Assessing respiratory airflow unsteadiness under different tidal respiratory frequencies using large eddy simulation method.

Unsteady respiratory airflow characteristics play a crucial role in understanding the deposition of toxic particles and inhaled aerosol drugs in the human respiratory tract. Considering the variations in respiratory flow rate and glottis motion under different respiratory frequencies, these respiratory airflow characteristics are studied by large-eddy simulations, including pressure field, power loss, modal spatial patterns, and vortex structures. Firstly, the results reveal that varying respiratory frequencies significantly affect airflow unsteadiness, turbulent evolution, and vortex structure dissipation, as they increase the complexity and butterfly effect introduced by the turbulent disturbance. Secondly, the pressure drops and flow rate at the glottis also conform to a power-law relationship considering the respiratory physiological characteristics, especially under low respiratory frequencies. Glottis motion plays different roles in energy consumption during inspiration and expiration, and its magnitude can be predicted using a polynomial function based on glottis area and respiratory flowrate under different respiratory frequencies. Finally, modal decomposition can be effectively applied to the study of respiratory flow characteristics, but we recommend separately studying the inspiration and expiration. The spatial distribution of the dominant mode characterizes the majority of respiratory flow characteristics and are influenced by respiratory frequency. Spectral entropy results indicate that glottis motion and slow breathing both delay the transitions in the upper respiratory tract during inspiration and expiration. These results confirm that the respiratory physiology characteristics under different respiratory frequencies have a significant impact on the unsteady respiratory airflow characteristics and warrant further study.

To compare the efficacy of the between-the-fingers grip with the conventional pen-holding grip to hold an endotracheal tube for orotracheal intubation: A randomised controlled trial.

Background and Aims: Correctly holding the endotracheal tube (ETT) is essential for successful tracheal intubation. The study's primary objective was to compare the between-the-fingers grip with the conventional pen-holding grip regarding the number of attempts required for orotracheal intubation and usage of external aids. Methods: Three hundred patients undergoing elective surgeries under general anaesthesia were randomised according to the method to hold the ETT to Group C (conventional grip) and Group M (modified, between-the-fingers grip) during oro-tracheal intubation. A designated anaesthetist blinded to the groups performed laryngoscopy in all the patients, and difficult Cormack-Lehane grade 3b and 4 (n = 24) were excluded. Then, the group was revealed to the anaesthetist, and intubation was done accordingly; the number of attempts, use of backward upward rightward pressure (BURP), and time taken were noted. The sample size was estimated using the software G*Power version 3.1.9.2. Statistical Package for Social Sciences, version 23 (SPSS-23, IBM, Chicago, USA) was used for data analysis. Results: Single-attempt intubation was comparable between the groups (99.3% versus 97.2%, P = 0.197). In contrast, the external assistance as BURP (0.75% versus 6.99%, P = 0.009) and the time taken for intubation (P = 0.008) were reduced in group M significantly. Conclusion: The between-the-fingers grip seems as effective as the standard grip to hold the ETT during intubation. However, it proved to be better as it can reduce the requirement for external assistance in BURP.

Deep Learning-Based Detection of Glottis Segmentation Failures.

Medical image segmentation is crucial for clinical applications, but challenges persist due to noise and variability. In particular, accurate glottis segmentation from high-speed videos is vital for voice research and diagnostics. Manual searching for failed segmentations is labor-intensive, prompting interest in automated methods. This paper proposes the first deep learning approach for detecting faulty glottis segmentations. For this purpose, faulty segmentations are generated by applying both a poorly performing neural network and perturbation procedures to three public datasets. Heavy data augmentations are added to the input until the neural network's performance decreases to the desired mean intersection over union (IoU). Likewise, the perturbation procedure involves a series of image transformations to the original ground truth segmentations in a randomized manner. These data are then used to train a ResNet18 neural network with custom loss functions to predict the IoU scores of faulty segmentations. This value is then thresholded with a fixed IoU of 0.6 for classification, thereby achieving 88.27% classification accuracy with 91.54% specificity. Experimental results demonstrate the effectiveness of the presented approach. Contributions include: (i) a knowledge-driven perturbation procedure, (ii) a deep learning framework for scoring and detecting faulty glottis segmentations, and (iii) an evaluation of custom loss functions.

A Comparison of Miller Straight Blade and Macintosh Blade Laryngoscopes for Intubation in Morbidly Obese Patients.

The primary objective of this study was to demonstrate whether the Miller blade laryngoscope could provide better visualization of the vocal cords in morbidly obese patients than the Macintosh blade laryngoscope. The secondary objective was to identify the patient-measured factors associated with better visualization of the vocal cords when using the Miller vs. Macintosh blade, as well as whether the application of external pressure might improve the visibility of the glottis during intubation. A prospective, observational study encompassing 110 patients with a BMI > 40 undergoing elective bariatric surgery and intubation procedure was performed. The evaluation of the vocal cords was performed according to the Cormack-Lehane scale and POGO scale in the same patient during intubation, performed with a Miller and a Macintosh blade laryngoscope, in a random matter. The following parameters were assessed: body weight, height, BMI, neck circumference, thyromental distance, sternomental distance, mouth opening, and Mallampati scale and their impact on visualization of the vocal cords using the Miller blade without the application of external pressure. The Miller blade provides an improved view of the glottis compared to the Macintosh blade measured with both the Cormac-Lehane scale (45 (40.91%) without external pressure application on the larynx, and 18 (16.36%) with external pressure application on the larynx) and the POGO scale (45 (40.91%) without external pressure application on the larynx, and 19 (17.27%) with external pressure application on the larynx). The application of laryngeal pressure improved the view of the glottis. Among the measured features, a significant improvement in the visibility of the glottis could be found in patients with a BMI over 44.244 kg/m2 and a neck circumference over 46 cm. To conclude, the usage of the Miller blade improves the visibility of the glottis compared to the Macintosh blade in morbidly obese patients. The recommendation to use the Miller blade in this group of patients requires further investigation, taking into account the effectiveness of the intubation. Trial Registration: NCT05494463.

Scale resolving simulations of the effect of glottis motion and the laryngeal jet on flow dynamics during respiration.

BACKGROUND AND OBJECTIVE: The movement of the respiratory walls has a significant impact on airflow through the respiratory tract. The majority of computational fluid dynamics (CFD) studies assume a static geometry which may not provide a realistic flow field. Furthermore, many studies use Reynolds Averaged Navier-Stokes (RANS) turbulence models that do not resolve turbulence structure. Combining the application of advanced scale-resolving turbulence models with moving respiratory walls using CFD will provide detailed insights into respiratory flow structures. METHODS: This study simulated a complete breathing cycle involving inhalation and exhalation in a nasal cavity to trachea geometry that incorporated moving glottis walls. A second breathing cycle was simulated with static glottis walls for comparison. A recently developed hybrid RANS-LES turbulence model, the Stress-Blended Eddy Simulation (SBES), was incorporated to resolve turbulent flow structures in fine detail for both transient simulations. Transient results were compared with steady-state RANS simulations for the same respiratory geometry. RESULTS: Glottis motion caused substantial effects on flow structure through the complete breathing cycle. Significant flow structure and velocity variations were observed due to glottal motion, primarily in the larynx and trachea. Resolved turbulence structures using SBES showed an intense mixing section in the glottis region during inhalation and in the nasopharynx during expiration, which was not present in the RANS simulations. CONCLUSION: Transient simulations of a realistic breathing cycle uncovered flow structures absent in simulations with a constant flow rate. Furthermore, the incorporation of glottis motion impacted airflow characteristics that suggest rigid respiratory walls do not accurately describe respiratory flow. Future research in respiratory airflow should be conducted using transient scale-resolving models in conjunction with moving respiratory walls to capture flow structures in detail.

Clinical and Anatomical Variation During Assessment of Maximum Glottic Angle.

INTRODUCTION: Quantitative measurement and analysis of glottic abduction is used to assess laryngeal function and success of interventions; however, the consistency of measurement over time has not been established. This study assesses the consistency of glottic abduction measurements across visits in healthy patients and anatomic factors impacting these measurements. METHODS: Review of patients with two sequential flexible stroboscopic exams over seven months from 2019-2022. Images of maximal glottic abduction were captured and uploaded into and measured with ImageJ. Cadaver heads were used to assess the impact of visualization angles on glottic measurements with a monofilament inserted into the supraglottis of each cadaver as a point of reference. Comparisons were done with a paired T-test, T-test, or Mann-Whitney U test as appropriate. RESULTS: Fifty-nine patients and twenty-six cadaveric exams were included. Absolute change in maximum glottic abduction angle (MGAA) was 6.90° (95% CI [5.36°, 8.42°]; p < 0.05). There were no significant differences in change in MGAA by gender or age. Twenty percent of patients had a change of at least 25% in their MGAA between visits. Absolute differences in glottic angle between nasal side for cadaveric measurements was 4.77 ± 4.59° (p < 0.005)-2.22° less than the change in MGAA seen over time (p = 0.185). CONCLUSION: Maximal glottic abduction angles varied significantly between visits. Factors considered to be contributing to the differences include different viewing windows between examinations due to the position and angulation of the laryngoscope and changes in patient positioning, intra- and inter-rater variations in measurement, and patient effort. LEVEL OF EVIDENCE: N/a Laryngoscope, 134:2793-2798, 2024.

Outcome of radiotherapy for the treatment of laryngeal squamous cell carcinoma in the very elderly population.

BACKGROUND: Treatment selection for squamous cell carcinoma patients aged over 84 years is controversial. This retrospective chart review examined and compared characteristics of laryngeal squamous cell carcinoma in very elderly (over 84 years) and younger patients (approximately 65 years). The secondary objective was to further evaluate the outcome of radiotherapy as a treatment modality in this patient population. METHODS: Of all 23 very elderly patients with laryngeal squamous cell carcinoma treated with radiotherapy, with or without surgery, in the Davidoff Cancer Center, from 1992 to 2012, 19 had sufficient data for analysis, and comprised the study group. RESULTS: Median age at diagnosis was 86 years. Disease stage at diagnosis was I, II, III and IVA in 53 per cent, 21 per cent, 21 per cent and 5 per cent, respectively. Median radiotherapy dose was 60 Gy given in 25 fractions. Three patients had recurrence. No patient discontinued treatment because of toxicity. Median overall survival was 3.6 years (range, 0-10 years). CONCLUSION: Very elderly laryngeal squamous cell carcinoma patients may derive a similar survival advantage as younger counterparts. Modern radiotherapy is effective and safe for treating laryngeal squamous cell carcinoma in this study population. Further, large-scale studies are needed.

Accelerated three-dimensional conformal radiotherapy for early-stage glottic cancer in reducing dose to the internal carotid artery and pharyngeal constrictor muscles.

BACKGROUND: We evaluated clinical and dosimetric outcomes of radiotherapy using two anterior oblique portals (AOP), to reduce the dose to the bilateral internal carotid arteries (CAs) and pharyngeal constrictor muscle (PCM) during early-stage glottic cancer (ESGC) treatment. METHODS: We identified patients with ESGC who underwent definitive radiotherapy between June 2014 and May 2020. RESULTS: Among the 66 patients, 32 (48%) underwent radiotherapy using AOP, and the remaining underwent typical radiotherapy using parallel opposed lateral portals (POLP). The median follow-up duration was 53 months. No significant differences were observed in the 5-year local failure (0%/9.4%), progression-free survival (90.6%/90.8%), and overall survival (90.6%/91.0%) rates between the two groups. The grade ≥2 acute mucositis incidence rate was significantly lower in the AOP group (44%/85%). Radiotherapy using AOP maintained an adequate dose coverage to the target while markedly reducing the CAs and PCM doses. CONCLUSION: Radiotherapy with AOP resulted in favorable clinical and dosimetric outcomes.

Closed- or open-glottis pushing for vaginal delivery: a planned secondary analysis of the TRAnexamic Acid for Preventing postpartum hemorrhage after vaginal delivery study.

BACKGROUND: The effect on obstetrical outcomes of closed- or open-glottis pushing is uncertain among both nulliparous and parous women. OBJECTIVE: This study aimed to assess the association between open- or closed-glottis pushing and mode of delivery after an attempted singleton vaginal birth at or near term. STUDY DESIGN: This was an ancillary planned cohort study of the TRAAP (TRAnexamic Acid for Preventing postpartum hemorrhage after vaginal delivery) randomized controlled trial, conducted in 15 French maternity units from 2015 to 2016 that enrolled women with an attempted singleton vaginal delivery after 35 weeks' gestation. After randomization, characteristics of labor and delivery were prospectively collected, with special attention to active second-stage pushing and a specific planned questionnaire completed immediately after birth by the attending care provider. The exposure was the mode of pushing, classified into 2 groups: closed- or open-glottis. The main endpoint was operative vaginal delivery. Secondary endpoints were items of maternal morbidity, including severe perineal laceration, episiotomy, postpartum hemorrhage, duration of the second stage of labor, and a composite severe neonatal morbidity outcome. We also assessed immediate maternal satisfaction, experience of delivery, and psychological status 2 months after delivery. The associations between mode of pushing and outcome were analyzed by multivariate logistic regression to control for confounding bias, with multilevel mixed-effects analysis, and a random intercept for center. RESULTS: Among 3041 women included in our main analysis, 2463 (81.0%) used closed-glottis pushing and 578 (19.0%) open-glottis pushing; their respective operative vaginal delivery rates were 19.1% (n=471; 95% confidence interval, 17.6-20.7) and 12.5% (n=72; 95% confidence interval, 9.9-15.4; P<.001). In an analysis stratified according to parity and after controlling for available confounders, the rate of operative vaginal delivery did not differ between the groups among nulliparous women: 28.7% (n=399) for the closed-glottis and 27.5% (n=64) for the open-glottis group (adjusted odds ratio, 0.93; 95% confidence interval, 0.65-1.33; P=.7). The operative vaginal delivery rate was significantly lower for women using open- compared with closed-glottis pushing in the parous population: 2.3% (n=8) for the open- and 6.7% (n=72) for the closed-glottis groups (adjusted odds ratio, 0.43; 95% confidence interval, 0.19-0.90; P=.03). Other maternal and neonatal outcomes did not differ between the 2 modes of pushing among either the nulliparous or parous groups. CONCLUSION: Among nulliparous women with singleton pregnancies at term, the risk of operative vaginal birth did not differ according to mode of pushing. These results will inform shared decision-making about the mode of pushing during the second stage of labor.

Effects of vocal fold lesions on particle deposition in a mouth-throat model: A numerical study.

OBJECTIVE: Dysphonia is very common worldwide and aerosol drug inhalation is an important treatment for patients with dysphonia. This study aimed to explore the effects of vocal fold (VF) lesions on the particle deposition pattern using computational modeling. METHODS: A realistic mouth-throat (MT) model of a healthy adult was constructed based on computed tomography images. Small and large vocal fold lesions were incorporated in the original model. A steady inhalation flowrate of 15 and 30 liter per minute (LPM) was used as the velocity inlet and monodisperse particles with diameters of 5 to 10 µm were simulated. RESULTS: Particles of larger size are more likely to be deposited in MT models, most of them distributed in oral cavity, oropharynx and supraglottis. The ideal sizes at 30 LPM ranged over 7-10 µm for healthy VFs and 6-8 µm for VF lesions. The best sizes at 15 LPM ranged over 6-8 µm for healthy VFs and 8-9 µm for VF lesions. CONCLUSION: Based on this study, VF lesions influence the deposition pattern in the glottis obviously. The ideal sizes differ at the flow rates of 15 and 30 LPM.

[Update on manual bronchial clearance techniques (adults and adolescents)]. / Mise au point sur les techniques manuelles de désencombrement bronchique (adultes et adolescents).

In adults and teenagers, airway clearance physiotherapy techniques (ACPT) are various and numerous. However, they for still awaiting scientific validation. Among ACPTs, Slow Expiration with the Glottis Opened in the Lateral Posture (ELTGOL), Autogenic Drainage (DA), and Active Cycling Breathing Technique (ACBT) present a Grade B level of evidence with weak recommendations. Even though these maneuvers are widely applied, precise description of chest physiotherapy (CP) is largely absent from the scientific literature; it is difficult to standardize its implementation and reproduce the results; scientific validation and faithful execution of the techniques are consequently problematic. In this paper, the authors aim to depict each of the three CP techniques as precisely as possible; with this in mind, graphic modeling of the different respiratory exercises is presented in such a way that they can be easily learned, applied and reproduced by physiotherapists.

The neonatal airway.

Safe and effective management of the neonatal airway requires knowledge, teamwork, preparation and experience. At baseline, the neonatal airway can present significant challenges to experienced neonatologists and paediatric anaesthesiologists, and increased difficulty can be due to anatomical abnormalities, physiological instability or increased situational stress. Neonatal airway obstruction is under recognised, and should be considered an emergency until the diagnosis and physiological implications are understood. When multiple types of difficulties are present or there are multiple levels of anatomical obstruction, the challenge increases exponentially. In these situations, preparation, multi-disciplinary teamwork and a consistent hospital-wide approach will help to reduce errors and morbidity.

Comparative evaluation of C-MAC and McGrath MAC videolaryngoscopes with Macintosh direct laryngoscope for endotracheal intubation in adult patients undergoing elective surgeries.

Background and Aims: Videolaryngoscopes have an undisputed role in difficult airway management, but their role in routine intubation scenarios remains underappreciated. McGrath MAC is a lightweight laryngoscope with a disposable blade. It remains to be proven if it performs as efficiently as the reusable videolaryngoscopes like C-MAC and whether it has an advantage over standard Macintosh laryngoscope in predicted normal airways. Material and Methods: We recruited 180 adult patients and randomly divided them into three groups for intubation with either Macintosh laryngoscope (Group-A), C-MAC (Group-B), and McGrath (Group-C). The primary objective was to compare the first attempt success rate. Secondary objectives included Cormack-Lehane (CL) grades, laryngoscopy time, intubation time, ease of intubation, need for optimization manoeuver, and the number of passes to place the endotracheal tube. Results: The two videolaryngoscopes provided a superior first attempt success rate as compared to Macintosh laryngoscope (P = 0.027). The CL grade-I was 100% in group B, 41.7% in group-A and 90% in group-C (B vs C; P = 0.037). Laryngoscopy time was 9.9 ± 2.5 s, 12.6 ± 0.8 s, and 13.1 ± 0.8 s for groups A, B, and C, respectively (B vs C; P = 0.001). Intubation time was 24.4 ± 12 s, 28.3 ± 1.9 s, and 37.3 ± 5.8 s for groups A, B, and C, respectively (P < 0.0001). The number of tube passes was highest in group C. Conclusion: Videolaryngoscopes provided a superior glottic view and resulted in a superior first attempt success rate as compared to Macintosh laryngoscope. When comparing the two videolaryngoscopes, C-MAC resulted in better intubation characteristics (shorter intubation time, better glottic views, and higher first-attempt success rates) and should be preferred over McGrath for intubation in adult patients with normal airways.

Horizontal middle partial laryngectomy with cricothyroidopexy: an effective treatment for stage T1b glottic carcinoma.

BACKGROUND: The current treatment options for T1b glottic carcinoma often lead to poor treatment outcomes or voice quality. OBJECTIVES: This study evaluates the therapeutic efficacy of horizontal middle partial laryngectomy with cricothyroidopexy (HMPL-CTP) for stage T1b glottic carcinoma. MATERIAL AND METHODS: A retrospective analysis was conducted on 73 patients with T1b glottic carcinoma. The patients were categorized into three groups: Group A (n = 22) underwent transoral laser microsurgery (TLMS), Group B (n = 21) received frontolateral vertical partial laryngectomy (FVPL), and Group C (n = 30) underwent HMPL-CTP. The study analyzed the 5-year overall survival rate (OS), recurrence rate, phonatory status, and incidence of laryngeal stenosis. RESULTS: Voice quality scores varied significantly in the three groups, while the 5-year OS were similar. The local recurrence rate is higher in Group A than in the other two groups. The laryngeal stenosis rate in Group B is higher than in Groups A and C. Adhesions in the anterior commissure were observed in 18 cases in Group A and nine cases in Group C. CONCLUSIONS AND SIGNIFICANCE: HMPL-CTP demonstrates efficacy as a treatment for stage T1b glottic carcinoma, offering favorable preservation of laryngeal function and minimal complications.

Effects of vocal fold adduction on the particle deposition in the glottis: A numerical analysis and in vitro assessment.

BACKGROUND: The efficacy of inhalation therapy depends on the drug deposition in the human respiratory tract. This study investigates the effects of vocal fold adduction on the particle deposition in the glottis. METHODS: A realistic mouth-throat (MT) geometry was built based on CT images of a healthy adult (MT-A). Mild (MT-B) and great (MT-C) vocal fold (VF) adduction were incorporated in the original model. Monodisperse particles range in size from 3 to 12 µm were simulated at inspiration flow rates of 15, 30 and 45 L per minute (LPM). The regional deposition of drug aerosols was performed in 3D-printed models and quantified using high-performance liquid chromatography. RESULTS: Both the numerical analysis and in vitro experiments show that most particles are deposited in the mouth, pharynx and supraglottis, while few are deposited in the glottis and subglottis. For most cases in MT-A, the particle quantity in glottis is lower than 0.02 N/mm2 at 15 and 30 LPM while they increase dramatically at 45 LPM. It peaked at 0.347 N/mm2 for 5-µm particles at 45 LPM in MT-B and 2.324 N/mm2 for 6-µm particles at 30 LPM in MT-C. The lowest drug mass faction in the glottis in vitro were found at 15 LPM for MT-A and MT-C, and at 30 LPM for MT-B, whereas it peaked at 45 LPM for all MT models, 0.71% in MT-A, 1.16% in MT-B, and 2.53% in MT-C, respectively. CONCLUSION: Based on the results of this study, larger particles are more likely to be deposited in the oral cavity, oropharynx, and supraglottis than in the glottis. However, particle deposition in the glottis generally increases with VF adduction and greater inspiratory flow rates.

Acquisition of the feature [+spread glottis] in Icelandic.

The feature [+spread glottis] ([+s.g.]) denotes that a speech sound is produced with a wide glottal aperture with audible voiceless airflow. Icelandic is unusual in the degree to which [+spread glottis] is involved in the phonology: in /h/, pre-aspirated and post-aspirated stops, voiceless fricatives and voiceless sonorants. The ubiquitousness of the feature could potentially affect the rate and process of its acquisition. This paper investigates the development of [+s.g.] in Icelandic, both in general and in a range of contexts, in a cross-sectional study of 433 typically developing Icelandic-speaking children aged two to seven years. As a feature, [+s.g.] is acquired early in Icelandic, although specific sound classes lag behind due to other output constraints. Children reach mastery of [+s.g.] by age three except in word-initial post-aspirated stops and voiceless nasals. Findings are interpreted in light of the literature on the feature and its development.

[The consensus among experts on the diagnosis and treatment of pediatric vocal cord paralysis].

Pediatric vocal ford paralysis is a vocal cord movement disorder caused by damage to the pediatric laryngeal motor nerves.It is mainly characterized by voice, breathing,and swallowing difficulties,and in severe cases,it can lead to choking in affected children. Currently, the diagnosis and treatment of this condition pose a significant challenge for pediatric otolaryngologists, as the goal is to minimize damage to the vocal folds and laryngeal framework.In order to standardize the diagnosis and treatment of pediatric vocal cord paralysis, the Pediatric Otolaryngology Committee of the Chinese Medical Association,in collaboration with multiple children's medical centers nationwide, have formulated this consensus document.

Direct versus indirect epiglottis elevation in cervical spine movement during videolaryngoscopic intubation under manual in-line stabilization: a randomized controlled trial.

BACKGROUND: During videolaryngoscopic intubation, direct epiglottis elevation provides a higher percentage of glottic opening score than indirect epiglottis elevation. In this randomized controlled trial, we compared cervical spine movement during videolaryngoscopic intubation under manual in-line stabilization between the two glottis exposure methods. METHODS: Videolaryngoscopic intubation under manual in-line stabilization was performed using C-MAC® D-blade: direct (n = 51) and indirect (n = 51) epiglottis elevation groups. The percentage of glottic opening score was set equally at 50% during videolaryngoscopic intubation in both groups. The primary outcome measure was cervical spine movement during videolaryngoscopic intubation at the occiput-C1, C1-C2, and C2-C5. The secondary outcome measures included intubation performance (intubation success rate and intubation time). RESULTS: Cervical spine movement during videolaryngoscopic intubation was significantly smaller at the occiput-C1 in the direct epiglottis elevation group than in the indirect epiglottis elevation group (mean [standard deviation] 3.9 [4.0] vs. 5.8 [3.4] °, P = 0.011), whereas it was not significantly different at the C1-C2 and C2-C5 between the two groups. All intubations were successful on the first attempt, achieving a percentage of glottic opening score of 50% in both groups. Intubation time was longer in the direct epiglottis elevation group (median [interquartile range] 29.0 [24.0-35.0] vs. 22.0 [18.0-27.0] s, P < 0.001). CONCLUSIONS: When performing videolaryngoscopic intubation under manual in-line stabilization, direct epiglottis elevation can be more beneficial than indirect epiglottis elevation in reducing cervical spine movement during videolaryngoscopic intubation at the occiput-C1. TRIAL REGISTRATION: Clinical Research Information Service (number: KCT0006239, date: 10/06/2021).

Difficult glottis: Diagnostic dilemma in viewof the clinical presentation.

<br><b>Introduction:</b> The taxonomy of vocal fold lesions has been refined, and it serves as a common descriptive language for diagnosis, treatment algorithms, and reporting of outcomes. However, we observe rare cases when numerous pathologies overlap, resulting in an unclear and complicated clinical presentation of the glottis.</br> <br><b>Aim:</b> The aim of this paper is to present cases of overlapping etiopathological factors which poses a challenge when making a diagnosis and referring a patient for adequate treatment.</br> <br><b>Material and method:</b> The study presents different photographs of the glottis, including some unique and unusual images in which overlapping pathologies were captured. The photographs are accompanied by case descriptions, comments, and pathological analyses.</br> <br><b>Results:</b> Four selected photographs showed a bunch of exophytic growth lesions with foci of whitish plaques, covered by yellowish crusts, with thinned, reddened vocal folds presenting foci of leukoplakia. The study discussed possible causes of vocal folds edema, diffuse erythema, presence of crusts or exudate, whitish debris/plaques or development of leukoplakia, non-neoplastic ulceration, as well as injected and reddened mucous membrane. Chronic infectious laryngitis, idiopathic ulcerative laryngitis, and drug-induced laryngitis were also mentioned. The study also raised the issues concerning diabetics and patients treated with inhaled corticosteroids, including candidiasis and primary aspergillosis of the larynx.</br> <br><b>Conclusions:</b> To conclude, everyday clinical practice involves encountering cases of unclear onset and course, with complicated presentation of the glottis. Therefore, comprehensive history-taking and thorough investigation of systemic causes are of immense importance. Recommended management includes conducting the most meticulous differential diagnosis, implementing treatment for the most likely cause, and, whenever possible, refraining from biopsy in order to avoid permanent damage to vocal cords.</br>.

Acoustic correlates of Burmese voiced and voiceless sonorants.

Voiceless sonorant consonants are typologically rare segments, appearing in only a few of the world's languages, including Burmese. In this study, Burmese sonorants and their adjacent vowels are investigated in an attempt to (1) determine what acoustic correlates distinguish voiced and voiceless sonorants and (2) determine whether there are multiple realizations of voiceless sonorants and, if so, establish what acoustic correlates distinguish them. In order to pursue these questions, a production study was carried out and target words were analyzed, demonstrating that Burmese voiceless sonorants have a spread glottis period resulting in turbulent airflow 78 % of the time. Findings from linear mixed-effects models showed that voiced and voiceless sonorants are significantly different in terms of duration of the sonorant, F0 of the sonorant, and strength of excitation measured over the following vowel. A linear discriminant analysis was able to predict voicing category with 86.7 % accuracy, with the duration of the spread glottis period being the best indicator of voicelessness, followed by the cues that were significant in the linear mixed-effects models. In cases when the spread glottis period is absent from voiceless sonorants, the sonorant only has correlates that are associated with voicelessness (such as F0 and strength of excitation) but not correlates that are associated with the spread glottis gesture (such as duration and harmonics-to-noise ratio). These results have implications both for our understanding of the acoustics of Burmese sonorants and for our understanding of voiceless sonorants more generally.