Computational Fluid Dynamics Modeling Examines Differences in Design Elements of High Flow Nasal Cannula Systems
Several high flow nasal cannula (HFNC) systems are widely used in clinical practice, yet few studies have evaluated the differences in design elements or clinical effectiveness. In 2014, Tero and colleagues published “Risks Associated With Conventional Humidifiers Adapted for High-Flow Nasal Cannula Therapy in Human Infants: Results of a Time and Motion Study”, which demonstrated HFNC using the Fisher & Paykel MR850™ was associated with greater staff workload and patient risk than with Vapotherm Precision Flow.
Recently, Miller et al., published a comparison study examining the upper airway gas dynamics for cannulae with different cannula prong sizes (Journal of Pulmonary & Respiratory Medicine titled Computational Fluid Dynamics Modeling of Extrathoracic Airway Flush: Evaluation of High Flow Nasal Cannula Design Elements). The study used advanced fluid dynamics software to characterize flow patterns and compare purge time between different cannula sizes. The model used large and small-bore prong designs and used actual human upper airway architecture (derived from CT scans). The authors conclude that the smaller cannula prongs achieved a faster purge of the extrathoracic dead space for a given flow rate than the larger prong configuration (28% faster at 20 L/min).
The Vapotherm Adult Nasal Cannula (MA-1700) uses a prong inner diameter of 2.7mm. The Fisher & Paykel Optiflow™ Adult Nasal Cannula (OPT546) uses a prong inner diameter of 5.4mm.
These findings help explain the differences between the various technologies in clinical use. Improving the ability to flush the nasal extrathoracic dead space is important for the management of signs and symptoms of respiratory distress, including not only hypoxia but also hypercapnia.
 Miller TL, Saberi B, Saberi S (2016) Computational Fluid Dynamics Modeling of Extrathoracic Airway Flush: Evaluation of High Flow Nasal Cannula Design Elements. J Pulm Respir Med 6:376. doi: 10.4172/2161-105X.1000376. (Bench, Prospective, Not Randomized)
 Doshi, Pratik et al. High-Velocity Nasal Insufflation in the Treatment of Respiratory Failure: A Randomized Clinical Trial. Annals of Emergency Medicine, 2018. Published online ahead of print. (Adult, Clinical Trial, Prospective, Multi-Center, n=204)
 Risks Associated With Conventional Humidifiers Adapted for High-Flow Nasal Cannula Therapy in Human Infants-Results of a Time and Motion Study. Int J Clin Pediatr. 2014-3(4)-99-104.pdf (Neonate, Clinical Trial, Observational, Not Randomized, Multi-Center, n=109)
This webpage contains links to third party abstracts and/or publications. With respect to those materials, please note that Vapotherm’s Hi-VNI® technology is a tool for treating the signs and symptoms of respiratory distress in patients for whom prescribers desire to add heat and moisture to breathing gases. The linked materials may describe certain outcomes in relation to the use of Vapotherm’s Hi-VNI Technology, but individual results may vary. Practitioners should refer to the full indications for use and operating instructions of any products referenced herein before prescribing them.