RESUMO
Sinus nitric oxide (NO) measurements present a novel and promising approach to help overcome difficulties and confounding variables associated with nasal NO measurements such as the nasal cycle, ostial patency, and individual contribution to total NO production of each sinus. Conflicting results reported on nasal NO measurements in various sinonasal diseases are presumed to originate from the variable diffusion of sinus NO into the nose where it is measured. This study presents a novel technique and research method for direct measurement of sinus NO. The authors' original technique of individual, non-destructive catheterization of the sinuses through their natural ostia is developed and refined to allow accurate measurements of NO produced in the sinuses. Our study indicates that reproducible catheterization of the sinuses through their natural ostia can be performed in the clinical research setting under local and topical anesthesia. The model can be used to test the effects of various conditions on nasal and sinus NO production in a variety of disease models and the variables affecting sinonasal gas exchange can be differentially studied. Volunteer healthy adult human subjects without nasal allergies are used. An endoscopic nasal exam with topical anesthesia followed by in vitro allergy testing is performed to determine eligibility. Sinus computerized tomography (CT) scans are used to delineate anatomic features and to calculate paranasal sinus volumes. Continuous flow sinus air sampling and NO measurement with a chemiluminescence analyzer is obtained through polyethylene tube catheters (PEC) placed endoscopically into an aerated major paranasal sinus. Catheters are introduced through natural ostia under local and topical anesthesia. Nasal and differential sinus NO measurements are performed.