Is trans-laryngeal ultrasound (TLUS) a useful tool in the assessment of inducible laryngeal obstruction? Heathy volunteer data

<bold>Background:</bold> Inducible laryngeal obstruction (ILO) is a narrowing of the larynx during inspiration. ILO is misidentified and mis-treated as asthma, with high associated morbidity and healthcare cost. The current reference-standard assessment tool for ILO is laryngoscopy. This is invasive and may be poorly tolerated. The cost and access to skilled personnel may impact on timely accessibility to laryngoscopy. <bold>Aim and Methods:</bold> We aimed to determine if mimicked ILO can be visualised using translarygeal ultrasound (TLUS) to acquire early data regarding potential of TLUS as a less invasive diagnostic screening tool for ILO. Thirty healthy volunteer participants without ILO; (mean age 40; 77% female) underwent TLUS following a protocol (Slinger 2024). Settings for successful visualisation for each participant were noted. Participants were asked to mimic ILO after instruction. <bold>Results:</bold> Using baseline US settings, vocal folds could be accurately visualised in 17 participants. US settings were changed to improve visualisation for the 13 non-visualised participants, leading to success for all 30 participants. 29/30 could mimic clinical signs of ILO. Using TLUS, mimicked ILO could be visualised in 28 (97%) participants. <bold>Conclusion:</bold> This study will inform further study of the utility of TLUS to assess ILO, e.g., as an early screening tool or non-invasive option for patients who cannot tolerate or access laryngoscopy. Diagnostic test accuracy studies using concurrent laryngoscopy and ultrasound, and enquiry into patient acceptability are needed to help ascertain the diagnostic capability and, acceptability of TLUS.