Swallowing function during high-flow nasal cannula therapy

Abstract

Background and Objective: High-flow nasal cannula therapy is used as a noninvasive treatment for respiratory disease. The safety of swallowing during the high-flow nasal cannula therapy has not been reported. The purpose of this study was to assess the effect of high-flow nasal cannula therapy on swallowing function.

Methods: Thirty-two healthy subjects underwent high-flow nasal cannula therapy at different flow rates chosen at random (0, 10, 20, 30, 40, and 50 L/min). All subjects underwent the 30-mL water swallow test (WST) and the repetitive saliva swallowing test (RSST) during use of the high-flow nasal cannula. Difficulty swallowing water during the WST was evaluated using a visual analog scale. The swallowing time and number of swallows in 30 seconds were evaluated during the RSST.

Results: In the WST, five subjects (15.6%) choked at flow rates of 40 and 50 L/min (p < 0.05). A flow rate of > 20 L/min was lower number of swallows during the RSST and greater difficulty swallowing than a flow rate of 0 L/min (p < 0.05). The change in the swallowing time was significantly associated with difficulty swallowing at 40 and 50 L/min (p < 0.05). Logistic regression analyses were performed to identify which WST and RSST parameters were associated with choking during high-flow nasal cannula therapy. In the adjusted model, the change in swallowing time was an independent predictor of choking during high-flow nasal cannula therapy (OR = 1.02, 95% CI = 1.01–1.04).

Conclusion: A high-flow nasal cannula flow rate of > 40 L/min was associated with decreased swallowing function in healthy subjects. Performance of the WST and RSST are necessary when patients begin eating while undergoing high-flow nasal cannula therapy.