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1 Dept of Child Health, University of Leicester, Leicester, UK, 2 Université Libre de Bruxelles, Laboratoire de Physiologie et de Physiopathologie, Faculté de Médecine Campus Erasme, Bruxelles, Belgium, 3 Association pour la Recherche en Physiologie de l'Environnement, Laboratoire de Physiologie, UFR de Médecine, France
CORRESPONDENCE: P.W. Barry, Dept of Child Health, University of Leicester, Clinical Sciences Building, Leicester Royal Infirmary, PO Box 65, Leicester, LE2 7LX, UK. Fax: 0116 2523282
Keywords: Altitude, nasal obstruction, spirometry
Received: November 11, 2000
Accepted July 25, 2001
This study was supported by grants from the Région Provence-Alpes-Côte d'Azur and the Ministère de la Jeunesse et des Sports (France).
The present study investigated whether there are changes in nasal peak inspiratory flow (NPIF) during hypobaric hypoxia under controlled environmental conditions.
During operation Everest III (COMEX '97), eight subjects ascended to a simulated altitude of 8,848 m in a hypobaric chamber. NPIF was recorded at simulated altitudes of 0 m, 5,000 m and 8,000 m. Oral peak inspiratory and expiratory flow (OPIF, OPEF) were also measured. Ambient air temperature and humidity were controlled.
NPIF increased by a mean±sd of 16±12% from sea level to 8,000 m, whereas OPIF increased by 47±14%. NPIF rose by 0.085±0.03 L·s1 per kilometre of ascent (p<0.05), significantly less than the rise in OPIF and OPEF of 0.35±0.10 and 0.33±0.04 L·s1 per kilometre (p<0.0005).
Nasal peak inspiratory flow rises with ascent to altitude. The rise in nasal peak inspiratory flow with altitude was far less than oral peak inspiratory flow and less than the predicted rise according to changes in air density. This suggests flow limitation at the nose, and occurs under controlled environmental conditions, refuting the hypothesis that nasal blockage at altitude is due to the inhalation of cold, dry air. Further work is needed to determine if nasal blockage limits activity at altitude.
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J.G. Widdicombe Nasal airflow resistance at simulated altitude Eur. Respir. J., January 1, 2001; 19(1): 4 - 5. [Full Text] [PDF] |
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