Effects of nasal prongs on nasal airflow resistance.
OBJECTIVE
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).


METHODS
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.


METHODS
The study was performed in 17 healthy supine subjects, 8 of whom had basal NR values within the normal range (< or = 2 cm H(2)O.L(-1).s, group 1), and 9 had increased basal NR values (> 2.5 cm H(2)O.L(-1).s, group 2), because of nare narrowness and/or deviated nasal septum.


RESULTS
NR increased significantly while breathing with nasal prongs (p < 0.0001 in both groups). The changes in NR (DeltaNR) induced by the different nasal prongs were characterized by large intersubject and intrasubject variability, with a maximum DeltaNR of 24.2 cm H(2)O.L(-1).s. Significant differences were found between the DeltaNR induced by the different nasal prongs (p < 0.001 in group 1, and p < 0.0003 in group 2), and for six of them, DeltaNR 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.
Service de Physiologie, and INSERM U 492, Hôpital Henri Mondor, AP-HP, Garches, France. anne-marie.lorino@hmn.ap-hop-paris.fr
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Lorino
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Lorino
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Dahan
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d'Ortho
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Coste
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Harf
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Lofaso
D000328:Adult; D000403:Airway Resistance / Q000502:physiology*; D003937:Diagnosis, Differential; D004867:Equipment Design; D005260:Female; D006801:Humans; D008297:Male; D008365:Manometry; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000295:instrumentation*; D015508:Nasal Obstruction / Q000175:diagnosis / Q000503:physiopathology; D009666:Nose; D017286:Polysomnography; D011312:Pressure; D012016:Reference Values; D012891:Sleep Apnea Syndromes / Q000175:diagnosis / Q000503:physiopathology