Hyperbaric
oxygen following acute acoustic trauma may be associated with improvement of
tinnitus and more rapid return of hearing.
Clinical Bottom Line:
1.
Some evidence that hyperbaric oxygen is associated with improvement in
tinnitus following acute acoustic trauma.
2.
Some evidence that hearing recovery may also be improved to some degree.
3.
Hyperbaric oxygen appears to reduce the incidence of later deterioration in
hearing and/or tinnitus.
Appraised
by: Mike Bennett, Dept of Diving and
Hyperbaric Medicine, Prince of Wales Hospital, Sydney; Sunday, 28 March 1999
Clinical
Scenario: A patient presenting with
acoustic trauma resulting in hearing loss.
Three-part
Question: In patients with acute hearing
loss and tinnitus following acoustic trauma, does the administration of
hyperbaric oxygen, in addition to a standard sorbitol and dextran infusion,
result in any improvement in outcome?
Search
Terms: Acoustic trauma, deafness,
tinnitus.
The
Study:
Non-blinded concealed randomised
controlled trial with intention-to-treat.
Young male patients with acute
acoustic trauma within the last 48 hours and associated with greater than 40dB
hearing loss which has not improved more than 20dB in the first 24 hours.
Control group (N = 59; 59
analysed): Standard IV protocol of 25g sorbitol and 50g dextran daily for 14
days. Half of this group also received 24mg betahistidine daily.
Experimental group (N = 61; 61
analysed): Same two IV protocol groups plus 100% oxygen at 2.8bar (?ATA) for 60
minutes daily for 10 days.
The
Evidence:
|
Outcome |
Time
to Outcome |
Air
group |
HBO
group |
Relative
risk reduction |
Absolute
risk reduction |
NNT |
|
Deterioration
after discharge |
14
days |
0.271 |
0.049 |
82% |
0.222 |
5 |
|
95%
CI: |
|
|
|
36%
to 100% |
0.096
to 0.348 |
3
to 10 |
Non-Event
Outcomes
Time to outcome Air group
HBO group
P-value
Mean
6kHz hearing loss(dB)
42 days
15
2
Not Given
Hearing
improvement(%)
7 days 52.7
75.8
Not Given
Hearing
improvement(%)
42 days
76.2
87.7
Not Given
Mean
improvement in
tinnitus(dB)
42
days
0
6.5
Not Given
Comments:
1. Very difficult study to read
as results are presented in a confusing manner.
2. No significance testing for
hearing improvement, tinnitus, rate of recovery or late deterioration make
interpretation difficult. The non-event results above have been calculated by
this reviewer
3. No definition for
'deterioration' given.
Expiry
date:
July
2002
References:
1. Pilgramm M, Schumann K. Hyperbaric
oxygen therapy for acute acoustic trauma. Archives of Otolaryngology 1985;
241:247-254.
