Influence of Different Flow Conditions via High-flow Nasal Cannula on Laryngeal Vestibule Kinematics During Swallowing in Healthy Adults

Abstract

The purpose of this experimental study was to determine if there were changes in laryngeal vestibule closure timing during swallowing across variable flow conditions via high-flow nasal cannula. Twenty-nine healthy adults participated in a repeated-measures design. Each participant completed a videofluoroscopic swallow study while receiving flow via high-flow nasal cannula across a control condition of zero flow and conditions of 10, 20, 30, 40, 50, and 60 liters per minute (LPM). Durations of laryngeal vestibule closure (dLVC), laryngeal vestibule closure reaction times in relation to the bolus and hyoid as well as Penetration-Aspiration Scale (PAS) scores were extracted for review by five raters. Laryngeal vestibule closure was rated as being complete on all boluses. A linear model approach was used with analysis of variance and regression. Results indicate that flow condition does influence duration of laryngeal vestibule closure, but not laryngeal vestibule closure reaction times. Penetration-Aspiration Scale scores were similar across all flow levels, with the most frequent scores being normal (scores of 1 and 2). No aspiration occurred. Findings refute the theory that high-flow stents the airway open. In fact, duration of laryngeal vestibule closure was longer for higher flow conditions. Longer durations of closure in response to higher flow in this study may indicate normal adaptation in healthy swallowing to maintain airway protection.