Computational Modelling of Cough Function and Airway Penetrant Behavior in Patients with Disorders of Laryngeal Function.

Objective/hypothesis: Patients with laryngeal disorders often exhibit changes to cough function contributing to aspiration episodes. Two primary cough variables (peak cough flow: PCF and compression phase duration: CPD) were examined within a biomechanical model to determine their impact on characteristics that impact airway compromise.

Study Design: Computational study.

Methods: A Computational Fluid Dynamics (CFD) technique was used to simulate fluid flow within an upper airway model reconstructed from patient CT images. The model utilized a finite-volume numerical scheme to simulate cough-induced airflow, allowing for turbulent particle interaction, collision, and break-up. Liquid penetrants at 8 anatomical release locations were tracked during the simulated cough. Cough flow velocity was computed for a base case and four simulated cases. Airway clearance was evaluated through assessment of the fate of particles in the airway following simulated cough.

Results: Peak-expiratory phase resulted in very high airway velocities for all simulated cases modelled. The highest velocity predicted was 49.96 m/s, 88 m/s, and 117 m/s for Cases 1 and 3, Base case, and Cases 2 and 4 respectively. In the base case, 25% of the penetrants cleared the laryngeal airway. The highest percentage (50%) of penetrants clearing the laryngeal airway are observed in Case 2 (with -40% CPD, +40% PCF), while only 12.5% cleared in Case 3 (with +40% CPD, -40% PCF). The proportion that cleared in Cases 1 and 4 was 37.5%.

Conclusion: Airway modelling may be beneficial to the study of aspiration in patients with impaired cough function including those with upper airway and neurological diseases. It can be used to enhance understanding of cough flow dynamics within the airway and to inform strategies for treatment with "cough-assist devices" or devices to improve cough strength.

Level Of Evidence: N/A.