Pilgramm1

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 improves tinnitus following acoustic trauma.
2. Some evidence that there may be some return of hearing
3. Hyperbaric oxygen may reduce the incidence of later deterioration in tinnitus or hearing

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Citations:1. Pilgramm M, Schumann K. Hyperbaric oxygen therapy for acute acoustic trauma. Archives of Otolaryngology 1985; 241:247-254.

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 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 2.8 bar (?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	0.27	0.05	82%	0.22	5
			95% CI:	36% to 100%	0.1 to 0.35	3 to 10

 

Non-event outcomes	Time to outcome	rTPA group	HBO and rTPA group	Difference	P-value
Mean 6kHz hearing loss(dB)	42 days	15	2	13	Not given
Hearing improvement(%)	7 days	52.7	75.8	23.1	Not given
Hearing improvement(%)	42 days	76.2	87.7	11.5	Not given
Mean improvement in tinnitus(dB)	42 days	0	6.5	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.

Appraised by:Mike Bennett, Dept of Diving and Hyperbaric Medicine, Prince of Wales Hospital, Sydney; Sunday, 28 March 1999

Expiry date:June 2020

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