Pharyngeal Collapse Research Articles

Anterior Palatoplasty With Expansion Sphincter Pharyngoplasty for All Type of Pharyngeal Collapse.

This study was aimed to compare the efficiency of the anterior palatoplasty and expansion sphincter pharyngoplasty (APwESP) technique for all patterns of velopharyngeal obstruction (anterior-posterior [APPC], lateral [LPC], or combined circular pharyngeal collapse [CPC]). The study was designed as a randomized prospective trial at Kâtip Çelebi University, Atatürk Training, and Research Hospital. Patients only with velopharyngeal obstruction were included. Three groups were created according to the obstruction pattern (APPC, LPC, and CPC) for the study. Outcome parameters included patient's demographics, apnea-hypopnea index (AHI), lowest oxygen saturation (LOS), Stanford subjective scale of snoring (SSSS), and Epworth sleepiness scale (ESS). Thirty-one (34.1%) patients were in APPC group, while 30 (33.0%) patients were in LPC, and 30 (33.0%) were in CPC group. Preoperatively for all patients, on average, AHI was 33.4 ± 13.6, SSSS was 8.3 ± 1.0, ESS was 16.5 ± 2.6, and LOS was determined as 85.5 ± 3.6. There was a significant postoperative improvement in all parameters for all patients. There was no significant difference in outcome parameters between the groups according to obstruction pattern postoperatively. After APwESP surgery, obstruction pattern was not a significant factor for AHI (P=.234), SSSS (P=.180), and LOS (P=.280) (repeated measure analysis of variance test). The rate of surgical success was detected similarly for both of the study groups (P=.435). The rate of successful surgery for severe obstructive sleep apnea in the APPC group was 72.2%, 88.2% in the LPC group, and 75.0% in the CPC group (P=.472). A combination of APwESP surgery can manage all types of pharyngeal obstruction confidently. 3 Laryngoscope, 132:1313-1319, 2022.

Predictors of response to sleep apnea surgery addressing the lateral pharyngeal wall collapse

PurposeTo evaluate the predictive factors for surgical success in sleep apnea surgical techniques addressing the lateral pharyngeal wall. Materials and methodsThis is a retrospective review of consecutive cases treated by functional expansion pharyngoplasty for OSA. Collected data included patients demographics, ENT physical examination and somnographic data. Furthermore inter pterygoid distance was assessed by CT scans. To determine predictors of surgical success, physical examination, CT findings, polysomnographic and demographic data were compared between the success and failure group. ResultsFifty two patients were enrolled. The mean AHI decreased significantly from 44.3 to 17 (p = 0.001). A total of 33 patients (63.5%) met the surgical success criteria. An inter pterygoid distance longer than 34 mm was the only significant predictor of success. ConclusionsInter pterygoid distance seems to be a promising parameter associated with the surgical outcomes that should be further studied to be validated as predictor of success.

Major risk factors for obstructive sleep apnea monitored in the home. A cross-sectional study.

Obstructive sleep apnea (OSA) is characterized by recurrent pharyngeal wall collapse during sleep caused by anatomical or functional changes associated with obesity or dislocation of maxillofacial structures. To determine the major risk factors for obstructive sleep apnea monitored in the home. Cross-sectional study conducted in a private clinic in Fortaleza (CE), Brazil. Between 2015 and 2018, 427 patients were screened for OSA with home-based monitoring, yielding 374 positives. Information was collected on age, sex, body mass index (BMI), hypertension, diabetes (DM), dyslipidemia, coronary artery disease (CAD), arrhythmia, peripheral artery occlusive disease (PAOD), heart failure (HF) and lung disease. The home sleep apnea test result was then compared with the clinical diagnosis. Lastly, parameters identified as significant in the univariate analysis were subjected to multivariate logistic regression. Male sex predominated, although not significantly. OSA was associated with hypertension, DM, dyslipidemia, age and BMI. The risk of OSA being associated with these parameters was 2.195 (hypertension), 11.14 (DM), 2.044 (dyslipidemia) and 5.71 (BMI). The association was also significant for BMI categories (normal, overweight or obese). No significant association was observed for CAD, arrhythmia, PAOD, HF or lung disease. After multivariate logistic analysis, only age and BMI (and its categories) remained significant. OSA was associated with hypertension, DM, dyslipidemia, age and BMI in univariate analyses, but only with age and BMI (and its categories) in multivariate logistic analysis.

The Biomechanical Mechanism of Upper Airway Collapse in OSAHS Patients Using Clinical Monitoring Data during Natural Sleep.

Obstructive sleep apnea hypopnea syndrome (OSAHS) is a common sleep disorder characterized by repeated pharyngeal collapse with partial or complete obstruction of the upper airway. This study investigates the biomechanics of upper airway collapse of OSASH patients during natural sleep. Computerized tomography (CT) scans and data obtained from a device installed on OSASH patients, which is comprised of micro pressure sensors and temperature sensors, are used to develop a pseudo three-dimensional (3D) finite element (FE) model of the upper airway. With consideration of the gravity effect on the soft palate while patients are in a supine position, a fluid–solid coupling analysis is performed using the FE model for the two respiratory modes, eupnea and apnea. The results of this study show that the FE simulations can provide a satisfactory representation of a patient’s actual respiratory physiological processes during natural sleep. The one-way valve effect of the soft palate is one of the important mechanical factors causing upper airway collapse. The monitoring data and FE simulation results obtained in this study provide a comprehensive understanding of the occurrence of OSAHS and a theoretical basis for the individualized treatment of patients. The study demonstrates that biomechanical simulation is a powerful supplementation to clinical monitoring and evaluation.

Opioids and obstructive sleep apnea.

Freire C, Sennes LU, Polotsky VY. Opioids and obstructive sleep apnea. J Clin Sleep Med. 2022;18(2):647-652.

O001 Reboxetine reduces obstructive sleep apnea severity: a randomized trial

Abstract Introduction Noradrenergic and muscarinic processes are crucial for pharyngeal muscle control during sleep. Selective norepinephrine reuptake inhibitors (SNRIs) such as reboxetine combined with an antimuscarinic reduce obstructive sleep apnea (OSA) severity. The effects of reboxetine alone on OSA severity are unknown. Methods Double-blind, placebo-controlled, three-way crossover trial in 16 people with OSA. Each participant completed three overnight polysomnograms (~1-week washout). Single doses of reboxetine 4mg, placebo, or reboxetine+oxybutynin 5mg were administered before sleep (randomized order). The primary outcome was apnea-hypopnea index (AHI). Secondary outcomes included other polysomnography parameters, next day sleepiness and alertness. Endotyping analysis was performed to determine the medications’ effects on OSA pathophysiological mechanisms. Results Reboxetine reduced the AHI by 5.4 [95% CI -10.4 to -0.3] events/h, P=0.03 (men: -24±27%; women: -0.7±32%). The addition of oxybutynin did not further reduce AHI. Reboxetine alone and reboxetine+oxybutynin reduced overnight hypoxemia versus placebo (e.g. 4% oxygen desaturation index 10.4±12.8 vs. 10.6±12.8 vs. 15.7±14.7 events/h, P=0.02). Mechanistically, reboxetine and reboxetine+oxybutynin improved pharyngeal collapsibility and respiratory control stability. Men had higher baseline loop gain. Larger reductions in AHI with reboxetine occurred in those with high loop gain. Neither drug intervention changed next day sleepiness or alertness. Discussion A single 4mg dose of reboxetine modestly reduces OSA severity without further improvement with the addition of an antimuscarinic. Reboxetine increases breathing stability via improvements in pharyngeal collapsibility and respiratory control. These findings provide new insight into the role of SNRIs on upper airway stability during sleep and have important implications for pharmacotherapy development for OSA.

P099 Physiological phenotypes of obstructive sleep apnoea (OSA) in Pacific Islanders and equally obese Caucasians

Abstract Background Pacific islanders (PI) have a high prevalence of severe OSA, attributed to obesity. Ethnic differences in mechanisms contributing to OSA have been reported. We compared physiological polysomnography characteristics in obese PI and Caucasian (C) patients with OSA. Methods Retrospective polysomnography (PSG) studies from a tertiary hospital sleep laboratory were identified for PI and age, gender and BMI matched C patients (BMI>30 kgm²). All PSGs were rescored by a single scorer, and pharyngeal collapsibility (Vpassive), upper airway muscle compensation (Vcomp), arousal threshold (AT), [all expressed as percentage of steady-state breathing (Veupnea)], and loop gain (LG) were determined non-invasively via established/validated techniques. Progress to date 14 PI [8 female] and 29 C [15 female] were identified. There were no differences in age [52.2±17.0 PI; 52.5±13.3 C years], BMI [46.9±7.7 PI; 48.2±10.1 C kgm²] or AHI (35.6 [17.9–77.5] PI; 41.2 [20.9–83.6] C events/hour) (mean±SD or median[IQR]; all p>0.4; paired t-test or Wilcoxon signed rank). There were no significant differences in Vpassive (88.8 [88.4–97.1] PI; 91.8 [44.4–95.8]C %Veupnea; p=0.38), Vcomp (1.2 [-12.0–9.2] PI; 5.8 [-1.9–9.6] C %Veupnea; p=0.30), AT (131.4 [110.5–140.8] PI; 126.1 [110.4–180.7] C %Veupnea; p=0.67) or LG (0.6±0.1 PI; 0.7±0.3 C; p=0.23). Intended outcome and impact In a small cohort of PI and age, gender and BMI matched C with OSA, upper airway obstructive event frequency was the same and there were no differences in physiological phenotypes, suggesting similar mechanisms contribute to OSA severity in both groups. Confirmation of these findings in a larger cohort is ongoing.

Cognition effectiveness of continuous positive airway pressure treatment in obstructive sleep apnea syndrome patients with cognitive impairment: a meta-analysis.

Obstructive sleep apnea (OSA) is a common respiratory disorder characterized by recurrent pharyngeal collapses during sleep leading to intermittent hypoxia and sleep disruption. Cognitive challenges and high risks of cognitive impairment, including Alzheimer's disease (AD), are closely associated with OSA. Currently, continuous positive airway pressure (CPAP) is widely used in the treatment of OSA. However, whether CPAP benefits cognitive functions in patients with OSA remains elusive. Here, we identified published studies through a systematic review of PubMed, Cochrane Library, Embase, Wanfang Data, CBM, and CNKI from January 1, 1970, to July 1, 2020. 288 patients from 7 articles (one was excluded in the meta-analysis for it was a follow-up study) were included in the present study. It revealed that cognitive functions of OSA patients with mild cognitive impairment (MCI) or AD were mildly but significantly improved after CPAP treatment (SMD 0.49, 95% CI 0.11-0.86), especially long-term CPAP treatment (SMD 0.56, 95% CI 0.10-1.02, p = 0.02), as measured by Mini-Mental State Examination (MMSE) (SMD 0.49, 95%CI 0.11-0.86). However, no significant cognition benefits were detected by the Montreal Cognitive Assessment (SMD 0.43, 95% CI 0.85-1.72). In terms of heterogeneity, cognitive improvements by CPAP were detectable on OSA patients either at a younger age or over longer periods of CPAP treatment. Therefore, our findings highlight the partial efficiency of CPAP treatment in cognition improvement of OSA patients with MCI or AD.

An Anti-Snoring Oral Appliance to Reduce Simple Snoring as a Non-Invasive Method for Management of Snoring: A Case Report and Literature Review

Background and Objective: Simple snoring affects millions of people and their partners in the world and it indicates increased upper airways resistance and pharyngeal collapsibility. Snoring, particularly loud and habitual, may indicate obstructive sleep apnea (OSA). Case Report: The presenting patient was a middle-aged man with chief compliant of snoring, who was diagnosed with simple snoring after undergoing an overnight polysomnography (PSG). By using a simple oral appliance that retracted the tongue and improved airway patency, snoring improved completely. Conclusion: Simple snoring is a common condition and after excluding OSA, particularly in suspected patients, it can be managed by some instructions and interventions such as using available oral appliances.

Continuous positive airway pressure adherence trajectories in sleep apnea: Clustering with summed discrete Fréchet and dynamic time warping dissimilarities.

Obstructive sleep apnea (OSA) is a chronic disease characterized by recurrent pharyngeal collapses during sleep. In most severe cases, continuous positive airway pressure (CPAP) consists in keeping the airways open by administering mild air pressure. This treatment faces adherence issues. Eight hundred and forty-eight subjects were equipped with CPAP prescribed at the Grenoble University Hospital between 2016 and 2018. Their daily CPAP uses have been recorded during the first 3 months. Our aim is to cluster these adherence time series. With hierarchical agglomerative clustering, we focused on the choices of the dissimilarity measure and the internal cluster validation index (CVI). The Euclidean distance, the dynamic time warping (DTW) and the generalized summed discrete Fréchet dissimilarity were implemented with three linkage strategies ("average," "complete," and "Ward"). The performances of each method (dissimilarity and linkage) were evaluated on a simulation study through the adjusted Rand index (ARI). The Ward linkage with DTW dissimilarity provided the best ARI. Then six different internal CVIs (Silhouette, Calinski Harabasz, Davies Bouldin, Modified Davies Bouldin, Dunn, and COP) were compared on their ability to choose the best number of clusters. The Dunn index beat the others. CPAP data were clustered with the Ward linkage, the DTW dissimilarity and the Dunn index. It identified six clusters, from a cluster of patients (N = 29 subjects) whose stopped the therapy early on to a cluster (N = 105) with increasing adherence over time. Other clusters were extremely good users (N = 151), good users (N = 150), moderate users (N = 235), and poor adherers (N = 178).

Ansa cervicalis stimulation increases pharyngeal patency in patients with obstructive sleep apnea.

Hypoglossal nerve stimulation (HNS) is an alternative treatment option for obstructive sleep apnea (OSA) that reduces pharyngeal collapsibility, but HNS nonresponders often demonstrate continued retropalatal and lateral pharyngeal wall collapse. Recent evidence suggests that caudal pharyngeal traction with sternothyroid muscle contraction via ansa cervicalis stimulation (ACS) can also stabilize the pharynx, but the underlying mechanisms have not been elucidated. Our objective was to evaluate the effect of ACS on pharyngeal patency during expiration when the airway is most hypotonic. Eight participants with OSA underwent sustained ultrasound-guided fine-wire stimulation of the medial branch of the right hypoglossal nerve with and without transient stimulation of the branch of the ansa cervicalis nerve plexus innervating the right sternothyroid muscle during drug-induced sleep endoscopy. Airway cross-sectional area and expiratory airflow (V̇e) were measured from endoscopy video with ImageJ and pneumotachometry, respectively. ACS significantly increased retropalatal cross-sectional area (CSARP) to 211% [159-263] of unstimulated CSARP (P < 0.05). Adding ACS to HNS increased CSARP from baseline by 341% [244-439] (P < 0.05), a 180% [133-227] increase over isolated HNS (P < 0.05). ACS increased V̇e from baseline by 177% [138-217] P < 0.05). Adding ACS to HNS increased V̇e by 254% [207-301], reflecting decreases in pharyngeal collapsibility. Combining ACS with HNS increased retropalatal cross-sectional area and increased expiratory airflow, suggesting decreases in pharyngeal collapsibility. Our findings suggest that ACS exerts caudal traction on the upper airway through sternothyroid muscle contraction and that it may augment HNS efficacy in patients with OSA.NEW & NOTEWORTHY Ansa cervicalis stimulation (ACS) is a recently proposed neurostimulation mechanism for generating caudal pharyngeal traction that may benefit patients with obstructive sleep apnea. Here, we document endoscopic findings with ACS during drug-induced sleep endoscopy and additionally detail the effects of ACS on expiratory airflow, when the pharynx is known to be most hypotonic.

Cardiovascular manifestations in obstructive sleep apnea: current evidence and potential mechanisms.

Obstructive sleep apnea (OSA) is an increasingly prevalent health concern characterized by repeated episodes of pharyngeal collapse during sleep. It is frequently associated with daytime sleepiness and impaired functional capacity, but it is also linked to cardiovascular disease by a growing body of epidemiological, clinical, and translational research. The severity of OSA is traditionally evaluated by the apnea‑hypopnea index (AHI), but the value of this marker as a predictor of cardiovascular outcomes is limited. Thus, there is an increasing focus on alternative classification methods such as the hypoxic burden, other polysomnographic traits, and phenotypic subgroups based on clinical symptoms. There is a need to identify subgroups of patients with OSA who will benefit most from treatment, as recent large randomized controlled trials in selected populations have failed to show benefit in reducing overall cardiovascular mortality. Obstructive sleep apnea adversely affects cardiovascular structure and function by several distinct mechanisms such as intermittent hypoxia, sleep fragmentation, and intrathoracic pressure swings. These mechanisms lead to sympathetic activation, inflammation, and oxidative stress, which may result in the clinical consequences of OSA such as hypertension, coronary artery disease, heart failure, and cerebrovascular disease. This review focuses on the epidemiology and potential mechanisms of cardiovascular diseases in OSA. Furthermore, we will briefly discuss the role of personalized medicine, alternative treatment options, and precise phenotyping to optimize treatment of this complex condition and its associated cardiovascular risk.

Correlation between craniofacial changes and respiratory improvement after nasomaxillary skeletal expansion in pediatric obstructive sleep apnea patients.

The aim of this study was to investigate the correlation between the changes in respiratory function and dimensions of the nasomaxillary complex (NMC) and upper airway (UA) compartments after nasomaxillary skeletal expansion (NMSE) treatment for pediatric patients withobstructive sleep apnea (OSA). Nonobese OSA patients (mean age, 13.6 ± 2.9years; mean body mass index, 18.1 ± 3.0kg/m2); mean apnea-hypopnea index (AHI, 7.0 ± 5.4 events/h) presenting with transverse nasomaxillary constriction were evaluated before and after NMSE using cone-beam computed tomography (CBCT), home sleep test, and modified pediatric sleep questionnaire (m-PSQ). Paired t tests were performed to examine the treatment-related changes in all the parameters, and a multiple regression analysis adjusted for age and sagittal and vertical skeletal patterns was conducted to determine the dimensional parameters to affect the functional improvement. Among 26 patients,NMSE treatment significantly increased NMC dimensions at all tested levels and all UA compartments in CBCT, except glossopharyngeal airway. Concurrently, AHI, oxygen desaturation index, the lowest oxygen saturation (LSaO2), flow limitation (FL), snoring, and m-PSQ were significantly improved. AHI reduction was correlated with UA enlargement with no correlation with NMC expansion, whereas FL reduction was affected by NMC expansion. The minimal cross-sectional area was the most predictive of functional improvement, presenting correlations with AHI, LSaO2, and m-PSQ. NMSE can be a good treatment for pediatric OSA patients when applied to enhance the nasal and pharyngeal airway patencies beyond the NMC, ultimately to improve pharyngeal collapsibility as well as nasal airflow.

Physiological Traits and Adherence to Sleep Apnea Therapy in Individuals with Coronary Artery Disease.

Rationale: Untreated obstructive sleep apnea (OSA) is associated with adverse outcomes in patients with coronary artery disease (CAD). Continuous positive airway pressure (CPAP) is the most common treatment, but despite interventions addressing established adherence determinants, CPAP use remains poor. Objectives: To determine whether physiological traits that cause OSA are associated with long-term CPAP adherence in patients with CAD. Methods: Participants in the RICCADSA (Randomized Intervention with CPAP in CAD and OSA) trial with objective CPAP adherence (h/night) over 2 years and analyzable raw polysomnography data were included (N = 249). The physiological traits-loop gain, arousal threshold (ArTH), pharyngeal collapsibility (Vpassive), and pharyngeal muscle compensation (Vcomp)-were measured by using polysomnography. Linear mixed models were used to assess the relationship between the traits and adherence. We also compared actual CPAP adherence between those with physiologically predicted "poor" adherence (lowest quartile of predicted adherence) and those with physiologically predicted "good" adherence (all others). Measurements and Main Results: The median (interquartile range) CPAP use declined from 3.2 (1.0-5.8) h/night to 3.0 (0.0-5.6) h/night over 24 months (P < 0.001). In analyses adjusted for demographics, anthropometrics, OSA characteristics, and clinical comorbidities, a lower ArTH was associated with worse CPAP adherence (0.7 h/SD of the ArTH; P = 0.021). Both high and low Vcomp were associated with lower adherence (P = 0.008). Those with predicted poor adherence exhibited markedly lower CPAP use than those with predicted good adherence for up to 2 years of follow-up (group differences of 2.0-3.2 h/night; P < 0.003 for all). Conclusions: A low ArTH, as well as a very low and high Vcomp, are associated with worse long-term CPAP adherence in patients with CAD and OSA. Physiological traits-alongside established determinants-may help predict and improve CPAP adherence. Clinical trial registered with www.clinicaltrials.gov (NCT00519597).

Aerodynamics Analysis of the Impact of Nasal Surgery on Patients with Obstructive Sleep Apnea and Nasal Obstruction

Objective: The purpose of this study was to evaluate the effects of nasal surgery on airflow characteristics in patients with obstructive sleep apnea (OSA) by comparing the alterations of airflow characteristics within the nasal and palatopharyngeal cavities. Methods: Thirty patients with OSA and nasal obstruction who underwent nasal surgery were enrolled. A pre- and postoperative 3-dimensional model was constructed, and alterations of airflow characteristics were assessed using the method of computational fluid dynamics. The other subjective and objective clinical indices were also assessed. Results: By comparison with the preoperative value, all postoperative subjective symptoms statistically improved (p < 0.05), while the Apnea-Hypopnea Index (AHI) changed little (p = 0.492); the postoperative airflow velocity and pressure in both nasal and palatopharyngeal cavities, nasal and palatopharyngeal pressure differences, and total upper airway resistance statistically decreased (all p < 0.01). A significant difference was derived for correlation between the alteration of simulation metrics with subjective improvements (p < 0.05), except with the AHI (p > 0.05). Conclusion: Nasal surgery can decrease the total resistance of the upper airway and increase the nasal airflow volume and subjective sleep quality in patients with OSA and nasal obstruction. The altered airflow characteristics might contribute to the postoperative reduction of pharyngeal collapse in a subset of OSA patients.

Role of transpalatal advancement pharyngoplasty in management of lateral pharyngeal wall collapse in OSA

IntroductionNon-response to palatal surgery for OSA is a problem. Residual lateral wall hypopharyngeal collapse is the proposed mechanism of failure. ObjectiveThis study aims to evaluate the role of transpalatal advancement pharyngoplasty in non-responders to primary palatal surgery with residual lateral wall hypopharyngeal collapse. MethodsThis is a retrospective study that was conducted on patients who underwent transpalatal advancement pharyngoplasty for residual lateral wall hypopharyngeal. Inclusion criteria were age greater than 18-years, OSA proved by the polysomnography with apnea hypopnea index >15, lateral wall collapse at the level of hypopharynx as proved by drug-induced sleep endoscopy and had a previous tonsillectomy or previous palatal surgery for OSA. Exclusion criteria were those with no history of tonsillectomy or any other surgery for OSA and those with a missed followup. Data of included patients were collected and included gender, age, polysomnographic data like the apnea hypopnea index, oxygen desaturation and the calculated preoperative Epworth sleepiness scale. The early outcome included symptom improvement as measured by Epworth sleepiness scale score and lateral pharyngeal wall evaluation by nasopharyngoscopic examination in the first postoperative month. Late outcome measurement was performed by the 6-month postoperative polysomnography. Data were analyzed using SPSS program. ResultsThe study included 37 patients with a mean age of (40.43 ± 6.51). The study included 26 men and 11 women. There was a statistically significant improvement of apnea hypopnea index from 37.8 ± 9.93 to 9.9 ± 2.55. In addition, a statistically significant improvement of lowest oxygen saturation from 78.9 ± 3.39 to 83.3 ± 3.31 was encountered. The patients improved clinically, and this improvement was measured by statistically significant improvement of Epworth sleepiness scale score and snoring visual analogue scale. ConclusionTranspalatal advancement pharyngoplasty widens the retropalatal airway and has a great role in the management of the vertical palate phenotype. In addition, it can have a role in the management of lateral walls, especially lateral wall hypopharyngeal collapse.

437 Efficacy of a novel oral appliance and the influence of OSA pathophysiological traits on treatment response

Abstract Introduction Oral appliance therapy is a recommended alternative to CPAP for OSA. Approximately 50% of patients have a major reduction in OSA severity but successful treatment outcome remains challenging to predict. Previous prediction methods have focused on clinical variables which have poor predictive value. OSA is recognised as a heterogenous disorder caused by 4 pathophysiological traits. The influence of OSA pathophysiological traits on oral appliance treatment outcome has been explored in recent physiological studies using simplified phenotyping methods. In this preliminary report, we prospectively compared differences in the 4 OSA phenotypes between responders and incomplete responders to a novel oral appliance with built in oral airway using gold standard phenotyping methodology. Methods Data from 22 people with OSA (AHI&amp;gt;10events/h) have been analysed to date. A diagnostic in-laboratory PSG was initially conducted to confirm OSA. A detailed physiology PSG was carried out prior to commencement of oral appliance therapy. For this study night participants were instrumented with standard PSG equipment, nasal mask, pneumotachograph, epiglottic pressure catheter and intramuscular electrodes inserted perorally into the genioglossus to quantify baseline OSA phenotypic traits. Pcrit was quantified via CPAP dial downs and the non-anatomical traits were quantified from naturally occurring apneas and hypopneas. Participants were then fitted with a next generation novel oral appliance with a built-in oral airway (Oventus O2Vent Optima™) and titrated to at least 75% of maximum mandibular advancement. After acclimatization to therapy, participants were invited to undergo a treatment efficacy PSG. Results Oral appliance therapy reduced the AHI by 52% (21[15,31] vs. 11[7,16] events/h, p&amp;lt;0.001). 46% of participants responded to oral appliance therapy based on the definition of AHI &amp;lt; 10events/h. Preliminary analyses indicated that estimates of baseline upper airway collapsibility tended to be different in responders versus non-responders (responders have less collapsible airways). Conclusion The novel oral appliance reduced OSA severity by 50% with resolution of OSA in half of participants. Baseline pharyngeal collapsibility may be an important physiological predictor of treatment outcome. Support (if any):

394 A convolutional neural networks model for the detection of cortical arousals from heart rate

Abstract Introduction Cortical arousals are transient events of disturbed sleep that occur frequently in sleep disordered breathing (SDB) and can be used as an indicator of sleep quality. While cortical arousals are typically scored from the electroencephalogram (EEG), arousals are associated with increased sympathetic activity and could therefore be detected from measures of sympathetic activity such as heart rate. Most home sleep test and consumer wearable devices enable continuous recording of heart rate via the electrocardiogram (ECG) or optical heart rate sensors without the inconvenience of EEG electrodes. In this preliminary study, we developed a deep learning-based convolutional neural networks (CNN) model to detect arousals from heart rate. Methods This study included 1,083 polysomnograms (PSGs) from five independent studies (Tucson Children’s Assessment of Sleep Apnea, Mechanisms of Pharyngeal Collapse in Sleep Apnea, Impact of the Arousal Threshold in Obstructive Sleep Apnea, Predicting Successful Sleep Apnea Treatment with Acetazolamide in Heart Failure Patients, Combination Therapy for the Treatment of Obstructive Sleep Apnea) that were scored for arousals according to American Academy of Sleep Medicine scoring rules. These studies included PSGs from both children and adults (ages 6 and above), with most data coming from participants with evidence or diagnosis of SDB. We used the Pan-Tomkins algorithm to detect R-peaks from the raw ECG signal, transformed the peaks into normalized instantaneous heart rate at 1 Hz frequency, and produced arousal probability in 1-second resolution using a simple CNN model. Due to slight asynchrony between the appearance of arousals in the EEG versus the heart rate, all overlaps between model-predicted arousals and manually scored arousals were considered true-positives. Results We evaluated the model on a validation set (n=216). The model achieved a gross area under precision-recall curve score of 0.67 and a gross area under receiver operating characteristics curve of 0.91 Correlation between the number of model-detected and manually scored arousal events was r=0.76. Conclusion This preliminary study demonstrates that a deep learning approach has the potential to accurately detect arousals in home sleep tests and consumer wearable devices that measure heart rate. Support (if any) The study was supported by grant #207-SR-19 from the American Academy of Sleep Medicine Foundation.

Obstructive Sleep Apnea and Pulmonary Hypertension: A Review of Literature.

Obstructive sleep apnea (OSA) is a disease process involving recurrent pharyngeal collapse during sleep, resulting in apneic episodes. Clinically, symptoms can include snoring, sudden awakening with a choking-like sensation, excessive somnolence, non-restorative sleep, difficulty in starting or maintaining sleep, and fatigue. It results in impaired gas exchange, subsequently causing various cardiovascular, metabolic, and neurocognitive pathologies. Historically, OSA has been underdiagnosed and undertreated, especially in women.OSA is associated with WHO (World Health Organization) class III pulmonary hypertension (PH) or PH due to lung disease. PH is a concerning complication of OSA and thought to occur in roughly 20% of individuals with OSA. The pathogenesis of PH in OSA can include pulmonary artery vasoconstriction and remodeling. Patients suffering from OSA who develop PH tend to have worse cardiovascular and pulmonary changes. We present a thorough review of the literature examining the interplay between OSA and PH.

Open oral cavity has little effects on upper airway aerodynamics in children with obstructive sleep apnea syndrome: A computational fluid dynamics study based on patient-specific models

Obstructive sleep apnea syndrome (OSAS) is a common disorder with recurrent pharyngeal airway collapse and sleep disruption. Recently, great progress has been made in investigating the physical mechanism of OSAS development and treatment using computational fluid dynamics (CFD). However, previous studies always neglected the oral cavity artificially in the patient’s upper airway CFD model, but did not give any specific explanation. The oral cavity effect on the OSAS upper airway flow is still a matter of unclear. This paper reconstructed the patient-specific upper airway models based on the cone beam computed tomography images of ten children subjects (seven boys and three girls) and used CFD to simulate both the steady and unsteady expiration and inspiration states in the upper airway model with or without the oral cavity. A series of pressure measurement experiments based on the in vitro 1:1 scaled airway model were performed to validate the reliability of the present CFD methods. Finally, the CFD results indicate that the open oral cavity is almost a region of flow stasis with constant pressure, and both the upper airway aerodynamics with and without the oral cavity have the similar trends, with the maximum average relative difference less than 6%. The present study shows that the open oral cavity causes very little impacts on the upper airway flow of the children patients with OSAS using the nasal respiration only, and confirms the reasonability of ignoring the oral cavity for CFD simulation.