(522i) Investigating the Effect of Non-Invasive Respiratory Therapy on Pressure Distribution in the Upper Airway

Computational models of two types of non-invasive respiratory therapy were run to investigate therapy type’s effect on upper airway pressure distribution. The simulated domain included the trachea, larynx, nasal passageways, mouth, and an environment region in front of the face. Multiple mouth openings were tested with high flow nasal cannula (HFNC) oxygen therapy and high velocity nasal insufflation (HVNI), a subset of HFNC therapy. Open and closed mouth models were run with a healthy airway and a partially inflamed nasal passageway. Pressure and velocity were collected at numerous points throughout the upper airway. At the same therapy flow rates, HVNI produced higher pressure in the airway than HFNC therapy. For both therapy types, pressure generated in the airway increased as the patient mouth was closed. However, this increase in pressure was coupled with an increase in CO₂ remaining in the upper airway. This information can be used to inform suggested patient mouth position during non-invasive respiratory therapy, dependent on the desired benefit. A closed mouth allows for additional distending pressure generation, while an open mouth facilitates additional CO₂ flush. HVNI generated higher pressure and resulted in lower levels of CO₂ remaining in the patient airway when the therapy flow rate was held constant across therapy types.