Combined effects of a nasal dilator and nasal prongs on nasal airflow resistance

Study objectives: Nasal prongs (NPs), when used to assess nasal flow, can r esult in dramatic increases in nasal airflow resistance (NR). The aim of th is study was to investigate whether the NP-induced increases in NR could be corrected by the simultaneous use of an internal nasal dilator (ND). Design: NIR was estimated by posterior rhinomanometry, in the basal state ( NRb), and while breathing,with NP (NRp), with ND (NRd), and with both ND an d NP (NRd + p). Participants: The study was performed in 15 healthy subjects. Measurements and results: NR (mean NRb [+/- SEM], 2.5 +/- 0.4 cm H2O/L/s) s ignificantly decreased with ND (NRd = 1.4 +/- 0.2 cm H2O/L/s; p < 0.001) an d significantly increased with NP (NRp = 3.8 +/- 0.8 cm H2O/L/s; p < 0.001) . A significant logarithmic relationship was found between NRd and NRb (r(2 ) = 0.95; p < 0.0001), and a significant exponential relationship was found between NRp and NRb (r(2) = 0.99; p < 0.0001). While breathing with both N D and NP, NRd + p was significantly lower than NRb (1.9 +/- 1.4 cm H2O/L/s; p < 0.02). Conclusions: Our results demonstrate that the ND tends to slightly overcorr ect the NP-induced increase in NR and suggest that, in view of the possible effects of NPs on upper airway resistance, the combination of both devices might be used for nasal airflow monitoring during nocturnal polysomnograph y in patients presenting with highly resistive nares.