OTITIC%20BAROTRAUMA

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OTITIC BAROTRAUMA

• Aero-otitis media / Aviation pressure deafness
• 1783 - Charles ? Hydrogen Balloon
• World War I - Sidney Scott
• World War II - Increase of Air power

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Mention anatomy of ET
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Boyles law

• Volume is inversely proportional to pressure in
  fixed mass of gas

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MECHANICS OF BAROTRAUMA

• As altitude ? environmental pressure ?
• At 18000 ft pressure is half that of sea level,
  and at 34000 ft ¼

Relationship between altitude and barometric
pressure
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• As depth increases during diving , pressure
  increases
• One atmospheric pressure increase for every 10
  mtrs

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MECHANICS OF BAROTRAUMA
elastin

• Medial end is slit like, lies collapsed, in close
  proximity to lymphoid tissue
• Opens on swallowing (pressure equalises) (effect
  of tensor levator palati)
• LEARN DIAGRAM

Ostman pad of fat
Cross-section of Cartilagenous part of Eustachian
tube
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MECHANICS OF BAROTRAUMA
ASCENT
At high altitude ME pressure is higher than env
pressure, therefore air from middle ear escapes
passively along ET equalising pressures
Middle Ear
Nasopharynx
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MECHANICS OF BAROTRAUMA

• During descent environmental pressure is higher
  than ME pressure, therefore we need to aerate the
  ME actively by VALSALVA manouvre/other methods
• If the tube does not open and the pressure
  gradient increases beyond 90 mm of Hg, tube gets
  locked
• Similar during deep sea diving hyperbaric
  chamber

Middle ear
DESCENT
Nasopharynx
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Aetiology of Otitic Barotrauma

• Healthy subjects
• Rapid descent
• No attempt at auto-inflation
• Sleep sedation position
• Effect of alcohol
• Anatomical differences
• Pathological states
• Acute infection ? oedema of ET mucosa
• Chronic ET obstruction ? infected tonsils/nasal
  polypi /allergic rhinitis/ DNS/nasal allergy

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OTITIC BAROTRAUMA

• Clinical Features
• Mild Fullness/ slight hearing loss
• Moderate Pain/ deafness/
• interstitial hemorrhage/ fluid
• Severe Severe pain/ deafness/ rupture

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OTITIC BAROTRAUMA- EARLY

• Tubal Occlusion

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(No Transcript)
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Findings Grade
Symptoms (pain, nausea, vomiting, etc.) Without changes in the tympanic membrane 0
Injection of the tympanic membrane (may be most noticeable along the handle of the malleus) I
Injection plus mild haemorrhage within the tympanic membrane II
Gross haemorrhage within the tympanic membrane III
Free blood in the middle ear (tympanic membrane blue and bulging) IV
Perforation of the tympanic membrane (commonest in AI quadrant) V
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Other possible features

• Middle ear
• Ossicular disruption
• Stapes avulsion
• RW membrane rupture
• 7th nerve barotrauma
• Inner ear
• Perilymph fistula
• Implosive mechanism ? forceful valsalva ? patent
  ET ? Implosive damage to RW
• Explosive mechanism ? forceful valsalva ? blocked
  ET ? ? CSF pressure ? explosive damage to RW
• Oval window in stapedectomized patients

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OTITIC BAROTRAUMA

• Treatment - Curative
• No flying
• Reascent gradual descent
• ET catheterisation
• Antibiotics
• Analgesics
• Nasal oral decongestants
• Myringotomy
• Grommets
• Eliminate septic foci

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Treatment

• TM rupture ? no active management, remove clots?
  if not healed by 3 mths ? myringoplasty
• Perilymph fistula ? Bed rest, head elevation,
  labyrinthine sedatives, stool softeners, cough
  suppressant, Acetazolamide

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Prevention

• Decompression chamber run on enrolment
• Education of aircrew/ divers
• Flying discipline
• Auto-inflation techniques frenzels manouvere
  for pilots