Hyperbaric Oxygen Treatments Attenuate the Neutrophil-to-Lymphocyte Ratio in Patients with Idiopathic Sudden Sensorineural Hearing Loss

The role of hyperbaric oxygen in idiopathic sudden sensorineural hearing loss

Idiopathic sudden sensorineural hearing loss is an unexplained sudden loss of sensorineural hearing, with no specific pathogenesis, and is difficult to treat. The most common therapeutic strategy for idiopathic sudden sensorineural hearing loss is the use of steroids combined with neurotrophic drugs, as other treatments have shown limited efficacy. However, in recent years, hyperbaric oxygen therapy has emerged as a promising treatment option. Studies have shown that hyperbaric oxygen therapy, in combination with conventional treatments, can effectively alleviate inner ear edema, improve blood circulation, and suppress inflammation. Therefore, hyperbaric oxygen therapy plays an important role in the treatment of idiopathic sudden sensorineural hearing loss. In this review, we aim to assess existing studies and summarize the clinical effects and mechanisms of hyperbaric oxygen therapy in idiopathic sudden sensorineural hearing loss, providing a basis for further research on the clinical treatment of this disorder.

The construction and validation of prognostic prediction model for sudden sensorineural hearing loss in middle-aged and elderly people

OBJECTIVE

Idiopathic sudden sensorineural hearing loss (ISSNHL), as an otologic emergency, is commonly encountered and its prevalence has been climbing every year recently. To our knowledge, the prognosis of middle-aged and elderly patients is worse than that of young patients. Previous researches mainly focused on the adult population, which was considered as prognostic models who performed hearing recovery in ISSNHL. However, few studies regarding the middle-aged and elderly population who are regarded as prognostic models have been reported. Therefore, we aim to construct and validate a nomogram-based prognostic prediction model, which can provide a reference for the prognostic assessment in the middle-aged and elderly patients with ISSNHL.

METHOD

A total of 371 middle-aged and elderly ISSNHL patients who were admitted to the Department of Otolaryngology-Head and Neck Surgery, Yanbian Hospital, Yanbian University, from April 2018 to April 2023 were enrolled in the study. All subjects were randomly divided into two groups including training group (n = 263) and validation group (n = 108). Lasso regression and multi-factor logistic regression were jointly utilized to screen out prognosis-related independent risk factors and establish a nomogram-based risk prediction model. The accuracy and clinical application value of the model were evaluated by combining the Bootstrapping method and k-fold cross-validation, plotting the receiver operating characteristic  (ROC)  curve, calculating the area under the ROC curve (AUC), plotting the decision curve analysis (DCA), and the calibrating curve.

RESULT

We used the method of lasso regression combined with multivariate logistic regression and finally screened out eight predictors (including age, number of affected ears, degree of hearing loss, type of hearing curve, duration of disease, presence of vertigo, diabetes, and lacunar cerebral infarction) that were included into the nomogram. The C-index were 0.823 [95% CI (0.725, 0.921)] and 0.851 [95% CI (0.701, 1.000)], and the AUC values were 0.812 and 0.823 for the training and validation groups, respectively. The calibration curve for the validation group was approximately conformed to that for the modeling group, indicating favorable model calibration. The DCA results revealed the modeling group (3%-86%) and the validation group (2%-92%) showed significant net clinical benefit under the majority of thresholds.

CONCLUSION

This study developed and validated a nomogram-based prognostic prediction model which based on the eight independent risk factors mentioned above. The predictors are conveniently accessible and may assist clinicians in formulating individualized treatment strategies.

Prognostic factors for hearing outcomes in patients that undergo adjuvant hyperbaric oxygen therapy for sudden sensorineural hearing loss

Introduction

The aim of this study is to explore the potential factors in hearing outcomes and verify the role of oxidant‐antioxidant equilibrium on the prognosis of sudden sensorineural hearing loss (SSNHL) treated with hyperbaric oxygen therapy (HBOT).

Methods

Ninety‐two patients who were diagnosed with SSNHL between January 2018 and December 2019 in our hearing clinic center were included in this study. All patients were treated with intravenous dexamethasone, and 72 cases were treated with additional HBOT for 10 consecutive days. Peripheral blood was collected prior to any treatment to determine the blood cell count and hemoglobin (HGB), hematocrit (HCT), and superoxide dismutase (SOD) levels. Pure tone audiometry was measured before and after treatment. Complete and overall recovery rate was evaluated. Multivariate logistic analysis was used to identify prognostic factors.

Results

The rate of overall recovery was significantly higher in the patient with combined therapy compared to patients treated with steroids only (51.4% vs 25.0%, p = .036). The levels of HGB, HCT, and SOD were much higher in the patients with better hearing outcomes (p = .027, .033, and .011, respectively). Multivariate logistic analysis demonstrated that patients with higher initial hearing thresholds, or hearing loss at overall frequency, were more prone to have poor hearing gains after HBOT.

Conclusion

HBOT is effective as an early adjuvant therapy for SSNHL. Hearing loss at low frequency, low initial hearing thresholds, as well as high HBG, HCT, and SOD levels are positive prognostic factors for SSNHL patients treated with HBOT.

The Effects of Hyperbaric Oxygenation on Oxidative Stress, Inflammation and Angiogenesis

Hyperbaric oxygen therapy (HBOT) is commonly used as treatment in several diseases, such as non-healing chronic wounds, late radiation injuries and carbon monoxide poisoning. Ongoing research into HBOT has shown that preconditioning for surgery is a potential new treatment application, which may reduce complication rates and hospital stay. In this review, the effect of HBOT on oxidative stress, inflammation and angiogenesis is investigated to better understand the potential mechanisms underlying preconditioning for surgery using HBOT. A systematic search was conducted to retrieve studies measuring markers of oxidative stress, inflammation, or angiogenesis in humans. Analysis of the included studies showed that HBOT-induced oxidative stress reduces the concentrations of pro-inflammatory acute phase proteins, interleukins and cytokines and increases growth factors and other pro-angiogenesis cytokines. Several articles only noted this surge after the first HBOT session or for a short duration after each session. The anti-inflammatory status following HBOT may be mediated by hyperoxia interfering with NF-κB and IκBα. Further research into the effect of HBOT on inflammation and angiogenesis is needed to determine the implications of these findings for clinical practice.

Effect of intermittent hyperoxia on stem cell mobilization and cytokine expression

The best known form of oxygen therapy is hyperbaric oxygen (HBO) therapy, which increases both concentration and atmospheric pressure. HBO supports tissue regeneration and is indicated in an increasing number of pathologies. Less known but still showing some promising effects is normobaric oxygen (NBO) therapy, which provides some advantages over HBO including eliminating barotrauma risk, increased ease of administration and a significant cost reduction. However, still little is known about differences and similarities in treatment effects between HBO and NBO. Therefore we tested whether NBO induces a biological response comparable to HBO with a focus on stem progenitor cell mobilization and changes in serum cytokine concentration. We randomly assigned Sprague-Dawley rats into an NBO treatment group (n = 6), and a room air control group (n = 6). The NBO treatment group was exposed to 42% oxygen for 2 hours a day for 10 days. The room air group was concurrently kept at 20.9% oxygen. The frequency and number of stem progenitor cells in peripheral blood were analyzed by flow cytometry. Plasma cytokine expression was analyzed by cytokine array enzyme linked immunosorbent assay. All analyses were performed 24 hours after the final exposure to control for transient post treatment effects. The NBO treatment group showed an increase in circulating CD133⁺/CD45⁺ stem progenitor cell frequency and number compared to the room air control group. This rise was largely caused by CD34^- stem progenitor cells (CD133⁺/CD34^-/CD45⁺) without changes in the CD34⁺ population. The plasma cytokine levels tested were mostly unchanged with the exception of tumor necrosis factor-α which showed a decrease 24 hours after the last NBO exposure. These findings support our hypothesis that NBO induces a biological response similar to HBO, affecting serum stem progenitor cell populations and tumor necrosis factor-α concentration. The study was approved by Institutional Animal Care and Use Committee (IACUC) of the University of Wisconsin, Madison, WI, USA (approval No. M005439) on June 28, 2016.

Markers of Pulmonary Oxygen Toxicity in Hyperbaric Oxygen Therapy Using Exhaled Breath Analysis

Introduction

Although hyperbaric oxygen therapy (HBOT) has beneficial effects, some patients experience fatigue and pulmonary complaints after several sessions. The current limits of hyperbaric oxygen exposure to prevent pulmonary oxygen toxicity (POT) are based on pulmonary function tests (PFT), but the limitations of PFT are recognized worldwide. However, no newer modalities to detect POT have been established. Exhaled breath analysis in divers have shown volatile organic compounds (VOCs) of inflammation and methyl alkanes. This study hypothesized that similar VOCs might be detected after HBOT.

Methods

Ten healthy volunteers of the Royal Netherlands Navy underwent six HBOT sessions (95 min at 253 kPa, including three 5-min “air breaks”), i.e., on five consecutive days followed by another session after 2 days of rest. At 30 min before the dive, and at 30 min, 2 and 4 h post-dive, exhaled breath was collected and followed by PFT. Exhaled breath samples were analyzed using gas chromatography-mass spectrometry (GC-MS). After univariate tests and correlation of retention times, ion fragments could be identified using a reference database. Using these fragments VOCs could be reconstructed, which were clustered using principal component analysis. These clusters were tested longitudinally with ANOVA.

Results

After GC-MS analysis, eleven relevant VOCs were identified which could be clustered into two principal components (PC). PC1 consisted of VOCs associated with inflammation and showed no significant change over time. The intensities of PC2, consisting of methyl alkanes, showed a significant decrease (p = 0.001) after the first HBOT session to 50.8%, remained decreased during the subsequent days (mean 82%), and decreased even further after 2 days of rest to 58% (compared to baseline). PFT remained virtually unchanged.

Discussion

Although similar VOCs were found when compared to diving, the decrease of methyl alkanes (PC2) is in contrast to the increase seen in divers. It is unknown why emission of methyl alkanes (which could originate from the phosphatidylcholine membrane in the alveoli) are reduced after HBOT. This suggests that HBOT might not be as damaging to the pulmonary tract as previously assumed. Future research on POT should focus on the identified VOCs (inflammation and methyl alkanes).

Efficacy and Prognostic Factors of Combined Hyperbaric Oxygen Therapy in Patients With Idiopathic Sudden Sensorineural Hearing Loss

Purpose Idiopathic sudden sensorineural hearing loss is a clinical emergency with an increased incidence of occurrence in recent years. Hyperbaric oxygen has been widely used in the clinical treatment of sudden hearing loss. However, prognostic factors related to its curative effects are still not clear, which hinders its clinical application. The aim of this study was to investigate the efficacy and prognostic factors of hyperbaric oxygen therapy (HBOT) plus drug therapies in the treatment of sudden hearing loss. Method Patients with sudden hearing loss who were treated with hyperbaric oxygen from April to October 2017 were retrospectively included. Clinical information was collected, including pure-tone audiometry data before and after hyperbaric oxygen treatment, age, gender, hearing curve classification, concomitant symptoms, history of diseases (diabetes and hypertension), history of hormone therapy, start time of hyperbaric oxygen treatment, and total number of hyperbaric oxygen treatments. The prognostic factors were analyzed with univariate and multivariate analyses. Results Sixty-four patients with sudden hearing loss were enrolled, including 7 cases of low-frequency loss, 4 cases of high-frequency loss, 32 cases of flat loss, and 21 cases of complete hearing loss. After HBOT, there were 16 cases (25%) of complete recovery, 15 cases (23.43%) of partial recovery, 7 cases (10.93%) of slight improvement, and 26 cases (40.63%) of no improvement. The total effective rate was 59.37%. Twelve of 21 cases (57.14%) of complete hearing loss showed recovery. Multivariate logistic regression analysis showed that the start time of HBOT ≤ 7 days from disease onset was independently associated with hearing recovery ( OR = 27.763, 95% CI [4.209, 183.115], p = .001). Conclusion Combined HBOT can improve the hearing impairment of sudden hearing loss. The early HBOT showed the most promising therapeutic effects, especially among patients with complete hearing loss.

Neutrophil-to-lymphocyte ratio predicts diagnosis and prognosis of idiopathic sudden sensorineural hearing loss: A systematic review and meta-analysis

BACKGROUND

Chronic inflammation has been regarded as one of the causes of idiopathic sudden sensorineural hearing loss (ISSHL). Several individual studies have reported the association between neutrophil-to-lymphocyte ratio (NLR) and ISSHL. However, the findings have been inconsistent, and these data have not been systematically evaluated. Thus, we conducted this meta-analysis to further explore the predictive value of NLR on formation and prognosis of ISSHL.

METHODS

A comprehensive literature search was performed to identify eligible studies based on PubMed, Embase, Web of Science, and China National Knowledge Infrastructure. The Standardized mean deviation (SMD) with its 95% confidence interval (CI) was applied to be the effect size estimate.

RESULTS

A total 10 papers with 15 retrospective case-control studies, which included 1029 ISSHL patients (the case group) and 1020 healthy people (the control group), were selected for the meta-analysis of the relationship between NLR and onset of ISSHL. The NLR levels in the case group were observed to be higher than the control group (SMD = 1.65, 95% CI = 1.20-2.09, P < .001). The pooled results did not significantly change by the subgroup analyses based on study region, baseline matching, and laterality. Moreover, 9 publications with 12 retrospective cohort studies, which included 590 recovered ISSHL patients and 438 unrecovered ISSHL patients, explored the association between NLR and ISSHL prognosis, and the combined data showed that the NLR value was much higher in unrecovered patients rather than recovered patients (SMD = 1.27, 95% CI: 0.62-1.92, P < .001). The subgroup analyses based on study region, laterality, type of steroid, medication administration, maintenance treatment, follow-up period, and definition of "recovered" further supported these results.

CONCLUSION

The results of this meta-analysis suggest that NLR might be a useful biomarker to determine the onset and prognosis of ISSHL.

Is nucleate cell count and neutrophil to lymphocyte ratio related to patients with audiographically distinct sudden sensorineural hearing loss?

The aim of this study was to investigate the possible relationships between sudden sensorineural hearing loss (SSNHL) patients with distinct audiographic data and nucleate cell count and neutrophil to lymphocyte ratio (NLR).SSNHL patients differed in audiographic curves were included, 40 with low-frequency SSNHL (LF-SSNHL), 33 with high-frequency SSNHL (HF-SSNHL), 36 with all-frequency SSNHL (AF-SSNHL), 34 with total-deafness SSNHL (TD-SSNHL), and 31 age- and sex-matched healthy controls. Peripheral venous blood samples were collected and nucleate cell such as white blood cell (WBC), neutrophil and lymphocyte, and NLR were measured. Each group was divided into recovery and unrecovery subgroup according to hearing levels after 1-month therapy, and then compared the difference of the count of WBC, neutrophil and lymphocyte, and NLR between the 2 subgroups.The WBC count of the HF-SSNHL, AF-SSNHL, and TD-SSNHL group was significantly higher than that of the control group (P = .024, P = .003, P = .008, respectively), not for LF-SSNHL group (P = .248). WBC count between LF-SSNHL and AF-SSNHL group was significantly different (P = .045). The neutrophil count of the HF-SSNHL, AF-SSNHL, and TD-SSNHL group was significantly higher than that of the control group (P = .002, P = .000, P = .000, respectively), not for LF-SSNHL group (P = .069). Neutrophil count of LF-SSNHL was significantly lower than that of AF-SSNHL and TD-SSNHL groups (P = .014, P = .013). The lymphocyte count of AF-SSNHL and TD-SSNHL group was significantly lower than that of the control group (P = .027, P = .003), not for LF-SSNHL and HF-SSNHL group (P = .119, P = .054). NLR of HF-SSNHL, AF-SSNHL, and TD-SSNHL group was significantly higher than that of the control group (P = .001, P = .000, P = .000, respectively), not for LF-SSNHL group (P = .070). NLR of LF-SSNHL was significantly lower than that of AF-SSNHL and TD-SSNHL group (P = .041, P = .005). In HF-SSNHL patients, lymphocyte count of unrecovery subgroup was significantly lower, while NLR of the unrecovery subgroup were significantly higher than those of recovery subgroup (P = .017, P = .015).The count of WBC, neutrophil, lymphocyte, and NLR may be related to SSNHL, but they were unreliable at predicting SSNHL characterized by differences in audiometric curves. Higher NLR and lower lymphocyte count maybe used to evaluate prognosis of HF-SSNHL patients.

Differences in platelet-related parameters among patients with audiographically distinct sudden sensorineural hearing loss: A retrospective study

We explored possible relationships between sudden sensorineural hearing loss (SSNHL) in patients differing in terms of audiographic data and the levels of vascular markers in routine blood data.We included 37 patients with low-frequency SSNHL (LF-SSNHL), 28 with high-frequency SSNHL (HF-SSNHL), 32 with all-frequency SSNHL (AF-SSNHL), 32 with total-deafness SSNHL (TD-SSNHL), and 31 age- and sex-matched healthy controls. Peripheral venous blood samples were collected, and routine blood parameters including platelet and lymphocyte count, mean platelet volume (MPV), and platelet-to-lymphocyte ratio (PLR) were measured. Each group was divided into recovery subgroup and unrecovery subgroup in accordance with hearing level after 1 month therapy, then compared the difference of platelet and lymphocyte count, MPV, and PLR between the 2 subgroups.No significant difference was observed between platelet count of all SSNHL patients and control group (all P > .05). MPV of AF-SSNHL and TD-SSNHL, PLR of all SSNHL patients were significantly higher than those of control group (all P < .05), while lymphocyte count of all audiographically distinct SSNHL patients was significantly lower than that of control group (all P < .05). However, the difference of platelet count, lymphocyte count, MPV, and PLR among audiographically distinct SSNHL patients was not significant (all P > .05). In HF-SSNHL patients, lymphocyte count of unrecovery subgroup was significantly lower, while MPV and PLR of the unrecovery subgroup were significantly higher than those of recovery subgroup (all P < .05). In AF-SSNHL patients, MPV of the unrecovery group was significantly higher than that of recovery subgroup (P < .05).Lymphocyte count, MPV, and PLR may be relative to SSSNHL, but they could not be used to distinct SSNHL audiographically. Lower lymphocyte, higher MPV, and PLR may be indicative for the prognosis of HF-SSNHL patients; higher MPV may be related to bad treatment outcome of AF-SSNHL patients.