Intraindividual variability of the Eustachian tube function: a longitudinal study in a pressure chamber.

INTRODUCTION: The Eustachian tube (ET) is essential for fast and direct pressure equalisation between middle ear and ambient pressure. It is not yet known to what extent Eustachian tube function in healthy adults changes in a weekly periodicity due to internal and external factors. This question is particularly interesting with regard to scuba divers among whom there is a need to evaluate intraindividual ET function variability. METHODS: Continuous impedance measurement in a pressure chamber was performed three times at one-week intervals between measurements. Twenty healthy participants (40 ears) were enrolled. Using a monoplace hyperbaric chamber, individual subjects were exposed to a standardised pressure profile consisting of a 20 kPa decompression over 1 min, a 40 kPa compression over 2 min, and a 20 kPa decompression over 1 min. Measurements of Eustachian tube opening pressure (ETOP), opening duration (ETOD), and opening frequency (ETOF) were made. Intraindividual variability was assessed. RESULTS: Mean ETOD during compression (actively induced pressure equalisation) on the right side was 273.8 (SD 158.8) ms, 259.4 (157.7) ms, and 249.2 (154.1) ms (Chi-square 7.30, P = 0.026) across weeks 1-3. Mean ETOD for both sides was 265.6 (153.3) ms, 256.1 (154.6) ms, and 245.7 (147.8) ms (Chi-square 10.00, P = 0.007) across weeks 1-3. There were no other significant differences in ETOD, ETOP and ETOF across the three weekly measurements. CONCLUSIONS: This longitudinal study suggests low week-to-week intraindividual variability of Eustachian tube function.

Subjective and Objective Effectiveness of Eustachian Tube Balloon Dilatation for Patients With Eustachian Tube Dysfunction-Evaluation in a Pressure Chamber.

INTRODUCTION: The Eustachian tube plays a crucial role in pressure equalization between the middle ear and ambient pressure for fast and large pressure differences. In patients with chronic Eustachian tube dysfunction, Eustachian tube balloon dilatation is increasingly used as surgical therapy. Subjectively, many patients report an improvement of the symptoms postoperatively. Hence, there is a need to objectively measure this effect. METHODS: The objectivity of Eustachian tube balloon dilatation was evaluated using a precise method of measuring Eustachian tube function. In a hypo/hyperbaric pressure chamber, 23 ears in 13 patients were exposed to a standardized profile of compression and decompression before Eustachian tube balloon dilatation and 4 weeks afterwards. Standardized parameters of Eustachian tube function were determined and statistically compared before and 4 weeks after intervention. In addition, an Eustachian Tube Dysfunction Questionnaire-7 (ETDQ7) questionnaire was completed beforehand and 4 weeks postoperatively to determine subjective surgical success. RESULTS: The results from the ETDQ7 questionnaire showed a significant improvement in symptoms after Eustachian tube balloon dilatation (p = 0.0002). Objective measurements results showed a significant reduction of the Eustachian tube opening pressure during pressure decrease 4 weeks after intervention (p = 0.0012). CONCLUSION: Eustachian tube balloon dilatation significantly reduced Eustachian tube opening pressure, in addition to subjective improvement of symptoms determined by ETDQ7.