An evaluation of tympanometric estimates of ear canal volume

The accuracy of tympanometric estimates of ear canal volume was evaluated by testing the following two assumptions on which the procedure is based: (a) ear canal volume does not change when ear canal pressure is varied, and (b) an ear canal pressure of 200 daPa drives the impedance of the middle ear transmission system to infinity so the immittance measured at 200 daPa can be attributed to the ear canal volume alone. The first assumption was tested by measuring the changes in ear canal volume in eight normal subjects for ear canal pressures between +/- 400 daPa using a manometric procedure based on Boyle's gas law. The data did not support the first assumption. Ear canal volume changed by a mean of .113 ml over the +/- 400 daPa pressure range with slightly larger volume changes occurring for negative ear canal pressures than for positive ear canal pressures. Most of the volume change was attributed to movement of the probe and to movement of the cartilaginous walls of the ear canal. The second assumption was tested by comparing estimates of ear canal volume from susceptance tympanograms with a direct measurement of ear canal volume adjusted for changes in volume due to changes in ear canal pressure between +/- 400 daPa. These data failed to support the second assumption. All tympanometric estimates of ear canal volume were larger than the measured volumes. The largest error (39%) occurred for an ear canal pressure of 200 daPa at 220 Hz, whereas the smallest error (10%) occurred for an ear canal pressure of -400 daPa at 660 Hz. This latter susceptance value (-400 daPa at 660 Hz) divided by three is suggested to correct the 220-Hz tympanogram to the plane of the tympanic membrane. Finally, the effects of errors in estimating ear canal volume on static immittance and on tympanometry are discussed.     

Tympanometry at a health center

We wanted to assess how much additional information could be gained from the results of tympanometry after first performing a clinical hearing examination at a mother and child clinic. 182 children aged from six months up to four years, had their hearing first examined clinically and afterwards by tympanometry. Pathological tympanograms were seen in 39% of the ears we examined, but most of them reverted to normal spontaneously at a later stage. There was little concordance between tympanometry and BOEL test in children aged six months and one year. Concordance between tympanometry and audiometry was fairly good in four-year old children. 27 children were referred to an ear, nose and throat specialist for evaluation, 11 of them as a result of tympanometry. Operative treatment was recommended for 17 of the children. In the anamnesis there was a connection between the parents perception of their child's hearing and the child having a cold and referral to an ear, nose and throat specialist. Tympanometry contributes to an early diagnosis of secretory otitis media, as well as being a means of helping parents understand the periodically poor middle ear function of their child.     

Multiple frequency tympanometry: effects of ear canal volume compensation on static acoustic admittance and estimates of middle ear resonance

Three methods for compensating multiple frequency acoustic admittance measurements for ear canal volume were studied in 26 men with normal middle ear transmission systems. Peak compensated static acoustic admittance (magnitude of y) and phase angle (phi) were calculated from sweep frequency tympanograms (226-1243 Hz in 113 Hz increments). Of the procedures used to compensate for volume in rectangular form, the ear canal pressure used to estimate volume had the largest effect on the estimate of middle ear resonance. Median resonance was 800 Hz for admittance measurements compensated at 200 daPa versus 1100 Hz for measurements compensated at -350 daPa. The remaining two methods, compensation of susceptance only versus both susceptance and conductance and compensation using the minimum volume versus separate volumes at each frequency, did not affect estimates of middle ear resonance. Estimates of middle ear resonance from compensated phase angle measurements also were compared with estimates of resonance from admittance and phase difference curves. Although resonance could not be estimated from the phase difference curve, resonance estimated from the admittance difference curve agreed with the estimate from compensated phase angle.     

Oropharyngeal tumors of dogs--a clinical study of 79 cases

Secretory otitis media is defined as a fluid in the middle ear without signs or symptoms of infection. As the aetiology and pathogenesis of the disease are unknown, and as it affects children aged from 3 to 12 years, treatment procedures proposed for management of secretory otitis media, are not uniform. Some authors [1, 4, 6] consider that functional or mechanical obstructions of the Eustachian tube could provoke secretory otitis. The purpose of the treatment is to remove exudate from the middle ear and appropriately ventilate it for a longer period. That could instantly normalize the hearing and exclude the appearance of late complications of secretory otitis. Although the disease could heal spontaneously, the treatment should be performed immediately for preventing sequelae of secretory otitis. The aim of the study was to evaluate possible aetiologic factors of secretory otitis in our population, and to evaluate results of lympanometry in children with exudate in the middle ear. There were 65 children, aged from 3 to 12 years (Table 1), who complained of deafness and were examined at the ORL Department in Banja Luka. The clinical examination revealed the integrity and color of tympanic membrane, scars, adhesions and atrophic areas. Audiometry and tympanometry had been performed in addition. Patients who proved to have exudate in the middle ear received nasal decongestants and mucolitics during three months, and were evaluated every three weeks by audiometry and tympanometry. Pathologic findings in the nose and epipharynx were the most common findings: enlarged adenoids in 38 (58%) patients, hypetrophic rhinitis in 15 (23%) and allergic rhinitis in 5 (8%) patients. Frequent relapses of middle ear infection in the first three years of life were found in 26 (40%) patients and early first attacks in the first year of life in 15 (23%) patients (Table 2). Premature onset (15%) and allergy (21%) had also been frequently found. Results of tympanometry and audiometry are shown in Table 3. Exudate in the middle ear and type B tympanogram were found in 86 ears, while in other patients dysfunction of the Eustachian tube and type C1 and C2 tympanograms were found. After 6 weeks the exudate disappeared in 16 ears and tympanogram converted in type A and type C2, while the initially found C1 tympanogram was transformed in type A in 5 of 13 ears. After 12 weeks the tympanogram type B was found in 46 ears, while in 40 ears (47%) the tympanogram was changed in type A and type C2. After 6 and 12 weeks of therapy tympanometric types were statistically examined by chi 2 test. We have found a significant difference in tympanometric types and prevalence of type A and C1 tympanograms. Paracentesis and insertion of ventilating tubes were done in 46 ears with the remaining exudate. We have found mucous exudate in 35 (76%) ears associated with retraction and scars of tympanic membrane (Table 4), what indicated that the longer duration of mucous exudate caused degenerative changes in the middle ear. Serous exudate, found in 9 ears (24%), did not affect the color and integrity of the tympanic membrane. Sensitivity of tympanometry in detection of exudate in the middle ear was 96%. Secretory otitis media is a frequent disease in childhood, that could cause functional and morphological sequelae in the middle ear. As for now, there is no unique concept of diagnosis and treatment of the disease, and it is still a current problem. We suggest a three-month evaluation of tympanometric and audiometric patterns, repeated every three weeks, in children suspected of having exudate in the middle ear. There is a large trend of spontaneous disappearance of exudate in the middle ear and changing of tympanogram type. Such children should be evaluated over the period of one year, and if there is no relapse additional treatment should not be carried out. If exudate in the middle ear persists for three months and type of the tympanogram is unchanged, myringotomy and insert     

Standard and multifrequency tympanometry in normal and otosclerotic ears

OBJECTIVES: The primary goal of this study was to evaluate alternative tympanometric parameters for distinguishing normal middle ears from ears with otosclerosis. A secondary goal was to provide guidelines and normative data for interpreting multifrequency tympanometry obtained using the Virtual 310 immittance system. DESIGN: Nine tympanometric measures were examined in 68 normal ears and 14 ears with surgically confirmed otosclerosis. No subjects in either group had a history of head trauma or otoscopic evidence of eardrum abnormalities. Two parameters, static admittance and tympanometric width, were derived from standard low-frequency tympanometry and two parameters, resonant frequency and frequency corresponding to admittance phase angle of 45 degrees (F45 degrees), were derived from multifrequency tympanometry. RESULTS: Differences between normal and otosclerotic ears were statistically significant only for resonant frequency and F45 degrees. Group differences in resonant frequency were larger when estimated using positive tail, rather than negative tail, compensation. Group differences in both resonant frequency and F45 degrees were larger when estimated from sweep frequency (SF), rather than sweep pressure, tympanograms. Test performance analysis and patterns of individual test performance point to two independent signs of otosclerosis in the patient group; 1) an increase in the stiffness of the middle ear, best indexed by F45 degrees derived from SF recordings, and 2) a change in the dynamic response of the tympanic membrane/middle ear system to changes in ear canal pressure, best indexed by tympanometric width. Most patients were correctly identified by only one of these two signs. Thus, optimal test performance was achieved by combining F45 degrees derived from SF recordings and tympanometric width. CONCLUSIONS: The findings confirm the advantage of multifrequency tympanometry over standard low-frequency tympanometry in differentiating otosclerotic and normal ears. Recommendations for interpreting resonant frequency and F45 degrees measures obtained using the Virtual Immittance system are also provided. In addition, the relationship among different tympanometric measures suggests a general strategy for combining tympanometric measures to improve the identification of otosclerosis.     

Antibiotic treatment of children with secretory otitis media. Amoxicillin-clavulanate is superior to penicillin V in a double-blind randomized study

OBJECTIVE: To compare the effect of 2 different antimicrobial agents in the treatment of secretory otitis media (SOM). DESIGN: Prospective, double-blind, randomized study. PATIENTS: From a pool of 1450 children (aged 1-10 years) with SOM, defined by tympanometry as having type B or C2 tympanograms, 429 with SOM of at least 3 months' duration were included in the trial. After exclusion of 69 patients, the remaining 360 were evenly distributed among 4 treatment groups: penicillin V (Primcillin) for 14 and 28 days, and amoxicillin and clavulanate potassium in combination (Spektramox) for 14 and 28 days. Criteria for improvement was a change in tympanometric findings to type C1 or type A. RESULTS: The success rates were in favor of amoxicillin-clavulanate treatment for 28 days (P < .001) (rates for respective 14- and 28-day groups: penicillin V, 23% and 19%; amoxicillin-clavulanate, 31% and 44%). Antimicrobial therapy was more efficient (P < .001) in unilateral vs bilateral disease. CONCLUSION: Antibiotic treatment improves the middle ear status in patients with SOM, and amoxicillin-clavulanate provides superior improvement to penicillin V.     

Involvement of dental occlusion and trigeminal neuralgia: a clinical report

Over a 12-month period 501 children (age range 11 months to 15 years) underwent surgery for a possible middle ear effusion. All had tympanometry performed within 2 h of surgery. The results of tympanometry were correlated with the surgical findings in 955 ears. A type-B tympanogram has a high sensitivity (0.91) in predicting middle ear effusion with good specificity (0.79). A type-A tympanogram has a very high specificity (0.99) in predicting a dry middle ear but low sensitivity (0.34). Both the positive (0.91) and negative (0.84) predictive values of a type-A tympanogram are high. The addition of a type-C tympanogram increases the sensitivity of predicting a dry middle ear to 0.79. The positive predictive value of a peaked (type-A or -C) tympanogram is 0.71 and should be considered strong evidence that the middle ear is dry. Tympanometry is the best clinical test for the presence or absence of a middle ear effusion, and on the basis of preoperative tympanometry alone the need for surgery should be carefully reassessed.     

Premedication with oral dextromethorphan reduces postoperative pain after tonsillectomy

The aim of the present study was to examine whether premedication with dextromethorphan, a clinically available N-methyl-D-aspartic acid (NMDA) receptor antagonist, could reduce postoperative pain after tonsillectomy. Thirty-six patients scheduled for elective bilateral tonsillectomy were investigated in a double-blinded, randomized study. The patients were randomly assigned to one of three groups: control, dextromethorphan 30 mg (Dex 30), and dextromethorphan 45 mg (Dex 45) groups. In the control group, premedication was with oral placebo and intramuscular (i.m.) midazolam and atropine. In the Dex 30 and Dex 45 groups, patients were premedicated with i.m. midazolam and atropine and oral dextromethorphan 30 mg and 45 mg, respectively. Pain was evaluated repeatedly throughout 7 postoperative days, at rest and on swallowing, using a self-rating visual analog scale (VAS). The total doses of analgesics administered postoperatively were also recorded. The Dex 45 group showed significantly lower VAS scores than the control group both at rest and on swallowing throughout the 7 days. The total doses of postoperative analgesics in the Dex 45 group were significantly less than those in the control group. The Dex 30 group showed significantly lower VAS scores than the control group at rest, but not on swallowing. These results indicate that premedication with Dex 45 reduces postoperative pain after tonsillectomy, not only at rest but on swallowing. IMPLICATIONS: Recently, it has been suggested that central sensitization caused by the activation of N-methyl-D-aspartic acid receptors may contribute to the postoperative pain. We found that premedication with 45 mg of dextromethorphan, a clinically available N-methyl-D-aspartic acid receptor antagonist, reduced postoperative pain after tonsillectomy.     

General anesthesia with and without nitrous oxide (N2O) and the weight of middle ear effusion in children undergoing adenoidectomy and tympanostomy

This study was designed to explore the effect of nitrous oxide (N2O) on the amount of middle ear effusion. Seventy-six children referred for adenoidectomy or tympanostomy tube placement were divided into two groups in the basis of the method of anesthesia. One group of 39 children was ventilated with a mixture of 30% oxygen and 70% nitrous oxide, while the other group of 37 patients was ventilated with a mixture of oxygen and air. The amounts of middle ear effusion obtained in myringotomy were weighed and compared between these groups. Preoperative and perioperative tympanograms were performed. Ventilation with nitrous oxide caused a distinct rise in middle ear pressure. The amount of the middle ear effusion, however, remained the same in the two groups. It is concluded that the operating surgeon can rely on the myringotomy finding even when nitrous oxide anesthesia is used.     

Correlation of radiologic and pathologic-anatomical findings in dust-induced pneumoconiosis in former coal miners]

Anecdotal evidence from several ENT departments suggests that pain following tonsillectomy is worst on the second and/or third days after surgery. This study tests this hypothesis. A pilot study with 19 subjects suggested this theory might well be true. A fuller study was then carried out on 91 subjects with standardised surgical and anaesthetic techniques, and standardised analgesia for five days postoperatively. Pain on the second and third postoperative days was compared with that eight hours after the operation and on the first, fourth and fifth postoperative days. No statistically significant difference was found. There is increasing pressure for early discharge from hospital after surgery. If pain following tonsillectomy is not going to become worse at home, this will tend to make early discharge more acceptable to patients.     

Interactions among tympanometric variables

To gain a better understanding of tympanometric results that have been difficult to interpret, such as asymmetrical and W-shaped tympanograms, acoustic susceptance and conductance tympanograms were measured from subjects with normal hearing and from subjects with well-defined middle ear pathology. Acoustic reactance, resistance, and impedance were computed and predicted from the measured data. Asymmetrical tympanograms derive in large part from the marked asymmetry in acoustic resistance as a function of ear canal pressure. W-shaped tympanograms result from interactions between reactance and resistance that occur when the two quantities assume similar absolute values or when reactance is mass controlled. A criterion for distinguishing between W-shaped tympanograms that are normal from those that are abnormal is discussed.     

Multifrequency tympanometry in chinchillas

Multifrequency tympanometry (MFT), using probe frequencies ranging from 226-2,000 Hz, was performed on normal chinchillas to obtain normative data against which to compare results from animals with middle ear pathology. A series of validating experiments was conducted to determine the effects of anatomical alterations of the middle ear on MFT. These included artificially extending the ear canal, opening the bulla, injecting saline into the middle ear, and disrupting the ossicular chain. The results indicate that MFT characteristics of chinchilla ears are qualitatively similar to those observed in normal humans and patients with middle ear disease, and MFT provides information that is not available from the 226-Hz tympanogram.     

The randomized double-blind study of postoperative tonsillectomy pain control by muscle relaxants

Tonsillectomy is accompanied by 7 to 14 days of pain. We entered 36 patients into a double blind placebo controlled study with dantrolene sodium, lioresal to evaluate modification of tonsillectomy pain and analgesic requirements after tonsillectomy. Patients were randomly assigned either dantrolene or lioresal or placebo orally four times a day for 5 days postoperatively. On a standardized questionnaire the patients recorded pain, activity level, analgesic requirements and side effects. We conclude that there is no significant differences in subjective pain or analgesic requirements between 3 groups. The muscle spasm is not the only factor of tonsillectomy pain. There is the association of other factors: nerve endings, individual sensitivity, local products of inflammation. In conclusion to control tonsillectomy pain we must use drugs with different action.     

The effect of post-operative instructions on recovery after tonsillectomy and adenoidectomy

The effect of postoperative diet and activity instructions on the recovery rate after tonsillectomy and adenoidectomy (T & A) was assessed in 92 children ages 3 to 14 years. Two types of postoperative instruction were randomly assigned: 'Restricted', which advised limited, stay at home activities and a soft food liquid diet for 7-10 days, and 'nonrestricted', which advised return to activity and diet as tolerated by the child. Parental evaluation of the levels of pain, activity, and diet using an equal intervals scale was obtained. The number of doses of pain medication, the types of food eaten and postoperative complications were also recorded. No significant differences were found between the two groups in pain level, activity tolerance, return to normal diet, and numbers of doses of pain medication at day 3 and day 7 after surgery. More 'junk' food and spicy foods were eaten in the 'nonrestricted' group. Postoperative hemorrhage requiring intervention occurred in one child in each group. Implications for the children and their families undergoing T & A are discussed with attention to a review of the literature.     

Tympanometry as a screening tool in the NICU: is it effective?

This study assess the usefulness of the tympanogram as a screening tool for identifying otitis media and serous otitis media in preterm infants. Twenty-six infants from the NICU were assessed on the same day by two examiners using tympanometry and pneumatic otoscopy. The results were recorded separately and compared after all infants were tested. An audiologist independently interpreted each of the tympanogram strips. There was very little agreement between tympanometry and otoscopy results. The tympanogram was not found to be a repeatable or a reliable screening tool for assessing otitis media and serous otitis media in the NICU population. It was concluded that the NICU nurse must be aware of the signs and symptoms of otitis media and serous otitis media. If this diagnosis is raised for an infant in the NICU, careful visualization of the tympanic membrane should be carried out along with referrals to ear, nose, and throat and audiology experts.     

Local infiltration of epinephrine and bupivacaine before tonsillectomy

The effects of peritonsillar injections of epinephrine and local anesthetics before tonsillectomy on blood loss and postoperative pain were evaluated in a prospective, randomized double-blind trial on 103 children. Patients were randomly assigned into one of three groups: controls given injections of 0.9% NaCl (n = 34), patients injected with 0.4 ml/kg (1:200,000) epinephrine combined with 0.25% bupivacaine (n = 33) and patients given only 1:200,000 epinephrine (n = 36). All injections and operations were performed by the same surgeon (KS). Blood loss was calculated by weighing all blood aspirated perioperatively and swabs used during surgery. Postoperative pain was assessed at regular intervals by using three methods: (1) use of a visual analogue scale by parents and nurses to estimate pain; (2) postoperative need for nalbuphine as analgesic; (3) the Hannallah-Broadman semi-objective pain score (including crying, anxiety, restlessness, and changes in blood pressure). The mean blood loss in the control group (given NaCl) was 132 g, which was significantly increased when compared with the epinephrine/bupivacaine group (85 g) and the group treated with only epinephrine (90 g). However, analysis of the postoperative pain scores did not reveal any significant differences among groups. These findings indicate that the peritonsillar injection of bupivacaine does not decrease postoperative pain, but peritonsillar injections of epinephrine will significantly reduce blood loss during tonsillectomy.     

Audiologic evaluation of deaf children

This paper describes an audiologic test battery for hearing-impaired children which includes otoscopic examination, tympanometry, pure-tone audiometry, speech perception testing, and hearing aid evaluation. Several of the procedures and modifications to apparatus have been developed specifically for use with deaf children. Clinical data are presented from 160 hearing-impaired children (age range three-16 years). Eighteen percent of their ears were found to contain excessive cerumen and to require ear canal irrigation. The incidence of abnormal tympanograms was high for young children but decreased with increasing age. A simple auditory speech perception test designed for use with both severely and profoundly deaf children is described, which provides for evaluation of a child's ability to recognize words, categorize them into stress patterns, or both. The children's word recognition and word categorization scores were found to relate to their audiometric averages. The overall test battery is easy to administer and also is efficient, in that considerable audiologic information can be obtained quickly.     

Effects of nasal packing on eustachian tube function

Eustachian tube function was assessed by tympanometry in 47 patients (94 ears) with anterior nasal packing placed after nasal surgery and in 12 patients (24 ears) requiring anterior and posterior packing for epistaxis. Twenty-four of the 94 ears (25.5%) in patients with anterior packing exhibited reductions in middle ear pressure (greater than or equal to --100 mm H2O), whereas 12 of 13 ears (92.3%) ipsilateral to and six of 11 ears (45.4%) contralateral to the posterior pack demonstrated comparable reductions in middle ear pressure. The observation that posterior packing is associated with a greater incidence of eustachian tube dysfunction than anterior packing suggests that the mechanism of this dysfunction may be related to stasis in the peritubal lymphatic plexus rather than to nasal obstruction per se.     

Observations on the zinc protoporphyrin/heme ratio in whole blood

The aim of this study was to examine whether severity of preoperative pain intensity is related to postoperative pain and morphine consumption. Sixty consecutive patients scheduled for total hip surgery during intrathecal anesthesia were studied. Preoperative visual analog scale (VAS) scores and analgesic intake was assessed 1 day before surgery. Three groups of patients were identified: those with mild pain (n = 12, VAS score 0-4), moderate pain (n = 18, VAS score 4-7), and severe pain (n = 28, VAS score 7-10). Postoperative pain scores were recorded in the first 24 h, as was the amount of morphine delivered by the patient-controlled analgesia pump. There were no differences among the groups in VAS scores at any time. Severe preoperative pain levels correlated with significantly greater postoperative morphine intake. The mean morphine intake during the first 24 h postoperatively was 19.2 mg in the mild pain group, 21.2 mg in the moderate pain group, and 29.5 mg in the severe pain group (P < 0.05 compared with both other groups). We conclude that patients with severe preoperative pain self-medicate to achieve postoperative pain scores equivalent to those of patients with mild and moderate pain and require a greater postoperative morphine intake for adequate analgesia than patients with mild or moderate preoperative pain. IMPLICATIONS: In this study, we showed that severity of preoperative pain intensity relates to postoperative pain levels and morphine consumption. Patients scheduled for total hip surgery with severe preoperative pain require more postoperative morphine in the first 24 h.     

Propofol-air-oxygen anesthesia reduces the incidence of sore throat after laryngeal mask anesthesia

We investigated the effects of the presence or absence of N2O in propofol anesthesia using a laryngeal mask on the incidence of postoperative sore throat. In the N2O-combined anesthesia group (n = 25), score 0 (no sore throat) was observed in 11 patients; score 1 (slight pain and discomfort that improved on the next day of operation) in 9; and score 2 (persistent pain on the next day) in 5. In the non-N2O-combined anesthesia group (n = 25), score 0 was observed in 21 patients, score 1 in 3; and score 2 in 1, showing a significantly lower incidence of sore throat and milder sore throat than in the N2O-combined anesthesia group. These results suggest that propofol anesthesia using a laryngeal mask not combined with N2O reduces the incidence of postoperative sore throat.