Effect of atropine on the eustachian tube function

The effect of atropine on the eustachian tube function was studied by means of a recently designed method. The results out of 20 examined ears showed that atropine significantly reduced both active and passive functions of the eustachian tube. The findings are discussed and it is concluded that the method used might be a valuable tool in forthcoming studies of pharmacological effects on the eustachian tube function.     

Effect of nasal packing on eustachian tube function

Sixty-three patients undergoing surgery to the nasal septum followed by bilateral packing had pre- and post-operative tympanometry in order to determine the effect on eustachian tube function. Fifty-five of the 126 ears tested (46 per cent) developed a reduction in middle ear pressure of at least 50 daPa; 76 per cent became normal within 24 hours of removing the nasal packs. All ears were asymptomatic and no patient had evidence of middle ear effusion. Nasal packing following septal surgery is a frequent cause of short-lasting eustachian tube dysfunction but rarely severe enough to cause symptoms or middle ear effusion. Tubal dysfunction is most likely due to a combination of surgical oedema and a direct effect of the nasal packing.     

Effect of terbutaline on human eustachian tube function

Terbutaline, a beta 2-adrenoceptor agonist, was administered subcutaneously to 10 healthy adult subjects. The pressure opening level (Pol) of the Eustachian tube (ET) and the remaining middle ear pressure when the ET closed (Pcl) after passive equilibration were measured as well as parameters for active tubal function. A quantitative impedance method in combination with a pressure chamber was used. Pol was reduced by 0.29 +/- 0.10 (-7.3%) kPa 90 min after injection of terbutaline 5 micrograms/kg body weight. There was also a decrease in Pcl, 0.17 +/- 0.06 kPa (-14.0%). No such decrease was seen after saline solution injected subcutaneously. It is suggested that terbutaline facilitates the ET opening by stimulating the secretion of surface tension lowering substances.     

Update on eustachian tube dysfunction and the patulous eustachian tube

PURPOSE OF REVIEW: The purpose of this review is to summarize the recent knowledge on eustachian tube dysfunction and the patulous eustachian tube. RECENT FINDINGS: A clinically useful test for eustachian tube function is still lacking. Narrowing of the isthmus alone was demonstrated to be an insufficient cause of otitis media. Inflammatory mediators identified within the eustachian tube and middle ear cells were causally linked with otitis media with effusion. Increasing evidence was found that allergic disease and reflux may be two of the most important contributors of tubal inflammation causing otitis media with effusion. The adenoid size and proximity to the torus tubaris may also be important in considering which patients with persistent otitis media with effusion may benefit from adenoidectomy. Computed tomography scan has documented loss of soft tissue within the cartilaginous eustachian tube in patients with patulous eustachian tubes. An endoscopic approach to seal the tubal lumen has been found to be effective in relieving patulous symptoms. SUMMARY: These studies suggest that allergic rhinitis and gastroesophageal reflux should be investigated in patients with eustachian tube dysfunction. Adenoidectomy should also be considered in patients who have adenoids that obstruct the torus tubaris. Patients with a patulous eustachian tube may benefit from an endoscopic closure. Further research is needed to identify a clinically useful test for eustachian tube dysfunction.     

Effect of nasogastric tubes on eustachian tube function

The Eustachian tube acts as pressure equalizing tube between the nasopharynx and the middle ear. It also functions as a conduit for removal of secretions from the middle ear and mastoid air cell system into the post nasal space. Eustachian tube function may be assessed objectively using tympanometric measurements. (Brooks, 1968, Lutman, 1987). The post-operative use of nasogastric Ryles tubes is associated with reduced peak middle ear pressure (mmH2O) and reduced peak compliance volumes (ml) as assessed by tympanometry. In addition changes in the appearance of the tympanic membrane may occur with the protracted use of Ryles tubes. This phenomenon is a transient one. Nasogastric tube-induced Eustachian tube dysfunction is a previously unreported entity.     

Effect of ambroxol on rabbit eustachian tube surfactant.

The effect of ambroxol administration on phospholipid and phosphatidyl-choline contents of rabbit eustachian tube and lung washings and on [14C]-choline incorporation by rabbit eustachian tube and lung tissue has been studied. Despite minor differences, the drug exerts the same activating effect in both locations. The results add a further piece of evidence to the several similarities existing between the lung surfactant and the surface-active substances present on the eustachian tube.     

Effect of inflation of the eustachian tube on tinnitus]

The purposes of this study were to evaluate the effect of inflating the Eustachian tube in patients with tinnitus, and to identify diseases in which tubal inflation is indicated. Fifty-four ears of as many patients complaining of tinnitus were examined by pure tone audiometry and decreases in pitch and loudness associated with tinnitus were also evaluated by tinnitus audiometry (Danac-100, DanaJapan). Tinnitus was associated with sensorineural hearing loss (SNHL) in 44 ears and not associated in the remaining 10. The subjects were classified further into two groups: the higher tone group showed a pitch range with tinnitus of 1000 Hz or higher, and the lower tone group showed a pitch range of less than 1000 Hz. In the higher tone tinnitus group with SNLH, the tubal inflation was effective in 3 of 31 ears (10%), and in the lower tone group, 10 of 13 ears (77%). On the other hand, in the tinnitus group with no hearing loss, the method relieved tinnitus in 6 of 10 ears (60%). In the higher tone tinnitus group with no hearing loss, the tubal inflation was effective in 3 of 6 ears (50%), and in the lower tone group, 3 of 4 ears (75%). In this study, however, no ears were permanently relieved of tinnitus with tubal inflation. In the higher tone group, the duration of the reduced tinnitus was less than 10 minutes. In 69% of the lower tone group, the reduction was from 20 minutes to 2 hours. The effect did not continue for more than 2 hours at the longest. In conclusion, Eustachian tubal inflation is indicated in diseases with tinnitus as follows: 1. Lower tone tinnitus with SNHL, particularly in Meniere's disease and acute onset low-tone type SNHL, may be temporarily relieved with tubal inflation. 2. Tinnitus in an ear without SNHL that may gain transitory relief from ringing with the tubal inflation.     

Mucociliary function of the eustachian tube in the eustachian tube dysfunction

Background: Most of the tests to evaluate the eustachian tube (ET) function are focused on the ventilation function of the ET.

Aim: Here we evaluate mucociliary function of the ET in patients with ET dysfunction.

Materials and methods: Ten patients with ET dysfunction were enrolled into the study. Six patients had chronic tympanic membrane retraction and four patients had chronic middle ear effusion (MEE). All patients had intact tympanic membranes. Tympanometry and clinical examinations were done to all patients. Mucociliary function was evaluated with technetium labeled albumin and blue dye. Tympanometry and clinical examinations were done to six patients with chronic tympanic membrane retraction and four patients with chronic middle ear effusion (MEE). Mucociliary function of the ET was evaluated with technetium labeled albumin and blue dye placed into middle ear through an intact tympanic membrane and followed from nasopharynx ET orifice (blue dye) and with gamma camera (technetium).

Results: Blue dye was observed in tubal orifice in six (6 of 10) patients during 30?min observation. Five of those patients (5 of 6) had tympanic membrane retraction and one patient (1 of 6) had MEE. Tracer activity decreased from middle ear in six (6 of 10) patients. Four of those patients had tympanic membrane retraction and two had MEE.

Conclusion: Mucociliary function of the ET seems to be better in patients with tympanic membrane retraction than patients with middle ear effusion.

Significance: Mucociliary function of the ET is an important function for middle ear aeration, blue dye test is easily available to be used also in clinical practice.     

Does the silastic eustachian tube prosthesis improve eustachian tube function?

This clinical study attempts to evaluate the effectiveness of Eustachian tube function in 30 ears, 11–29 months after insertion of the Silastic® Eustachian tube prosthesis (SETP). Indications for the SETP were limited to persistent Eustachian tube dysfunction. Preoperatively, 13 patients had intact tympanic membranes with persistent serous otitis media. Seventeen patients underwent tympanoplasty and demonstrated persistent serous otitis media in the opposite ear. Postoperatively, aeration of the middle ear was evaluated by tympanometry, microscopic examination, and myringostomy. Microphotographs demonstrate the state of the middle ear. Histology of the middle ear mucosa was obtained in a few cases. Ninety-six percent of the ears with an SETP demonstrated confirmed persistent Eustachian tube dysfunction beginning an average of six months after insertion. Complications were common.     

Effect of inflammation on the ventilatory function of the eustachian tube

In an attempt to determine the effect of an upper respiratory tract infection on the ventilatory function of the Eustachian tube, 20 children who had recurrent acute or chronic middle ear effusions were studied. Baseline Eustachian tube function testing was obtained when there were no signs or symptoms of upper respiratory infection. These tests were repeated at six-week intervals and whenever an upper respiratory tract infection supervened. The results of this study were the following:

• 1 In the absence of an upper respiratory tract infection, the Eustachian tube function tests indicated that all 20 children had a persistent function al obstruction of the Eustachian tube, which was attributed to an inefficient active tubal opening mechanism or increased tubal compliance, or both.
• 3 During periods of upper respiratory tract infection, Eustachian tube function became worse, which was attributed to intrinsic mechanical obstruction.
• 3 During the course of the study, middle ear effusion or atelectasis recurred in some of the children, which was not necessarily in association with an upper respiratory tract infection.

The basic problem in all of the children was functional obstruction of the Eustachian tube that could result in a middle ear effusion; however, in the absence of an effusion, their poor Eustachian tube function would place them at particularly high risk for developing one, especially during periods of upper respiratory infection. Since management of the functional Eustachian tube obstruction remains obscure at present, therapy should be directed toward alleviating the transient or persistent middle ear negative pressure or the intrinsic mechanical Eustachian tube obstruction when an upper respiratory infection is present     

Effect of exogenous surfactant on eustachian tube function in the rat

Three solutions, surfactant prepared from pig lungs, a mixture of synthetic phospholipids, and saline solution, were instilled into the middle ears of rats. The middle ear pressure necessary to force the eustachian tube open was studied. Ten minutes after instillation of pulmonary surfactant there was a 0.58 +/- 0.10 kPa decrease in the pressure opening level (P less than .001). The reduction persisted throughout the 50-minute experiment. There was also a reduction 0.17 +/- 0.16 kPa in the pressure opening level (P less than .01) after the administration of the synthetic phospholipid mixture. This reduction was significantly less than the reduction produced by the pulmonary surfactant. No decrease in the pressure opening level was seen after the instillation of saline solution into the middle ear cavity. The fact that surfactants are demonstrable in the middle ear and eustachian tube, coupled with these findings of an effect on the tubal opening, suggests a physiologic role for surface tension-lowering substances in tubal function.     

Effect of tensor veli palatini muscle paralysis on eustachian tube mechanics

Several physiological functions, such as regulating middle ear (ME) pressure and clearing ME fluid into the nasopharynx, require an opening of the collapsed eustachian tube (ET). The ability to perform these functions has been related to several mechanical properties of the ET: opening pressure (Popen), compliance (ETC), and hysteresis (eta). These global properties may be influenced by the mechanics of the surrounding tissue and/or the mucosa-air interface. In this study, we investigated the influence of tissue mechanics by paralyzing the right tensor veli palatini (TVP) muscle in 12 cynomolgus monkeys via botulinum toxin injection. A previously developed modified forced-response protocol was used to measure Popen, ETC, and eta under normal conditions and after muscle paralysis. The loss of muscle tone and/or stiffness resulted in a significant decrease in Popen (p < .01) and a significant increase in ETC (p < .01). In addition, muscle paralysis reduced the viscoelastic properties of the TVP muscle and therefore resulted in a significant decrease in eta (p < .05). A comparison with previous measurements on the influence of surface tension mechanics indicates that the ET's compliance is primarily determined by tissue elastic properties. The ET hysteresis, however, is equally affected by viscoelastic tissue properties and surface tension hysteretic properties. Knowledge of how these physical components affect the global mechanical environment may lead to improved treatments for ET dysfunction that target the underlying mechanical abnormality.     

Ligation of eustachian tube for intractable patulous eustachian tube: a preliminary report

Pharyngeal orifice of the eustachian tube was ligated on ten patients, 15 ears with intractable patulous eustachian tube. While the eustachian tube orifice was observed by an endoscope inserted through the contralateral nostril, the orifice was ligated transnasally and/or transorally using instruments usually used in the endoscopic nasal surgery. Now 13–27 months after the surgery, the outcome was excellent (both symptoms and sonotubometry were normalized) in two ears, good (either symptoms or sonotubometry was improved) in seven ears, and unchanged in the remaining six ears. In one of the ears with an outcome of unchanged, the ligation was found to be spontaneously released soon after surgery, but the symptom was improved after the second operation 2.5 months after the first operation. Temporary otitis media with effusion was seen in one ear, mild inflammation around the ligated site also in one ear, but no other serious complication has been observed. Although further improvement in the surgical procedure and further discussion about its long-term outcome should be required, this procedure appeared to be one of the therapeutic options for intractable patulous eustachian tube.     

Impact of evolution on the eustachian tube

I posit that humans appear to be the only species that develops otitis media. If animals in the wild had developed middle‐ear disease to any significant degree, they would have been selected out during evolution because they would not have survived their predators given the associated hearing loss. Why do humans have otitis media? Evolution has had a significant impact. It is well known that humans are born 12 months too early, which is the result of adaptations to bipedalism and our big brain that, over time, resulted in a relatively small female pelvic outlet compared with nonhuman primates. As a consequence of too early a birth, not only is our immune system immature, but the eustachian tube is too short and floppy in the first year of life. But why is otitis media still common in older individuals? What other adaptation is uniquely human? We developed speech that was associated with descent of the larynx and hyoid bone, which, along with a decrease in prognathism (i.e., facial flattening), resulted in a change in palatal morphology as compared with other primates. Comparative anatomic and physiologic studies have demonstrated significant differences between humans and monkeys, especially in the muscles of the eustachian tube. Paradoxic constriction, as apposed to dilation, on swallowing is a common tubal dysfunction in humans and certain monkey models with chronic middle‐ear effusion. My hypothesis is that chronic otitis media with effusion in patients with tubal constriction is a consequence of adaptation for speech and that, most likely, the levator veli palatini muscle is the cause.