Cochlear temperature correlates with both temporalis muscle and rectal temperatures. Application for testing the otoprotective effect of hypothermia

Abstract

The strongest correlations with the internal temperature of the cochlea during the induction of mild-to-moderate hypothermia were obtained for the temperatures of the ipsilateral temporalis muscle and rectum.

Induction of localized cochlear hypothermia

“…The level of hypothermia achieved by the irrigation of the open bulla and the bag of ice on bulla groups correlates well with previous human clinical trials demonstrating neuroprotective effects of hypothermia [12,13]. Although we have previously demonstrated that mild systemic hypothermia decreases the loss of hearing in an animal model of electrode trauma-induced hearing loss [16], and that cochlear temperature correlates with body core temperature during systemic hypothermia [15], additional study will be required to definitively demonstrate that localized cochlear hypothermia prevents loss of residual hearing during cochlear implantation.…”

“…In a murine model, systemic hypothermia (308C) was protective against noiseinduced sensorineural hearing loss [14]. Mild systemic hypothermia results in a concurrent change in cochlear temperature [15]. We have recently demonstrated that mild systemic hypothermia (348C) can significantly reduce loss of residual hearing in an animal model of cochlear implantation trauma [16].…”

Mild Hypothermia Protects Auditory Function During Cochlear Implant Surgery

“…In the first phase of establishing this rat model for testing of a possible otoprotective effect of mild hypothermia, we demonstrated that cochlear temperature has a highly linear correlation with brain, rectal, and the temporalis muscle temperature using microprobes 15 . This procedure established that accurate, noninvasive estimation of inner ear temperature by monitoring rectal temperature could be obtained and was used to reflect the internal temperature of the cochlea during whole body cooling in the current experiment.…”

Early postnatal development of rat brain: In vivo diffusion tensor imaging

“…Therefore, after an exposure of about 1 hr to a flow of warm air, it is reasonable to assume that the core temperature of the brain does not significantly differ from the surface temperature. For older animals, the rectal temperature is shown to correlate strongly with the core temperature (Eshraghi et al, 2005;Greer et al, 2007). The oxygen level and heart rate were monitored with an MRI-compatible pulse oximeter (NONIN, Plymouth, MN).…”