Objective. Sudden hearing loss (SHL) is a frightening symptom that often prompts an urgent or emergent visit to a physician. This guideline provides evidence-based recommendations for the diagnosis...

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Clinical practice guideline: sudden hearing loss.

Radiation therapy is an established modality in the treatment of head and neck cancer patients. Compromised wound healing in irradiated tissues is a common and challenging clinical problem. The pathophysiology and underlying cellular mechanisms including the complex interaction of cytokines and growth factors are still not understood completely. In this review, the current state of research regarding the pathomechanisms of compromised wound healing in irradiated tissues is presented. Current and possible future treatment strategies are critically reviewed.

/pdf/wound-healing-after-radiation-therapy-review-of-the-54wtlmb3ny.pdf

Wound healing after radiation therapy: Review of the literature

In the mammalian central nervous system, reactive oxygen species (ROS) generation is counterbalanced by antioxidant defenses. When large amounts of ROS accumulate, antioxidant mechanisms become overwhelmed and oxidative cellular stress may occur. Therefore, ROS are typically characterized as toxic molecules, oxidizing membrane lipids, changing the conformation of proteins, damaging nucleic acids, and causing deficits in synaptic plasticity. High ROS concentrations are associated with a decline in cognitive functions, as observed in some neurodegenerative disorders and age-dependent decay of neuroplasticity. Nevertheless, controlled ROS production provides the optimal redox state for the activation of transductional pathways involved in synaptic changes. Since ROS may regulate neuronal activity and elicit negative effects at the same time, the distinction between beneficial and deleterious consequences is unclear. In this regard, this review assesses current research and describes the main sources of ROS in neurons, specifying their involvement in synaptic plasticity and distinguishing between physiological and pathological processes implicated.

https://journals.sagepub.com/doi/pdf/10.4137/JEN.S39887

Reactive Oxygen Species: Physiological and Physiopathological Effects on Synaptic Plasticity.

The treatment of delayed radiation injuries (soft tissue and bony radiation necrosis) is one of thirteen conditions approved by the Hyperbaric Oxygen Therapy Committee of the Undersea and Hyperbaric Medical Society as appropriate indications for hyperbaric oxygen (HBO2). This paper provides a systematic review of the literature reporting the results of HBO2 therapy in the treatment and/or prophylaxis of delayed radiation injury. Since the introduction of the concept of evidence based medicine, the medical community in general has set out to apply more critical and stringent standards in evaluating published support for therapeutic interventions. Evidence based medicine is designed to discover the best evidence available and apply it in daily practice for treatment of the individual patient. The preferred level of evidence is the randomized controlled trial, however, other evidence has merit as well. In this review, seventy-four publications are represented reporting results of applying HBO2 in the treatment or prevention of radiation injuries. These are appraised in an evidence-based fashion by applying three established systems of evaluation. All but seven of these publications report a positive result when HBO2 is delivered as treatment for or prevention of delayed radiation injury. These results are particularly impressive in the context of alternative interventions. Without HBO2, treatment often requires radical surgical intervention, which is likely to result in complications. Other alternatives including drug therapies are rarely reported, and for the most part have not been the subject of randomized controlled trials. Based on this review, HBO2 is recommended for delayed radiation injuries for soft tissue and bony injuries of most sites. Of note, an increasing body of evidence supports HBO2 for radiation-induced necrosis of the brain. For other radiation-induced neurological injuries, additional study is required before recommendations for routine hyperbaric therapy can be made.

A systematic review of the literature reporting the application of hyperbaric oxygen prevention and treatment of delayed radiation injuries: An evidence based approach

Objectives:

To study the safety and efficacy of continuous intratympanic dexamethasone-phosphate (Dex-P) for severe to profound sudden idiopathic sensorineural hearing (ISSHL) or sudden idiopathic anacusis after failure of systemic therapy.



Study Design:

Randomized, double-blind, placebo controlled multicenter trial.



Methods:

Patients with ISSHL and insufficient recovery (mean 4PTA = 97 dB HL) after systemic high dose glucocorticoid therapy received either Dex-P (4mg/ml) or placebo (NaCl 0.9%) continuously applied for 14 days into the round window niche via a temporarily implanted catheter. For ethical reasons, intratympanic treatment was continued with Dex-P in all patients for another 14 days after the placebo-controlled study period. According to a two-step adaptive study design an interim analysis was performed after inclusion of 23 patients.



Results:

Intention-to-treat analysis for the primary outcome criterion (4PTA: 0.5-3kHz) during the placebo controlled study period (14 days) showed an average hearing improvement in the treatment group of 13.9 dB (SD: 21.3) and in the placebo group of 5.4 dB (SD: 10.4). This difference in hearing improvement between the two groups (mean: 8.4 dB, SD: 17.0, 95% CI: −7.1–24.1) was statistically not significant (p = .26). Of the secondary outcome parameters, the largest benefit of local salvage therapy was found for maximum speech discrimination with an improvement of 24.4% (SD: 32.0) in the treatment and 4.5% (SD: 7.6) in the placebo group (p = 0.07). After a 3 month follow-up period (i.e. after all patients received intratympanic Dex-P) hearing improvement in the two groups was very similar. No serious adverse events were observed. Sample size calculation after the interim analysis resulted in stopping of the trial.



Conclusions:

The tendency toward better hearing improvement in the treatment group, the rather conservative inclusion criteria, the limited placebo-controlled observation period and the absence of serious adverse events supports further investigation local inner ear drug delivery as a first or second line treatment option for ISSHL. Laryngoscope, 119:359–369, 2009

Randomized, double blind, placebo controlled trial on the safety and efficacy of continuous intratympanic dexamethasone delivered via a round window catheter for severe to profound sudden idiopathic sensorineural hearing loss after failure of systemic therapy.

Objectives:We investigated prognostic factors in sudden sensorineural hearing loss (SSNHL).Methods:Our study group consisted of 133 patients with SSNHL who were treated at our department between 19...

Prognostic factors in sudden sensorineural hearing loss : Our experience and a review of the literature

OBJECTIVE We investigated the effect of pharmacologic (steroids, vasodilators, vitamins, and Betaserc) and hyperbaric oxygen therapy on patients with sudden sensorineural hearing loss. METHODS The pharmacologic arm of the study consisted of 52 patients with defined sudden sensorineural hearing loss treated simultaneously in the ENT Department and National Center for Hyperbaric Medicine of the Medical University of Gdansk, Poland, from 1997 to 2000 (Group A). The hyperbaric oxygen therapy consisted of exposure to 100% oxygen at a pressure of 250 kPa for a total of 60 minutes in a multiplace hyperbaric chamber. The control group included 81 patients with defined sudden sensorineural hearing loss treated in the ENT Department, Medical University of Gdansk, from 1980 to 1996 (Group B). Both groups were comparable regarding the age of the patients, season of hearing loss occurrence, tinnitus and vestibular symptom frequency, delay before therapy, and average threshold loss before the start of treatment. The treatment results (hearing gain) were estimated using pure-tone audiometry. We retrospectively analyzed the audiograms of all patients. RESULTS Patients from Group A (blood flow-promoting drugs, glucocorticoids in high doses, betahistine, and hyperbaric oxygen therapy) showed significantly better recovery of hearing levels compared with those from Group B (blood flow-promoting drugs and glucocorticoids in low doses) at seven frequencies (500, 1,000, 2,000, 3,000, 4,000, 6,000, and 8,000 Hz) (p < 0.05) and four groups of frequencies (pure-tone average, high-tone average, pure middle-tone average, and overall average) (p < 0.05). Percentage hearing gain in all investigated frequencies was also better in Group A versus Group B, and the differences were statistically significant (p < 0.05). CONCLUSION We conclude that hyperbaric oxygen therapy with high doses of glucocorticoids improves the results of conventional sudden sensorineural hearing loss treatment and should be recommended. In addition, the best results are achieved if the treatment is started as early as possible.

Usefulness of high doses of glucocorticoids and hyperbaric oxygen therapy in sudden sensorineural hearing loss treatment.

Background and purpose We have investigated the treatment results of hyperbaric oxygen (HBO2) to patients with radiation-induced tissue complications. Material and methods Eight patients (1.4%) from 548 with head and neck cancers treated surgically with post- or preoperative radiotherapy or radiotherapy alone in standard doses who developed postradiation complications (6 patients with laryngeal chondroradionecrosis, 1 patient with osteoradionecrosis of the temporal bone, and 1 patient with soft tissue radionecrosis) are presented. To evaluate radiation reactions occuring in the head and neck region, we used the Chandler grading system for classification of postradiation larynx injuries and SOMA/LENT score for classification of postradiation injuries of mucosa of upper aerodigestive tract. Grades I and II in those grading systems are expected side effects of radiation therapy, thus our cases were all in grades III and IV. The HBO2 was performed after failure of the conventional treatment (antibiotics, steroids, topical therapy). The number of HBO2 expositions was from 8 to 39 and the delay to therapy from 2 to 22 months. Results Symptoms resolved in all treated patients. Six patients with laryngeal chondroradionecrosis had no symptoms after therapy and in three of them after partial laryngectomy the decannulation was performed. In one patient with mucosal radionecrosis after total laryngectomy, the esophageal fistula was closed and in one patient with osteoradionecrosis of the temporal bone, wound debridement followed. Conclusion The authors' experience supports the increasing clinical evidence that HBO2 is an effective adjunct therapy for treatment of complications of irradiation in head and neck area.

Hyperbaric oxygen therapy in the treatment of complications of irradiation in head and neck area.

Reactive oxygen species, including oxygen free radicals are normally generated in human cells during aerobic metabolism. Their production may increase during breathing of hyperoxic mixtures. The 'oxidative stress' has been postulated to be an important contributor to CNS oxygen toxicity. One of the highest partial pressure of oxygen used in healthy humans is 280 kPa(a) during 30 min of 'oxygen tolerance tests' (OTT). This test is conducted in order to detect some individuals with an increased sensitivity to high partial pressures of oxygen leading them to develop CNS oxygen toxicity earlier than others. The purpose of this study was to investigate whether the OTT (30 min of breathing pure oxygen at 280 kPa(a)) would significantly induce oxidative stress in healthy population. The first group consisted of 52 subjects, in whom total antioxidant status (TAS) was measured. The second group consisted of 44 subjects, in whom protein carbonyls (PC), total thiol (t-SH) and heat shock proteins (HSP70) were measured. All measurements were done just before and immediately after the OTT. There was no statistically significant change of TAS. We observed a small, however statistically significant increase of PC and decrease of t-SH. A significant decrease of HSP70 was detected, however false positives of initial measurements are suspected. In summary, in young healthy subjects 30 min of breathing oxygen under pressure of 280 kPa(a) induces oxidative stress which can be detected by increase of protein carbonyls and by decrease of total thiol. In our study this stress was not reflected in measurement of total oxidative status and heat shock proteins.

Oxidative stress during oxygen tolerance test.

BACKGROUND Direct spectrophotometry has been recognized as a standard reference method in the treatment of victims of carbon monoxide (CO) poisoning. Recently, Masimo (USA) has developed a pulse oximeter for the detection of HbCO. Using new probes, similar to those used for traditional pulse oximetry, several different light wavelengths enable detection of different haemoglobins. METHODS We have compared forty-nine capillary blood samples taken from patients admitted to the hyperbaric center with CO poisoning. The samples were analyzed using direct spectrophotometry (HbCO) and compared with the corresponding pulse CO-oximeter (SpCO) readings. The Bland-Altman method was used for statistical analysis. RESULTS The mean HbCO concentration was 18.1+/-12.7% (range 0.1% to 47.4%) and the mean SpCO concentration, 17.6+/-11.3% (range 1.0% to 46.0%). There was a strong positive correlation between laboratory results and bedside readings (r2=0.88). The mean difference between readings was 0.5+/-4.3% (range -11.0% to +9.0%), and the distribution was uniform over the whole range of measured levels. For detection of HbCO levels higher than 20%, the sensitivity of the pulse-CO-oximeter was 77.8%, PPV 82.4%, specificity 90.3%, and NPV 87.5%. CONCLUSIONS Our study confirmed the accuracy of pulse CO-oximetry for rapid detection of the presence and concentration of HbCO. Since this method is based on analysis of peripheral blood flow, it is not clear if it could be used in patients with low perfusion, hypothermia or burns.

Zdzisław Sićko

Papers

Prognostic factors in sudden sensorineural hearing loss : Our experience and a review of the literature

Usefulness of high doses of glucocorticoids and hyperbaric oxygen therapy in sudden sensorineural hearing loss treatment.

Hyperbaric oxygen therapy in the treatment of complications of irradiation in head and neck area.

Oxidative stress during oxygen tolerance test.

Carbon monoxide pulse oximetry vs direct spectrophotometry for early detection of CO poisoning