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Background: Mechanical insufflation-exsufflation (MI-E) uses positive and negative pressures to assist weak cough and to help clear airway secretions. Laryngeal visualization during MI-E has revealed that inappropriate upper airway responses can impede its efficacy. However, the dynamics of pressure transmission in the upper airways during MI-E are unclear, as are the relationships among anatomic structure, pressure, and airflow., Research Question: Can airflow resistance through the upper airway and the larynx feasibly be calculated during MI-E, and if so, how are the pressures transmitted to the trachea?, Study Design and Methods: Cross-sectional study of 10 healthy adults with and without active cough to whom MI-E was provided, using pressure settings +20/-40 cm H 2 O and ± 40 cm H 2 O. Airflow and pressure at the level of the facemask were measured using a pneumotachograph, whereas pressure transducers (positioned via transnasal fiber-optic laryngoscopy) recorded pressures above the larynx and within the trachea. Upper airway resistance (R uaw ) and translaryngeal resistance (R tl ) were calculated (in centimeters of water per liter per second) and were compared with direct observations via laryngoscopy., Results: Positive pressures reached the trachea effectively, whereas negative tracheal pressures during exsufflation were approximately half of the intended settings. Insufflation pressure increased slightly when passing through the larynx. Participant effort influenced tracheal pressures and the resistances, with findings consistent with laryngoscopic observations. During MI-E, resistance seems to be dynamic, with R uaw exceeding R tl . Inappropriate laryngeal closure increased R tl during both positive and negative pressures., Interpretation: R uaw and R tl can be calculated feasibly during MI-E. The findings indicate different transmission dynamics for positive and negative pressures and that resistances are influenced by participant effort. The findings support using lower insufflation pressures and higher negative pressures in clinical practice., Competing Interests: Financial/Nonfinancial Disclosures None declared., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Objective: Exercise-induced laryngeal obstruction is an important cause of exertional dyspnoea. The diagnosis rests on visual judgement of relative changes of the laryngeal inlet during continuous laryngoscopy exercise (CLE) tests, but we lack objective measures that reflect functional consequences. We aimed to investigate repeatability and normal values of translaryngeal airway resistance measured at maximal intensity exercise., Methods: 31 healthy nonsmokers without exercise-related breathing problems were recruited. Participants performed two CLE tests with verified positioning of two pressure sensors, one at the tip of the epiglottis (supraglottic) and one by the fifth tracheal ring (subglottic). Airway pressure and flow data were continuously collected breath-by-breath and used to calculate translaryngeal resistance at peak exercise. Laryngeal obstruction was assessed according to a standardised CLE score system., Results: Data from 26 participants (16 females) with two successful tests and equal CLE scores on both test sessions were included in the translaryngeal resistance repeatability analyses. The coefficient of repeatability (CR) was 0.62 cmH 2 O·L -1 ·s -1 , corresponding to a CR% of 21%. Mean±sd translaryngeal airway resistance (cmH 2 O·L -1 ·s -1 ) in participants with no laryngeal obstruction (n=15) was 2.88±0.50 in females and 2.18±0.50 in males. Higher CLE scores correlated with higher translaryngeal resistance in females (r=0.81, p<0.001)., Conclusions: This study establishes translaryngeal airway resistance obtained during exercise as a reliable parameter in respiratory medicine, opening the door for more informed treatment decisions and future research on the role of the larynx in health and disease., Competing Interests: Conflict of interest: Z. Fretheim-Kelly has nothing to disclose. Conflict of interest: M. Engan has nothing to disclose. Conflict of interest: H. Clemm declares unpaid roles as the leader of of the Bergen ILO group and chair of subgroup 6 on the upper airway in the IOC consensus of acute respiratory illness in athletes. Conflict of interest: T. Andersen declares funding for the present manuscript from Haukeland University Hospital, as well as research funding from the Western Norway Health Authority (grant number F-12564-D10550) in the 36 months prior to manuscript submission. Conflict of interest: J-H. Heimdal has nothing to disclose. Conflict of interest: E. Strand has nothing to disclose. Conflict of interest: T. Halvorsen declares funding for the present manuscript from Haukeland University Hospital and the University of Bergen, and research funding from the Western Norway Health Authority (grant number F-12564-D10550) in the 36 months prior to manuscript submission. Conflict of interest: O. Røksund declares funding for the present manuscript from Haukeland University Hospital and the Faculty of Health and Social Sciences, Bergen University College,a nd funding from the Western Norway Health Authority (grant number F-12564-D10550) in the 36 months prior to manuscript submission. Conflict of interest: M. Vollsæter declares unpaid fiduciary or leadership roles with WestPaed Research and Project Extreme Prematurity, and that they are a Board member of HelpILO., (Copyright ©The authors 2022.)

Background: Exercise-induced laryngeal obstruction (EILO) is a common cause of exertional breathing problems in young individuals, caused by paradoxical inspiratory adduction of laryngeal structures, and diagnosed by continuous visualization of the larynx during high-intensity exercise. Empirical data suggest that EILO consists of different subtypes, possibly requiring different therapeutic approaches. Currently applied treatments do not rest on randomized controlled trials, and international guidelines based on good evidence can therefore not be established. This study aims to provide evidence-based information on treatment schemes commonly applied in patients with EILO., Methods and Analysis: Consenting patients consecutively diagnosed with EILO at Haukeland University Hospital will be randomized into four non-invasive treatment arms, based on promising reports from non-randomized studies: (A) standardized information and breathing advice only (IBA), (B) IBA plus inspiratory muscle training, (C) IBA plus speech therapy, and (D) IBA plus inspiratory muscle training and speech therapy. Differential effects in predefined EILO subtypes will be addressed. Patients failing the non-invasive approach and otherwise qualifying for surgical treatment by current department policy will be considered for randomization into (E) standard or (F) minimally invasive laser supraglottoplasty or (G) no surgery. Power calculations are based on the main outcomes, laryngeal adduction during peak exercise, rated by a validated scoring system before and after the interventions., Ethics and Dissemination: The study will assess approaches to EILO treatments that despite widespread use, are insufficiently tested in structured, verifiable, randomized, controlled studies, and is therefore considered ethically sound. The study will provide knowledge listed as a priority in a recent statement issued by the European Respiratory Society, requested by clinicians and researchers engaged in this area, and relevant to 5-7% of young people. Dissemination will occur in peer-reviewed journals, at relevant media platforms and conferences, and by engaging with patient organizations and the healthcare bureaucracy., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The reviewer CM declared a shared Committee with one the author J-HH at time of review., (Copyright © 2022 Clemm, Røksund, Andersen, Heimdal, Karlsen, Hilland, Fretheim-Kelly, Hufthammer, Sandnes, Hjelle, Vollsæter, Halvorsen and Bergen ILO-group.)

Background: Bits have often been incriminated as a cause of upper respiratory tract obstruction in horses; however, no scientific studies are available to confirm or refute these allegations. Clinical signs of dynamic laryngeal collapse associated with poll flexion (DLC) are induced when susceptible horses are ridden or driven into the bit., Objective: To determine whether use of Dr Cook's ™ Bitless Bridle, instead of a conventional snaffle bit bridle, would reduce the severity of DLC in affected horses measured objectively using inspiratory tracheal pressures., Study Design: Intervention study using each horse as its own control in a block randomised order., Methods: Nine Norwegian Swedish Coldblooded trotters previously diagnosed with DLC were exercised on two consecutive days using a standardised high-speed treadmill protocol with either a conventional bridle with a snaffle bit, or Dr Cook's ™ Bitless Bridle. Head and neck position, rein tension, inspiratory tracheal pressure measurements, and laryngeal videoendoscopy recordings were obtained. A heart rate greater than 200 bpm, and similar degrees of poll flexion/head height, had to be achieved in both bridles for the individual horse's data to be included for comparison., Results: Seven horses' data met the inclusion criteria. The change in mean inspiratory tracheal pressure between free and flexion phases in the bitless bridle (-15.2 ± 12.3 cmH 2 O) was significantly greater (P < .001) than in the snaffle bit bridle (-9.8 ± 7.9 cmH 2 O). Mean inspiratory pressure during the free phase was significantly (P < .001) more negative with the snaffle bit bridle (-32.3 ± 6.3 cmH 2 O), vs the bitless bridle (-28.5 ± 6.9 cmH 2 O). Mean pressures in flexion phase, snaffle bridle (-42.1 ± 10.8 cmH 2 O), vs bitless bridle (-43.7 ± 15.6 cmH 2 O) where not significantly different between bridles (P = .2)., Main Limitation: Small sample size due to difficulty recruiting suitable clinical cases., Conclusions: This study could not provide any clear evidence that the effect of a snaffle bit in a horse's mouth influences the development or severity of DLC. Instead, head and neck angles induced by rein tension seem to be the key event in provoking DLC in susceptible horses., (© 2020 The Authors. Equine Veterinary Journal published by John Wiley & Sons Ltd on behalf of EVJ Ltd.)

Objectives/hypothesis: To determine if simultaneous tracheal and supraglottic pressure measurement performed during a continuous laryngoscopy exercise (CLE) test is possible, tolerable, and feasible, and if so, whether measurements can be used to determined airflow resistance over the larynx, thus providing an objective outcome measure for the CLE test, the gold standard for diagnosing exercise-induced laryngeal obstruction., Study Design: Explorative descriptive clinical study., Methods: A CLE test was performed with the addition of two pressure sensors (Mikro-Cath 825-0101; Millar, Houston, TX) placed at the epiglottic tip and at the fifth tracheal ring. To place sensors, laryngeal anesthesia and a channel scope were required. Tolerability and feasibility was determined by a Likert score and subjective indication from subjects and operators. Adjustments to the technique were made to increase tolerability. The pressure data were continuously collected and analyzed for artifacts, drifts, frequency response, and used with flow data to calculate translaryngeal resistance., Results: All subjects (n = 7) completed all procedures. Two main areas of concern were identified regarding tolerability: application of topical anesthesia to the larynx and nasal discomfort due to the added diameter of the laryngoscope. Protocol adjustments improved both. Pressure data were obtained from all procedures in all subjects, were consistent, and followed physiological trends., Conclusions: Continuous measurement of the translaryngeal pressure gradient during a CLE test is possible, feasible, and tolerable. A CLE test with direct measurement of the translaryngeal pressure gradient might become a valuable tool in the objective assessment of respiratory function, and normal values should be established in health and disease., Level of Evidence: NA Laryngoscope, 129:2748-2753, 2019., (© 2019 The Authors. The Laryngoscope published by Wiley Periodicals, Inc. on behalf of The American Laryngological, Rhinological and Otological Society, Inc.)