Pharyngeal Collapse Research Articles

Is it important to stabilize palatopharyngeus muscle to pterygomandibular raphe under vision during surgery for OSA?

Access the importance of visualizing the pterygomandibular raphae (PMR) while fixing palatopharyngeous (PPM) muscle to the pterygomandibular raphae (PMR). Randomized controlled trial. First group, forty-two OSA patients performed either Anterolateral advancement pharyngoplasty (ALA) or Barbed reposition pharyngoplasty (BRP) while visualizing the PMR according to the following criteria: age between 21 and 60 years, body mass index (BMI) < 35, and patients with lateral pharyngeal collapse diagnosed with drug induced sleep endoscopy (DISE). The results were compared to the second control group of 42 patients performed the same procedures without exposing the PMR. PMR was bilaterally present in 27 (64.28%) patients and bilaterally absent in 5 (11.8%) patients while unilateral in 10 (23.9%) patients. PSG findings in group 1: Apnea hypopnea index (AHI) decreased from 40.84 ± 26.93 to 14.81 ± 7.43 (P < 0.001), mean Lowest oxygen saturation (LOS) significantly increased from 79.25 ± 14.93 to 89.92 ± 10.7 (P < 0.001) and Epworth sleepiness scale (ESS) significantly dropped from 13.25 ± 4.65 to 6.1 ± 2.06 (P < 0.001). Group 2 results showed AHI decrease from 27.50 ± 11.56 to 11.22 ± 7.63 (P ≤ 0.001), LOS increased from 81.86 ± 6.41 to 90.21 ± 3.70 and ESS dropped from 14.95 ± 3.72 to 7.91 ± 3.05. The difference between both groups was not statistically significant (P > 0.001). Fixation of PPM to the PMR under direct vision doesn't significantly affect the surgical outcomes but can increase the procedure efficiency and reduce complication rate keeping in mind that PMR may be absent in some patients.

Pharyngeal Manometry and Upper Airway Collapse During Drug-Induced Sleep Endoscopy

Drug-induced sleep endoscopy (DISE) is used to guide therapeutic management of obstructive sleep apnea (OSA), depending on the levels and patterns of pharyngeal collapse. However, the collapsibility of specific pharyngeal sites remains unknown. To assess collapse sites in patients with OSA undergoing DISE and whether number and location are associated with differences in airway collapsibility; and to quantify differences in collapsibility between primary and secondary sites in multilevel collapse. This cohort study assessed adult patients (≥18 years) with OSA undergoing DISE with manometry and positive airway pressure (PAP) titration at a tertiary care center from November 2021 to November 2023. Patients with an AHI score greater than 5 were included; those with less than 1 apnea event during DISE or incorrect catheter placement were excluded. Data were analyzed from September 28, 2022, to March 31, 2024. DISE with manometry and PAP titration. Active pharyngeal critical pressure (Pcrit-A) and pharyngeal opening pressure (PhOP) were used to quantify airway collapsibility, adjusted for covariates (age, sex, race, and body mass index [BMI]). Of 94 screened, 66 patients (mean [SD] age, 57.4 [14.3] years; BMI, 29.2 [3.9]; 51 [77.3%] males) with a mean (SD) apnea-hypopnea index (AHI) of 31.6 (19.0) were included in the analysis. Forty-seven patients (71.2%) had multilevel collapse, 10 (15.2%) had single-level nasopalatal collapse, and 9 (13.6%) had single-level infrapalatal collapse. Groups did not differ in demographic characteristics or established measures of OSA severity. The single-level nasopalatal group had substantially elevated levels of airway collapsibility (Pcrit-A and PhOP covariate adjusted mean, 2.4; 95% CI, 1.1 to 3.8; and 8.2; 95% CI, 6.4 to 9.9 cmH2O) compared to the single-level infrapalatal group (-0.9; 95% CI, -2.4 to 0.5 cmH2O; and 4.9; 95% CI, 3.0 to 6.8 cmH2O, respectively) and similar to the level among the multilevel group (1.3; 95% CI, 0.7 to 2.0; and 8.5; 95% CI, 7.7 to 9.3 cmH2O). The multilevel group had more negative inspiratory pressure (-24.2; 95% CI, -28.1 to -20.2 cmH2O) compared to the single-level nasopalatal group (-9.8; 95% CI, -18.3 to -1.28 cmH2O). In patients with multilevel collapse, airway collapsibility was significantly higher at the primary nasopalatal compared to secondary infrapalatal site (mean difference, 13.7; 95% CI, 11.3 to 16.1 cmH2O). The findings of this cohort study suggest that intervention should target the primary site of pharyngeal collapse, and secondary sites only if they are nearly as collapsible as the primary site. Future work is needed to precisely define the difference in primary and secondary collapsibility that necessitates multilevel treatment.

Novel physiologic predictors of positive airway pressure effectiveness (NICEPAP) study: rationale, design and methods.

Continuous positive airway pressure (CPAP) is the primary therapy for obstructive sleep apnea (OSA); however the effectiveness of CPAP remains suboptimal. We describe the Novel PhysIologiC prEdictors of Positive Airway Pressure Effectiveness (NICEPAP) study. Its purpose is to determine whether physiological traits of OSA contribute to CPAP effectiveness. NICEPAP (NCT05067088) is a prospective, observational cohort study conducted at an academic sleep center. Adults newly diagnosed with OSA (n = 267) are assessed for OSA traits of loop gain, arousal threshold, pharyngeal collapsibility, and muscle compensation from baseline polysomnography. We perform a comprehensive assessment of covariates relevant to CPAP adherence, efficacy, and patient-centered outcomes. Participants are followed for 12 months. Primary outcomes include (1) CPAP adherence (hours/night), (2) CPAP efficacy (apneas-hypopneas/hour), and (3) quality of life at six months measured by objective CPAP data and Functional Outcomes of Sleep Questionnaire. Secondary outcomes include sleep quality, sleepiness, insomnia, and neurocognitive function. Data on covariates, including demographics, sleep symptoms, medical history, medications, sleep quality, OSA and treatment self-efficacy, decisional balance, and socio-economic and social and partner support, are collected using validated instruments. The analysis for primary outcomes includes a generalized linear mixed model for an outcome (e.g., CPAP adherence) with OSA traits as exposures followed by the addition of relevant covariates. The findings of the NICEPAP study will inform research aimed to enhance CPAP effectiveness. Understanding the role of physiological OSA traits in CPAP effectiveness is a crucial step toward a precision medicine approach to OSA.

Do tight nosebands have an effect on the upper airways of horses?

The public perception relating to the welfare of horses involved with equestrian sports is associated with training methods used and the presentation of horses at events. In this context, very tight nosebands, which are intended to prevent the horse from opening its mouth, also attract a lot of attention. Various studies have evaluated the impact of tight nosebands on stress parameters, whereas the effect of tight nosebands on upper airway function is unknown. Therefore, the aim of the study was to use overground endoscopy to evaluate changes in pharyngeal and laryngeal function when a tight noseband is fitted. Moreover, the ridden horse pain ethogram (RHpE) was applied to investigate signs of discomfort (Dyson et al., 2018). A randomized, blinded, and prospective study was performed. Sixteen warmblood horses consisting of twelve mares and four geldings with a mean age of 11.63 ± 3.53 years were ridden on 2 consecutive days with either loose or tight nosebands (two fingers or no space between bridge of the nose and noseband, respectively) and inserted endoscope in a random order. Videos were taken in a riding arena during a standardized exercise protocol involving beginner level tasks for 30 min in all gaits. For video analysis, freeze frames were prepared and analyzed at the beginning of the expiration phase. Pharyngeal diameter was measured using the pharynx-epiglottis ratio. Other findings (swallowing, pharyngeal collapse, soft palate movements, and secretion) were also evaluated. Moreover, the RHpE was applied. Descriptive statistics and generalized linear mixed effects models were used. Results with a p-value < 0.05 were considered statistically significant. While the pharynx-epiglottis ratio did not change significantly in horses ridden with loose versus tight nosebands, there was an increase in mean grade and total counts of parameters assessed in the pharyngeal region, for example, grade of secretion (1.5 [±SD 0.89] vs. 3.13 [±SD 0.96]; p = 0.0001), axial deviation of the aryepiglottic folds (0.29 [±SD 0.73] vs. 1.33 [±SD 1.44]; p = 0.01), and pharyngeal collapse (0.69 [±SD 0.87] vs. 1.88 [±SD 1.54]; p = 0.005) in horses ridden with tight nosebands. There was no RHpE score above 8 indicating musculoskeletal pain, but the RHpE scores were significantly higher in horses ridden with tight nosebands (p < 0.001). Video quality was limited when horses showed large amounts of secretion. Another limitation was the small number of horses. Results add to the evidence obtained in other studies that tight nosebands do not only cause adverse reactions based on the RHpE score such as head behind the vertical or intense staring but also contribute to changes in the pharyngeal region, such as increased secretion and collapse of pharyngeal structures. This may provide further support for future decisions regarding regulations on nosebands.

A gated recurrent unit model based on ultrasound images of dynamic tongue movement for determining the severity of obstructive sleep apnea

Obstructive sleep apnea (OSA) presents as a respiratory disorder characterized by recurrent upper pharyngeal airway collapse during sleep. Dynamic tongue movement (DTM) analysis emerges as a promising avenue for elucidating the pathophysiological underpinnings of OSA, thereby facilitating its diagnosis. Recent endeavors have utilized artificial intelligence techniques to categorize OSA severity leveraging electrocardiography and blood oxygen saturation data. Nonetheless, the integration of ultrasound (US) imaging of the tongue remains largely untapped in the development of machine learning models aimed at determining the severity of OSA. This study endeavors to bridge this gap by capturing US images of DTM dynamics during wakefulness, encompassing transitions from normal breathing (NB) to the performance of the Müller maneuver (MM) in a cohort of 53 patients. Leveraging the modified optical flow method (MOFM), the trajectories of patients’ DTM were tracked, facililtating the extraction of 27 parameters vital for model training. These parameters encompassed nine-point lateral movement, nine-point axial movement, and nine-point total displacement of the tongue, resulting in a dataset of 186,030 samples. The gated recurrent unit (GRU) method, renowned for its efficacy in motion tracking, was employed for model development in this study. Validation of the developed model was conducted via stratified k-fold cross-validation (SCV). The systems’ overall performance in classifying OSA severity, as quantified by mean accuracy (MA), yielded a value of 43.49%. This pilot investigation marks an exploratory endeavor into the utilization of artificial intelligence for the classification of OSA severity based on US images and dynamic movement patterns. This novel model holds potential to assist clinicians in categorizing OSA severity and guiding the selection of pertinent treatment modalities tailored to the individual needs of patients afflicted with OSA.

0623 Effects of Nasal and Upper Airway Surgery on Pharyngeal Collapsibility in People with Obstructive Sleep Apnea

0623 Effects of Nasal and Upper Airway Surgery on Pharyngeal Collapsibility in People with Obstructive Sleep Apnea

Identifying key antioxidative stress factors regulating Nrf2 in the genioglossus with human umbilical cord mesenchymal stem-cell therapy

Intermittent hypoxia in patients with obstructive sleep apnea (OSA) hypopnea syndrome (OSAHS) is associated with pharyngeal cavity collapse during sleep. The effect of human umbilical cord mesenchymal stem cells (HUCMSCs) on OSA-induced oxidative damage in the genioglossus and whether nuclear factor erythroid 2-related factor 2 (Nrf2) or its upstream genes play a key role in this process remains unclear. This study aimed to identify the key factors responsible for oxidative damage during OSAHS through Nrf2 analysis and hypothesize the mechanism of HUCMSC therapy. We simulated OSA using an intermittent hypoxia model, observed the oxidative damage in the genioglossus and changes in Nrf2 expression during intermittent hypoxia, and administered HUCMSCs therapy. Nrf2 initially increased, then decreased, aggravating the oxidative damage in the genioglossus; Nrf2 protein content decreased during hypoxia. Using transcriptomics, we identified seven possible factors in HUCMSCs involved in ameliorating oxidative stress by Nrf2, of which DJ-1 and MEF2A, showing trends similar to Nrf2, were selected by polymerase chain reaction. HUCMSCs may reduce oxidative stress induced by intermittent hypoxia through Nrf2, and the possible upstream target genes in this process are MEF2A and DJ-1. Further studies are needed to verify these findings.

The role of atypical deglutition in children and adolescents with moderate to severe obstructive sleep apnea syndrome.

This cross-sectional study aimed to assess the prevalence of atypical deglutition (tongue thrust) in children diagnosed with moderate to severe obstructive sleep apnea syndrome (OSAS) and to explore its associations, particularly in relation to the type of dentition (mixed or permanent). The study was conducted over a 5 year period at a paediatric hospital in Paris, France. Children aged 6-18 years with moderate to severe OSAS (apnea-hypopnea index ≥5/h) underwent a comprehensive evaluation, including the recording of demographic data, symptoms of snoring and breathing issues, and otolaryngology examination. The swallowing pattern was assessed and orthodontic evaluations were performed. Cephalometric radiography and pharyngometry tests (pharyngeal collapsibility was computed) were conducted. The study found a high prevalence of atypical deglutition in children with mixed 74% [56-87] or permanent 38% [25-51] dentition. In children with mixed dentition and atypical deglutition, the pharyngeal compliance and lower facial dimensions were increased. In children with permanent dentition, atypical deglutition was associated with more severe OSAS and a lower hyoid bone position. Independent of the type of dentition, atypical deglutition was associated with an increase in the apnea-hypopnea index, an increase in the lower facial dimension, increased pharyngeal compliance, and a more caudal hyoid bone position. Atypical deglutition was strongly associated with increased pharyngeal collapsibility, more severe OSAS and altered facial measurements in children. The findings suggest that identifying atypical deglutition in children with OSAS could help to guide a personalised therapeutic approach, including myofunctional therapy.

A pilot study to assess the effects of preventing fluid retention in the legs by wearing compression stockings on overnight airway narrowing in mild asthma.

Nocturnal asthma is a sign of asthma worsening and could be partially due to more fluid drawn into the thorax during sleep by gravitational force and/or pharyngeal collapse in those with obstructive sleep apnea. Wearing compression stockings during the day reduces fluid shift from the legs to the neck overnight. However, the potential effect of wearing compression stockings to reduce fluid accumulation in the leg and to improve nocturnal small airway narrowing in patients with asthma has not been investigated. This study investigates whether reducing leg fluid volume by wearing compression stockings during the day would attenuate small airway narrowing in patients with asthma before and after sleep. We enrolled 11 participants with asthma. All participants underwent overnight polysomnography with or without wearing compression stockings for 2weeks. Before and after sleep, leg fluid volume (LFV) was measured by bioelectrical impedance, and airway narrowing was primarily assessed by respiratory system resistance and reactance at 5Hz (R5 and X5 respectively) using oscillometry. After 2weeks of wearing compression stockings, the LFV measured in the evening was reduced (∆ = - 192.6 ± 248.3ml, p = 0.02), and R5 and X5 improved (∆ = - 0.7 ± 0.9 cmH2O/L/s, p = 0.03 and 0.2 ± 1.4 cmH2O/L/s, p = 0.05 respectively). No changes were observed in the morning. Preventing fluid retention in the legs by wearing compression stockings for 2weeks during the day, reduced LFV and airway narrowing in the evening in all participants with asthma, but not in the morning after sleep.

Assessment of MMP-9 and clinical characteristics in dogs with tracheal collapse based on cough severity and fluoroscopic findings: a cross-sectional study

BackgroundTracheal collapse (TC), a common disease in dogs, is characterized by cough; however, little is known about the serum biomarkers that can objectively evaluate the severity of cough in canine TC. Furthermore, studies elucidating the relationship of fluoroscopic characteristics with the severity of cough are lacking. Therefore, this study aimed to evaluate the relationship between cough severity and clinical characteristics, fluoroscopic images, and new serum biomarkers in canine TC.ResultsFifty-one client-owned dogs diagnosed with TC based on fluoroscopic and clinical signs were enrolled in this study and divided into three groups according to the severity of cough (grade of cough: 0, 1, and 2). Signalments, comorbidities, and fluoroscopic characteristics were compared among the groups retrospectively. The serum matrix metalloproteinase-9 (MMP-9), interleukin-6 (IL-6), surfactant protein-A (SP-A), and syndecan-1 (SDC-1) levels were measured in all groups. No significant differences in age, breed, sex, or clinical history were observed among the groups. Concomitant pharyngeal collapse increased significantly with the severity of cough (p = .031). Based on the fluoroscopic characteristics, the TC grade of the carinal region increased significantly and consistently with the grade of cough (p = .03). The serum MMP-9 level was significantly higher in the grade 2 group than that in the grade 0 group (p = .014). The serum IL-6 level was significantly lower in the grade 1 group than that in the grade 0 group (p = .020). The serum SP-A and SDC-1 levels did not differ significantly among the groups.ConclusionsThe severity of cough with the progression of TC can be predicted with the fluoroscopic TC grade at the carinal region. MMP-9 may be used as an objective serum biomarker that represents cough severity to understand the pathogenesis.

Clinical Application of Pediatric Sleep Endoscopy: An International Survey.

To investigate through an international survey the actual clinical application of drug-induced sleep endoscopy (DISE) in pediatric patients with obstructive sleep apnea (OSA) and to clarify the use, application, clinical indications, and protocol of pediatric DISE. A specific survey about pediatric DISE was initially developed by five international otolaryngologists with expertise in pediatric sleep apnea and drug-induced sleep endoscopy and was later spread to experts in the field of sleep apnea, members of different OSA-related associations. A total of 101 participants who answered all the survey questions were considered in the study. Sixty-four sleep apnea experts, equivalent to 63.4% of interviewed experts, declared they would perform DISE in pediatric OSA patients. A total of 81.9% of responders agreed to consider the DISE as the first diagnostic step in children with persistent OSA after adenotonsillectomy surgery, whereas 55.4% disagreed with performing DISE at the same time of scheduled adenotonsillectomy surgery to identify other possible sites of collapse. In the case of young patients with residual OSA and only pharyngeal collapse during DISE, 51.8% of experts agreed with performing a velopharyngeal surgery. In this case, 27.7% disagreed and 21.4% were neutral. Pediatric DISE is internationally considered to be a safe and effective procedure for identifying sites of obstruction and collapse after adenotonsillectomy in children with residual OSA. This is also useful in cases of patients with craniofacial malformations, small tonsils, laryngomalacia or Down syndrome to identify the actual site(s) of collapse. Despite this evidence, our survey highlighted that pediatric DISE is not used in different sleep centers.

A novel TASK channel antagonist nasal spray reduces sleep apnea severity in physiological responders: a randomized, blinded, trial.

Preclinical and human physiological studies indicate that topical, selective TASK 1/3 K+ channel antagonism increases upper airway dilator muscle activity and reduces pharyngeal collapsibility during anesthesia and nasal breathing during sleep. The primary aim of this study was to determine the effects of BAY2586116 nasal spray on obstructive sleep apnea (OSA) severity and whether individual responses vary according to differences in physiological responses and route of breathing. Ten people (5 females) with OSA [apnea-hypopnea index (AHI) = 47 ± 26 events/h (means ± SD)] who completed previous sleep physiology studies with BAY2586116 were invited to return for three polysomnography studies to quantify OSA severity. In random order, participants received either placebo nasal spray (saline), BAY2586116 nasal spray (160 µg), or BAY2586116 nasal spray (160 µg) restricted to nasal breathing (chinstrap or mouth tape). Physiological responders were defined a priori as those who had improved upper airway collapsibility (critical closing pressure ≥2 cmH2O) with BAY2586116 nasal spray (NCT04236440). There was no systematic change in apnea-hypopnea index (AHI3) from placebo versus BAY2586116 with either unrestricted or nasal-only breathing versus placebo (47 ± 26 vs. 43 ± 27 vs. 53 ± 33 events/h, P = 0.15). However, BAY2586116 (unrestricted breathing) reduced OSA severity in physiological responders compared with placebo (e.g., AHI3 = 28 ± 11 vs. 36 ± 12 events/h, P = 0.03 and ODI3 = 18 ± 10 vs. 28 ± 12 events/h, P = 0.02). Morning blood pressure was also lower in physiological responders after BAY2586116 versus placebo (e.g., systolic blood pressure = 137 ± 24 vs. 147 ± 21 mmHg, P < 0.01). In conclusion, BAY2586116 reduces OSA severity during sleep in people who demonstrate physiological improvement in upper airway collapsibility. These findings highlight the therapeutic potential of this novel pharmacotherapy target in selected individuals.NEW & NOTEWORTHY Preclinical findings in pigs and humans indicate that blocking potassium channels in the upper airway with topical nasal application increases pharyngeal dilator muscle activity and reduces upper airway collapsibility. In this study, BAY2586116 nasal spray (potassium channel blocker) reduced sleep apnea severity in those who had physiological improvement in upper airway collapsibility. BAY2586116 lowered the next morning's blood pressure. These findings highlight the potential for this novel therapeutic approach to improve sleep apnea in certain people.

Anterolateral advancement pharyngoplasty versus barbed reposition pharyngoplasty in patients with obstructive sleep apnea

ObjectivesTo compare functional outcomes and complication rates of anterolateral advancement pharyngoplasty (ALA) versus barbed reposition pharyngoplasty (BRP) in the treatment of obstructive sleep apnea patients with palatal and lateral pharyngeal wall collapse.Study designProspective study.SettingUniversity hospitals.Subjects and methodsForty-six patients were included in this study. Patients were divided into two groups randomly, group 1 (23 cases) underwent anterolateral advancement pharyngoplasty and group 2 (23 cases) underwent barbed relocation pharyngoplasty. According to the following criteria: both sex, age between 18 and 65 years, body mass index ≤ 32 kg/m2, Friedman stage II or III, type I Fujita, nocturnal polysomnography study diagnostic for OSA, retropalatal and lateral pharyngeal wall collapse, diagnosis with flexible nasoendoscopy during a Muller’s maneuver based on a 5-point scale and drug-induced sleep endoscopy. Patients who suffered from retroglossal airway collapse were rolled out.ResultsApnea–hypopnea index decreased from 27.50 ± 11.56 to 11.22 ± 7.63 (P ≤ .001) in group 1 and from 33.18 ± 10.94 to 12.38 ± 6.77 (P ≤ .001) in group 2. Retropalatal posterior airway space increased from 9.84 ± 1.29 mm to 21.48 ± 2.8 mm (P ≤ .001) in group 1 and increased from 10.26 ± 1.2 mm to 22.86 ± 2.62 mm (P ≤ .001) in group 2. Retropalatal space volume increased from 1.9 ± 0.68 cm3 to 2.75 ± 0.7 cm3 (P ≤ .001) in group 1 and increased from 1.96 ± 0.88 cm3 to 2.82 ± 0.83 cm3 (P ≤ .001) in group 2. Surgical success was 86.95% in group 1 compared to 82.6% in group 2.ConclusionsBoth techniques appear to be effective with a high surgical success rate in the treatment of OSA patients with retropalatal and lateral pharyngeal wall collapse.

Severely obese 14-year-old boy with central sleep apnea several years after head trauma

Severely obese 14-year-old boy with central sleep apnea several years after head trauma

Early-onset pharyngeal airway collapse in infants: a retrospective single-center study.

Early-onset pharyngeal airway collapse (PAC) in infants, which presents with onset within 6-months old is relatively rare. This disease has not been given enough attention in clinic. The aim of this study was to explore the clinical features, endoscopic findings and outcomes of early-onset PAC in infants. The children of PAC with onset within 6-months old were included. A retrospective study was conducted. (1) Total 26 cases were included. The age of onset was neonatal period in 20 cases, 1 to 3-months old in 5 cases, and 4 to 6-months old in 1 case. (2) The main clinical manifestations were noisy breathing (26/26), suprasternal retraction (18/26), snoring (14/26) and hypoxic episode (13/26). (3) Based on the endoscopic findings, collapse at the retropalatal level was most common (24/26). (4) Twelve cases underwent pharyngolaryngeal CT examination, which revealed abnormal findings in 7 cases. (5) Fifteen cases were accompanied with the other airway malformations. (6) In the group with comorbidities of cerebral impairment or craniofacial abnormalities, 1 case was lost to follow up, 4 cases died, and 10 cases survived, in which 9 cases had neurodevelopmental disorders. In the group without comorbidities, 2 cases were lost to follow up, 9 cases survived, in which 1 case had neurodevelopmental disorders. The incidence of poor prognosis including death and neurodevelopmental disorders was significantly higher in the group with comorbidities than that without comorbidities (P<0.01). (7) An symptomatic improvement of PAC was found in the majority of the survived cases (18/19) with age. Early-onset PAC in infants usually exhibits varying degrees of relief with age, whereas the cases with comorbidities had a poor prognosis.

Identifying the pathophysiological traits of obstructive sleep apnea during dexmedetomidine sedation.

Dexmedetomidine (DEX) has been described as a safe sedative in clinical practice, but its effects on the pathophysiological traits of obstructive sleep apnea (OSA) are unclear. We estimated the effects of DEX sedation on the four key pathophysiological traits of OSA (pharyngeal collapsibility, dilator muscle function, arousal threshold, and loop gain) in adult patients with OSA by conducting a secondary analysis of a prospective diagnostic trial. Pathophysiological traits estimated from polysomnography and the respiratory parameters under natural sleep and DEX-induced sleep were compared. Bivariate and multivariate linear regression analyses were used to estimate the relationship between pathophysiological traits and OSA severity for both sleep states. Adult patients with OSA had a significantly higher pharyngeal collapsibility (Vpassive: 44.9 [15.7 to 53.8] vs. 53.3 [34.2 to 66.3] %eupnea, p < 0.001), arousal threshold (178.5 [132.5 to 234.6] vs. 140.5 [123.2 to 192.3] %eupnea, p < 0.001), and loop gain (LG1: 0.74 ± 0.25 vs. 0.60 ± 0.17, p < 0.001; LGn: 0.52 ± 0.12 vs. 0.44 ± 0.08, p < 0.001) during DEX-induced sleep compared with natural sleep. There was no significant difference in dilator muscle function or PSG respiratory parameters between natural versus DEX-induced sleep states. Bivariate regression analysis showed varying degrees of correlation between OSA traits and severity. Multiple regression analysis indicated that collapsibility was the strongest predictor of the apnea-hypopnea index for both sleep states. Dexmedetomidine sedation in patients with OSA increased the pharyngeal collapsibility without impairing dilator muscle function, while elevating arousal threshold and increasing loop gain.

Airway Collapsibility during Drug-Induced Sleep Endoscopy Relates with Clinical Features of Obstructive Sleep Apnea.

Increased pharyngeal collapsibility leads to obstructive sleep apnea (OSA). Positive airway pressure titration during drug-induced sleep endoscopy (DISE-PAP) provides objective collapsibility metrics, the pharyngeal opening pressure (PhOP), and active pharyngeal critical pressure (PcritA ). We examined the interrelationships between risk factors of OSA, airway collapsibility measures, and clinical manifestations of the disease. This is a cross-sectional analysis of consecutive OSA patients undergoing DISE-PAP. Nasal PAP was increased stepwise until inspiratory flow limitation was abolished, signifying PhOP. PcritA was derived from the resulting titration pressure-flow relationships. Clinical data including demographics, anthropometrics, sleep studies, and patient-symptom questionnaires were obtained from the electronic medical record. Multivariate regression was used to evaluate the relationship between risk factors, airway collapsibility, and clinical data. On average, the 164 patients meeting inclusion criteria were middle-aged (54.2 ± 14.7 years), overweight/obese (BMI 29.9 ± 4.5 kg/m2 ), male (72.6%), White (79.3%) and had severe OSA (AHI 32.0 ± 20.5 events/hour). Mean PhOP was 7.5 ± 3.3 cm H2 O and mean PcritA was 0.80 ± 3.70 cm H2 O. Younger age (Standardized β = -0.191, p = 0.015) and higher BMI (Standardized β = 0.176, p = 0.028) were associated with higher PhOP, but not PcritA . PhOP and PcritA were both associated with AHI, supine AHI, and SpO2 nadir. Higher PhOP was associated with higher snoring scores (Standardized β = 0.246, p = 0.008), but not other patient-reported outcomes. Objective assessment of passive and active airway mechanics during DISE relates with clinical risk factors for OSA. Quantitative measures of collapsibility provide accessible and meaningful data, enhancing the standard sleep surgery evaluation. 4 Laryngoscope, 134:1978-1985, 2024.

A noisy airway: Varying causes for upper airway obstruction in a child

ABSTRACT Noisy breathing is a common symptom in infancy and childhood. It can sometimes be intimidating to the parents and a diagnostic challenge to the treating physician. Causes for a noisy airway include congenital and acquired conditions. They can vary in etiology from self-resolving conditions like laryngomalacia to more sinister entities like malignant tumors. We present a 3-year-old girl who presented with noisy breathing since the age of 6months associated with poor weight gain and chest deformity. Due to persistence of her symptoms, she underwent upper airway evaluation at different time points and was found to have varied causes for her noisy respiration that included airway malacia, pharyngeal wall inspiratory collapse and later adenoidal hypertrophy which was complicated by symptoms suggestive of obstructive sleep apnea. The above three conditions are known to co-exist and can manifest at varied points of time. Since it is unusual to encounter varied causes of upper airway obstruction in the same patient, this case is being presented for its rarity and to highlight the importance of evaluating the upper airway repeatedly if symptoms are persistent, variable or progressive.

A Prospective Study on Obstructive Sleep Apnea, Clinical Profile and Polysomnographic Variables.

Background: Obstructive sleep apnea (OSA) is characterized by recurring episodes of pharyngeal collapse, which can partially or completely block airflow during sleep and cause cardiorespiratory and neurological imbalances. Therefore, the purpose of this study was to assess OSA and the relationship between AHI and polysomnographic characteristics in OSA patients. Methodology: A prospective study was conducted at the Department of Pulmonology and Sleep Medicine for two years. All 216 participants underwent polysomnography, and 175 of them were reported to have OSA (AHI ≥ 5), while 41 of them did not (AHI < 5). ANOVA and Pearson's correlation coefficient test were performed. Results: In terms of the study population's average AHI, Group 1 had 1.69 ± 1.34, mild OSA had 11.79 ± 3.55, moderate OSA had 22.12 ± 4.34, and severe OSA was found to have 59.16 ± 22.15 events/hour. The study group's average age was 53.77 ± 7.19 out of 175 OSA patients. According to AHI, the BMI for mild OSA was 31.66 ± 8.32 kg/m2, for moderate OSA, it was 30.52 ± 3.99 kg/m2, and for severe OSA, it was 34.35 ± 8.22 kg/m2. The average number of oxygen desaturation events and snoring duration were 25.20 ± 18.63 and 24.61 ± 28.53 min, respectively. BMI (r = 0.249, p < 0.001), average oxygen saturation (r = -0.387, p < 0.000), oxygen desaturation (r = 0.661, p < 0.000), snoring time (r = 0.231, p < 0.002), and the number of snores (r = 0.383, p < 0.001) were the polysomnographic variables that showed significant correlations with AHI in the study group. Conclusions: In this study, a substantial prevalence of obesity and a high OSA frequency were found in men. Our research showed that individuals with obstructive sleep apnea experience nocturnal desaturations. Polysomnography is the primary test for early detection of this treatable condition.

0427 Airway Pressures Define Collapsibility of Specific Pharyngeal Sites of Obstruction during Drug-induced Sleep Endoscopy

Abstract Introduction Obstructive sleep apnea (OSA) is characterized by repetitive episodes of pharyngeal obstruction at one or more collapse sites. Multilevel collapse is a negative predictive factor for PAP-alternative surgical treatments. Pharyngeal manometry during drug-induced sleep endoscopy (DISE) permits an objective evaluation of anatomical obstruction sites and mechanisms, and may play a role in patient selection for PAP alternative therapies. We hypothesized that patients with multilevel collapse would have primary velopharyngeal collapse and secondary, downstream sites. Methods This prospective cohort of twenty consecutive patients with diagnosed OSA underwent DISE with nasal airflow monitoring and pharyngeal manometry. Two pressure catheters were placed at the (1) distal margin of the soft palate (Pus) and (2) retroepiglottic space (Pds). We sought to delineate site(s) of collapse by evaluating dissociations in airflow and air pressure during inspiratory flow limitation and/or complete obstruction. The primary site of collapse was defined by the initial segment at which inspiratory airflow and pressure dissociated (the critical pressure, Pcrit). Secondary site(s) were defined as the pressure at which the Pus and/or Pds signals subsequently dissociated (beyond the initial point of maximal flow). Results Twenty-one patients were evaluated of which signal quality and catheter placement in twenty were sufficient for analysis. Participants were elderly (58.3±14.3yrs, mean±SD), overweight (BMI 28.7±2. kg/m2), and had moderate-severe OSA (AHI 28.2±14.2 events/hour). Six patients had a single site of collapse, of which one was naso-palatal (Pcrit -2.6cmH2O) and five were infra-palatal (mean Pcrit -1.3cmH2O). In the patients with multilevel collapse (N=14), all had primary naso-palatal collapse (mean Pcrit 0.17±2.0cmH2O) and secondary infra-palatal sites of collapse (mean Pcrit -11.7±5.8cmH2O). Pcrit differed between the primary and secondary site by 11.9±6.5cmH2O (p&amp;lt; 0.01). Conclusion These findings suggest that single-site pharyngeal collapse is usually infra-palatal. In contrast, multilevel collapse is primarily due to velopharyngeal collapse with varying degrees of instability in downstream pharyngeal segments. When secondary infra-palatal sites readily collapse with minimal additional respiratory effort, laxity of the tongue and/or lateral walls may be strongly implicated in the pathogenesis of pharyngeal obstruction. Future studies can utilize pharyngomanometry to further target specific pharyngeal structures for OSA therapy. Support (if any) National Institutes of Health 1R01HL144859 (PIs: Schwartz, Dedhia)