The most frequent etiologic factor in chronic otitis media is an occlusion of the eustachian tube, caused by an extension of the inflammatory process of the mucosa of the nose and throat to the mucosa of the eustachian tube. The occlusion, according to Bezold, produces an absorption of oxygen from the blood in the tympanic cavity and an increased production of carbon dioxide. Heat increases the flow of blood, thereby increasing the production of oxygen and eliminating acids, chiefly carbon dioxide.
In most infectious processes, nature produces what we call "inflammation": an increased amount of heat followed by an increased flow of blood to the infected area, which eliminates the increased acidity and renders the exudate alkaline. In all inflammatory affections, heat has a potent remedial effect for the reason before stated. In obstinate joint conditions, heat, in the form of so-called baking, is an efficient and frequently used remedial
GUTTMAN J. A NEW INSTRUMENT FOR THE TREATMENT OF CHRONIC CATARRHAL OTITIS MEDIA WITH SUPERHEATED AIR. Arch Otolaryngol. 1926;3(5):453–455. doi:10.1001/archotol.1926.00580010483009