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Gas Supply, Demand and Middle Ear Gas Balance -- Fly/Dive Simulation

This study is currently recruiting participants.
Verified November 2017 by Cuneyt M. Alper, University of Pittsburgh
Sponsor:
ClinicalTrials.gov Identifier:
NCT01976429
First Posted: November 5, 2013
Last Update Posted: November 8, 2017
The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Know the risks and potential benefits of clinical studies and talk to your health care provider before participating. Read our disclaimer for details.
Collaborator:
National Institute on Deafness and Other Communication Disorders (NIDCD)
Information provided by (Responsible Party):
Cuneyt M. Alper, University of Pittsburgh
  Purpose
This study will determine if newly developed and more standard tests of Eustachian tube function can identify those persons who have ear pain (barotrauma) or develop middle-ear inflammation and/or fluid (barotitis) when they are exposed to rapid changes in air pressure as, for example, during airplane flights or scuba diving. Up to 150 adults and children (10-50 years old) who fly or dive at least 1-2 times and experience ear pain or develop middle-ear fluid during those activities and approximately 60 adults and children who fly or dive but do not experience these problems will undergo Eustachian tube function testing during simulated flight and diving.

Condition Intervention
Middle-ear Barotrauma Other: flight/diving simulation Other: ET function testing at ambient pressure Other: nasal video-endoscopy

Study Type: Interventional
Study Design: Allocation: Non-Randomized
Intervention Model: Single Group Assignment
Masking: None (Open Label)
Primary Purpose: Diagnostic
Official Title: Gas Supply, Demand and Middle Ear Gas Balance -- Project 1, Specific Aim 4, Protocol 2

Further study details as provided by Cuneyt M. Alper, University of Pittsburgh:

Primary Outcome Measures:
  • ET function testing as a predictor of failed flight/dive simulations [ Time Frame: Day 1 ]
    various ET function test parameters will be analyzed for their ability to predict development of symptoms during flight/dive simulations


Secondary Outcome Measures:
  • nasal video-endoscopy [ Time Frame: Day 1 ]
    In subjects who entered with a history of symptoms during flight/diving, the nose, nasopharynx and Eustachian tube orifices will be examined to determine if there is a gross anatomical basis for the symptoms.


Estimated Enrollment: 210
Study Start Date: October 2013
Estimated Study Completion Date: December 2018
Estimated Primary Completion Date: December 2018 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
asymptomatic on flight/dive
individuals who experience no middle-ear problems on flying or diving
Other: flight/diving simulation
measurement of ET function during simulated flight/diving in pressure chamber
Other: ET function testing at ambient pressure
ET function testing at ambient pressure using sonometry, tubomonometry, 9-step test, maneuver sequence
symptomatic on flying/diving
individuals who have experienced middle-ear problems on flying or diving
Other: flight/diving simulation
measurement of ET function during simulated flight/diving in pressure chamber
Other: ET function testing at ambient pressure
ET function testing at ambient pressure using sonometry, tubomonometry, 9-step test, maneuver sequence
Other: nasal video-endoscopy
examination of nose, nasopharynx,and Eustachian tube orifice

  Hide Detailed Description

Detailed Description:

Subjects will be recruited who only experience symptoms or present signs interpretable as Eustachian (ET) dysfunction (ETD) when exposed to rapid changes in ambient pressure as, for example, during flights in airplanes (in the absence of a concurrent cold/active nasal allergy) or during free and tanked diving. In general, subjects presenting to physicians with these conditions are diagnosed with poor ET function (ETF) based solely on symptom/sign presentation. However, it is not known how to identify those persons who will experience these symptoms/signs at a future time which is the goal of this study or how to prevent those presentations in susceptible individuals. To calibrate the test protocol, 20 subjects/age ranges of 10-19, 20-29 and 30-50 years (total=60 control subjects) who are in good health, fly and/or dive frequently but report no ear-related problems on ascent or descent, will be recruited. One hundred fifty symptomatic subjects in general good health aged 10 to 50 years with the lower age limit chosen to assure good communication between the subject and investigators, will also be recruited. These and the control subjects will have intact tympanic membranes since subjects with non-intact tympanic membranes do not experience barotrauma but maintain ambient middle-ear (ME) pressures throughout a flight.

A general history with a focus on the specific symptomatic complaints and the maneuvers performed in attempting to relieve any otologic symptoms during airplane flight/diving will be taken, an ear, nose and throat (ENT) exam, including tympanometry, done to confirm intact tympanic membranes and a disease-free ME and nasal exam done to rule out concurrent nasal inflammation. Then, sonotubometry, the 9-step test, tubomanometry and the "sniffing", Valsalva and Toynbee maneuvers will be done to establish baseline ETF. If a patulous (by observation of synchronized breathing and tympanic membrane movements) or physically obstructed ET (by an inability to transfer gas through the ET at normal driving pressures) is suggested by the results of these tests, the subject will be dismissed from further ETF testing and will be referred to their ENT physician or to the ETD clinic at Children's Hospital of Pittsburgh if they want to pursue a more complete workup to evaluate the underlying cause of the condition and possible treatment options. Those who are able to continue will have the ET stress test. Briefly, the presence/absence of ET openings by swallowing will be assessed by sonotubometry at stepped decreases from 2500 daPa (ref. ambient) to local ambient to determine the relative efficiency of muscle-assisted ET opening. The highest applied pressure at which the ET can be opened will be the outcome variable. If the individual completes the applied pressure sequence without experiencing a problem in opening their ET by swallowing or other maneuvers typically used by him/her to open their ET, the subject will have a simulated flight/dive relevant to their expected exposure.

Flight Simulation: The standard flight simulation parameters are based on those for a Boeing 747 but can be modified to simulate other, including personal, aircraft. For the simulations, we assume that the airport is at sea level, the maximum cabin pressurization is equal to the atmospheric pressure at 7000 feet and the ascent/descent rate is 350 ft/min (for the cabin altitude). With the subject seated comfortably in the pressure-chamber, chamber pressure is decreased from ambient to ambient minus 2280 daPa (gauge pressure=-2280 daPa) over a 15 minute period, maintained at ambient-2280 daPa for 15 minutes (cruising) and then increased to ambient over a 15 minute period. The subject reports symptoms throughout and middle-ear pressure is measured bilaterally by tympanometry periodically.

Diving Simulation: The standard dive simulation assumes sea level ambient pressure and, to avoid the possibility of the bends, is limited to a simulated maximum depth of 20 feet and a maximum "dive" duration of 1 hour. We make a first assumption that the diver rapidly descends to 5 feet at which point they attempt to equalize ME-ambient pressure and then proceed to the maximum depth of 20 feet within 5 minutes (These parameters can be modified depending on the diver's experience and the chamber pressure can be increased to simulate a dive to 30 feet). We also assume that the return to the surface is approximately 10 feet per minute. With the subject seated comfortably in the chamber, pressure is increased to 1500 daPa+ambient (gauge pressure =1500 daPa, approximately depth of 5 feet), the subjects middle-ear pressures are measured by tympanometry and any symptoms/signs evaluated. If these assessments are normal, the chamber pressure is increased to 6100 daPa+ambient (approximate depth of 20 feet for sea and fresh water), maintained at that pressure for 20 minutes and then decreased to ambient (ascent to surface). The rate of change in depth is set at 5 ft/minute. The subject reports symptoms throughout and middle-ear pressure is measured bilaterally by tympanometry periodically.

The simulations will be interrupted at the first report of an inability to "clear" their ears by swallowing or other maneuvers typically used for that purpose. At that pressure, the subjects will again attempt to equalize the ME-chamber pressure by swallowing, and if unsuccessful, will attempt to open the ET using a Valsalva maneuver, jaw movements/rotations and voluntary yawning. If these maneuvers are unsuccessful, instrumented nasopharyngeal overpressures using the "ear popper"® or Otovent® devices will be tried. If successful, the simulation will be continued, else the chamber pressure will be reduced to atmospheric and ME pressure equalized with ambient pressure. Then, only in subjects entered as symptomatic subjects, a video-nasoendoscopic exam of the nasopharynx will be performed to diagnose nasal and nasopharyngeal pathologies and physical obstruction of the ET orifice.

All subjects in the symptomatic group who pass the simulation without symptoms/signs of barotrauma will be retested using the appropriate simulation on a second day to confirm "symptom-free" flights/dives. For those subjects who fail this test and/or cannot complete the simulation without otologic symptoms/signs, we will refer them to their physician or to the ETD clinic if they want to pursue further work-up and treatment. We expect that all of the control subjects will successfully complete both the test protocol and simulation while the majority of subjects reporting flight/diving related symptoms will fail the stepped ETF test and not be able to complete the simulation without symptoms/signs of ME barotrauma. The sensitivities, specificities and accuracies of the ET stress test and the simple ETF tests done at baseline with respect to predicting a failed/successful simulation will be calculated.

  Eligibility

Information from the National Library of Medicine

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Ages Eligible for Study:   10 Years to 50 Years   (Child, Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion Criteria:

  • bilaterally intact tympanic membranes
  • flyer or diver with middle-ear symptoms
  • flyer or diver without middle-ear symptoms (controls)
  • generally good health
  • no recent history of non-activity related otitis media

Exclusion Criteria:

  • existing middle-ear disease
  • allergic rhinitis symptoms or "cold" on day of testing
  • syndrome predisposing to otitis media
  • history of ossicular reconstruction
  Contacts and Locations
Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT01976429


Contacts
Contact: Julie Banks, BS 412-692-3595 juliane.banks@chp.edu

Locations
United States, Pennsylvania
University of Pittsburgh Middle Ear Physiology Laboratory Recruiting
Pittsburgh, Pennsylvania, United States, 15213
Principal Investigator: Cuneyt M Alper, MD         
Sub-Investigator: Charles D Bluestone, MD         
Sub-Investigator: Margaretha L Casselbrant, MD, PhD         
Sub-Investigator: Ellen M Mandel, MD         
Sub-Investigator: Douglas J Swarts, PhD         
Sub-Investigator: Miriam S Teixeira, MD         
Sponsors and Collaborators
University of Pittsburgh
National Institute on Deafness and Other Communication Disorders (NIDCD)
Investigators
Principal Investigator: Cuneyt M Alper, MD University of Pittsburgh
  More Information

Responsible Party: Cuneyt M. Alper, Professor, Otolaryngology, University of Pittsburgh
ClinicalTrials.gov Identifier: NCT01976429     History of Changes
Other Study ID Numbers: PRO13040671-2
2P50DC007667 ( U.S. NIH Grant/Contract )
First Submitted: October 18, 2013
First Posted: November 5, 2013
Last Update Posted: November 8, 2017
Last Verified: November 2017
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: No

Keywords provided by Cuneyt M. Alper, University of Pittsburgh:
barotrauma
barotitis
middle ear
flying
diving
Eustachian tube

Additional relevant MeSH terms:
Barotrauma
Wounds and Injuries