Histamine Applied Topically to the Nasal Mucosa Increases the Transmucosal Nitrous Oxide Exchange for the Middle Ear.

OBJECTIVE: Determine if the middle ear transmucosal nitrous oxide (N2O) exchange rate is affected by nasal inflammation caused by topical application of histamine. METHODS: In a randomized, double-blind, crossover study, 20 adults were challenged intranasally with histamine (5 mg) and placebo on separate occasions. At each session, the subjects were fitted with a non-rebreathing mask and breathed room air for 20 minutes, 50% N2O:50% O2 for 20 minutes, and 100% O2 for 10 minutes. Throughout, heart rate, blood pressure, and blood O2 saturation were monitored, and bilateral middle ear pressure was recorded by tympanometry every minute. The primary outcome measure was the slope of the middle ear pressure-time function for the 50% N2O:50% O2 breathing period, which is a measure of the transmucosal N2O exchange-constant. The effects of challenge substance, session, and period on the measured vital signs and of treatment, session, ear disease history, and test ear on the pressure-time slopes were evaluated using repeated measures ANOVAs. RESULTS: The post-challenge total symptom score and the slope of the middle ear pressure-time function were greater after histamine when compared to placebo challenge. Of the signs, only heart rate was affected, responding to challenge substance and study period. CONCLUSION: The transmucosal N2O exchange rate for the middle ear is increased during inflammation caused by nasal histamine exposure.

A method to assess the accuracy of sonotubometry for detecting Eustachian tube openings.

Sonotubometry is a simple test for Eustachian tube (ET) opening during a maneuver. Different sonotubometry configurations were suggested to maximize test accuracy, but no method has been described for comparing sonotubometry test results with those for a definitive measure of ET opening. Here, we present such a method and exemplify is use by an accuracy assessment of a simple sonotubometry configuration. A total of 502 data-sequences from 168 test sessions in 103 adult subjects were analyzed. For each session, subjects were seated in a pressure chamber and relative middle ear over- and under-pressures created by changing chamber pressure. At each pressure, the test sequence of bilateral tympanometry, bilateral sonotubometry while the subject swallowed twice, and bilateral tympanometry was done. Tympanometric data were expressed as the fractional gradient equilibrated (FGE) by swallowing and sonotubometric signals were analyzed to record the shape of detected sound signals. Tympanometric and sonotubometric tubal opening assignments were analyzed by cross-correlation. For the data sequences with FGE = 0 (n = 32) evidencing no tubal opening and one (n = 249) evidencing definitive tubal opening, detection of a sonotubometry sound signal during a swallow had a sensitivity and specificity of 74.2 and 65.6 % for identifying ET openings and an accuracy of 73.3 % for assigning ET opening/non-opening by swallowing. Measures of sound signal shape were significantly different between those groups. This protocol allows a sonotubometry accuracy assessment for detecting ET openings. For the test configuration used, accuracy was moderate, but this should improve as more sophisticated sonotubometry test configurations are evaluated.

Eustachian tube function in young children without a history of otitis media evaluated using a pressure chamber protocol.

CONCLUSIONS: Protocol limitations were identified and accounted for in the analysis. Percent gradient equilibrated (PGE) was affected by driving gradient direction in a similar manner to other efficiency measures. A finer resolution of possible age-related changes in eustachian tube opening efficiency is expected with the application of more sophisticated statistical models to the complete dataset at study end. OBJECTIVE: To report the results of an interim analysis for an ongoing study designed to characterize the age-related changes in eustachian tube opening efficiency measured using a pressure chamber protocol in children without a history of middle ear disease. METHODS: To date, 41 children aged 3 years without a history of otitis media have been enrolled in a longitudinal study of the age-related changes in eustachian tube function and evaluated at yearly intervals between 3 and 7 years of age. Eustachian tube opening efficiency, the percent of the applied pressure gradient equilibrated by swallowing, was measured by repeat tympanometry during a pressure chamber protocol. Data (120 tests) were analyzed using an ANOVA with variance partitioned by age (3 through 6 years), gradient direction (positive/negative), and ear (left/right). RESULTS: PGE was higher for left ears and positive driving gradients, but was not different among age groups.

Pressure chamber tests of eustachian tube function document lower efficiency in adults with colds when compared to without colds.

CONCLUSIONS: Fractional gradient equilibrated (FGE) for ears with applied positive but not negative middle ear (ME)-ambient pressure gradients is highly sensitive to a cold-like illness (CLI). OBJECTIVE: The sequential development of eustachian tube (ET) dysfunction, ME under-pressure, and otitis media (OM) characterizes many children during a CLI. If linked, OM burden would be lessened by interventions that promote/preserve good ET function during a CLI. Evaluating this requires a quantitative ET function test for MEs with an intact tympanic membrane responsive to a CLI. METHODS: Pressure chamber testing of ET function was performed at +200 and -200 daPa in 3 groups of adults: group I, 21 subjects with an extant CLI and groups II and III, 14 and 57 adults, respectively, without a CLI. ME-chamber pressure gradient was recorded by tympanometry before and after the subject swallowed twice. ET functional efficiency was quantified as the FGE, which was then compared among groups using a Mann-Whitney U test. RESULTS: At chamber pressures of 200 daPa, the ME-chamber pressure gradient was negative, and FGE was low and not different among groups. At chamber pressures of -200 daPa that gradient was positive, and FGE was significantly higher in groups II and III when compared with group I.