Middle ear gas exchange in isobaric counterdiffusion

1979 ◽  
Vol 47 (6) ◽  
pp. 1239-1244 ◽  
Author(s):  
C. W. Dueker ◽  
C. J. Lambertsen ◽  
J. J. Rosowski ◽  
J. C. Saunders
Keyword(s):  
Nitrous Oxide ◽  
Gas Exchange ◽  
Tympanic Membrane ◽  
Eustachian Tube ◽  
Middle Ear ◽  
Inert Gas ◽  
Pressure Measurements ◽  
Gas Sampling ◽  
Gas Space ◽  
Counter Diffusion

Nitrous oxide entry into the middle ear gas space was studied in cats in relation to anesthesia and the vestibular dysfunction caused by isobaric inert gas counter-diffusion in diving. A catheter implanted in the auditory bulla was used for direct gas sampling and pressure measurements. Experiments were designed to evaluate the participation of the eustachian tube, mucosal blood vessels, and tympanic membrane in middle ear gas exchange. The eustachian tube did not contribute to N2O entry and the mucosal blood supply only contributed about one-third of the total N2O accumulation. Diffusion across the tympanic membrane accounted for most of the N2O entering the middle ear from ambient and respiratory environments containing N2O.

scholarly journals Epitympanic Diaphragm: Endoscopic Functional Tympanoplasty

2018 ◽  
Vol 01 (01) ◽  
pp. 023-028
Author(s):  
Sreerama Boddepalli ◽  
Rajesh Boddepalli
Keyword(s):  
Gas Exchange ◽  
Tympanic Membrane ◽  
Eustachian Tube ◽  
Middle Ear ◽  
Normal Mucosa ◽  
Tympanic Membrane Perforation ◽  
Middle Ear Mucosa ◽  
Tympanic Membrane Perforations ◽  
Membrane Perforation ◽  
Middle Ear Cleft

Abstract Background Simple closure of tympanic membrane perforation is not a successful myringoplasty. It has to obey a lot of functional aspects of the middle ear cleft. Certain factors play a role in failure cases. The endoscopic functional myringoplasty or tympanoplasty is a clear visualization of all the parts of the middle ear; examination and removal of the disease from the hidden parts of the middle ear, examination of inter-attico-tympanic diaphragm; and removal of blocks, if any, in isthmus, to reestablish the gas exchange pathways and finally preserve the middle ear mucosa at maximum to further restore the ventilation. Methods Endoscopic tympanoplasty was performed in 100 patients with large tympanic membrane perforations and patent eustachian tube, using 4-mm “0” and “45” degree endoscopes by proper visualization of the tympanic diaphragm and isthmus in every patient and clearing its blockage if present. Results Among the 100 patients, 78 had epitympanic diaphragm blockage at the level of isthmus, 5 patients were found with closed tensor tympani folds, both vertical and horizontal without any ventilatory routes in them. Although in all the patients the eustachian tube was patent, we found majority of them had a dysventilation at the level of the epitympanic diaphragm. Thus, by performing endoscopic ventilatory pathway clearance and tympanoplasty, we achieved 94% positive results. Conclusion Epitympanic diaphragm is a functional barrier between upper and lower compartments of the middle ear cleft, which play important role in the ventilation and partial pressure regulation, blockage of its isthmus may lead to tympanic membrane retractions and perforations. With the aid of endoscopes of various degrees, removing any pathological blocks, recreating proper ventilation, reestablishing gas exchange mechanism, and maximum preservation of normal mucosa for the gas exchange are the aims of an endoscopic functional tympanoplasty procedure.

Causes of failure of combined approach tympanoplasty in the treatment of acquired cholesteatomas of the middle ear and the mastoid

1995 ◽  
Vol 109 (8) ◽  
pp. 710-712 ◽  
Author(s):  
T. R. Kapur
Keyword(s):  
Tympanic Membrane ◽  
Eustachian Tube ◽  
Middle Ear ◽  
Squamous Epithelium ◽  
Combined Approach ◽  
Tube Obstruction ◽  
Incomplete Removal ◽  
Tube Dysfunction ◽  
Cause Of Failure ◽  
Causes Of Failure

AbstractForty cases of failed combined approach tympanoplasty were analysed. The commonest cause of failure was adhesions between the facial ridge and the tympanic membrane, causing segmental attico-mastoid malaeration in 51.3 per cent of cases followed-up continually. Other causes were, large dermoids, incomplete removal of squamous epithelium, and eustachian tube obstruction. Eustachian tube dysfunction did not appear to be a major cause of failure.

Eustachian Tube Ventilatory Function in Children

1976 ◽  
Vol 85 (2_suppl) ◽  
pp. 171-177 ◽  
Author(s):  
Erdem I. Cantekin ◽  
Charles D. Bluestone ◽  
Leon P. Parkin
Keyword(s):  
Tympanic Membrane ◽  
Eustachian Tube ◽  
Middle Ear ◽  
Chronic Otitis Media ◽  
Response Characteristic ◽  
Ventilatory Function ◽  
Stimulus Response ◽  
Tympanostomy Tubes ◽  
History Of ◽  
Middle Ear Disease

In order to establish a simple stimulus-response characteristic of Eustachian tube physiology in children, the tubal ventilatory function was studied. The parameters of active and passive opening of the tube were measured for three groups of patients with non-intact tympanic membranes. The group with traumatic perforations of the tympanic membrane without any history of middle ear disease had better active equilibration function than the group with chronic otitis media and perforations of the tympanic membrane and the group with tympanostomy tubes in the tympanic membrane. Quantitatively, this could be expressed in terms of residual positive pressures. In the study of repeated inflation of the middle ear, all groups had lower second opening pressures which are attributed to the effect of surface forces.

Experimental Retraction Pocket Cholesteatoma

1986 ◽  
Vol 95 (6) ◽  
pp. 639-644 ◽  
Author(s):  
David E. Wolfman ◽  
Richard A. Chole
Keyword(s):  
Animal Model ◽  
Experimental Evidence ◽  
Tympanic Membrane ◽  
Eustachian Tube ◽  
Middle Ear ◽  
Mongolian Gerbils ◽  
Retraction Pocket ◽  
Tube Obstruction ◽  
Middle Ear Fluid ◽  
Acquired Cholesteatoma

An animal model for retraction pocket (primary acquired) cholesteatoma is presented. Bilateral eustachian tube obstruction by electrocauterization of the nasopharyngeal portion was performed in 16 Mongolian gerbils. Animals were killed at 2, 4, 8, and 16 weeks. At 2 weeks all animals had bilateral serous effusions and retracted tympanic membranes. At 4 weeks, four of eight ears had middle ear fluid, retractions, and cholesteatomas. After 8 weeks, five of eight ears had middle ear effusions, and four of these had cholesteatomas; one ear had total atelectasis with a cholesteatoma filling the bulla. By 16 weeks, six of eight ears had developed cholesteatomas. Some animals did not develop effusion or retraction because of failure or recanalization of eustachian tube obstruction. This study provides experimental evidence that aural cholesteatomas may arise by retraction of the tympanic membrane.

“EFFECT OF ANTERIOR NASAL PACKING ON MIDDLE EAR FUNCTION AND HEARING: A PROSPECTIVE STUDY”

2020 ◽  
Vol VOLUME 8 (ISSUE 1) ◽  
pp. 9-14
Author(s):  
Sachin Jain
Keyword(s):  
Prospective Study ◽  
Key Words ◽  
Tympanic Membrane ◽  
Eustachian Tube ◽  
Middle Ear ◽  
Hearing Threshold ◽  
Nasal Packing ◽  
Middle Ear Pressure ◽  
A Prospective Study

Introduction- The Eustachian tube provides an anatomic communication between the middle ear and nasopharynx, and maintains pressure equality across the tympanic membrane. Objective- To see the effect of anterior nasal packing on Otological symptoms, middle ear pressure and hearing Materials and method- This prospective study was carried out during period of September 2018 till August 2019. 100 ears were taken in the study. Middle ear pressure and hearing threshold were evaluated by Tympanometry and Audiometry respectively. Results- Postoperatively two days after anterior nasal packing, there was increase in no. of patient ears with ear fullness, ear ache, tinnitus, hearing threshold and abnormal negative middle ear pressure. After removal of nasal packing up to twelve weeks, improvement in middle ear pressure and hearing threshold was seen. Conclusion- Anterior nasal packing causes decrease in middle ear pressure and increase in hearing threshold. Key words- Eustachian tube, Middle ear pressure, Hearing threshold

The influence of nitrous oxide anaesthetic on middle-ear fluid

1978 ◽  
Vol 92 (2) ◽  
pp. 131-135 ◽  
Author(s):  
James O. Shaw ◽  
Earl W. Stark ◽  
Stephen D. Gannaway
Keyword(s):  
Nitrous Oxide ◽  
Eustachian Tube ◽  
Middle Ear ◽  
Positive Pressure ◽  
Middle Ear Fluid ◽  
Nitrous Oxide Anaesthesia ◽  
Oxide Anaesthesia

AbstractNITROUS OXIDE anaesthesia invades the middle-ear cavity, resulting in a positive pressure within this cavity. It has been suggested that the pressure may be sufficient to force open the Eustachian tube and evacuate fluid from the middle ear. This study examined the possible influence of nitrous oxide on middle-ear fluid. Pre- and intra-operative tympanograms were obtained on 39 children scheduled for myringotomy surgery. Fluid was found in 83-1 per cent of the operated ears while the absence of fluid was noted in 16-9 per cent. It is possible that the nitrous oxide anaesthetic did cause an evacuation of fluid from this latter group of ears prior to actual surgery.

A case of primary diphtheria of the outer ear

1927 ◽  
Vol 23 (4) ◽  
pp. 472-473
Author(s):  
L. Ilyina
Keyword(s):  
Tympanic Membrane ◽  
Otitis Media ◽  
Eustachian Tube ◽  
Middle Ear

The author notes that diphtheria, especially primary diphtheria of the outer ear, is extremely rare. The usual way of spreading the infection should be considered the pharynx, the Eustachian tube, the middle ear, and finally the outer ear. Therefore, all cases of supposedly primary diphtheria with perforation of the tympanic membrane and former, existing or subsequent otitis media should be considered doubtful.

Eustachian Tube Function and Retraction of the Tympanic Membrane

1980 ◽  
Vol 89 (3_suppl) ◽  
pp. 65-66 ◽  
Author(s):  
Jörgen Holmquist ◽  
Ulf Renvall ◽  
Pål Svendsen
Keyword(s):  
Tympanic Membrane ◽  
Eustachian Tube ◽  
Middle Ear ◽  
Air Pressure ◽  
Eustachian Tube Function ◽  
Present Material ◽  
Pressure Equalization ◽  
Air Volume ◽  
Middle Ear Cholesteatoma ◽  
Tube Function

The medial displacement of the tympanic membrane or the retracted tympanic membrane is a common clinical finding. Also, retractions are looked upon as the precursor of middle ear cholesteatoma. In current otologic literature there seems to be some dispute whether the retractions of the tympanic membrane are caused by negative intratympanic air pressure or by shrinkage of middle ear adhesions pulling the tympanic membrane or part of it medially. In this study only ears with posterior/superior retractions of the tympanic membrane were investigated. Tympanometry revealed that only 33% of the ears did have middle ear pressure within ± 100 mm H2O. After insertion of a polyethylene tube through the tympanic membrane, the eustachian tube function was tested using the air pressure equalization technique. None of the ears could change the negative air pressure upon swallowing. Planometric measurements on the x-ray of the mastoid air cell system of the present material deviate from those of a normal material, indicating a significantly smaller air volume in the present material. It may be concluded that dysfunction of the eustachian tube and a small air volume of the mastoid are characteristic features of an ear with posterior/superior retraction of the tympanic membrane.

scholarly journals Eustachian tube mucociuary transport in chronic suppurative otitis media

2004 ◽  
Vol 132 (5-6) ◽  
pp. 148-151 ◽  
Author(s):  
Snezana Jesic ◽  
Vladimir Nesic
Keyword(s):  
Tympanic Membrane ◽  
Otitis Media ◽  
Eustachian Tube ◽  
Middle Ear ◽  
Chronic Suppurative Otitis Media ◽  
Traumatic Rupture ◽  
Mucociliary Transport ◽  
Tympanic Cavity ◽  
Suppurative Otitis Media ◽  
Mean Time

Eustachian tube dysfunction is one of the well-known factors leading to development of chronic suppurative otitis media. Tube mucociliary transport is important for elimination of the inflammation products from the middle ear enabling recovery of the affected mucosa of the middle ear, local circulation and restoration of normal air pressure in the middle ear. The study was aimed at determining: 1. whether perforation site on the tympanic membrane influences tube mucociliary transport time in individuals with traumatic rupture of the eardrum; 2. possible time difference of tube mucociliary transport between group of patients with chronic suppurative otitis media and group of patients with traumatic rupture of the tympanic membrane; 3. possible time difference of tube mucociliary transport between chronic tubotympanic type of suppurative otitis media, so called tubotympanic otitis media and atticoantral type of chronic suppurative otitis media, the so called atticoantral otitis; 4. the association between the degree of defect of the tympanic membrane mucosa and time of tube mucociliary transport in each individual type of chronic suppurative inflammation of the middle ear. Eustachian tube mucociliary transport was studied in 16 patients with tubotympanic otitis, in 13 patients with atticoantral otitis and in 9 patients with traumatic rupture of the eardrum (control group of patients). All patients were treated at the Institute of Otorhinolaryngology and Maxillofacial Surgery, Clinical Centre of Serbia in Belgrade during 2002. Tube mucociliary transport was studied upon instillation of 10 ?l 5% sterile saccharine solution through the existing eardrum perforation in the course of preoperative preparation of the patient for surgical intervention. The time interval from the moment of sterile saccharine solution application till perception of the sweet taste in the mouth and pharynx was measured in studied patients. The obtained results were analyzed using the methods of descriptive and analytical statistics (t-test for small independent samples). The mean time of tube mucociliary transport in patients with traumatic rupture of the tympanic membrane was 7.6 minutes. The mean time of tube mucociliary transport in tubotympanic otitis with normal mucosa of the tympanic cavity promontorium was 15 minutes, while mean time of tube mucociliary transport in tubotympanic otitis with polypoid changes of the promontory mucosa was 24 minutes (t=5.218; p<0.01). Mean time of tube mucociliary transport in atticoantral otitis with normal promontory mucosa of the tympanic cavity was 35.5 minutes, while mean time of mucociliary tube transport in atticoantral otitis with polypoid changes of promontory mucosa was 48 minutes (t=6.99; p<0.01). In the irreversibly changed tympanic cavity mucosa, tube clearance saccharine test was negative even after one hour. The results of our study indicate the possibility that prolonged mucociliary tube transport has greater influence to development of atticoantral otitis rather than to development of tubotympanic otitis. The association between the degree of mucosal defect and time of mucociliary transport was evidenced in both types of chronic suppurative inflammation of the middle ear.

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