In:
Journal of Applied Physiology, American Physiological Society, Vol. 115, No. 2 ( 2013-07-15), p. 157-166
Abstract:
Acute exposure to high altitude may induce changes in carbon monoxide (CO) membrane conductance (Dm CO ) and capillary lung volume (Vc). Measurements were performed in 25 lowlanders at Brussels (D 0 ), at 4,300 m after a 2- or 3-day exposure (D 2,3 ) without preceding climbing, and 5 days later (D 7,8 ), before and after an exercise test, under a trial with two arterial pulmonary vasodilators or a placebo. The nitric oxide (NO)/CO transfer method was used, assuming both infinite and finite values to the NO blood conductance (θ NO ). Doppler echocardiography provided hemodynamic data. Compared with sea level, lung diffusing capacity for CO increased by 24% at D 2,3 and is returned to control at D 7,8 . The acute increase in lung diffusing capacity for CO resulted from increases in Dm CO and Vc with finite and infinite θ NO assumptions. The alveolar volume increased by 16% at D 2,3 and normalized at D 7,8 . The mean increase in systolic arterial pulmonary pressure at rest at D 2,3 was minimal. In conclusion, the acute increase in Vc may be related to the increase in alveolar volume and to the increase in capillary pressure. Compared with the infinite θ NO value, the use of a finite θ NO value led to about a twofold increase in Dm CO value and to a persistent increase in Dm CO at D 7,8 compared with D 0 . After exercise, Dm CO decreased slightly less in subjects treated by the vasodilators, suggesting a beneficial effect on interstitial edema.
Type of Medium:
Online Resource
ISSN:
8750-7587
,
1522-1601
DOI:
10.1152/japplphysiol.01455.2012
Language:
English
Publisher:
American Physiological Society
Publication Date:
2013
detail.hit.zdb_id:
1404365-8
SSG:
12
SSG:
31
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