Rhinosinusitis is one of the most common reasons for seeking medical attention. While the role of the nose in sinonasal health is relatively well-known, the function of the sinuses has remained unclear. It has been suggested that ventilation of the sinuses plays an important role in maintaining sinonasal health. However investigation of this concept requires an accurate understanding of the morphology of the sinus ostia, which connect the sinus to the nose. In vivo measurements of the complex ostium geometry and exchange processes are hampered by the inaccessibility of the sinuses. Current knowledge is mostly based on cadaver studies and basic experiments. The discovery of high concentrations of Nitric Oxide (NO) in the nose and sinuses has prompted interest in its role in sinonasal pathophysiology and it has been suggested that upper airway NO is predominantly produced in the sinuses. Tbis thesis aims to investigate the relationship between sinonasal morphology and ventilation and in particular its effect on the exchange of NO. Detailed measurements of the anatomy, using specialist software, were obtained and found to be in agreement with the literature. These characterisations were used to estimate exchange processes with simple modelling techniques and the results were compared with computational methods. Sinuses with a sole small ostium were found to have diffusion-dominated exchange, whereas sinuses with a larger ostium have added convective effects to the diffusive transport. Sinuses with a double ostium configuration were found to have a net flow, which significantly accelerates the exchange process. These findings suggest it is unlikely that the sinuses produce all NO measured in the nose. A pilot experiment was designed to verify the accuracy of the modelling relations and preliminary results suggest that 81m Krypton is a suitable tracer for quantifying sinus ventilation.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:556611 |
| Date | January 2011 |
| Creators | Blenke, Esther |
| Publisher | Imperial College London |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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