Effect of High-Flow Nasal Therapy on swallowing performance

<bold>Background:</bold> High Flow Nasal Therapy (HFNT) is a popular noninvasive respiratory support to manage patients with acute respiratory failure. Its nasal interface potentially enables patients to have oral feeding during treatment. However, the effect of HFNT on respiratory-swallow coordination is unknown. <bold>Aim:</bold> To evaluate the effects of HFNT at different flow rates on swallowing performances in patients with acute respiratory failure due to COPD exacerbation. <bold>Material and Methods:</bold> Fiberoptic endoscopic evaluation of swallowing was performed while administering a 10-cc bolus of water coloured with methylene blue. Data were recorded at baseline on conventional oxygen therapy and during a 5-min HFNT trial at different flow rates (30L/min, 50 L/min, 60 L/min) applied in random order and constant FiO2. <bold>Results:</bold> Six hospitalized patients (3F/3M) were enrolled and showed adequate oral continence and soft palate mobility at baseline. During HFNT, 3 patients (50%) had post-swallow residue at 30 L/min (P=0.2482), 5 (83.3%) at 50 L/min (P=0.0736) and 6 (100%) at 60 L/min (P= 0.0412), mostly on valleculae and/or pyriform sinuses. None (0/6, 0%) reported cough or experienced bolus drop during HFNT, and normal laryngeal motility was preserved even at increased flow values. <bold>Conclusions:</bold> Increased HFNT flow rates may influence swallowing, causing increased oral residue retention in the mouth.