Xylometazoline-induced change in aspirated nasal nitric oxide detects obstructed paranasal ostia

The concentrations of nasal nitric oxide (nNO) vary in patients with chronic rhinosinusitis (CRS) supposedly depending upon whether the paranasal ostia are open or obstructed. Our aim was to assess whether nNO levels and their response to topical xylometazoline (a local vasoconstrictor used to alleviate nasal congestion) in patients with CRS differ between those with open or obstructed ostia and if the results were altered by the use of nasal corticosteroids. Sixty-six patients with CRS (43% with nasal polyps) or recurrent acute rhinosinusitis and 23 healthy controls were included. Nasal NO was measured (EcoMedics CLD 88p analyser) before and after two xylometazoline sprays during three consecutive visits: with the medication they were using when they were referred, after 4 weeks of medication pause, and after 4 weeks of using intranasal fluticasone propionate. The relative difference between the nNO before and after dosing of xylometazoline was calculated, and ostial obstruction was evaluated with cone-beam computed tomography at every visit. The nNO measurements were lowest in the patients with CRS and obstructed paranasal ostia. The presence or absence of nasal polyps did not affect the results. Xylometazoline did not significantly affect nNO in the subjects with obstructed ostia, but there was a significant reduction of nNO in those with open ostia. The Xylometazoline-induced change in nNO between the groups with open or obstructed ostia was significantly different at each visit: 'on previous medication' 10% (-5-25) versus -14% (-19 to -9),<i>p</i>= 0.004, 'after medication pause' 6% (-5-17) versus -16% (-23 to -9),<i>p</i>= 0.001 and 'after regular fluticasone spray' 6% (-3-15) versus -9% (-16 to -3),<i>p</i>= 0.04. The native nNO and xylometazoline-induced change in nNO can be used to detect the status of ostial obstruction in patients with CRS irrespective of their topical corticosteroid usage.