Transient increases in total pressure in the ear (1) during sleep, after hypoventilating in a supine position with a closed eustachian tube, and (2) after the partial pressures in middle-ear gas are lowered by a total pressure decrease and the eustachian tube is voluntarily maintained closed can be accounted for quantitatively on the basis of the standard mucosal gas exchange model and the following data: (1) partial pressures in tissue: p*N2 = 573 mm Hg (7621 decaPascals [daPa]), p*O2 = 40 mm Hg (532 daPa), p*CO2 = 46 mm Hg (612 daPa), and p*H2O R = 47 mm Hg (625 daPa); (2) partial pressures in the nasopharynx: p′N2 = 566 mm Hg (7528 daPa), p′O2= 120 mm Hg (1596 daPa), p′CO2 = 27 mm Hg (359daPa), and p′H2O = 47 mm Hg (625daPa); (3) a middle-ear gas space of 2×10−5 m3; (4) an absorption rate for nitrogen, when the partial pressure difference is 1 atm, of 3×1015 molecules per second; and (5) mucosal absorption rates for oxygen and carbon dioxide 1.8 and 34 times larger, respectively, than for nitrogen.
(Arch Otolaryngol Head Neck Surg. 1991;117:1390-1394)
Ostfeld EJ, Silberberg A. Transient Pressure Changes in the Middle Ear. Arch Otolaryngol Head Neck Surg. 1991;117(12):1390-1394. doi:10.1001/archotol.1991.01870240082013