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February 1985

Inhalation of Carbon Dioxide Mixtures for Sensorineural Deafness: Evaluation of a Rebreathing Method

Author Affiliations

From the Departments of Otolaryngology (Dr Freeman) and Anesthesiology (Dr Salamonsen), Alfred Hospital, and Monash University (Dr Mainland), Melbourne.

Arch Otolaryngol. 1985;111(2):75-78. doi:10.1001/archotol.1985.00800040039002

• A laboratory study in 11 healthy subjects was conducted to evaluate the performance of a rebreathing device as a means of raising the effective carbon dioxide level in the inspiratory mixture. In all subjects, there was a sustained rise in end-tidal carbon dioxide levels and a transient rise in end-tidal nitrogen tensions associated with an equivalent fall in end-tidal oxygen levels. Although the rise in end-tidal carbon dioxide tensions was variable, the mean elevation for the 11 subjects (from 36 to 43 mm Hg) was not equivalent to elevations reported to follow inhalation of 5% carbon dioxide mixtures. Nevertheless, the volume of the device was sufficient to cause a marked depression of the end-tidal oxygen level (to 67 mm Hg) in one subject. Despite the simplicity and cost-effectiveness of the rebreathing method, it cannot be recommended in the treatment of sudden or fluctuant sensorineural deafness.

(Arch Otolaryngol 1985;111:75-78)

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