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Objective: To assess the surgical outcomes and identify predictors of surgical success in patients with positional and non-positional obstructive sleep apnea following multilevel airway surgery., Study Design: Retrospective cohort study., Setting: Singe-tertiary medical center., Methods: This study included 158 patients with obstructive sleep apnea who underwent multilevel airway surgery. Patients were divided into 2 groups according to position dependency: "positional patients" group (n = 100), and "nonpositional patients" group (n = 58). The characteristics and surgical outcomes of the 2 groups were compared., Results: The nonpositional group included younger and more obese patients in comparison to the positional group. Moreover, the nonpositional group had more severe disease than the positional group. Both groups showed overall improvement after surgery, and the surgical success rate did not differ significantly between the 2 groups (nonpositional, 41.4% vs positional, 48.0%; P = .424). Notably, 69.0% of patients belonging to the non-positional group converted to positional group postoperatively. Logistic regression analysis revealed that larger tonsil size, female sex, and higher mean O 2 saturation were associated with higher success rate in the positional group, whereas larger tonsil size was associated with surgical success in the nonpositional group., Conclusion: Both nonpositional and positional groups showed improvements following multilevel airway surgery, and surgery induced a transition from nonpositional to positional group. Given that the factors related to surgical success differed between the two groups, surgeons should consider position dependency and these distinct factors during decision-making., (© 2024 American Academy of Otolaryngology–Head and Neck Surgery Foundation.)

Obstructive sleep apnea (OSA) is characterized by cyclic normoxic and hypoxic conditions (intermittent hypoxia, IH) induced by the repeated closure of the upper-airway respiratory tract. As a pathomechanism of OSA, IH results in various comorbidities via chronic inflammation and related pathways. However, the role of other inflammatory cells, such as lymphocytes, has not been well-explored. This study aimed to examine the effects of IH on the distribution and balance of T cell subsets and other related cytokines, and mechanisms in the immune system. We modified OSA mouse model (male C57BL/6N male) using our customized chamber that controls specific sleep and oxygenic cycles. To induce hypoxia, the IH group was repeatedly exposed to 5% O2 and 21% O2 lasting for 120 s each for 7 h daily for 4 weeks. Mice were then subjected to a recovery period of 4 weeks, in which IH stimulation was ceased. T cells and related cytokines were analyzed using flow cytometry and immunohistochemistry. Compared with the control group, the IH group had significantly lower levels of CD4+CD25+Foxp3+ regulatory T cells but higher levels of Th 17, IL-4, HIF-1, and inflammatory cytokines. After the recovery period, these altered changes in the immune cells were recovered, and we found no significant difference in their levels between the control and recovery groups. This study revealed that the Th17/Treg ratio is increased by intermittent hypoxia, and this imbalance can explain immune-related diseases, including recently reported allergies, autoimmune, and even cancer diseases, arising from OSA., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Park et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Patients with obstructive sleep apnea (OSA) exhibit a high prevalence of pulmonary hypertension and right ventricular (RV) hypertrophy. However, the exact molecule responsible for the pathogenesis remains unknown. Given the resistance to RV dilation observed in transient receptor potential canonical 3 (Trpc3) -/- mice during a pulmonary hypertension model induced by phenylephrine (PE), we hypothesized that TRPC3 also plays a role in chronic intermittent hypoxia (CIH) conditions, which lead to RV dilation and dysfunction. To test this, we established an OSA mouse model using 8- to 12-week-old 129/SvEv wild-type and Trpc3 -/- mice in a customized breeding chamber that simulated sleep and oxygen cycles. Functional parameters of the RV were evaluated through analysis of cardiac cine magnetic resonance images, while histopathological examinations were conducted on cardiomyocytes and pulmonary vessels. Following exposure to 4 weeks of CIH, Trpc3 -/- mice exhibited significant RV dysfunction, characterized by decreased ejection fraction, increased end-diastole RV wall thickness, and elevated expression of pathological cardiac markers. In addition, reactive oxygen species (ROS) signaling and the endothelin system were markedly increased solely in the hearts of CIH-exposed Trpc3 -/- mice. Notably, no significant differences in pulmonary vessel thickness or the endothelin system were observed in the lungs of wild-type (WT) and Trpc3 -/- mice subjected to 4 weeks of CIH. In conclusion, our findings suggest that TRPC3 serves as a regulator of RV resistance in response to pressure from the pulmonary vasculature, as evidenced by the high susceptibility to RV dilation in Trpc3 -/- mice without notable changes in pulmonary vasculature under CIH conditions.

Objective: This study was aimed to investigate clinical implications of mixed apnea (MA) in patients with obstructive sleep apnea (OSA), particularly whether surgical outcomes differ between OSA patients with and without MA events., Study Design: Retrospective cohort study., Setting: Single tertiary medical center., Methods: Eighty-eight patients with OSA who underwent multilevel upper airway surgery were included. Patients were divided into 2 groups according to the presence of MA events: "pure group" (n = 30) and "mixed group" (n = 58). The clinical characteristics and surgical outcomes were compared between the 2 groups., Results: The mixed group included more males (P = .020) and hypertensive patients (P = .009) and had a higher apnea-hypopnea index (AHI; P < .001) than the pure group. The surgical success rate was lower in the mixed group (29.3%) than in the pure group (73.3%; P < .001). Furthermore, the postoperative improvements in total AHI (P < .001), supine AHI (P < .001), and oxygen desaturation index (P = .006) were lower in the mixed group than in the pure group. Logistic regression analysis confirmed that the presence of MA (P = .002) was an independent predictor of poor surgical outcomes in patients with OSA., Conclusion: OSA patients with MA showed different clinical features and poor surgical outcomes compared to those without MA. These results imply that OSA with MA components may have a distinct pathophysiology, and the presence of MA should be considered in the surgical treatment of OSA., (© 2022 American Academy of Otolaryngology-Head and Neck Surgery Foundation.)

Objectives: This study is aimed to investigate the differences in the clinical features and surgical outcomes between hypopnea- and apnea-predominant obstructive sleep apnea (OSA)., Design: Cohort study., Setting: Single tertiary care centre., Participants: This study included 190 patients with OSA who underwent multilevel upper airway surgery between September 2012 and September 2021. The patients were divided into two groups according to the proportion of each respiratory event: hypopnea-predominant (n = 102) and apnea-predominant (n = 88)., Main Outcome Measures: The primary outcome measure was the percentage improvement in the apnea-hypopnea index (AHI) from baseline AHI after surgery., Results: The apnea-predominant group included more male patients and had higher AHI, respiratory disturbance index (RDI) and oxygen desaturation index (ODI) than the hypopnea-predominant group. Both groups showed significant improvements in AHI, apnea index, RDI, supine AHI, REM AHI, non-REM AHI, ODI, lowest O 2 saturation and Epworth Sleepiness Scale scores following the surgery. Notably, hypopnea index increased after surgery in the apnea-predominant OSA group. Although the improvement in the absolute value of AHI by surgery was significantly greater in the apnea-predominant group than in the hypopnea-predominant group, the two groups showed no significant difference in the percentage improvement in AHI from baseline AHI., Conclusion: Patients with apnea-predominant OSA had more severe disease than those with hypopnea-predominant OSA; however, surgical outcomes, as evaluated by percentage AHI improvement, were comparable between the two groups. In addition, multilevel upper airway surgery may induce the transition from apnea to hypopnea in patients with apnea-predominant OSA., (© 2022 John Wiley & Sons Ltd.)

Introduction: Serum level of high-mobility group box 1 protein is reportedly correlated with the severity of obstructive sleep apnea., Objective: We tried to evaluate the possibility of using the serum high-mobility group box 1 protein level as a biologic marker in obstructive sleep apnea patients., Methods: We generated a chronic intermittent hypoxia murine model that reflected human obstructive sleep apnea. Obstructive sleep apnea patients who underwent polysomnography were prospectively enrolled. Serum samples were obtained from mice and obstructive sleep apnea patients, and the serum high-mobility group box1 protein level was measured by enzyme-linked immunosorbent assay., Results: Serum high-mobility group box 1 protein level was 56.16 ± 30.33 ng/mL in chronic intermittent hypoxia and 18.63 ± 6.20 ng/mL in control mice (p < 0.05). The mean apnea-hypopnea index and respiratory disturbance index values of enrolled obstructive sleep apnea patients were 50.35 ± 27.96 and 51.56 ± 28.53, respectively, and the mean serum high-mobility group box 1 protein level was 30.13 ± 19.97 ng/mL. The apnea-hypopnea index and respiratory disturbance index were not significantly correlated with the serum high-mobility group box 1 protein level (p > 0.05). Instead, this protein level was significantly correlated with lowest arterial oxygen concentration (SaO 2 ) (p < 0.05)., Conclusion: High-mobility group box 1 protein may be involved in the pathogenesis of obstructive sleep apnea, and the possibility of this protein being a useful biologic marker in obstructive sleep apnea should be further evaluated., (Copyright © 2020 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.)

Children with Down syndrome (DS) have distinct orofacial structures that predispose them to sleep-disordered breathing. The management options for obstructive sleep apnea include continuous positive airway pressure, adenotonsillectomy, mandibular advancement, and maxillary expansion. However, most of these treatment options are less effective or less viable for children with DS. Rapid maxillary expansion with a fixed orthodontic appliance is a viable alternative for DS patients because it separates the midpalatal suture and dilates the airway, regardless of the patient's compliance. We present a case of a 15-year-old boy with DS and severe obstructive sleep apnea, which dramatically improved with rapid maxillary expansion and subsequent orthodontic treatment. Although only the short-term changes have been presented in this report, this case emphasizes the need for further discussions on the viability of rapid maxillary expansion for treating obstructive sleep apnea in children with DS., Citation: Kim A, Cho HJ, Choi EK, Choi YJ. Improvement in obstructive sleep apnea in a child with Down syndrome with rapid palatal expansion. J Clin Sleep Med . 2022;18(7):1885-1888., (© 2022 American Academy of Sleep Medicine.)

Background: Obstructive sleep apnea syndrome (OSAS) is being observed in an increasing number of cases. It can be diagnosed using several methods such as polysomnography., Objectives: To overcome the challenges of time and cost faced by conventional diagnostic methods, this paper proposes computational fluid dynamics (CFD) and machine-learning approaches that are derived from the upper-airway morphology with automatic segmentation using deep learning., Method: We adopted a 3D UNet deep-learning model to perform medical image segmentation. 3D UNet prevents the feature-extraction loss that may occur by concatenating layers and extracts the anteroposterior coordination and width of the airway morphology. To create flow characteristics of the upper airway training data, we analyzed the changes in flow characteristics according to the upper-airway morphology using CFD. A multivariate Gaussian process regression (MVGPR) model was used to train the flow characteristic values. The trained MVGPR enables the prompt prediction of the aerodynamic features of the upper airway without simulation. Unlike conventional regression methods, MVGPR can be trained by considering the correlation between the flow characteristics. As a diagnostic step, a support vector machine (SVM) with predicted aerodynamic and biometric features was used in this study to classify patients as healthy or suffering from moderate OSAS. SVM is beneficial as it is easy to learn even with a small dataset, and it can diagnose various flow characteristics as factors while enhancing the feature via the kernel function. As the patient dataset is small, the Monte Carlo cross-validation was used to validate the trained model. Furthermore, to overcome the imbalanced data problem, the oversampling method was applied., Result: The segmented upper-airway results of the high-resolution and low-resolution models present overall average dice coefficients of 0.76±0.041 and 0.74±0.052, respectively. Furthermore, the classification accuracy, sensitivity, specificity, and F1-score of the diagnosis algorithm were 81.5%, 89.3%, 86.2%, and 87.6%, respectively., Conclusion: The convenience and accuracy of sleep apnea diagnosis are improved using deep learning and machine learning. Further, the proposed method can aid clinicians in making appropriate decisions to evaluate the possible applications of OSAS., Competing Interests: Declaration of Competing Interest The authors declare no conflict of interest., (Copyright © 2021. Published by Elsevier B.V.)

By affecting the tongue position and oropharyngeal airway volume, torus mandibularis is an anatomical factor associated with obstructive sleep apnea (OSA). This study aimed to investigate the influence of torus mandibularis on the surgical outcomes of multilevel upper airway surgery with tongue base resection (TBR) in patients with OSA. Patients with OSA who underwent palatal surgery and TBR were retrospectively analyzed. The patients were divided into two groups according to the presence or absence of torus mandibularis upon physical examination or on computed tomography images. The anatomical characteristics of the upper airway and pre/postoperative polysomnography were analyzed. The control and torus mandibularis groups comprised 69 and 35 patients, respectively, with all of them showing improved sleep quality after surgery. Apnea-hypopnea index (AHI) scores decreased from 42.1 ± 22.2 preoperatively to 23.9 ± 21.4 postoperatively in the control group (p < 0.001), and from 45.2 ± 19.9 to 22.5 ± 13.5 in the torus mandibularis group (p < 0.001). Comparing the postoperative changes in AHI, the AHI of the torus mandibularis group improved by 22.7 ± 23.4, whereas that of the control group improved by 18.1 ± 19.6 (p = 0.296). Sleep efficiency improved from 90.0 ± 7.5 to 92.8 ± 6.8 in the control group, and from 90.3 ± 8.7 to 93.6 ± 6.5 in the torus mandibularis group; however, there was no statistical difference between the two groups (p = 0.816). The presence of torus mandibularis did not appear to significantly affect the surgical results in OSA patients, but it did elicit significant changes in polysomnographic parameters compared with the control group. Therefore, following the identification of torus mandibularis in OSA patients, TBR should be considered as part of planning, as it may help to predict surgical outcomes., Competing Interests: Declaration of competing interest The authors have no financial or personal conflicts of interest to declare., (Copyright © 2021 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.)

This meta-analysis is aimed to investigate the association between the neutrophil-to-lymphocyte ratio (NLR) and obstructive sleep apnea (OSA). The PubMed, Web of Science, Google Scholar, and Cochrane Library databases were searched to collect all relevant articles. The pooled standardized mean difference (SMD) with a 95% confidence interval (CI) was calculated using the random effects model. In addition, subgroup analysis and meta-regression analysis were performed. Eleven eligible articles containing 2,259 patients with OSA were included in this study. Pooled outcomes revealed that the NLR was significantly higher in patients with OSA than in controls (SMD 0.62, 95% CI 0.29-0.94, P = 0.002). In subgroup analyses, differences in the NLR between patients and controls increased with worsening OSA grades. Furthermore, meta-regression analysis showed that differences in mean BMI exerted a significant effect on differences in the NLR (P = 0.0003). In summary, our meta-analysis demonstrated that the NLR in OSA patients was significantly higher than that in controls, and the difference was larger in patients with severe OSA. These results indicate that the NLR may be a reliable marker for detecting systemic inflammation and predicting disease severity in patients with OSA.

Background: The purpose of this study was to determine the therapeutic value of drug-induced sleep endoscopy (DISE) by comparing the outcomes of tongue base surgery based on Muller's maneuver (MM) and those based on DISE in obstructive sleep apnea (OSA) patients., Methods: Ninety-five patients who underwent the tongue base surgery in combination with palatal surgery for OSA at a tertiary referral hospital between March 2012 and March 2019 were enrolled in this retrospective comparative study. Forty-seven patients underwent MM for surgical decision and 48 patients underwent DISE in addition to MM for surgical decision. Surgical success was defined according to the Sher criteria (postoperative apnea-hypopnea index [AHI] < 20/h and ≥ 50% reduction in preoperative AHI), and AHI improvement (%) was defined as (preoperative AHI-postoperative AHI) × 100/preoperative AHI. For comparison between the MM and DISE groups, p-values were calculated using independent or paired t-tests for continuous variables and using chi-square test for categorical variables., Results: By comparing the results of MM and DISE, consensus on the tongue base level showed insignificant concordance (kappa = 0.017, p = 0.865), whereas that on the oropharynx level showed fair agreement (kappa =0.241, p = 0.005). AHI, supine AHI, rapid eyeball movement (REM) AHI, non-REM AHI, and nadir oxygen saturation were all significantly improved after the tongue base surgery in both groups. The MM group showed a significant improvement in the Epworth sleepiness scale after the tongue base surgery (p = 0.014), whereas the DISE group did not (p = 0.165). However, there was no significant difference in the AHI improvement (MM group = 47.0 ± 32.0, DISE group = 48.3 ± 35.4, p = 0.852) and surgical success (MM group = 42.6%, DISE group = 45.8%, p = 0.748) between the groups. Tonsil grade (p < 0.05) and occlusion at the oropharynx lateral wall (p = 0.031) were significantly related to surgical success in the MM group., Conclusions: In the judgment of the tongue base surgery, MM and DISE findings showed poor agreement. DISE might affect the surgical decision on the tongue base surgery in OSA patients; however, there was a lack of evidence regarding the superiority of DISE over MM with respect to the surgical outcomes.

The present study aimed to detail the relationship between the flow and structure characteristics of the upper airways and airway collapsibility in obstructive sleep apnea. Using a computational approach, we performed simulations of the flow and structure of the upper airways in two patients having different facial morphologies: retruding and protruding jaws, respectively. First, transient flow simulation was performed using a prescribed volume flow rate to observe flow characteristics within upper airways with an unsteady effect. In the retruding jaw, the maximum magnitude of velocity and pressure drop with velocity shear and vortical motion was observed at the oropharyngeal level. In contrast, in the protruding jaw, the overall magnitude of velocity and pressure was relatively small. To identify the cause of the pressure drop in the retruding jaw, pressure gradient components induced by flow were examined. Of note, vortical motion was highly associated with pressure drop. Structure simulation was performed to observe the deformation and collapsibility of soft tissue around the upper airways using the surface pressure obtained from the flow simulation. At peak flow rate, the soft tissue of the retruding jaw was highly expanded, and a collapse was observed at the oropharyngeal and epiglottis levels. NEW & NOTEWORTHY Aerodynamic characteristics have been reported to correlate with airway occlusion. However, a detailed mechanism of the phenomenon within the upper airways and its impact on airway collapsibility remain poorly understood. This study provides in silico results for aerodynamic characteristics, such as vortical structure, pressure drop, and exact location of the obstruction using a computational approach. Large deformation of soft tissue was observed in the retruding jaw, suggesting that it is responsible for obstructive sleep apnea.

Purpose: Considerable number of patients with obstructive sleep apnea (OSA) failed to respond to positive airway pressure therapy and so turned to surgical procedures. A wide variety of surgical procedures have been developed and advanced, according to obstruction and target site through nasal cavity to trachea. We introduced our overlapping lateral pharyngoplasty (OLP) technique as a surgical option for OSA and evaluated its surgical outcomes both with and without endoscope-guided coblator tongue base resection (CobTBR)., Methods: Sixty-five patients underwent either OLP alone or OLP combined with CobTBR to treat OSA at academic tertiary center. Twenty-nine patients underwent postoperative polysomnography and were divided into two groups, as an OLP group and an OLP combined CobTBR group. Various parameters from physical examinations and polysomnographic results were compared and analyzed., Results: Most enrolled patients improved on various polysomnographic parameters, including AHI and oxygen levels. In the OLP group, 91.7% of patients showed a surgical response and the overall success rate was 66.7%. Mean AHI improved significantly from 36.3 to 14.8. In the OLP + CobTBR group, all patients showed improvement in AHI and the surgical response rate was 100%. The overall success rate was 70.6% and mean AHI improved from 38.8 to 13.1. In both groups, various parameters such as RDI, lowest O 2 saturation, mean O 2 saturation, oxygen desaturation index, supine AHI, and ESS significantly improved after surgery., Conclusion: Our OLP technique appears to be safe and effective among OSA patients. Multi-level OLP surgery combined with CobTBR can be a good surgical strategy for patients experiencing retroglossal obstruction.

Objective: Body mass index (BMI) has been shown to be strongly correlated with severity of OSA. However, BMI has not been shown to be correlated with sleep apnea in all patients studied. The purpose of this study was to evaluate the relationship between various anthropometric measures and severity of OSA according to BMI in men., Methods: We conducted a retrospective analysis of the medical records of patients who visited for evaluation of OSA. Polysomnography results, height, weight, neck circumference, waist circumference, and hip circumference were obtained in all subjects. BMI, body adiposity index, waist to hip ratio, and waist to height ratio were also calculated., Results: A total of 195 male participants were included in the final analysis. BMI showed the strongest correlation with AHI in all subjects. In 125 participants with a BMI of 25 or more, BMI was most strongly correlated with high AHI compared to other measurements. However, waist to hip ratio showed the strongest correlation with AHI in 70 participants with a BMI of less than 25 and, in this group, BMI did not show significant correlation with AHI., Conclusion: Considerations about anthropometric measurements in OSA patients should differ according to degree of obesity or BMI., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Continuous positive airway pressure (CPAP) therapy may decrease left ventricular (LV) loads and improve myocardial oxygenation. In this study, we investigated the effect of CPAP on LV diastolic function compared with sham treatment in patients with severe obstructive sleep apnoea (OSA).This 3-month prospective single-centre randomised sham-controlled trial analysed 52 patients with severe OSA. Patients were randomly assigned (1:1) to receive either CPAP or sham treatment for 3 months. The main investigator and patients were masked to the trial randomisation. The primary end-point was change of early diastolic mitral annular (e') velocity over the 3-month period. Secondary end-points were pulse wave velocity (PWV), 24-h ambulatory blood pressure (BP) and variables of ventricular-vascular coupling at 3 months.After 3 months of follow-up, CPAP treatment significantly increased the e' velocity, and was greater than the sham treatment (0.65±1.70 versus -0.61±1.85 cm·s -1 , p=0.014). The PWV, 24-h mean diastolic BP, night-time diastolic BP, arterial elastance index and ventricular-vascular coupling index after 3 months of follow-up decreased significantly in the CPAP group.In patients with severe OSA, CPAP treatment for 3 months improved LV diastolic function more than sham treatment, and was accompanied by improvements in arterial stiffness and ventricular-vascular coupling., Competing Interests: Conflict of interest: None declared., (Copyright ©ERS 2018.)

The base of the tongue has been recognized as a significant site of obstruction in patients with obstructive sleep apnea (OSA). Our aim was to determine the independent predictors of surgical success in tongue base resection combined with lateral pharyngoplasty for OSA. Thirty-one OSA patients who underwent endoscopie-guided coblator or transoral robotic tongue base resection in combination with lateral pharyngoplasty for the treatment of retroglossal obstruction between March 2012 and December 2015 were enrolled in this study. Retroglossal obstruction was identified by preoperative nasopharyngoscopy with drug-induced sleep endoscopy and/or Müller's maneuver in supine position. Patients were divided into success and failure groups according to surgical outcome (postoperative apnea-hypopnea index (AHI) less than 20 and reduction more than 50% in baseline AHI). Physical profile, polysomnography, cephalometry parameters, and drug-induced sleep endoscopy and/or Müller's maneuver findings were compared between the two groups. Tonsil grade (p = 0.002), lateral oropharyngeal wall collapse on Müller's maneuver (p = 0.002), and AHI during rapid eye movement (REM AHI) (p = 0.038) were significantly higher in the success group than in the failure group. Tongue base collapse was more evident in the failure group than in the success group when patients open their mouth. (p = 0.037) Bigger tonsil size and higher REM AHI are favorable predictive factors, even in multilevel surgery such as tongue base resection, whereas tongue base collapse during mouth opening may be an unfavorable predictive factor.

Study Objectives: The aims of this study were to determine if a correlation exists between the level of hypoxia induced by severe obstructive sleep apnea syndrome (OSAS) and the level of auditory dysfunction when verifying such a relationship using polysomnography (PSG)., Methods: A retrospective review of 41 patients with severe OSAS was performed. Independent risk factors for hearing impairment included parameters of PSG, which were analyzed in two hearing groups at a level ≥ 40 decibels (dB)., Results: Oxyhemoglobin saturation, especially the lowest oxyhemoglobin saturation level, showed lower thresholds in the hearing impairment group than in the control group (p = 0.039 at NREM stage; p = 0.029 at REM stage; p = 0.001 at total sleep stage). After adjusting for other risk factors, the sole variable that remained significant was lowest oxyhemoglobin saturation (total; p = 0.046). In the correlation analysis, a decreasing lowest oxyhemoglobin saturation (from all subjects, n = 41) correlated with a greater mean hearing threshold (R(2) = 0.297; p < 0.001)., Conclusion: Our results indicated that lowest oxyhemoglobin saturation in PSG is the only variable correlated with the hearing threshold. This finding could be predictive of possible hearing alternation in patients with severe OSAS., Commentary: A commentary on this article appears in this issue on page 641., (© 2016 American Academy of Sleep Medicine.)

Background: Multilevel obstruction in obstructive sleep apnea commonly includes retroglossal obstruction. To improve surgical success rates, tongue volume reduction with posterior midline glossectomy and/or lingual tonsillectomy is widely performed., Methods: Nasotracheal intubation was utilized, and the combined tongue procedure was performed as a final step after palatal surgery. The tongue was pulled maximally by a retraction suture and a McIVOR (Karl Storz, Tuttlingen, Germany) or Davis mouth gag (Karl Storz,Tuttlingen, Germany), and a medium-length tongue blade was applied to expose the tongue base. A 70-degree rigid endoscope was fixed by the holding system and introduced into the oral cavity. Endoscope-guided coblator tongue base resection was then performed., Results: The surgeon could use both hands for the surgery, enabling a more delicate resection of tongue base tissue., Conclusion: This technique was acceptable and can be successfully used in patients with a large tongue, in whom exposing the tongue base for surgery is difficult., (© 2015 Wiley Periodicals, Inc.)

Purpose: Resistant hypertension (HTN) occurs in 15-20% of treated hypertensive patients, and 70-80% of resistant hypertensive patients have obstructive sleep apnea (OSA). The characteristics of resistant HTN that predispose patients to OSA have not been reported. Therefore, we aimed to determine the clinical, laboratory, and polysomnographic features of resistant HTN that are significantly associated with OSA., Materials and Methods: Hypertensive patients (n=475) who underwent portable polysomnography were enrolled. The patients were categorized into controlled (n=410) and resistant HTN (n=65) groups. The risk factors for the occurrence of OSA in controlled and resistant hypertensive patients were compared, and independent risk factors that are associated with OSA were analyzed., Results: Out of 475 patients, 359 (75.6%) were diagnosed with OSA. The prevalence of OSA in resistant HTN was 87.7%, which was significantly higher than that in controlled HTN (73.7%). Age, body mass index, neck circumference, waist circumference, and hip circumference were significantly higher in OSA. However, stepwise multivariate analyses revealed that resistant HTN was not an independent risk factor of OSA., Conclusion: The higher prevalence and severity of OSA in resistant HTN may be due to the association of risk factors that are common to both conditions.

Objectives: The aim of this study was to identify correlations between sleep apnea severity and tongue volume or posterior airway space measured via three-dimensional reconstruction of volumetric computerized tomography (CT) images in patients with obstructive sleep apnea (OSA) for use in predicting OSA severity and in surgical treatment. We also assessed associations between tongue volume and Mallampati score., Methods: Snoring/OSA male patients (n = 64) who underwent polysomnography, cephalometry, and CT scans were enrolled in this retrospective study. OSA was diagnosed when the apnea-hypopnea index (AHI) was greater than 5 (mild 5-14; moderate 15-29; severe>30). The patients were also categorized into the normal-mild group (n = 22) and the moderate-severe group (n = 42). Using volumetric CT images with the three-dimensional reconstruction technique, the volume of the tongue, posterior airway space volume, and intra-mandibular space were measured. The volumes, polysomnographic parameters, and physical examination findings were compared, and independent factors that are related to OSA were analysed., Results: No associations between tongue volume or posterior airway space and the AHI were observed. However, multivariate linear analyses showed that tongue volume had significantly negative association with lowest O2 saturation (r = 0.365, p = 0.027). High BMI was related to an increase in tongue volume. Modified Mallampati scores showed borderline significant positive correlations with absolute tongue volume (r = 0.251, p = 0.046) and standardized tongue volume (absolute tongue volume / intramandibular area; r = 0.266, p = 0.034). Between the normal-mild and moderate-severe groups, absolute tongue volumes were not different, although the standardized tongue volume in the moderate-severe group was significantly higher., Conclusion: Absolute tongue volume showed stronger associations with lowest O2 saturation during sleep than with the severity of AHI. We also found that high BMI was a relevant factor for an increase in absolute tongue volume and modified Mallampati grading was a useful physical examination to predict tongue size.

Purpose: Drug-induced sleep endoscopy (DISE) allows for direct airway observation in patients with obstructive sleep apnea. This study compared the safety profiles and efficacies of three regimens for DISE., Methods: Sixty-six patients were randomly assigned to receive propofol alone (n = 22), a propofol-remifentanil combination (n = 22), or a dexmedetomidine-remifentanil combination (n = 22). Remifentanil was infused at a concentration of 1.5 ng·ml(-1) in the propofol-remifentanil and dexmedetomidine-remifentanil groups, whereas saline was infused in the propofol group. The propofol and propofol-remifentanil groups received propofol at a starting concentration of 1.0 μg·ml(-1), then 0.1 μg·ml(-1) increments at 5 min intervals. The dexmedetomidine-remifentanil group received 1.0 μg·kg(-1) loading dose of dexmedetomidine for 10 min and then 0.2 μg·kg(-1)·h(-1) increments at 5 min intervals., Results: The incidence of oxygen desaturation was significantly higher in the propofol-remifentanil group compared with that of the dexmedetomidine-remifentanil group (77 vs. 45%, respectively, P = 0.024). Even with a maximum dose of dexmedetomidine (1.4 μg·kg(-1)·h(-1)), 50% of the dexmedetomidine-remifentanil group did not reach sufficient sedation and required additional propofol. Cough reflex occurred in five patients of propofol group and in neither of the other groups (P = 0.004)., Conclusions: The propofol-remifentanil combination was associated with a higher incidence of desaturation. The dexmedetomidine-remifentanil combination was associated with inadequate sedation in one half of the patients, even though it produced less respiratory depression. Addition of remifentanil reduced the cough reflex.

Purpose: Obstructive sleep apnea (OSA) is considered an independent risk factor for hypertension. However, it is still not clear which clinical factors are related with the presence of hypertension in OSA patients. We aimed to find different physical features and compare the sleep study results which are associated with the occurrence of hypertension in OSA patients., Materials and Methods: Medical records were retrospectively reviewed for patients diagnosed with OSA at Severance Cardiovascular Hospital between 2010 and 2013. Males with moderate to severe OSA patients were enrolled in this study. Clinical and polysomnographic features were evaluated to assess clinical variables that are significantly associated with hypertension by statistical analysis., Results: Among men with moderate to severe OSA, age was negatively correlated with hypertension (odds ratio=0.956), while neck circumference was positively correlated with the presence of hypertension (odds ratio=1.363). Among the polysomnographic results, the lowest O₂ saturation during sleep was significantly associated with the presence of hypertension (odds ratio=0.900)., Conclusion: Age and neck circumference should be considered as clinically significant features, and the lowest blood O₂ saturation during sleep should be emphasized in predicting the coexistence or development of hypertension in OSA patients.

Introduction: We hypothesized that the size of the hyoid bone itself may affect the severity of sleep apnea. The aim of this study was to identify the relationship between hyoid bone dimensions and the severity of sleep apnea using computerized tomography (CT) axial images., Methods: We retrospectively measured the hyoid bone in axial images of neck CTs and correlated these measurements with results of polysomnography in a total of 106 male patients. The new hyoid bone parameters studied in this study were as follows: distance between bilateral lesser horns (LH-d), distance between bilateral greater horns (GH-d), distance from the most anterior end of the hyoid arch to GH-d (AP), distance from the greater to the lesser horn on right and left sides (GH-LH), and the anterior angle between bilateral extensive lines from the greater to the lesser horn (H-angle). Data was analyzed using univariate and multivariate logistic regression, and Pearson correlation tests., Results: We found a significant inverse correlation between the apnea-hypopnea index (AHI) and GH-d or AP. Neither the LH-d, GH-LH, nor H-angle were associated with the AHI. The patient group that met the criteria of both GH-d<45.4 and AP<33.4 demonstrated the most severe AHI., Conclusion: The lateral width or antero-posterior length of hyoid bone was associated with AHI and predicted the severity of sleep apnea in male patients. This finding supports the role of expansion hyoidplasty for treatment of sleep apnea. Pre-operative consideration of these parameters may improve surgical outcomes in male patients with sleep apnea.