CO2 gas exchange across the human tympanic membrane is not appreciably aVected by pathology
- نوع فایل : کتاب
- زبان : انگلیسی
- مؤلف : Sancak Yuksel · J. Douglas Swarts · Juliane Banks · William J. Doyle
- چاپ و سال / کشور: 2011
Description
Past in vivo studies in humans showed that the tympanic membrane (TM) is permeable to physiological gases. Animal studies show that transTM CO2 conductance is increased by TM pathology. The objective of the study was to determine if transTM CO2 exchange in humans is aVected by atrophic and sclerotic pathologies. The study used an ear canal (EC) probe (ECP) constructed from a custom- Wtted acrylic body, a glass capillary tube enclosing an oil meniscus to maintain ambient ECP + EC pressure and a silica glass microtube linked to a mass spectrometer (MS) for measuring gas composition that was hermetically sealed within the ear canal of the test ear. ECP + EC volume was measured and gas samples taken at 10 min intervals for 1 h. The fractional CO2 pressure measured in the ECP + EC for each sample was regressed on time and the slope of the function multiplied by the ECP + EC volume and divided by the estimated transTM CO2 gradient at the start of the experiment to yield transTM CO2 conductance (L/min/ Pa). Data were complete for 15 normal, 13 sclerotic and 9 atrophic TMs. The average (+std) transTM CO2 conductances were 1.76 £ 10،4 + 7.27 £ 10،5, 2.26 £ 10،4 + 1.5 £ 10،4 and 2.36 £ 10،4 + 1.14 £ 10،4 L/min/Pa/TM for the normal, sclerotic and atrophic TMs, respectively. A pairwise comparison of data for the normal and atrophic TMs under the directional hypothesis of a greater CO2 exchange rate for thinner TMs approached statistical signiWcance (P = 0.07). A similar pairwise comparison for the sclerotic and normal TMs did not approach statistical signiWcance (P = 0.28). The eVect of TM pathologies on CO2 conductance was limited.
Eur Arch Otorhinolaryngol (2011) 268:203–206, Received: 30 May 2010 / Accepted: 12 August 2010 / Published online: 1 September 2010 © Springer-Verlag 2010
