Computational modeling of nasal nitric oxide flux from the paranasal sinuses: Validation against human experiment

Nitric oxide (NO) is important in respiratory physiology and airway defense. Although the paranasal sinuses are the major source of nasal NO, transport dynamics between the sinuses and nasal cavities are poorly understood. Exhaled nasal NO tracings were measured in two non-asthmatic subjects (one with allergic rhinitis, one without) using NO analyzer connected via face mask. We subsequently performed computational fluid dynamics NO emission simulations based on individual CT scans and compared to the experimental data. Simulated exhaled NO tracings match well with experimental data (r > 0.84, p 67%, other sinuses combined 70%. Historically, nasal NO emissions were thought to be contributed mostly by the maxillary sinuses (the largest sinuses) and active air movement (convection). Here, we showed that the ethmoid sinuses and diffusive transport dominate the process. These findings may have a substantial impact on our view of nasal NO emission mechanisms and sinus physiopathology in general. •A first simulation of Nitric Oxide emission from all sinuses based on individual CT scans.•The simulations match well with experimental measured nasal NO concentrations.•Surprisingly, ethmoid sinuses and diffusive transport dominate the NO emission process.