cochlear vasculature and blood flow were examined in 24 guinea pigs. Six animals were exposed to white noise at 120 dB SPL while breathing carbogen (10% CO2 and 90% O2) for 30 min. Six subjects were noise exposed while breathing air. Six breathed carbogen without noise exposure and six served as unexposed air-breathing controls. The statistically significant results indicate that noise resulted in reduced blood supply to the cochlea and that carbogen increased cochlear blood flow. When animals were exposed to both noise and carbogen, carbogen tended to counteract the reduced blood supply effects of noise.