CO(2) gas exchange across the human tympanic membrane is not appreciably affected by pathology.
Past in vivo studies in humans showed that the tympanic membrane (TM) is permeable to physiological gases. Animal studies show that transTM CO(2) conductance is increased by TM pathology. The objective of the study was to determine if transTM CO(2) exchange in humans is affected by atrophic and sclerotic pathologies. The study used an ear canal (EC) probe (ECP) constructed from a custom-fitted 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 CO(2) 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 CO(2) gradient at the start of the experiment to yield transTM CO(2) conductance (microL/min/Pa). Data were complete for 15 normal, 13 sclerotic and 9 atrophic TMs. The average (+std) transTM CO(2) 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) microL/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 CO(2) exchange rate for thinner TMs approached statistical significance (P = 0.07). A similar pairwise comparison for the sclerotic and normal TMs did not approach statistical significance (P = 0.28). The effect of TM pathologies on CO(2) conductance was limited.
Yuksel
Sancak
S
Department of Otorhinolaryngology-Head and Neck Surgery, University of Texas Medical School at Houston, 6431 Fannin Street, MSB 5.036, Houston, TX 77030, USA. sancak.yuksel@uth.tmc.edu
Douglas Swarts
J
J
Banks
Juliane
J
Doyle
William J
WJ
D000293:Adolescent; D000328:Adult; D001284:Atrophy; D002245:Carbon Dioxide / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012598:Sclerosis; D014432:Tympanic Membrane / Q000378:metabolism* / Q000473:pathology; D055815:Young Adult
D002245:Carbon Dioxide
Acta Otolaryngol. 2009 Jul;129(7):716-25
18728916
Respir Physiol. 1970 Apr;9(1):74-85
5443582
Acta Otolaryngol. 1990 Jul-Aug;110(1-2):92-9
2386039
Acta Otolaryngol. 1998 Jul;118(4):567-73
9726685
Acta Otolaryngol Suppl. 1980;371:1-23
6272533
Auris Nasus Larynx. 2004 Dec;31(4):353-9
15571907
J Appl Physiol (1985). 2005 May;98(5):1592-602
15608090
Acta Otolaryngol. 1970 Mar;69(3):185-91
5446885
J Appl Physiol Respir Environ Exerc Physiol. 1979 Dec;47(6):1239-44
536296