Collapse Of Upper Airway Research Articles

Obstructive sleep apnoea and coronary revascularisation outcomes.

Obstructive sleep apnoea (OSA) is achronic sleep disorder characterised by recurrent cyclical episodes of upper airway collapse causing apnoea or hypopnoea. Despite being highly prevalent in patients with cardiovascular conditions, OSA has been aneglected component in cardiovascular practice. Fortunately, in the past few decades, increasing acknowledgement of the vulnerability of cardiac patients to OSA-related stressors and its adverse cardiovascular outcomes has made it arecognised cardiovascular risk factor in practice guidelines. Consequences of OSA include oxidative stress, endothelial dysfunction, autonomic dysfunction, and increased catecholamine release. The perturbations caused by OSA not only provide aclear mechanistic link to cardiovascular disease but also to poor outcomes after coronary revascularisation. This review article focuses on the correlation of OSA to coronary revascularisation outcomes. Our team reported that OSA is present in approximately 50% of patients undergoing coronary revascularisation. Importantly, untreated OSA was found to be an independent predictor of adverse events after both percutaneous coronary intervention and coronary artery bypass grafting. Although randomised trials did not confirm the benefits of OSA treatment in improving cardiovascular outcomes, these early trials were limited by poor treatment adherence. For now, systematic screening for OSA in patients undergoing coronary revascularisation is not indicated. Yet, with the proven benefit of OSA treatment in improving blood pressure control and quality of life, screening for and treatment of OSA is still indicated if patients have reported excessive daytime sleepiness and/or suboptimally controlled hypertension.

Can functional septoturbinoplasty, with or without nasal valve suspension suture (FSTVS), alter the initial findings of drug-induced sleep endoscopy (DISE) in patients with obstructive sleep apnea syndrome (OSAS)?

Drug-induced sleep endoscopy (DISE) is routinely performed to assess the upper airway collapse in patients with obstructive sleep apnea syndrome (OSAS). Its purpose is to identify cases of multilevel collapse, which helps to determine the appropriate surgical approach. The current proposal to analyze the functional septoturbinoplasty with or without nasal valve suspension suture (FSTVS) has the potential to change the original findings of DISE in OSAS patients who were initially planned for one-stage multilevel surgery based on the pre-FSTVS DISE results. Prospective study. All OSAS patients with moderate to severe symptoms who underwent DISE pre-FSTVS and noticed multilevel collapse were subjected to post-FSTVS re-evaluation using DISE at three-month intervals. This study included a total of thirty-two patients, with males outnumbering females in a ratio of 15:1. The average age of the patients was 38.88years (standard deviation, SD ± 10.12), and the mean body mass index (BMI) was 28.66 (SD ± 3.73). Significant improvements (p = 0.0417) were observed in both pre- and post-FSTVS measurements at three-month intervals, as well as in the Epworth sleepiness score (ESS). Enhancements in the apnea-hypopnea index (AHI) and snoring event post-FSTVS were also observed. Around 50% of the patients exhibited concentric collapse at the velum, lateral collapse at the oropharynx, and anteroposterior (AP) collapse at the tongue base. Post-FSTVS, the dynamics at the velum were modified by 23.33%, at the oropharynx by 10%, at the tongue base by 11.76%, and at the epiglottis by 23.07%. One patient who did not experience collapse at the tongue base pre-FSTVS exhibited partial collapse after the procedure. Moreover, all cases of complete AP collapse of the epiglottis changed to partial collapse. Our study confirms that FSTVS may offer a simpler and more accessible approach for patients with OSAS. It is a viable option to consider even prior to DISE in clinical anticipated multilevel collapse. By conducting DISE at intervals subsequent to addressing nasal resistance through surgery, valuable insights can be obtained regarding the collapsibility of the upper airway. These findings can guide surgical interventions, ultimately resulting in improved outcomes for patients.

Craniofacial Phenotype in Obstructive Sleep Apnea and Its Impact on Positive Airway Pressure (PAP) Adherence.

Positive airway pressure (PAP) is an important treatment tool for patients with moderate and severe obstructive sleep apnea (OSA), and adherence to PAP significantly affects treatment outcomes. Disease severity, adverse effects, and psychosocial factors are known to predict medication adherence. Cephalometric parameters have been reported to positively correlate with upper airway collapse. However, research on the correlation between these cephalometric parameters and PAP adherence remains insufficient. This study aimed to identify this relationship. This study included 185 patients with OSA who were prescribed PAP. Polysomnography (PSG) was performed to diagnose OSA, and paranasal sinus computed tomography (PNS CT) was performed to check for comorbidities of the upper airway. In addition, cephalometric parameters such as the hyoid-posterior nasal spine (H-PNS), posterior nasal spine-mandibular plane (PNS-MP), and hyoid-mandibular plane (H-MP) were measured in the midsagittal and axial CT views. Adherence was evaluated 3-12 months after the PAP prescription. A total of 136 patients were PAP-adherent, and 49 were nonadherent. There were more males in the adherent group and a higher average height in the adherent group. The PSG results showed that the apnea-hypopnea index (AHI), respiratory disturbance index (RDI), oxygen desaturation index (ODI), arousal index (AI), rapid eye movement (REM) AHI, and supine AHI were significantly higher, and the lowest oxygen saturation was lower in the adherent group. In the analysis of covariance (ANCOVA) model adjusted for sex and height, among the cephalometric parameters, H-MP was significantly longer in the adherent group (p = 0.027), and H-PNS showed a longer tendency (p = 0.074). In the logistic regression analysis model, the odds ratio (OR) and 95% confidence intervals (95% CI) of adherence and severe OSA in the third tertile compared to the first tertile of H-MP were 2.93 (1.25-6.86) and 4.00 (1.87-8.56). In the case of H-PNS, they were 2.58 (1.14-5.81) and 4.86 (2.24-10.54), respectively. This study concluded that an inferiorly placed hyoid bone in adult patients is associated with PAP adherence and disease severity.

Functional Endoscopic Sinonasal Surgery in Obstructive Sleep Apnea

Abstract Background: Functional Endoscopic Sinonasal Surgery needs indicators to determine success outcomes in the management of nasal obstruction-related obstructive sleep apnea (OSA). Materials and Methods: Preexperimental pretest and posttest designed studies were performed to evaluate the percentage changes value of Visual Analog Scale (VAS) nasal obstruction, Nasal Obstruction Symptom Evaluation (NOSE), Epworth Sleepiness Scale (ESS), polysomnographic parameters, and upper airway collapsibility examined by drug-induced sleep endoscopy. Results: Seventeen patients from 2 studies were recruited with mean Apnea-Hypopnea Index of 3.74 ± 3.30 and respiratory disturbance index of 7.03 ± 3.56. The first study showed a significant percentage change in inferior turbinate size, nasal obstruction VAS, peak nasal inspiratory flow, and ESS Score as well as the second study of significant differences pre- and postoperatively of NOSE (from 49.50 ± 19.2 to 4.50 ± 4.4) and ESS (from 12.60 ± 3.6 to 6.60 ± 3.9). Both studies significantly changed the percentage of the duration of Rapid Eye Movement (REM) to 81.4% ±100% (95% confidence interval − 23.6, 186.3) and a significant difference from preoperative of 4.93 ± 4.40% to post-operative of 11.89 ± 6.19%. Three subjects with preoperative epiglottic collapse (EC) showed a mean value of NOSE 60 ± 5 compared to the non-EC collapse of 45 ± 21.6. In postoperative, there were 4 subjects with EC collapse with a NOSE of 6.25 ± 4.7 and 6 subjects without EC collapse with a NOSE of 3.33 ± 4.1. Conclusion: Functional Endoscopic sinonasal surgery improves NOSE, ESS score, and REM sleep in OSA.

Obstructive Sleep Apnea Is a Distinct Physiological Endotype in Individuals with Comorbid Insomnia and Sleep Apnea (COMISA).

With up to 40% of individuals with either insomnia or obstructive sleep apnea (OSA) demonstrating clinically significant symptoms of the other disorder, the high degree of comorbidity amongst the two most common sleep disorders suggests a bi-directional relationship and/or shared underpinnings. Whilst the presence of insomnia disorder is believed to influence the underlying pathophysiology of OSA, this influence is yet to be examined directly. To investigate whether the four OSA endotypes (upper airway collapsibility, muscle compensation, loop gain, and the arousal threshold) are different in OSA patients with and without comorbid insomnia disorder. Using the ventilatory flow pattern captured from routine polysomnography, the four OSA endotypes were measured in 34 OSA patients who met diagnostic criteria for insomnia disorder (COMISA) and 34 OSA patients without insomnia (OSA-only). Patients demonstrated mild-to-severe OSA (AHI: 25.8±2.0 events/h) and were individually matched according to age (50.2±1.5 years) sex (42M:26F), and body mass index (29.3±0.6 kg/m2). Compared to OSA patients without comorbid insomnia, COMISA patients demonstrated significantly lower respiratory arousal thresholds (128.9 [118.1-137.1] vs. 147.7 [132.3-165.0] %Veupnea, U=261, 95%CI[-38.3, -13.9], d=1.1, p<.001), less collapsible upper airways (i.e., higher Vpassive: 88.2 [85.5-94.6] vs. 72.9 [64.7-79.2] %Veupnea, U=1081, 95%CI[14.0, 26.7], d=2.3, p<.001) and more stable ventilatory control (i.e., lower loop gain: 0.51 [0.44-0.56] vs. 0.58 [0.49-0.70], U=402, 95%CI[-0.2, -0.01], d=.05, p=.03). Muscle compensation was similar between groups. Moderated linear regression revealed the arousal threshold moderated the relationship between collapsibility and OSA severity in COMISA, but not OSA-only patients. A low arousal threshold is an overrepresented endotypic trait in individuals with COMISA and may exhibit a greater relative contribution to OSA pathogenesis in these patients. Contrastingly, the prevalence of a highly collapsible upper airway in COMISA was low, suggesting that anatomical predisposition may contribute less to OSA development in COMISA. Based on our findings we theorise that conditioned hyperarousal perpetuating insomnia may translate to a reduced arousal threshold to respiratory events, thereby increasing the risk or severity of OSA. Therapies which target increased nocturnal hyperarousal (e.g., through CBT-I) may be effective in individuals with COMISA.

Multi-Level 3D Surgery for Obstructive Sleep Apnea: Could It Be the Future?

(1) Background: Obstructive sleep apnea (OSA) is the most common sleep-related breathing disorder and is characterized by recurrent episodes of complete or partial obstruction of the upper airway, leading to reduced or absent breathing during sleep. A nocturnal upper airway collapse is often multi-levelled. The aim of this communication is to describe a 3D multi-level surgery setting in OSA pathology, introducing new surgical approaches, such as 4K-3D endoscopic visualization for the tongue base approach with the aid of a coblator and exoscopic visualization in the palatal approach. (2) Methods: Seven patients affected by OSA underwent 3D Barbed Reposition Pharyngoplasty (BRP) surgery associated with transoral coblation tongue base reduction and nose surgery. (3) Results: No patients experienced intra-operative, post-operative or delayed complications. For OSA multi-level 3D surgery, it took less than 2 h: the median 3D system setting time was 12.5 ± 2.3 min; the overall procedure time was 59.3 ± 26 min. (4) Conclusions: The use of the 4K-3D endoscope and coblator for tongue base resectioning and of the 3D exoscope for lateral pharyngoplasty represents an excellent system in multi-level OSA related surgery that could reduce the time and the costs compared to those of robotic surgery.

Relationship between Symptom Profiles and Endotypes among Patients with Obstructive Sleep Apnea: A Latent Class Analysis.

Rationale: Obstructive sleep apnea (OSA) is a heterogeneous syndrome with various endotypic traits and symptoms. A link among symptoms, endotypes, and disease prognosis has been proposed but remains unsupported by empirical data. Objectives: To link symptom profiles and endotypes by clustering endotypic traits estimated using polysomnographic signals. Methods: We recruited 509 patients with moderate to severe OSA from a single sleep center. Polysomnographic data were collected between May 2020 and January 2022. Endotypic traits, namely arousal threshold, upper airway collapsibility, loop gain, and upper airway muscle compensation, were retrieved using polysomnographic signals during non-rapid eye movement periods. We used latent class analysis to group participants into endotype clusters. Demographic and polysomnographic parameter differences were compared between clusters, and associations between endotype clusters and symptom profiles were examined using logistic regression analyses. Results: Three endotype clusters were identified, characterized by high collapsibility/loop gain, low arousal threshold, and low compensation, respectively. Patients in each cluster exhibited similar demographic characteristics, but those in the high collapsibility/loop gain cluster had the highest proportion of obesity and severe oxygen desaturation observed in polysomnographic studies. The low compensation cluster was characterized by fewer sleepy symptoms and exhibited a lower rate of diabetes mellitus. Compared with the excessively sleepy group, disturbed sleep symptoms were associated with the low arousal threshold cluster (odds ratio, 1.89; 95% confidence interval, 1.16-3.10). Excessively sleepy symptoms were associated with the high collapsibility/loop gain cluster (odds ratio, 2.16; 95% confidence interval, 1.39-3.37) compared with the minimally symptomatic group. Conclusions: Three pathological endotype clusters were identified among patients with moderate to severe OSA, each exhibiting distinct polysomnographic characteristics and clinical symptom profiles.

Sleep-disordered Breathing in Children With Craniofacial Anomalies.

Sleep-disordered breathing (SDB) is a common disorder in children, characterized by snoring and/or increased breathing force due to narrowing and increased upper airway collapse while sleeping. Over the last decade, it has been recognized that SDB occurs more frequently in children with craniofacial anomalies, but data in Thailand is quite limited. This study retrospective descriptive study aims to find the prevalence of SDB among children with craniofacial anomalies in Thailand and associated risk factors by collecting data among Thai children with congenital craniofacial anomalies younger than 15 years old who visited the Princess Sirindhorn Craniofacial Center at King Chulalongkorn Memorial Hospital between 2016 and 2021. All children were defined into syndromic and nonsyndromic groups. Data collected from the electronic medical record includes baseline characteristics, diagnosis of craniofacial anomalies, associated risk factors, diagnosis of SDB, diagnostic tools, and treatment. Total of 512 children, there were 80 children (15.4%) who had SDB. The most diagnosis was 51 (10%) obstructive sleep apnea followed by 27 (5.3%) primary snoring and 2 (0.4%) obstructive hypoventilation. The prevalence of SDB in the syndromic group was 43 (46.7%) while the nonsyndromic group was 37 (8.6%), ( P <0.001). The risk factors associated with SDB were overweight, allergic rhinitis, tonsillar hypertrophy, high arch palate, micrognathia, and syndromic craniofacial anomalies. The prevalence of SDB is higher in children with syndromic craniofacial anomalies than in the nonsyndromic group. Knowledge of the prevalence and related factors can lead to better care, including early screening and monitoring of SDB in craniofacial patients.

Adaptive responses to chronic intermittent hypoxia: contributions from the European Sleep Apnoea Database (ESADA) Cohort.

Obstructive sleep apnoea (OSA) is a common disease in the general population, and is associated with increased cardiovascular risk and several comorbidities. Obesity favours upper airway collapsibility, but other pathophysiological traits have been identified, i.e. upper airway muscle activity, modulation of the respiratory drive, and the arousal threshold. OSA causes chronic intermittent hypoxia, inflammatory activation and autonomic imbalance with diurnal and nocturnal sympathetic hyperactivity. Disentangling so many components to investigate the pathogenesis of OSA's consequences is very hard clinically. However, albeit imperfect, clinical medicine constitutes a major source of inspiration for basic research, and a mutual exchange of information is essential between clinicians and physiologists to improve our understanding of disease states. OSA is no exception, and this narrative review will summarize the results of clinical studies performed over the years by the European Sleep Apnoea Database (ESADA) Study Group, to explore the variables linked to markers of intermittent hypoxia as opposed to the traditional assessment of OSA severity based on the frequency of respiratory events during sleep (the Apnoea Hypopnoea Index). The results of the clinical studies indicate that intermittent hypoxia variables are associated with several comorbidities, although evidence of a cause-effect relationship is still missing in many cases. It is also possible that adaptive rather than maladaptive responses could be evoked by intermittent hypoxia. The intensity, duration and frequency of intermittent hypoxia episodes causing adaptive rather than maladaptive responses, and their clinical implications, deserve further investigation.

Proposal of a Full Digital Workflow for a Bite Fork to Assess Mandibular Advancement during Drug-Induced Sleep Endoscopy (DISE) for Obstructive Sleep Apnea

(1) Background. Drug-induced sleep endoscopy (DISE) is currently regarded as the gold standard diagnostic procedure to assess the site(s) of upper airway collapse in subjects affected by Obstructive Sleep Apnea Syndrome (OSAS). During DISE, a jaw thrust maneuver is performed to advance the mandible and to predict the effectiveness of outcomes of treatment with mandibular advancement devices (MADs). However, the maneuver is not predictable and could be influenced by specific patients’ anatomical/functional conditions. The aim of this work is to propose a full-digital workflow for customizing an individual mandibular advancement fork, usable by otorhinolaryngologists during DISE. (2) Materials. Two patients with a diagnosis of mild-to-moderate OSAS (AHI ≥ 5 to ≤30/h of sleep) underwent orthodontic examination to verify the usability of the MAD. Intra-oral scans and registration were performed, including bite registration with 65% of mandibular advancement. The latter measurement was used as a reference to design a 3D-printed fork for DISE, as well as for the future MAD. Both patients underwent DISE in the operating room in the presence of an anesthesiologist, otolaryngologist, orthodontic specialist and neurophysiopathology technician. (3) Results. In the intraoperative polysomnography recording, during sleep, the presence of obstructive apnea was confirmed based on respiratory parameters (PNG1, PNG2, PNG3) with associated desaturation and increased muscle activities on PNG4 (mylohyoid muscle), EMG1 (right masseter muscle) and EMG2 (left masseter muscle). With the advancement fork in place, the immediate improvement effect on all respiratory parameters with normal saturation values and the complete suppression of masseter muscles were observed. Accordingly, both patients were considered potential good-responders to the MAD treatment. (4) Conclusions. The preliminary data shown are encouraging and would suggest that the fork represents a stable reference for the otorhinolaryngologist to evaluate the airway patency within the physiological range of movement. The efficiency of the work-flow from data registration to the DISE procedure and laboratory process represent two significant advantages that justify the integration of a digital system in the management of patients affected by OSAS.

Neuromuscular block: Monitoring, reversal, and residual blockade in small animals.

Nondepolarizing neuromuscular blocking agents are used frequently during ophthalmic surgery of dogs and cats. Residual neuromuscular block (NMB)-impaired neuromuscular function at recovery from anesthesia-is a main concern when these agents are used in small animals. In humans, residual NMB reduces the ability to protect the airway (swallow and cough) and increases the incidence of hypoxia and upper airway collapse after recovery from anesthesia. In dogs, impaired neuromuscular function of the larynx can be detected even after common indicators of neuromuscular function suggest that recovery from NMB is complete. Objective monitoring of NMB is a simple, cost-effective strategy to minimize the risk of residual NMB. This review summarizes relevant aspects of monitoring and reversal of NMB, and strategies to minimize the risk of residual NMB in clinical practice of small animals.

0451 Dronabinol Plus Acetazolamide for the Treatment of Obstructive Sleep Apnoea: A Proof of Concept and Mechanistic Exploration Study

Abstract Introduction Current treatments for obstructive sleep apnoea (OSA) typically target the anatomical pathophysiological endotype and are either not tolerated or effective in a significant proportion of patients. Pharmaceuticals may provide an alternative therapeutic option and may address some or all of the remaining endotypes (loop gain, muscle compensation and arousal threshold). This randomised, double-blind, placebo-controlled, cross-over study examined the effect of combination acetazolamide and dronabinol (IHL-42X) at low, medium and high doses on OSA severity and the OSA endotypes. Methods Participants with OSA (apnoea-hypopnoea index; AHI≥15events/hr) received 1-week of IHL-42X at each of the 3 doses and 1-week of placebo, each separated by 1-week washout. The change from baseline in AHI, oxygen desaturation index (ODI), Epworth sleepiness score (ESS), and mood (profile of mood states) on the final night of each treatment arm relative to placebo were the major endpoints. Adverse events (AEs) were monitored throughout. Exploratory analyses examined the change in OSA endotypes determined from polysomnography from baseline values. Results Ten of 11 participants (mean baseline AHI 40.7events/hr) completed the final night of at least one treatment arm. All doses of IHL-42X demonstrated a significant reduction in AHI from baseline when compared with placebo (low, -19.7±27.1; medium, -17.5±23.3; high, -16.4±23.8 versus placebo, -2.8±21.0events/hr; all p&amp;lt; 0.05). The change from baseline in ODI3% at the low, medium and high doses of IHL-42X (-15.2±24.8; -15.4±19.0 and -8.3±13.2events/hr, respectively) were not significantly different from placebo (-2.8±21.0events/hr). IHL-42X did not significantly alter ESS or mood. No serious AEs occurred. However, 31 mild-moderate possibly, probably or treatment related AEs occurred during IHL-42X dosing (4 at the low dose) and 4 occurred during placebo. Relative to baseline, loop gain decreased by 15, 21 and 20% (Cohen’s d all ≥0.59) at the low, medium and high doses, respectively, and collapsibility improved by 12.5% (d=1.06) at the low dose only. Conclusion One week of nightly IHL-42X at all doses was well tolerated, safe and associated with significant reductions in OSA severity. IHL-42X may act to reduce OSA severity by decreasing loop gain and upper airway collapsibility, particularly at the low dose. Support (if any) Incannex Healthcare Ltd supported this study.

0444 Racial Differences in Positive Airway Pressure Requirements Amongst Obstructive Sleep Apnea Patients (The RACE-PAP Study)

Abstract Introduction Prior studies of patients with obstructive sleep apnea (OSA) show racial differences in clinical presentation. When compared with White patients, Black patients present with more severe OSA and greater sleepiness. Racial differences in upper airway collapsibility could explain these differences. Here, we investigated whether mean positive airway pressure (PAP) levels, a clinically accessible measure of upper airway collapsibility, differed by race in a cohort of patients adherent to PAP. Methods We conducted a retrospective analysis of White and Black adults with OSA who were prescribed auto-adjusting PAP (aPAP) therapy at a single academic center between January 2018 and January 2020. The analysis included adherent patients (usage on &amp;gt;70% of nights for ≥4 hours per night) with well-controlled OSA (defined as ≥50% reduction in apnea-hypopnea index [AHI] on aPAP and residual AHI&amp;lt; 10). Mean PAP level was compared between White and Black patients using linear regression controlled for age, gender, body mass index (BMI), AHI, O2 nadir, and mask type (full face, nasal, or unknown). Results Overall, 148 Black (56% women) and 230 White (36% women) patients were included. On average, Black patients were younger (50.7±14.6 vs. 53.8±12.7 years; p=0.037) with higher BMI (40.4±9.5 vs. 34.9±7.6 kg/m2; p&amp;lt; 0.0001). Black patients had less severe OSA on average, but this difference was not statistically significant (AHI of 33.9±25.5 vs 38.6±24.9 events/hour; p=0.077). After adjusting for covariates, Black patients had a 0.62 cm H2O (95% CI: 0.21 to 1.03) higher mean PAP level than White patients (p=0.003). There was a larger racial difference in mean PAP level among men (0.76 [0.16, 1.35] cm H2O; p=0.013) compared to a non-significant difference among women (0.34 [-0.23, 0.91] cm H2O; p=0.242). While statistically significant, differences were &amp;lt; 1 cm H2O and, thus, not clinically meaningful. Conclusion Black patients with OSA had a statistically significant but clinically insignificant difference in mean PAP level when compared with White patients. There was evidence of stronger differences in men than women. Further studies are needed to explore other potential mechanisms, including craniofacial anatomy, which may underlie racial differences in OSA presentation and outcomes. Support (if any) National Institutes of Health R01 1R01HL144859 (PIs: Schwartz, Dedhia)

The role of video-fluoroscopy in the assessment of obstructive sleep apnea patients: comparative study

BackgroundPre-operative imaging tools play a crucial role in the anatomic assessment of the upper airway and adjacent structures in obstructive sleep apnea patients. The current study was aimed at comparing and correlating the results of videofluoroscopy in evaluating upper airway obstruction in surgically fit obstructive sleep apnea “OSA” patients with fiberoptic nasoendoscopic examination during the awake “Muller’s maneuver” and during sleep induced with propofol for better selection of the suitable surgical maneuver. The present study was an observational cross-sectional study of 69 surgically fit OSA patients (36 males and 33 females); their ages ranged between 29 and 65 years with mean age of 45.87 ± 9.68 years. The patients were selected from otorhinolaryngology, phoniatric, and pulmonology outpatient clinics during the period from February 2019 to January 2020.ResultsThe present study demonstrated that no statistically significant difference was found between the three techniques (video-fluoroscopy, awake fiber-optic nasoendoscopy, and drug-induced sleep nasoendoscopy “DISE”) as regards the shape of upper airway collapse at retropalatal, retroglossal, and hypopharyngeal levels in OSA patient (P: 0.621, 0.669, and 1.0 respectively). Statistically, a significant difference was observed between video-fluoroscopy, awake fiber-optic nasoendoscopy on one hand, and DISE on the other one regarding the grade of upper airway collapse at all levels (P: 0.006, 0.037, and 0.003). It was a mild significant difference in favor of DISE.ConclusionVideo-fluoroscopy is a good, reliable complementary preoperative assessment tool to identify obstruction patterns of the upper airway in OSA patients with quantitative measurements.

Hypoglossal nerve trunk stimulation: electromyography findings during drug-induced sleep endoscopy: a case report

BackgroundLiterature has demonstrated hypoglossal nerve stimulation to be a safe and effective treatment for patients with obstructive sleep apnea nonadherent to positive airway pressure therapy. However, the recommended criteria for patient selection are still unable to identify all the unresponsive patients, highlighting the need for improved understanding about hypoglossal nerve stimulation for obstructive sleep apnea.Case presentationA 48-year-old Caucasian male patient with obstructive sleep apnea had been successfully treated with electrical stimulation of the hypoglossal nerve trunk, documented by level 1 polysomnography data. However, due to snoring complaints, he underwent postoperation drug-induced sleep endoscopy for evaluation of electrode activation during upper airway collapse, aiming to improve electrostimulation parameters. Concurrent surface electromyography of the suprahyoid muscles and masseter was obtained. Activation of electrodes 2, 3, and 6 promoted upper airway opening most strongly at the velopharynx and tongue base during drug-induced sleep endoscopy. The same channels also significantly increased the electrical activity on suprahyoid muscles bilaterally, but predominantly on the stimulated side (right). The masseters also presented a considerable asymmetry in electrical potential on the right side (> 55%).ConclusionBeyond the genioglossus muscle, our findings demonstrate recruitment of other muscles during hypoglossal nerve stimulation, which may be attributed to the electrical stimulation of the nerve trunk. This data provides new insights on how stimulation of the hypoglossal nerve trunk may contribute to obstructive sleep apnea treatment.

0533 Healthcare Utilization by Patients with Obstructive Sleep Apnea and Excessive Daytime Sleepiness After Airway Therapy in the UK

Abstract Introduction Obstructive Sleep Apnea (OSA) is a chronic condition characterized by repetitive episodes of upper airway collapse during sleep. Despite standard treatment with continuous positive airway pressure (CPAP), some patients continue to experience residual excessive daytime sleepiness (rEDS). Pharmacotherapy use for rEDS is low in Europe and some wake-promoting agents are no longer allowed as treatments by the European Medicines Agency. The objective of this study was to characterize the patient demographics, comorbidities, medications, and healthcare resource utilization (HCRU) in a population of OSA patients with and without rEDS after CPAP initiation. Methods The retrospective observational cohort study used the Clinical Practice Research Datalink (CPRD) AURUM, a primary care database, linked at the patient level to the Hospital Episode Statistics (HES) database, which covers secondary care for all of England. The population included 10,746 adult OSA patients with a first record of CPAP treatment during the eligibility period (Jan 1, 2009-Mar 21, 2018). rEDS patients were identified 6 months after initiating CPAP treatment. Results Among all eligible OSA patients in the AURUM database, 596 (5.6%) had rEDS; 80.5% of rEDS patients were identified using recorded diagnosis code of daytime fatigue, and 21.7% using ESS score ≥11 (13 patients had both measures). A greater percentage of patients had a history of psychiatric (21.5%; p&amp;lt; 0.0001), gastrointestinal (7.7%; p&amp;lt; 0.0001), and neurodegenerative (13.6%; p=0.003) disorders in the rEDS group, compared with the non-rEDS group, while the prevalence of obesity, cardiovascular, and sleep disorders did not significantly differ between groups. Across all patients, rates of prescription for stimulants or modafinil were low during the 12 months prior to CPAP initiation. Patients with rEDS had significantly higher HCRU compared to non-rEDS patients in the first and second years after CPAP initiation. Conclusion Despite low rates of rEDS identified in this study, the clinical needs of patients with rEDS are significant, as evidenced by the volume of HCRU, low use of pharmacotherapy, and high comorbidity rates, highlighting the need to improve patient care in rEDS. Support (if any) Axsome Therapeutics and Jazz Pharmaceuticals

Mechanics and Dynamics of the Pharynx

Maintaining airway patency during anaesthesia is the primary responsibility of the anaesthesiologist. Apart from anaesthetic agents, there are many factors which influence the pharyngeal patency. Understanding the pharyngeal collapsibility and behaviour of the upper airway during sleep would help in increasing the safety of patients under anaesthesia. The mechanism of pharyngeal collapse, the role of pharyngeal dilators, negative intra-thoracic pressure and multiple other factors involved to maintain pharyngeal patency are described in the article. Clinical and radiological tools to predict upper airway collapsibility have also been explained with supportive evidence. This article should be considered a resource for concepts of pharyngeal dynamics and mechanics to improve airway patency and to predict pharyngeal collapsibility and thereby safety during anaesthesia.

Myasthenic crisis.

Myasthenic crisis (MC) is a life-threatening manifestation of myasthenia gravis (MG) defined by respiratory insufficiency that requires the use of invasive or non-invasive ventilation. This is often the result of respiratory muscle weakness but can also be due to bulbar weakness with upper airway collapse. MC occurs in approximately 15%-20% of patients with MG usually within the first 2 to 3 y of the disease course. Many crises have a specific trigger with respiratory infections being most common; however, no specific trigger is found in 30%-40% of patients. MG patients with a history of MC, severe disease, oropharyngeal weakness, muscle-specific kinase (MuSK) antibodies and thymoma appear to be at higher risk. Most episodes of MC do not occur suddenly, providing a window of opportunity for prevention. Immediate treatment is directed toward airway management and removing any identified triggers. Plasmapheresis is preferred over intravenous immune globulin as the treatments of choice for MC. The majority of patients are able to be weaned from mechanical ventilation within 1 mo and the outcomes of MC are generally favorable. The mortality rate in United States cohorts is less than 5% and mortality in MC seems to be driven by age and other medical co-morbidities. MC does not appear to affect long-term prognosis as many patients are able to eventually achieve good MG control.

Distraction Osteogenesis as a reliable method in management of Obstructive Sleep Apnoea (OSA) secondary to TMJ Ankylosis: A Case Report.

Obstructive sleep apnoea (OSA) is identified as repetitive and intermittent upper airway collapse or narrowing during sleep. Skeletal advancement through maxillomandibular surgery remains the most effective surgical treatment for OSA but is radical with certain relapse rate. Distraction Osteogenesis of mandible is a single-jaw surgical treatment alternative to bi-jaw surgeries having lesser complications. This case report describes successful management of a 46-year-old patient who reported with a chief complain of obstruction in breathing while sleeping since one year. Obstructive Sleep Apnoea (OSA) secondary to a retrognathic mandible was the final diagnosis, which was successfully treated by Distraction Osteogenesis (DO) of the mandible. The case showed enhancement in airway by 13mm and marked forward movement of Point-B (SNB increased by 6 degrees). The Epworth Sleepiness Scale value decreased from 19mm to 8 mm indicating substantial increase in the airway with stable results after 18 months of follow-up (elimination of symptoms and subsequent sound sleep). Distraction osteogenesis is an effective and reliable method to treat obstructive sleep apnoea secondary to retrognathic mandible.

Racial differences in upper airway collapsibility and loop gain in young adult males.

Previous studies reported that the apnea-hypopnea index was similar in young adult Black and White participants. However, whether this similarity reflects an analogous combination of apneas and hypopneas is unknown. Likewise, the physiological mechanisms underlying this similarity has not been explored. 60 Black and 48 White males completed the study. After matching for age and body mass index, 41 participants remained in each group. All participants completed a sleep study. Subsequently, standard sleep indices along with loop gain and the arousal threshold were determined. In addition, airway collapsibility (24 of 60 and 14 of 48 participants) and the hypoxic ventilatory response during wakefulness (30 of 60 and 25 of 48 participants) was measured. The apnea-hypopnea index was similar in Blacks and Whites (p = .140). However, the index was comprised of more apneas (p = .014) and fewer hypopneas (p = .025) in Black males. These modifications were coupled to a reduced loop gain (p = .0002) and a more collapsible airway (p = .030). These differences were independent of whether or not the groups were matched. For a given hypoxic response, loop gain was reduced in Black compared to White males (p = .023). Despite a similar apnea-hypopnea index, more apneas and fewer hypopneas were evident in young adult Black compared to White males. The physiological mechanisms that contribute to these events were also different between groups. Addressing these differences may be important when considering novel therapeutic approaches to eliminate apnea in Black and White participants.