Document Detail

Airway responses to methacholine and exercise at high altitude in healthy lowlanders.
MedLine Citation:
PMID:  19940099     Owner:  NLM     Status:  MEDLINE    
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.
Riccardo Pellegrino; Pasquale Pompilio; Marco Quaranta; Andrea Aliverti; Bengt Kayser; Giuseppe Miserocchi; Valter Fasano; Annalisa Cogo; Manlio Milanese; Giuseppe Cornara; Vito Brusasco; Raffaele Dellacà
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Publication Detail:
Type:  Journal Article     Date:  2009-11-25
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  108     ISSN:  1522-1601     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  2010 Feb 
Date Detail:
Created Date:  2010-02-01     Completed Date:  2010-04-23     Revised Date:  2013-09-26    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol (1985)     Country:  United States    
Other Details:
Languages:  eng     Pagination:  256-65     Citation Subset:  IM    
Allergologia e Fisiopatologia Respiratoria, Azienda Ospedaliera S. Croce e Carle, Cuneo, Italy.
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MeSH Terms
Airway Resistance / physiology
Blood Volume / physiology
Bronchi / drug effects,  physiology
Exercise / physiology*
Exercise Test
Forced Expiratory Flow Rates / physiology
Lung / drug effects,  physiology
Lung Compliance / physiology
Lung Volume Measurements
Methacholine Chloride / pharmacology*
Middle Aged
Muscarinic Agonists / pharmacology*
Respiratory Function Tests
Respiratory Mechanics / drug effects
Tidal Volume / physiology
Reg. No./Substance:
0/Muscarinic Agonists; 62-51-1/Methacholine Chloride
Comment In:
J Appl Physiol (1985). 2010 Apr;108(4):765-6   [PMID:  20133442 ]

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