High-flow nasal cannula and non-invasive ventilation impact on swallowing physiology: review

Deglutition requires adequate coordination between breathing and swallowing. In the clinical context, the use of non-invasive ventilatory devices such as high-flow nasal cannulas (HFNC) or non-invasive ventilation (NIV) has become highly relevant in recent years. However, there is little information regarding how these devices could interfere with the physiology of deglutition. This study aimed to describe the impact of HFNC and NIV on swallowing physiology. To this end, a literature review was carried out using PubMed, Medline, Embase, Web of Science, Lilacs, and Scielo. Studies performed on populations ≥18 years old where HFNC or NIV were used were included. Studies where the population had a history of dysphagia, need for intubation, and presented neurological, neuromuscular, or respiratory diseases, among others, were excluded. The results show that HFNC could decrease the swallowing rate (with flows ≥ 20 L/min; p<.05), decrease the mean activation time of the swallowing reflex in proportion to the flow (p<.05), increase the risk of aspiration when using higher flows (>40 L/min, p<0.05), and increase the average duration of the laryngeal vestibule closure (p<.001). NIV, particularly BiPAP, could increase the risk of aspiration due to the higher rate of post-swallowing inspiration (SW-I, p<.01). Although the evidence available on this matter is limited, these results offer relevant information that should be considered when working with patients who use these ventilatory devices. Further research should be carried out to strengthen the evidence that is provided in this study.