HYPERBARIC OXYGEN IN THE ACUTE HYPERBARIC OXYGEN IN THE ACUTE TREATMENT OF SUDDEN IDIOPATHIC SUDDEN IDIOPATHIC TREATMENT OF SENSORINEURAL HEARING LOSS SENSORINEURAL HEARING LOSS RANDOMISED, PROSPECTIVE STUDY OF HBO A RANDOMISED, PROSPECTIVE STUDY OF HBO A AFTER FAILURE OF PREVIOUS MEDICAL TREATMENT AFTER FAILURE OF PREVIOUS MEDICAL TREATMENT COST Action B14 COST Action B14 January 2001- December 2003 January 2001- December 2003
FACTS : FACTS : • Sudden sensorineural hearing loss • Sudden sensorineural hearing loss ("sudden deafness") is a frequent disease ("sudden deafness") is a frequent disease • 5 to 20 / 100.000 per year • 5 to 20 / 100.000 per year • Only in 20% a causal factor can be identified (vascular, • Only in 20% a causal factor can be identified (vascular, viral, traumatic, auto-immune, tumor) viral, traumatic, auto-immune, tumor) • Sudden deafness is not a banality • Sudden deafness is not a banality • Bilateral hearing is important for spatial orientation • Bilateral hearing is important for spatial orientation • Psychosocial isolation of deaf people • Psychosocial isolation of deaf people • Tinnitus is frequent and can be psychologically • Tinnitus is frequent and can be psychologically devastating devastating
FACTS : FACTS : • Treating "Sudden Deafness" is frustrating : • Treating "Sudden Deafness" is frustrating : • General consensus: treat early and agressively • General consensus: treat early and agressively • Treatments are generally not very successful • Treatments are generally not very successful • About 50% of patients spontaneously recover to a • About 50% of patients spontaneously recover to a functional hearing level functional hearing level • No treatment has fully proven its value • No treatment has fully proven its value • Spontaneous recovery rate is still controversial • Spontaneous recovery rate is still controversial • Placebo-controlled studies : most medication equivalent • Placebo-controlled studies : most medication equivalent to placebo to placebo • General "shotgun" approach = "give everything" • General "shotgun" approach = "give everything"
How to treat a disease How to treat a disease without a cause ? without a cause ? • Vascular : thrombosis, embolus, bleeding, • Vascular : thrombosis, embolus, bleeding, vasospasm, rheological disturbance ? vasospasm, rheological disturbance ? • Viral infection : (echovirus, adenovirus, • Viral infection : (echovirus, adenovirus, mumps virus, coxsackie virus ) ? mumps virus, coxsackie virus ) ? • Inner ear trauma ? • Inner ear trauma ? • Auto-immune disease ? • Auto-immune disease ? • Retrocochlear tumor ? • Retrocochlear tumor ?
All treatments aim at improving treatments aim at improving All blood supply to to the cochlear the cochlear blood supply inner hair cells cells inner hair Corticosteroids, vasodilators, heparin, low-molecular weight heparins, haemodilution therapy, dextrans, vasodilators, rheological substances, red blood cell membrane deformability enhancers, carbogen breathing, stellate ganglion block, calcium channel blockers, corticosteroids, vasodilators, heparin, low- molecular weight heparins, haemodilution therapy, dextrans, vasodilators, rheological substances, red blood cell membrane deformability enhancers, carbogen breathing, stellate ganglion block, calcium channel blockers, corticosteroids, vasodilators, heparin, low-molecular weight heparins, haemodilution therapy, dextrans, vasodilators, rheological substances, red blood cell membrane deformability enhancers, carbogen breathing, stellate ganglion block, calcium channel blockers, …
Improving oxygen supply Improving oxygen supply Oxygen supply to inner hair cells occurs via Oxygen supply to inner hair cells occurs via Oxygen supply to inner hair cells occurs via diffusion from stria vascularis to endolymph fluid diffusion from stria vascularis to endolymph fluid diffusion from stria vascularis to endolymph fluid • Increase blood flow to • Increase blood flow to a. cochleovestibularis a. cochleovestibularis • Increase oxygen • Increase oxygen content of blood content of blood Hyperbaric Oxygen Hyperbaric Oxygen Therapy ? Therapy ?
Hyperbaric Oxygen Therapy Hyperbaric Oxygen Therapy • Respiration of 100% oxygen under • Respiration of 100% oxygen under pressure (2.5 Atmospheres) pressure (2.5 Atmospheres) • Increases dissolved oxygen in plasma • Increases dissolved oxygen in plasma • Provides high oxygen pressure • Provides high oxygen pressure gradient for increased diffusion gradient for increased diffusion • Oedema reduction by arteriolar • Oedema reduction by arteriolar vasoconstriction vasoconstriction • Decreases ischemia-reperfusion • Decreases ischemia-reperfusion effects effects
Hyperbaric Oxygen Therapy Hyperbaric Oxygen Therapy • Has been sporadically used in this indication • Has been sporadically used in this indication for about 20 years for about 20 years • Use limited by need for pressure chamber • Use limited by need for pressure chamber • Few prospective studies (when started early • Few prospective studies (when started early after onset, results often "blurred" by after onset, results often "blurred" by spontaneous recovery) spontaneous recovery) • Efficacy of about 50% in cases refractory to a • Efficacy of about 50% in cases refractory to a classical drug therapy course classical drug therapy course (Lamm et al. – meta-analysis, 1998) (Lamm et al. – meta-analysis, 1998)
COST: Cooperation Cooperation in Science in Science and and COST: Technology Technology • European Commission programme • European Commission programme • To stimulate development of scientific networks • To stimulate development of scientific networks in Europe in Europe • Promoting multicentric clinical and experimental • Promoting multicentric clinical and experimental research research • In domains with large socio-economical impact • In domains with large socio-economical impact • COST Action B14 Hyperbaric Oxygen Therapy • COST Action B14 Hyperbaric Oxygen Therapy (December 1998 – December 2003) (December 1998 – December 2003)
COST B14 : Hyperbaric Oxygen Therapy Hyperbaric Oxygen Therapy COST B14 : • HBO Experts from 15 European Countries • HBO Experts from 15 European Countries • 5 Working Groups on selected clinical • 5 Working Groups on selected clinical research research • Collaboration with independent experts in • Collaboration with independent experts in each research area each research area • Consensus Protocol for Multicentric Study • Consensus Protocol for Multicentric Study • Coordination and monitoring of Study • Coordination and monitoring of Study
The COST B14 COST B14 Sudden Deafness Study Sudden Deafness Study The • To establish the clinical efficacy of HBO in the treatment of • To establish the clinical efficacy of HBO in the treatment of Sudden Deafness, not responsive to a classical medical Sudden Deafness, not responsive to a classical medical treatment. Prospective, randomised, controlled study. treatment. Prospective, randomised, controlled study. • Main endpoint: • Main endpoint: • changes in auditory function, as tested by tonal and • changes in auditory function, as tested by tonal and speech audiometry speech audiometry • Secondary endpoints: • Secondary endpoints: • changes in intensity and pitch of tinnitus, if present • changes in intensity and pitch of tinnitus, if present • changes in feeling of fullness to the ear • changes in feeling of fullness to the ear • establishment of the safety of HBO: presence of side • establishment of the safety of HBO: presence of side effects and complications effects and complications
The COST B14 COST B14 Sudden Deafness Study Sudden Deafness Study The • Study Setup: • Study Setup: • Patients will first receive "standard" drug therapy • Patients will first receive "standard" drug therapy • "Non-responders" will be randomised to : • "Non-responders" will be randomised to : – HBO therapy (10 daily sessions) – HBO therapy (10 daily sessions) – Placebo therapy (placebo oral medication, 3x/day, 10 – Placebo therapy (placebo oral medication, 3x/day, 10 days) days) • Randomisation: • Randomisation: • Telephone randomisation service • Telephone randomisation service • Patient and audiologist will be blinded • Patient and audiologist will be blinded • Cross-over possible if no result after • Cross-over possible if no result after placebo or HBO placebo or HBO
Study outline Study outline • Estimated patient sample = 400 (2x200) • Estimated patient sample = 400 (2x200) • Duration of study: 3 years • Duration of study: 3 years
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