R . I FA N A R I E F FA H R U R O Z I

THE ROLE OF HYPERBARIC OXYGEN THERAPY IN SUDDEN SENSORINEURAL HEARING LOSS : A RETROSPECTIVE REVIEW OF 50 PATIENTS

HIPERBARIK

DEFINISI

•  Pengobatan oksigenasi menggunakan ruang udara bertekanan tinggi dan pemberian oksigen murni 100% pada tekanan lebih dari satu atm dalam jangka waktu tertentu

SARANA

•  Ruang Udara Bertekanan Tinggi / RUBT (Hyperbaric Chamber) •  Tipe RUBT •  RUBT Ruang Tunggal / Monoplace

•  Tekanan < 3 ATA, Individual, Infeksi, Intensif •  Mudah di operasikan, mudah ditempatkan, tidak perlu masker, mudah

dilakukan observasi. •  RUBT Ruang Ganda / Walk in Chamber

•  Tekanan > 3 – 6 ATA, Kelompok, Emboli udara, Dekompresi •  Pernafasan dengan masker menutupi hidung dan mulut

•  RUBT Pengangkut / Mobile •  Untuk operasional militer

•  RUBT Latihan Penyelam •  Untuk uji coba penyelam

•  Small Hyperbaric Chamber •  Untuk Neonatus dan Hewan percobaan.

SARANA

•  Peralatan tambahan untuk RUBT •  Masker oksigen •  Respirator dan Ventilator •  Peralatan untuk terapi •  Peralatan RJP, Tabung endotrakeal, Suction, Infus

•  Peralatan diagnostik •  Alat diagnostik kedokteran, alat monitor oksigen, EKG, EEG, Alat

ukur AGD, Alat monitor TIK

•  Alat neurologi à ofthalmoskop •  Alat latihan à treadmill •  Alat terapi à traksi servikal

TEKANAN DAN INDIKASI

Tipe Tekanan Tipe Ruang Indikasi

≥ 1,5 ATA RUBT Ruang Tunggal dan Ruang Ganda

Iskemia cerebri Iskemia jantung

Iskemia peripheral vaskular Kebugaran

Kedokteran olahraga Skin Flaps

Trauma Akustik

≥ 2,5 ATA

Non portable dan portable

Gas gangren Luka bakar

Crush injury pada ujung lengan / kaki

≥ 3 ATA Non portable dan portable

Kondisi darurat à penyakit dekompresi

≥ 6 ATA RUBT Ruang Ganda Emboli udara Dekompresi

INDIKASI

•  Dekompresi •  Emboli udara •  Keracunan gas •  Gas gangren •  Morbus hansen •  Penyakit jamur sistemik •  Luka bakar •  Ulkus dan gangren diabetikum •  Penyembuhan pasca bedah plastik dan rekontruksi •  Crush injury •  Bedah ortopedi •  Penyakit vaskular à shock, iskemik •  Neurologi à stroke, multipel sclerosis, migrain, edema cerebral •  Hematologi à sickle cell anemia •  Ofthalmologi à oklusi arteri sentralis retina •  THT à sudden deafness, penyakit meniere, radang telinga menahun •  Paru à abses paru

KONTRAINDIKASI

•  Absolut •  Pneumothorax yang belum diterapi •  Keganasan yang belum diterapi •  Hamil

•  Relatif •  ISPA •  Sinusitis kronik •  Kejang •  Emfisema •  Febris tidak terkontrol •  Riwayat pneumothorax spontan •  Riwayat bedah thorax •  Riwayat operasi telinga

KOMPLIKASI

•  Berat •  Barotrauma telinga, sinus, gigi dan paru •  Keracunan oksigen •  Temporer myopia •  Kejang

•  Ringan •  Mual, muntah •  Berkeringat •  Batuk kering •  Sakit dada •  Berkedut / muscle twitching •  Tinitus

MEKANISME TERAPI

•  Aktifitas koklea tergantung dari suplai energi yang dibentuk oleh metabolisme oksigen.

•  Stria vaskularis dan organ Corti dengan aktifitas metabolisme yang tinggi membutuhkan konsumsi oksigen yang sangat besar.

•  Tekanan oksigen pada perilimfe menurun secara signifikan pada pasien dengan tuli mendadak.

•  Tindak lanjut dari keadaan ini adalah rusaknya neuroepitelium sensori karena adanya anoksia sehingga suplai oksigen merupakan kunci utama terjadinya disfungsi pada telinga dalam.

•  Rasionalitas terapi tuli mendadak yaitu peningkatan kelarutan oksigen yang masif, vasokontriksi yang dapat mengurangi edema, memperbaiki aliran darah dan sel darah.

•  Koklea sangat dipengaruhi oleh dua mekanisme metabolisme yaitu oksidatif aerobik pada stria vaskularis dan glikolitik anaerobik pada organ Corti.

•  HBO mempunyai dua efek yaitu membangkitkan kembali metabolisme oksidatif pada stria vaskularis serta melindungi sel neurosensori yang telah menjadi lambat

•  Untuk oksigenasi telinga dalam, HBO berperan meningkatkan potensial transmembran dan sintesis adenosine triphosphate (ATP) serta aktifitas metabolisme sel dan pompa natrium kalium yang mengakibatkan terjadinya keseimbangan ion dan fungsi elektrofisiologi pada labirin.

THE ROLE OF HYPERBARIC OXYGEN THERAPY IN SUDDEN SENSORINEURAL HEARING LOSS : A RETROSPECTIVE REVIEW OF 50 PATIENTS

BACKGROUND

•  Sudden Sensorineural Hearing Loss (SSNHL) is hearing impairment of more than 30 dB of three consecutive pure tone frequencies developing within 3 days or less.

•  It is a clinical manifestation with proposed diverse etiologies such as viral infection, vascular compromise, intra-cochlear membrane rupture or inner ear disease among others.

•  It is more common in young and middle aged people with unilateral ear involvement in more than 90% cases.

•  Due to lack of definite cause of SSNHL, its treatment is largely empirical and includes use of a wide variety of therapies like systemic and intratympanic steroids, vasodilators, osmotic drugs, antiviral and anticoagulants to counteract possible inflammatory mechanism, modify hydrostatic pressure and improving cochlear blood flow.

•  The possible final goal of any treatment modality of SSNHL has been the restoration of oxygen tension in the cochlea to encourage healing and return of hearing to normal levels.

•  Hyperbaric oxygen therapy (HBOT) is a treatment modality involving the intermittent inhalation of 100% oxygen in chambers pressurized above 1 atmosphere absolute (ATA). HBOT has been used as an adjunctive therapy for SSNHL as it raises the amount of oxygen in the inner ear by diffusion which activates cell metabolism leading to restoration of ionic balance and electrophysiological functions of cochlea

PROBLEMS

•  How is the efficacy of addition of HBOT to conventional treatment in patients with SSNHL?

OBJECTIVES

•  To evaluate the efficacy of addition of HBOT to conventional treatment in patients with SSNHL •  To identify specific groups of patients likely to

benefit from the addition of this therapy.

METHODS

DESIGN

•  Retrospective study

TIME & PLACE

•  Time •  6 year from 2006 to 2011

•  Place •  Department of Internal and Hyperbaric Medicine and

Department of ENT of Indraprastha Apollo Hospital

SAMPLE

•  150 patients with SSNHL who presented to our unit during the period 2006 to 2011. •  50 Patients who met the following inclusion criteria

were taken for the study

CRITERIA

•  Unilateral onset of SSNHL of 30 dB or greater in at least three contiguous frequencies •  Unknown cause of hearing loss •  No previous surgery in the affected ear

SAMPLING METHODS

•  The patients received HBOT in addition to conventional treatment as prescribed by the referring ENT Surgeon. •  The conventional treatment however was not

standardized for patients. •  HBOT was administered in a multi place chamber at

2.40 ATA for 90 min once daily for at least 10 days. •  The data collected included •  Demographics •  Initial symptoms of hearing loss, tinnitus, vertigo •  Coexisting symptom •  Pure tone audiogram (PTA) •  Duration of onset of hearing loss from starting of HBOT.

SAMPLING METHODS

•  The patient's audiograms were reviewed before starting treatment and after 10 sessions of HBOT.

•  If the audiogram showed improvement after 10 treatments, patients were advised for additional 10 sessions of HBOT, this process was repeated after further 10 sessions and a maximum of 30 sessions were given if they continuously showed improvement.

•  All patients were assessed with PTA at 500, 1000, 2000, 4000 and 6000 Hz and hearing gain at these frequencies was calculated separately.

•  The level of hearing loss at these 5 frequencies was evaluated in 3 groups: <40 dB (mild), between 41 and 70 dB (moderate), >70 dB (severe).

•  The average of mean hearing gain of patients according to age group and therapeutic delay along with presence of associated complaints as contributory factors to prognosis of SSNHL was assessed.

•  Data of study was evaluated using descriptive statistical methods i.e. mean and standard deviation.

RESULTS

CLINICAL PROFILE

•  The 50 subjects in our study were in the age range of 18 to 75.

•  Proportion : 28 males and 22 females.

•  The co-morbid factors : •  Hypertension (8%). •  Diabetes Mellitus (16%). •  Coronary artery disease (8%).

•  There was history of smoking in 2 2 % o f c a s e s a n d 3 4 % addit ional ly complained of tinnitus and vertigo.

MEAN HEARING LEVELS AT DIFFERENT FREQUENCIES

•  The initial and final mean hearing levels at 500, 1000, 2000, 4000 and 6000 Hz of patients are presented in Table 2.

•  The mean hearing gain was highest at frequencies above 1000 Hz.

MEAN HEARING GAIN BASE ON INTENSITY

•  The mean hearing gain after treatment is shown in Table 3.

•  The average hearing gain at the five frequencies was significantly higher in patients with initial level of >70 dB in comparison to patients with hearing levels of <70 dB.

MEAN HEARING GAIN BASE ON THERAPEUTIC DELAY

•  Table 4 shows the mean hearing gain according to therapeutic delay of starting HBOT.

•  Time of presentation ranged between 1 and 60 days. The patients who received treatment within 14 days had higher hearing gain (76 ± 20.06 dB - 51.9 ± 17.1 dB) as compared to patients with therapeutic delay of 15 - 30 days (77.85 ± 29.12 dB - 59.85 ± 22.50 dB) and in patients who started therapy after 30 days (77.8 ± 23.81 dB - 64.5 ± 21.82 dB).

CORRELATION BETWEEN TIME LAG & SEVERITY ON THE HEARING IMPROVEMENT

•  Table 5 shows a correlation between the time lag and severity on the improvement in mean hearing gain in patients.

•  82% patients presenting within 14 days showed maximum improvement as compared to other subset of patients.

MEAN HEARING GAIN BASE ON AGE GROUP

•  Average hearing gain of patients according to age group is presented in Table 6 and was significantly high in patients younger than 50 years.

•  No statistically significant difference was found among patients with coexisting complaints of hypertension, diabetes, smoking and presence of tinnitus or vertigo.

•  The hearing gain were 30 dB or more in 40%, between 20 and 30 dB in 20% and up to 20 dB in 34% of patients.

•  There was no response to HBOT in 6% patients (n = 3). •  The average number of hyperbaric sessions ranged from

10 to 25 with maximum number of patients showing improvement after 10 exposures.

•  Only one patient was given 25 sessions of HBOT, however the patient did not show additional improvement.

•  In all patients the treatment was well tolerated and no patient complained of any side effects. Hearing loss did not worsen in any case.

DISCUSSION

•  SSNHL is considered as a clinical manifestation of possible several underlying causes such as viral infection, vascular compromise, intra-cochlear membrane rupture or inner ear disease. •  This divers i ty demonstrates the prevai l ing

uncertainty in etiologies and an inability to predict the prognosis.

•  The high spontaneous recovery rate of SSNHL and its low incidence make validation of empirical treatment modalities difficult. Many treatment regimens have been proposed such as antiviral agents, vasodilators, anti-inflammatory and oral and intratympannic steroids. •  Hyperbaric oxygen therapy in recent years has

gained relevance for treating SSNHL in combination with other agents. The Undersea & Hyperbaric Medicine Society (UHMS) has approved the use of HBOT in SSNHL in October 2011.

•  HBOT increases oxygen tension (pO2) in blood by dissolving in the plasma and diffuses into tissue fluids such as those surrounding the sensory and neural elements of the cochlea.

•  Gills showed oxygen induced osmosis as the mechanism for healing property of HBOT in such cases.

•  Aslan et al and Bennett et al demonstrated that earlier the treatment received, better is the prognosis. This was confirmed in our study. The maximum recovery was in the cases which received HBOT within 14 days after onset. They showed significant mean hearing gain from 75.93 ± 20.06 dB to 51.90 ± 17.19 dB.

•  Topuz et al reported HBOT as more effective in severe hearing loss. In our study, 64% cases had hearing loss of >70 dB and 81% of these patients showed improvement of >30 dB with mean hearing gain of 86 ± 11.9 dB - 58.75 ± 13.0 dB.

•  We observed a significant correlation between patients with severe hearing loss presenting to us within 2 weeks of onset. 82% of patients in this subset showed maximum improvement.

•  Presence of tinnitus and vertigo has been reported to affect reversibility of hearing loss in various studies. In our study, 34% cases (n =17) with hearing loss had accompanied tinnitus and vertigo but no significant difference was observed between cases with and without these complaints.

•  Age has been found to be a prognostic factor for improvement. In our study, patients in <50 year age group showed better hearing gain as compared to patients with age of >50 years.

•  Presence of diabetes, hypertension and other associated complaints in this age group might have been the contributory factors to poor prognosis; however we were not able to establish any correlations.

•  There is no consensus on the right number of treatments with HBOT in the treatment of SSNHL. While some cases show improvement within a few days other cases might need it longer to achieve good results, however few studies report the optimum number of sessions. In our study, maximum patients showed improvement after 10 exposures and maximum improvement was seen on an average of 20 sessions. We recommend that 20 sessions of HBOT may be optimum for recovery in a majority of patients.

•  While the number of cases in this study is small, 94% of patients in the study group showed statistically significant improvement in hearing, when HBOT was administered along with conventional therapy. While all patients were on oral steroids the conventional treatment was not standardized in our patients.

•  There appears to be a scientific rationale for use of HBOT in SSNHL and our results are encouraging. We recommend additional multicentric, prospective trials be carried out with a standardized protocol to establish role of HBOT in SSNHL patients.

CONCLUSION

•  This retrospective study reveals that the addition of HBOT to conventional therapy significantly improves outcome in patients of SSNHL if started within 14 days. •  Improvement is best at frequencies above 500 Hz

and in hearing loss of above 70 dB. HBOT was more effective in patients younger than 50 years of age.