Exchange Rates of Gases Across the Tympanic Membrane in Rhesus Monkeys

• Published in: Acta oto-laryngologica Vol. 118; no. 4; pp. 567 - 573
• Main Authors: DOYLE, W. J, ALPER, C. M, SEROKY, J. T, KARNAVAS, W. J
• Format: Journal Article
• Language: English
• Published: Stockholm Informa UK Ltd 1998; Taylor & Francis; Taylor and Francis
• Subjects: Animals; Biological and medical sciences; Carbon Dioxide - pharmacokinetics; Ear, Middle - metabolism; Ear, Middle - physiology; Ent. Stomatology; Helium - pharmacokinetics; Investigative techniques, diagnostic techniques (general aspects); Macaca mulatta; Medical sciences; Partial Pressure; Pathology. Cytology. Biochemistry. Spectrometry. Miscellaneous investigative techniques; Tympanic Membrane - metabolism; Tympanum; Device; Monkey; Exploration; Experimental study; Pressure; Vertebrata; Spectrometry; Mammalia; Animal; Primates; Gas exchange; Middle ear
• ISSN: 0001-6489; 1651-2251
• DOI: 10.1080/00016489850154748

The exchange rates of CO2 and He across the tympanic membrane were estimated in 5 monkeys. For these experiments, the monkey was anesthetized and one arm of a polyethylene ?T? tube was introduced into the external canal of the test ear and sealed to the ambient environment with wax. One arm of the T tube was attached to a pressure transducer and the other to an argon gas source via a valve. Silica tubing sealed within the probe provided periodic gas samples for composition analysis by an online mass spectrometer. Prior to each experiment, the probe was washed with Argon. In 5 experiments the probe was sealed within the external canal of animals with physiological middle ear gas compositions, and in 5 experiments the probe was sealed within the external canal of animals whose middle ears were partially washed with He. The gas in the probe was sampled and analyzed at 10-min intervals for up to 4 h. The results documented a significant increase in the percentage composition of CO2 but not He in the experiments conducted with physiological middle ear gas compositions, and increases in both He and CO2 in the experiments conducted after the middle ear was washed with He. Estimated, average exchange constants for He and CO2 were 0.0005