- We identified three comparative studies that evaluate the effectiveness of carbogen gas in the treatment of sudden sensorineural hearing loss.
- The studies compared carbogen gas to heparin infusion and standard care, and evaluated improvement in hearing.
- The studies found no statistically significant differences between carbogen gas and either heparin infusion or standard care.
- All studies have potential for bias due to non-randomisation, group differences at baseline, and differences in how the groups were treated.
- One study indicates that carbogen may be more effective than anticoagulant therapy in patients with high sloping hearing losses (according to auditory threshold curves).
- Comparative studies mostly over estimate a treatment effect, so it is probably safe to accept the conclusion that carbogen inhalation is no more effective than heparin or standard care in most patients with sudden sensorineural hearing loss.
