Airway Responses to Methacholine and exercise at High Altitude in Healthy Lowlanders.

Peribronchial edema has been proposed as a mechanism enhancing airway responses to constrictor stimuli. Acute exposure to altitude in nonacclimatized lowlanders leads to subclinical interstitial pulmonary edema that lasts for several days after ascent, as suggested by changes in lung mechanics. We, therefore, investigated whether changes in lung mechanics consistent with fluid accumulation at high altitude within the lungs are associated with changes in airway responses to methacholine or exercise. Fourteen healthy subjects were studied at 4,559 and at 120 m above sea level. At high altitude, both static and dynamic lung compliances and respiratory reactance at 5 Hz significantly decreased, suggestive of interstitial pulmonary edema. Resting minute ventilation significantly increased by ?30%. Compared with sea level, inhalation of methacholine at high altitude caused a similar reduction of partial forced expiratory flow but less reduction of maximal forced expiratory flow, less increments of pulmonary resistance and respiratory resistance at 5 Hz, and similar effects of deep breath on pulmonary and respiratory resistance. During maximal incremental exercise at high altitude, partial forced expiratory flow gradually increased with the increase in minute ventilation similarly to sea level but both achieved higher values at peak exercise. In conclusion, airway responsiveness to methacholine at high altitude is well preserved despite the occurrence of interstitial pulmonary edema. We suggest that this may be the result of the increase in resting minute ventilation opposing the effects and/or the development of airway smooth muscle force, reduced gas density, and well preserved airway-to-parenchyma interdependence.

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Riccardo Pellegrino (Allergy and Respiratory Physiopathology, Hospital S. Croce and Carle,) - Pasquale Pompilio (TBMLab Laboratory of Biomedical Technologies, Polytechnic of Milan" (Technical University)) - Marco Quaranta (TBMLab Laboratory of Biomedical Technologies, Polytechnic of Milan" (Technical University)) - Andrea Aliverti (TBMLab Laboratory of Biomedical Technologies, Polytechnic of Milan) - Bengt Kayser (Institute of movement sciences and sports medicine, University of Geneva) - Giuseppe Miserocchi (Department of Experimental medicine, University of Milano-Bicocca) - Valter Fasano (Department of Cardio Thoracic and Vascular Desease, University of Milan) - Annalisa Cogo (Biomedical Research Centre applied to sport,University of Ferrara) - Manlio Milanese (Pneumology, Hospital S. Corona, Pietra Ligure) - Giuseppe Cornara (Anaesthesia and Intensive Care, Hospital St. Croce and Carle) - Vito Brusasco (Respiratory Pathophysiology, Department of Internal Medicine, University of Genova) - Raffaele Dellacà (Department of Bioengineering, Polytechnic of Milan) (2009) . Airway Responses to Methacholine and exercise at High Altitude in Healthy Lowlanders.. https://geoportal.mountaingenius.org/geonetwork/srv/api/records/d182c72a-c718-4336-b9e8-c2a371ef31dc

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File identifier: d182c72a-c718-4336-b9e8-c2a371ef31dc XML

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Elevation
Health

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Peribronchial edema , respiratory resistance. , sea level , interstitial pulmonary edema , fluid accumulation , methacholine , ventilation

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high altitude

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Date ( Publication ): 2009-09-25T00:00:00

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“Airway Responses to Methacholine and exercise at High Altitude in Healthy Lowlanders. “

Journal of Applied Physiology, 108: 256-265.

Pellegrino, R., P. Pompilio, M. Quaranta, A. Aliverti, B. Kayser, G. Miserocchi, V. Fasano, A. Cogo, M. Milanese, G. Cornara, V. Brusasco & R. Dellacà. 2010.