Laryngeal ultrasound to visualize laryngeal movements during mechanically assisted cough in healthy volunteers

<bold>Introduction:</bold> Transnasal fiberoptic laryngoscopy (TFL) has uncovered that mechanical insufflation-exsufflation (MI-E), a method used to aid weak cough, may trigger laryngeal adduction, obstructing treatment efficacy. TFL allows for titration of optimal individual settings in challenging patients. Still, its invasive nature has spurred the exploration of non-invasive alternatives. <bold>Objective:</bold> Evaluate if laryngeal point of care ultrasound (L-POCUS) can substitute TFL for visualization of laryngeal responses to MI-E. <bold>Methods:</bold> Thirty healthy adults performed MI-E sessions with active cough and without active cough (i.e. passive), using pressure settings of ±40 cmH₂O. Simultaneous TFL and L-POCUS (applying anterior and both lateral approaches) were performed, followed by participants rating their experiences to the TFL, L-POCUS and MI-E using Numeric Rating Scale (NRS) 0-10. Laryngeal visualization rates were calculated for a preplanned number of breaths. <bold>Results:</bold> Thirty participants (19 females) were enrolled, all of whom took part in the assessment of passive MI-E, after which one was excluded due to retching, leaving 29/30 participants for the assessment of active MI-E. All participants could be visualized with at least one L-POCUS approach. The visualization rates for all breaths for TFL and L-POCUS for passive MI-E were 94.1% and 67.4%, respectively, and for active MI-E the figures were 93.0% and 77.0%, respectively. Median NRS scores were 1.5 for TFL, zero for L-POCUS, and 2.0 for MI-E. <bold>Conclusion:</bold> L-POCUS presents as an alternative to TFL for assessing laryngeal movements during MI-E in patients difficult to treat. Further validation of clinical utility is warranted.