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A L Yee

Publications and source records attributed to A L Yee.

2 recordsLinked to original sources
PubMedDate not supplied

Effect of changes in systemic oxygen tension on middle ear gas exchange.

The effect of alterations in the systemic oxygen tension on middle ear (ME) gas exchange was studied in three juvenile rhesus monkeys (Macaca mulatta) using five different inspired oxygen concentrations ranging from 15% to 100%. The anesthetized animals were ventilated for 4 hours, breathing the set of predetermined, constant oxygen-nitrogen gas mixtures. During this period, arterial and venous oxygen and carbon dioxide partial pressures were measured at 30-minute intervals; total ME gas pressure was determined indirectly using tympanometry at 10-minute intervals. Systemic oxygen blood gas tension showed predictable changes which were dependent on the fraction of inspired oxygen. However, fluctuations in the total ME gas pressure were insignificant. Findings suggested that increased systemic oxygen partial pressure does not influence ME gas exchange.

Animals↗
PubMedDate not supplied

Middle ear pressure after changes in steady state.

The combined effect of changes in middle ear (ME) gas composition and changes in systemic arterial blood oxygenation on total ME pressure was studied in three anesthetized juvenile Rhesus monkeys (Macaca mulatta). The gas composition of the ME was altered by ME inflation (politzerization) using either pure nitrogen, oxygen, or carbon dioxide while the animal was ventilated with either room air or 100% oxygen at constant carbon dioxide blood gas tension. Total ME pressure was measured indirectly by tympanometry (acoustic impedance) for a 5-hour duration. The changes in ME pressure were consistent and reproducible, exhibiting different pressure-time patterns unique for each gas. Carbon dioxide resulted in the most rapid decrease in ME pressure, followed by oxygen. The slowest decrease was observed in experiments with nitrogen. The systemic hyperoxygenation had little or no effect on the results. The findings were explained by the differences in relative permeabilities of these gases influencing ME gas diffusion, but the lack of systemic hyperoxygenation effect remained unexplained.

Animals↗