Towards microprocessor-based control of droplet parameters for endoscopic laryngeal adductor reflex triggering

Fast, Jacob Friedemann; Muley, Apurva; Kühn, D.; Meisoll, Frederik J; Ortmaier, Tobias; Jungheim, M.; Ptok, M.; Kahrs, Lüder A.

doi:10.1515/cdbme-2017-0050

Cited by 6 publications

(4 citation statements)

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“…On the technical side, droplet formation stability in MIT‐LAR should be enhanced as formation of satellite droplets was observed in this study. Fluid system pressure should be controlled by an autonomous system to further increase usability 41,42 …”

Section: Discussionmentioning

confidence: 99%

“…Fluid system pressure should be controlled by an autonomous system to further increase usability. 41,42…”

Section: Limitationsmentioning

confidence: 99%

“…Fluid system pressure should be controlled by an autonomous system to further increase usability. 41,42 CONCLUSION A reaction to laryngeal penetration or aspiration is probably composed of a complex pattern of individual reflexive mechanisms from multiple organs. The UES contributes to this pattern by performing a contractile reflex, preventing regurgitation of gastric or esophageal contents, for example, when coughing occurs for airway clearance.…”

Section: Limitationsmentioning

confidence: 99%

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Upper Esophageal Sphincter Response to Laryngeal Adductor Reflex Elicitation in Humans

et al. 2020

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The laryngeal adductor reflex (LAR) is an important mechanism to secure the airways from potential foreign body aspiration. An involvement of the upper esophageal sphincter (UES) in terms of a laryngo-UES contractile reflex has been identified after laryngeal mucosa stimulation. However, the LAR-UES relationship has not yet been fully explained. This study aimed to determine the magnitude, latency, and occurrence rate of the UES pressure response when the LAR is triggered in order to elucidate the functional relationship between the larynx and the UES.Methods: This prospective study included seven healthy volunteers (5 female, 2 male, age 22-34 years). Laryngeal penetration was simulated by eliciting the LAR 20 times in each individual by applying water-based microdroplets onto the laryngeal mucosa. UES pressures were measured simultaneously using high-resolution manometry.Results: Two distinct pressure phases (P1, P2) associated with the LAR were identified. P1 corresponded with a shortterm UES pressure decrease in two subjects and a pressure increase in five subjects occurring 200 to 500 ms after the stimulus. In P2, all subjects experienced an increase in UES pressure with a latency time of approximately 800 to 1700 ms and an average of 40 to 90 mmHg above the UES resting tone.Conclusion: Foreign bodies penetrating the laryngeal inlet lead to a reflex contraction of the UES. Phase P1 could be a result of vocal fold activity caused by the LAR, leading to pressure changes in the UES. The constriction during P2 could strengthen the barrier function of the UES in preparation to a subsequent cough that may be triggered to clear the airways.

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Section: Discussionmentioning

confidence: 99%

“…Fluid system pressure should be controlled by an autonomous system to further increase usability. 41,42…”

Section: Limitationsmentioning

confidence: 99%

Section: Limitationsmentioning

confidence: 99%

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Upper Esophageal Sphincter Response to Laryngeal Adductor Reflex Elicitation in Humans

et al. 2020

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“…A commercially available high-speed laryngoscope was combined with a droplet applicator module to perform Microdroplet Impulse Testing of the LAR (MIT-LAR) [9]. In previous work, a mechatronic system was designed to control droplet formation [5]. An enhanced MIT-LAR laryngoscope with stereoscopic droplet impact site prediction was developed [4].…”

Section: Introductionmentioning

confidence: 99%

An actuated larynx phantom for pre-clinical evaluation of droplet-based reflex-stimulating laryngoscopes

Fast

Ortmaier

et al. 2019

Current Directions in Biomedical Engineering

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The laryngeal adductor reflex (LAR) is an important protective function of the larynx to prevent aspiration and potentially fatal aspiration pneumonia by rapidly closing the glottis. Recently, a novel method for targeted stimulation and evaluation of the LAR has been proposed to enable non-invasive and reproducible LAR performance grading and to extend the understanding of this reflexive mechanism. The method relies on the laryngoscopically controlled application of accelerated water droplets in association with a high-speed camera system for LAR stimulation site and reflex onset latency identification. Prototype laryngoscopes destined for this method require validation prior to extensive clinical trials. Furthermore, demonstrations using a realistic phantom could increase patient compliance in future clinical settings. For these purposes, a model of the human larynx including vocal fold actuation for LAR simulation was developed in this work. The combination of image processing based on a custom algorithm and individual motorization of each vocal fold enables spatio-temporal droplet impact detection and controlled vocal fold adduction. To simulate different LAR pathologies, the current implementation allows to individually adjust the reflex onset latency of the ipsi- and contralateral vocal fold with respect to the automatically detected impact location of the droplet as well as the maximum adduction angle of each vocal fold. An experimental study of the temporal offset between desired and observed LAR onset latency due to image processing was performed for three average droplet masses based on highspeed recordings of the phantom. Median offsets of 100, 120 and 128 ms were found (n=16). This offset most likely has a multifactorial cause (image processing delay, inertia of the mechanical components, droplet motion). The observed offset increased with increasing droplet mass, as fluid oscillations after impact may have been detected as motion. In future work, alternative methods for droplet impact detection could be explored and the observed offset could be used for compensation of this undesirable delay.

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Towards Fully Automated Determination of Laryngeal Adductor Reflex Latencies through High-Speed Laryngoscopy Image Processing

Fast

Ptok

Jungheim

et al. 2018

Bildverarbeitung Für Die Medizin 2018

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Towards microprocessor-based control of droplet parameters for endoscopic laryngeal adductor reflex triggering

Cited by 6 publications

References 2 publications

Upper Esophageal Sphincter Response to Laryngeal Adductor Reflex Elicitation in Humans

Upper Esophageal Sphincter Response to Laryngeal Adductor Reflex Elicitation in Humans

An actuated larynx phantom for pre-clinical evaluation of droplet-based reflex-stimulating laryngoscopes

Towards Fully Automated Determination of Laryngeal Adductor Reflex Latencies through High-Speed Laryngoscopy Image Processing

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