Study objectives: The aim of this study was to
investigate whether nasal prongs, which have been proposed to assess
nasal flow during sleep, affect nasal airflow resistance (NR).
Design: NR was estimated by posterior rhinomanometry at a
0.5 L/s flow, under eight conditions: in the basal state, and with
seven different nasal prongs.
Participants: The study
was performed in 17 healthy supine subjects, 8 of whom had basal NR
values within the normal range (≤ 2 cm
H2O·L−1·s, group 1), and 9 had increased
basal NR values (> 2.5 cm
H2O·L−1·s, group 2), because of nare
narrowness and/or deviated nasal septum.
and results: NR increased significantly while breathing with
nasal prongs (p < 0.0001 in both groups). The changes in NR (ΔNR)
induced by the different nasal prongs were characterized by large
intersubject and intrasubject variability, with a maximum ΔNR of 24.2
cm H2O·L−1·s. Significant differences were
found between the ΔNR induced by the different nasal prongs
(p < 0.001 in group 1, and p < 0.0003 in group 2), and for six of
them, ΔNR was significantly higher in group 1 than in group 2
(p < 0.02).
Conclusions: This study demonstrates
that nasal prongs can markedly increase NR in subjects presenting with
nare narrowness and/or deviated nasal septum. Further investigations
that would include nocturnal polysomnography are still required to
evaluate the possible influence of nasal prongs on the diagnosis of
obstructive sleep apnea syndrome and its severity.