Information
Editors
Middle Ear Barotrauma (Ear Problems Associated with an Increase in Atmospheric Pressure)
Essentials
- Mucosal oedema and/or malfunction of the Eustachian tube predispose the patient in a descending (landing) aircraft to pressure differences leading to barotrauma.
- The development of barotrauma can be prevented by avoiding flying and diving during an upper respiratory tract infection (acute common cold) and untreated allergy.
Background
- Ear barotrauma is a common condition: 14% of airline passengers have significant difficulties in adjusting the pressure in their ears and consequent barotrauma. In up to 40% of children after a flight, tympanometry reveals a negative pressure in their middle ear.
- During descent (landing), equalising the pressure in ears requires active effort (fully opening and closing the jaws, yawning, swallowing, Valsalva manoeuver); inadequate technique of equalizing ear pressure is also a significant cause for the develoment of middle ear barotrauma.
- 56% of commercial pilots have experienced ear pain during descent associated with an upper respiratory infection (common cold) during the previous year.
- During very rapid increase in atmospheric pressure (elevators in mines, fighter jets, metro), the middle ear has to be able to equalise pressure, at least, at the speed of 350 mmHg per minute.
Mechanism
- When the atmospheric pressure in an aircraft decreases (during take off) and creates a pressure difference exceeding 15 mmHg, the higher volume of air created in the middle ear in accordance with Boyle's law passes out passively through the Eustachian tube to the nasopharynx without causing any symptoms. The Eustachian tube functions like a unidirectional valve.
- As the atmospheric pressure increases (when an aircraft is descending/landing) the equalisation of pressure within the middle ear requires active effort. Under normal circumstances these active manoeuvres equalise the middle ear pressure thus preventing the retraction of the tympanic membrane.
- The diameter of the Eustachian tube is 1 mm at its narrowest in the bony part of the tube and its inner surface is covered by mucosa with cilia. During swallowing, the opening of the Eustachian tube requires precisely synchronized activity of a muscle group (veli palatini, levator palatini, salpingopharyngeus and tensory tympani muscles) and the 5th cranial nerve, whereby the Eustachian tube opens for a period of 0.1-0.9 seconds.
- If the pressure difference between the atmospheric air and the middle ear space is greater than 60 mmHg, the retraction of the tympanic membrane is experienced as the ear being clogged and additionally as pain. If the pressure difference is greater than 90 mmHg the Eustachian tube is no longer able to open even with Valsalva manoeuvre (see Prevention), and the negative pressure created will suck serous fluid from the mucosa into the middle ear space because of capillary dysfunction within a couple of hours.
- Middle ear barotrauma was earlier also known as barotitis or aero-otitis even though there is no bacterial effusion in the middle ear.
- Factors predisposing to the development of barotrauma include mucosal swelling in the nasopharynx (common cold or allergy), chronic Eustachian tube dysfunction (ETD), nasal polyps, enlarged adenoids, oesophageal reflux, nasopharyngeal tumour, ciliary dysfunction, submucous cleft palate, or a scar caused by an intervention (adenotomy, postnasal packing).
Symptoms
- Feeling of clogged/blocked ears
- Severe pain in the ear (when the pressure difference is more than 60 mmHg)
- Tympanic membrane perforation may occur when pressure difference exceeds 100 mmHg. In such a situation, the pain subsides and may be followed by serous discharge mixed with blood from the ear.
- Acute hearing loss originating from the inner ear, carousel-like vertigo and vomiting are suggestive of a barotrauma-induced rupture (perilymphatic fistula) of the oval or round window in the cochlea. A suspicion of such a rupture is an indication for emergency ear surgery.
Clinical findings
- Retracted tympanic membrane with poor compliance (picture )
- Clear or bloody fluid in the middle ear and possibly gas bubbles.
- Tympanometry will either show a curve with its peak displaced to the left (negative pressure; picture ) or a flat curve (serous effusion in the middle ear).
- Petechial haemorrhages on the tympanic membrane
- If the tympanic membrane is perforated, the site of perforation is usually situated centrally in the anterior part of the pars tensa.
- Tuning fork tests reveal mild conductive hearing impairment (the Rinne test is negative or indeterminate, the Weber test shows sound lateralisation to the affected ear).
Treatment
- The prognosis is good in middle ear barotrauma, and most patients recover without any specific treatment.
- A NSAID is usually sufficient for pain relief.
- Mucosal swelling in the nasopharynx and Eustachian tube can be reduced by using nasal drops or oral pseudoephedrine.
- At the same time, pressure equalisation should be performed several times a day by Valsalva manoeuver (an adult patient may also use the Politzer device to open the Eustachian tube) for a period of 10 days.
- A child may be able to open his/her Eustachian tube by using the Otovent® balloon several times a day.
- The functioning of the Eustachian tube can be assessed at the surgery during otoscopy by monitoring the tympanic membrane movement during active Valsalva manoeuver.
- If symptomatic treatment proves to be unsuccessful within 10 days, tympanocentesis should be considered. Perforating the tympanic membrane will ease the pain and the removal of exudate with suctioning improves hearing.
- In recurrent middle ear barotrauma, regular treatment with nasal steroids for a period of half a year and consultation of an otorhinolaryngologist to treat the underlying cause are both indicated. In difficult cases, the insertion of tympanostomy tubes may be warranted to equalise the pressure in the middle ear.
- Fear of flying may in some cases be the result of recurrent pain due to middle ear barotrauma.
- Middle ear barotrauma in aviation or diving professionals warrants an absence of 10 days from flying or diving activities and, before returning to work, a safe verification of the ability of the middle ear to equalise pressure in a hypobaric chamber. Such facilities/services may be available e.g. through centres specializing in aviation medicine.
- The next option for assessing the function of the Eustachian tube is tubomanometry testing at the pressures of 30 mBar, 40 mBar and 50 mBar.
- In chronic Eustachian tube dysfunction (ETD), when the ear symptoms are associated with rapid change of pressure, one treatment alternative is balloon dilation of the Eustachian tube performed in general anaesthesia.
Prevention
- The avoidance of flying and diving during an upper respiratory tract infection or allergic symptoms.
- Pressure equalisation manoeuvres should be commenced as soon as the descent of an aircraft starts, about 35 minutes before the landing time. The manoeuvres should be repeated every minute throughout the landing phase.
- Moving and opening the mouth and lower jaw, swallowing, yawning
- Valsalva manoeuvre: increasing the pressure within the nasopharynx by forced expiration with the mouth closed and the fingers pinching the nostrils.
- Children over 3 years of age may equalise the middle ear pressure during the descent by blowing up a special balloon (Otovent® ) by using their nose.
- Oral sympathomimetics may be beneficial. Also nasal drops and sprays should be used both before the flight and during the flight before the descent starts.
- If pressure equalisation problems occur when diving, a 3 metre ascent to reduce the pressure difference is recommended as well as the repetition of the pressure equalisation manoeuvres. For professional pilots this means increasing the height of the aircraft by 2 000 feet and repeating the pressure equalisation manoeuvres before attempting a slower descent.
- Sleeping should be avoided during the descent of an aircraft.
- Small children are on their parent's lap in sitting position during the descent. Offering liquids from a feeding bottle may assist in the equalisation of the middle ear pressure.
References
- Stangerup SE, Klokker M, Vesterhauge S ym. Point prevalence of barotitis and its prevention and treatment with nasal balloon inflation: a prospective, controlled study. Otol Neurotol 2004;25(2):89-94. [PubMed]
- Klokker M, Vesterhauge S. Perilymphatic fistula in cabin attendants: an incapacitating consequence of flying with common cold. Aviat Space Environ Med 2005;76(1):66-8. [PubMed]
- Luukkainen V, Kivekäs I, Silvola J ym. Balloon Eustachian Tuboplasty: Systematic Review of Long-term Outcomes and Proposed Indications. J Int Adv Otol 2018;14(1):112-126. [PubMed]