Yes. Vapotherm has conducted preliminary work with computational fluid dynamic modeling of an adult patient on high velocity therapy with a surgical facemask covering the mouth and nose with the cannula in place. The results suggest that the surgical mask receives the overwhelming majority of the flow in this model, and acts to diffuse the flow. This practice is also consistent with guidance from the Chinese Thoracic Society.6
The greatly lowered velocity of this gas stream allows for the mask to capture the particles as intended. The resulting outflow patterns from patients may resemble those from patients simply spontaneously breathing while wearing such masks without high velocity therapy.
In these simulations, the most obvious source of particulate movement was through leaks in the mask. Therefore, we suggest paying close attention to securing the mask on the patient to minimize mask leakage.
Further work continues, and we will shortly be providing guidance on the actual geometry of deposition around the patient.