As the use of high-flow nasal cannula (HFNC) has become increasingly popular in the treatment of acute respiratory distress and failure across the lifespan, it is important for speech-language pathologists to understand how high-flow oxygen delivery may impact swallowing function. Benefits of using HFNC in place of low-flow (standard nasal cannula) or face mask include a, no surprise, much higher flow of gas; delivery of heated and humidified gas to decrease airway inflammation; increased comfort and decreased dead space by eliminating the use of a mask; and improved mucous clearance while reducing the caloric expenditure in acute respiratory failure (Chidekel 2012 and Dysart 2009). 

Publications focused on HFNC data are mostly available for the neonatal field, however over the last 10-15 years, use of HFNC has become more prevalent for adults as well. Nishimura published the physiological effects of high flow in 2015, listed as follows: 

  1. High flow washes out carbon dioxide in anatomical dead space
  2. Although delivered through an open system, high flow overcomes resistance against expiratory flow and creates positive nasopharyngeal pressure. While the pressure is relatively low compared with closed systems, it is considered adequate to increase lung volume or recruit collapsed alveoli.
  3. The difference between the inspiratory flow of patients and delivered flow is small and FiO2 remains relatively constant.
  4. Because gas is generally warmed to 37°C and completely humidified, mucociliary functions remain good and little discomfort is reported.

Additional benefits of using HFNC include the following: reduced need for re-intubation, which is associated with increased hospital length of stay and mortality; alleviation of upper airway obstruction for patients with obstructive sleep apnea; a comfortable modality for providing supplemental oxygen in patients with heart failure; and a comfortable alternative to BiPAP or CPAP for patients in respiratory failure who have a do-not-intubate status.

Understandably, speech-language pathologists tend to feel hesitant regarding dysphagia assessment in patients with altered respiratory conditions who are receiving high flow rates. Points of concern include changes to upper airway pressures that may impact airway closure and pharyngeal clearance as well as the potential impact of high flow on swallowing and respiratory coordination.

Emerging literature describes the clinical importance of appropriate patient selection and use of instrumental swallow evaluation to discern readiness for PO intake while on HFNC therapy. To learn more about oxygen therapies and swallow considerations, register for our upcoming LIVE webinar taking place on March 8th at 4:00 pm eastern!

Can’t make the live event? No problem! Go ahead and register, the recording will be posted on 3/9/23 and you will have until 3/31/23 to complete the post test and receive credit.



Chidekel, A et al. The Effects of Gas Humidification with High-Flow Nasal Cannula on Cultured Human Airway Epithelial Cells. Pulmonary Medicine 2012. PMID: 22988501

Devlin, C. & O’Bryan, R. Effects of Oxygen via High-Flow Nasal Cannula on Adult Oropharyngeal Swallowing: A Literature Review. Perspectives of the ASHA Special Interest Groups June 2021. Vol. 6. 631-638.

Dysart, K et al. Research in High Flow Therapy: Mechanisms of Action. Respiratory Medicine 2009.  PMID: 19467849

Nishimura, M. High-flow nasal cannula oxygen therapy in adults. j intensive care 3, 15 (2015).