This document summarizes otitic barotrauma, which refers to injuries to the ear caused by pressure changes during diving or flying. It discusses the history of diving and describes the three main manifestations of barotrauma: sinus/middle ear issues, decompression sickness, and arterial gas emboli. It then covers the physiological effects of pressure changes on descent and ascent, outlines different types of ear barotrauma injuries, and provides treatment recommendations.

1. OTITIC BAROTRAUMA

2. Introduction
• Diving as a profession can be traced back more than 5000
years, yet diving-related disease was not described until Paul
Bert wrote about caisson disease in 1878.
• Diving barotrauma can present with: Pain in ear, face or mouth
and headaches to major joint pain, paralysis, coma and death

4. • Three major manifestations:
(1) Sinus or middle ear
(2) Decompression sickness
(3) Arterial gas emboli
Introduction

5. History
• Diving bell:
- Alexander the Great at the siege of Tyre in 323 Bc
• Modern diving bell:
- A form of caisson, was invented by John Smeaton in 1788
• SCUBA: self contained underwater breathing apparatus
- Invented by Emile Gagnon and Jaques Cousteau in 1943

6. • In 1897, Alt described middle and inner ear injuries caused by
compression and decompression in caisson workers
• Alt and Vail:
- Animal experiment
- Inner ear compression barotrauma was related to the failure of
middle ear pressure equalization

7. • Vail: also hypothesized that decompression injury was caused
by an effect on the inner ear by nitrogen bubbles

8. Definition
• Defined as an injury produced by mechanical forces caused by
a change of pressure in a gas-filled space.
• Otitic barotrauma: pathological conditions of the ear
induced by pressure changes.

9. • Pressure/volume relationships:
- Inverse relationship between the pressure of a gas and the
volume it occupies is described by Boyle's Law
• The pressure increase with depth is a linear relationship of
approximately 1 kPa for every 10 cm depth

11. • Descent in air from 5500 m to sea level represents a pressure
increase of only 0.5 atmospheres (50.5 kPa)
• When diving, the largest percentage change in gas volume
occurs during the first 10 metres of descent
• For aviators during the first 1000m of altitude

12. Ambient pressure change
• The external pressure is uniformly distributed over an object
• In a system which has no air spaces within it, this pressure is
transmitted equally throughout the structure
• Head-out immersion causes a significant squeezing of blood
volume from the lower limbs into the chest and into the head
causing an increasing cardiac output and raised intracranial
pressure and headaches respectively

13. • In the submerged diver, or aviator, the pressure is equally applied to
all body structures, there is no differential pressure across any
membranes or systems so function is essentially unchanged
• The exception is an air-filled cavity within the body
• Middle ear is a bony cavity, no distension or expansion is able to
take place
Ambient pressure change

14. • Failure to equalize via the Eustachian tube -> negative middle
ear pressure
• Difference between the intraluminal vascular pressure and the
middle ear air pressure
• Oedema and even rupture of those vessels within the mucosal
lining will occur
Ambient pressure change

15. • Physiological Consequences of compression (Descent):
• As the diver descends, the ambient pressure increases
• The middle ear pressure becomes increasingly negative
compared to the ambient pressure unless equalization via the
Eustachian tube takes place
• This occurs by the voluntary action of the tensor and levator
palati muscles opening the usually closed tube

16. • If Eustachian tube cannot be opened -> pressure equalization in
middle ear space, with that of the external pressure, cannot
occur
• Further descent -> resulting in a pressure differential across the
tympanic membrane, which is therefore pushed inwards by the
external water pressure
Descent:

17. • This stretching is perceived as a sensation of external pressure
and discomfort, which stimulates further attempts at
equalization
• Diver should return towards the surface
• If descent continues, then middle and inner ear barotrauma
Descent:

18. • The perception of the requirement to equalize occurs at a
maximum of 86 cm (2.6 ft) reflecting a pressure change of only
8.7 kPa (60 mmHg).
• At this pressure, if no equalizing manoeuvre -> increases the
transmural pressures, thus increasing transudation -> mucosal
congestion and oedema
• Continued descent results in 'Eustachian locking' at 13 kPa (90
mmHg), an equivalent depth of approximately 1.3 m (3.9 ft)
Descent:

19. • Levator palati muscles is insufficient to voluntarily overcome the
external closing pressures -> middle ear barotrauma
• If the pressure gradient across the tympanic membrane is large
and occurs before the middle ear fills with an effusion or blood,
then the tympanic membrane may rupture
Descent:

22. • Physiological consequences of decompressin (Ascent):
• During normal ascent, as the middle ear pressure exceeds that
of the ambient pressure, passive ventilation through the
Eustachian tube into the pharynx occurs.
• When flying, this normally occurs every 13.25 m (43.5 ft) of
ascent, regardless of the speed of decompression.

23. • If both Eustachian tubes are functioning correctly then the only
conditions experienced on ascent are decompression illness
• During a diver's descent mild middle ear barotrauma may occur
due to suboptimal Eustachian tube function
• To continue ascending -> positive middle ear pressure ->
outward bulging of the tympanic membrane

24. • Tympanic membrane is pushed outwards
• Inward force on the round window membrane
• Pressure gradient is increased further as the perilymphatic pressure,
reflecting the ambient pressure, has decreased with ascent.
• It is possible, therefore for perilymphatic fistulae to occur during this
phase of a dive.

25. Manifestations of otitic barotrauma divided into:
1. Compression injuries
a) External ear barotrauma
b) Middle ear barotrauma
c) Inner ear barotrauma
2. Injuries at stable pressure
3. Decompression injuries

26. A) External ear barotrauma

27. Clinical presentation
• Main symptom is of pain, increasing with depth
• The ear canal skin and tympanic membrane:
- hyperemic, petechial haemorrhages and even bleeding

28. B) Middle ear barotrauma
Clinical Features:
1. The initial symptom is the sensation of a blocked ear with a strong
desire to equalize
2. Otalgia, which worsens with increased compression
3. Minimal initial conductive loss (decreased compliance)
to the Larger conductive loss (due to damage to the stapes foot
plate, incus dislocation and fractured malleus handle)

29. 4. Tympanic membrane perforation
5. Caloric vertigo - sudden ingress of water into the middle ear
 Tympanic membrane appearance in middle ear barotrauma (Modified
Teeds grading):
Grade Symptoms and signs
O Symptoms, no signs
1 Redness and retraction

30. Grade Symptoms and signs
2 Intratympanic membrane haemorrhage
3 Gross tympanic membrane haemorrhage
4 Haemotympanum
5 Perforation

32. • Equalization tests:
1. Valsalva's manoeuvre - poor predictive test for potential
barotrauma
2 Toynbee's test (positive predictive value of 25 percent)
3 Nine-step Eustachian tube test (positive predictive value, 25
percent; negative predictive value, 75 percent).
4. Combining the nine-step test with Toynbee's test -Reliable (100
percent)

33. 5. Sonotuberometry and tubotympanometry: accurately predict
• Degree of mastoid pneumatization:
- Pneumatization of greater than 34.7 cm2-> decreased
barotrauma
- Pneumatization less than 13.6 cm2 -> inceased
barotrauma

34. Treatment of ME Barotrauma
• Treatment regimen (on basis of 3 level clinical classification of
severity):
• Type 1. symptoms, but no (or minimal) signs
- requires no specific treatment
Type 2. significant signs, but no perforation
- conservative with oral or topical nasal decongestants

35. Type 3. with perforation
- initial observation
- myringoplasty (fail to heal)

36. Prevention of middle ear barotrauma
 Medical:
1. Nasopharyngeal irradiation
- Poor success rates and radiation induced tumors, stopped
this practice
2. Topical nasal decongestants and oral pseudoephedrine

37. • 3. Nasal balloon inflation (auto-Politzerization) using Otovents
 Surgical:
• Myringotomies with or without the insertion of ventilation
tubes

38.  Diving and flying after Middle ear surgery:
• Restriction of any activity for at least six weeks
• Stapedotomy technique:
- As the potential consequences of a perilymphatic fistula when
diving are so extreme, postoperative wait of 12 months is
recommended

39.  Caloric Vertigo:
• Rupture of tympanic membrane
• Severe acute caloric vertigo
• Colder the water, more severe the effect
• Vertigo is self-correcting if caloric stimulus is removed

40. Inner ear barotrauma
• Two mechanisms:
a) Implosive
b) Explosive

41. a) Implosive mechanism:
Inner ear barotrauma

42. Inner ear barotrauma

43. b) Explosive mechanism Inner ear barotrauma

44.  Classification:
1. Inner ear haemorrhage
2. Labyrinthine membrane tears
3. Perilymphatic fistula
Inner ear barotrauma

45. • Inner ear haemorrhage:
- Transient, or minimal, vestibular symptoms
- Mild to moderate sensorineural hearing loss
- Good recovery
Inner ear barotrauma

46. • Labyrinthine membrane tears:
- Vertigo and tinnitus
- Characteristic low frequency hearing loss
- Inner ear damage: haemorrhage around Reissner's and the
round window membranes
- Rupture of the utricle and saccule
Inner ear barotrauma

47. • Temporal bone:
- Reissner's membrane rupture
• In normally ventilated ears, the inner ear is more susceptible to
decompression trauma
• Implosive forces to the inner ear causes middle ear
overpressure (ascent with a locked ET), than compression
(descent)
Inner ear barotrauma

48. Perilymphatic fistulae
• Sudden onset of vertigo
• Sensorineural hearing loss
• Tinnitus
• Positional nystagmus
• Tullio phenomenon

49. • Tympanic membrane: signs of middle ear barotrauma
• Nystagmus usually towards the opposite side
• Romberg's test is normal in more mild cases
• Unterberger's step test
• Side-step test
Perilymphatic fistulae

50. • Inner ear decompression sickness:
• Commercial and military divers who breathe a compressed
mixture of helium and oxygen
• Decompression (ascent), or shortly after surfacing from a dive
• Hyperbaric chamber for recompression
Perilymphatic fistulae

51. Treatment:
• Initial conservative approach (bed rest for 05 days)
• Exploration reserved for:
(1) Those with progressive hearing deterioration observed
on daily, or more frequent, audiometry
(2) If the vestibular symptoms fail to improve after 05 days
(3) Failure of complete resolution after one month
Perilymphatic fistulae

52. • Moderate to Severe hearing loss:
- Emergency exploration in severe acute cases with both a
significant hearing loss and vertigo (40 dB HL)
Perilymphatic fistulae

53. • Minimal Hearing loss:
- Mild vestibular symptoms and hearing losses ( high frequency only,
or < 20 dB HL)
- Initial conservative (bed rest with elevation of the bed head to 30-40
degree)
Perilymphatic fistulae

54. • Surgical exploration:
- Daily audiometry
- Subjective deterioration
- Vestibular symptoms
Perilymphatic fistulae

55. • Mild to moderate hearing loss:
• Persistant vestibular symptoms without hearing loss:
- Conservatively for upto 04 weeks
- Hearing loss with vestibular component presenting more than
24 hours following the incident -> conservative
Perilymphatic fistulae

56. • Surgical exploration:
- Earlier the presentation with hearing loss after the event, and
worse the vestibular component-> urgent surgery
- Evidence of deteriorating hearing
- if vestibular symptoms and hearing loss persist (exploration
after 05 days)
Perilymphatic fistulae

57. • Surgery for perilymphatic fistula:
• Exploratory tympanotomy
- Look at the round, oval windows and Eustachian tube orifice
for a source of the leak

58. - Tissue plug and absorbable middle ear packing material
- If no fistula is observed, then tissue graft in the round window
and over the foot plate
- Vein (sticky nature of its adventitial surface)
- Fluid collection for beta 2-transferrin

59. Injuries at Stable Depth
High-pressure nervous syndrome:
Clinical presentation:
• General dizziness and tremors
• Ataxia and myoclonus
• Sudden onset of vertigo and nausea with nystagmus
has been reported as part of this syndrome.

60. • Permanent vestibular damage has been described, but there is
no hearing loss
• Prevention:
- Minimized by ensuring slow descents and by avoiding inert gas
changes at depth
High-pressure nervous syndrome

61. • If symptoms are encountered when a helium-oxygen mix
is changed to air during ascent, then the treatment is to
recompress back on helium-oxygen
High-pressure nervous syndrome

62. Decompression injuries
• Alternobaric vertigo:
• Condition of asymmetrical middle ear overpressure stimulation
occurring in both divers and aircrew.
• Pathoetiology:
- On ascent, failure of equalization due to minor middle ear
congestion and oedema -> relatively higher pressure in one middle
ear than the other.

63. • Condition occurs on ascent or within two minutes of surfacing.
• Episodes are short lived, with a maximum duration of ten
minutes.
• Divers may also describe a tumbling sensation or a tilting of
their surroundings
Alternobaric vertigo

64. Barotraumatic facial palsy
• Patho-aetiology:
• Pressure-induced neuropraxia (most widely accepted
explanation for transient unilateral facial palsy .
• Dehiscence of the facial nerve in its intramastoid portion (0.5 to
57%)

65. • Animal studies have demonstrated that blood flow in the vasa
nervora of the facial nerve decreases if increased middle ear
pressure is transmitted through a dehiscence of the facial canal
• Alternative hypothesis:
- In a non-dehiscent facial canal, pressure may be transmitted
through the fenestra of the chorda tympani.

66. Persistent palsy:
• Myringotomy
• If rapid resolution does not occur, then oral steroids should be
considered.
• A persisting palsy should be investigated and treated as for a
decompression illness.

67. THANK YOU