Airway responses to methacholine and exercise at high altitude in healthy lowlanders.

Details

Serval ID
serval:BIB_40C5FE148A31
Type
Article: article from journal or magazin.
Collection
Publications
Title
Airway responses to methacholine and exercise at high altitude in healthy lowlanders.
Journal
Journal of Applied Physiology
Author(s)
Pellegrino R., Pompilio P., Quaranta M., Aliverti A., Kayser B., Miserocchi G., Fasano V., Cogo A., Milanese M., Cornara G., Brusasco V., Dellacà R.
ISSN
1522-1601 (Electronic)
ISSN-L
0161-7567
Publication state
Published
Issued date
2010
Volume
108
Number
2
Pages
256-265
Language
english
Abstract
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 approximately 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.
Keywords
Acclimatization, Adult, Airway Resistance/physiology, Altitude, Blood Volume/physiology, Bronchi/drug effects, Bronchi/physiology, Exercise/physiology, Exercise Test, Forced Expiratory Flow Rates/physiology, Humans, Lung/drug effects, Lung/physiology, Lung Compliance/physiology, Lung Volume Measurements, Male, Methacholine Chloride/pharmacology, Middle Aged, Muscarinic Agonists/pharmacology, Respiratory Function Tests, Respiratory Mechanics/drug effects, Tidal Volume/physiology
Pubmed
Web of science
Create date
19/09/2013 10:13
Last modification date
03/03/2018 16:29
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