Document Detail


Pulmonary perfusion heterogeneity is increased by sustained, heavy exercise in humans.
MedLine Citation:
PMID:  19745192     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Exercise presents a considerable stress to the pulmonary system and ventilation-perfusion (Va/Q) heterogeneity increases with exercise, affecting the efficiency of gas exchange. In particular, prolonged heavy exercise and maximal exercise are known to increase Va/Q heterogeneity and these changes persist into recovery. We hypothesized that the spatial heterogeneity of pulmonary perfusion would be similarly elevated after prolonged exercise. To test this, athletic subjects (n = 6, Vo(2max) = 61 ml. kg(-1).min(-1)) with exercising Va/Q heterogeneity previously characterized by the multiple inert gas elimination technique (MIGET), performed 45 min of cycle exercise at approximately 70% Vo(2max). MRI arterial spin labeling measures of pulmonary perfusion were acquired pre- and postexercise (at 20, 40, 60 min post) to quantify the spatial distribution in isogravitational (coronal) and gravitationally dependent (sagittal) planes. Regional proton density measurements allowed perfusion to be normalized for density and quantified in milliliters per minute per gram. Mean lung density did not change significantly in either plane after exercise (P = 0.19). Density-normalized perfusion increased in the sagittal plane postexercise (P =or <0.01) but heterogeneity did not (all P >or= 0.18), likely because of perfusion redistribution and vascular recruitment. Density-normalized perfusion was unchanged in the coronal plane postexercise (P = 0.66), however, perfusion heterogeneity was significantly increased as measured by the relative dispersion [RD, pre 0.62(0.07), post 0.82(0.21), P < 0.0001] and geometric standard deviation [GSD, pre 1.74(0.14), post 2.30(0.56), P < 0.005]. These changes in heterogeneity were related to the exercise-induced changes of the log standard deviation of the ventilation distribution, an MIGET index of Va/Q heterogeneity (RD R(2) = 0.68, P < 0.05, GSD, R(2) = 0.55, P = 0.09). These data are consistent with but not proof of interstitial pulmonary edema as the mechanism underlying exercise-induced increases in both spatial perfusion heterogeneity and Va/Q heterogeneity.
Authors:
K J Burnham; T J Arai; D J Dubowitz; A C Henderson; S Holverda; R B Buxton; G K Prisk; S R Hopkins
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2009-09-10
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  107     ISSN:  1522-1601     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  2009 Nov 
Date Detail:
Created Date:  2009-11-05     Completed Date:  2010-01-13     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:  1559-68     Citation Subset:  IM    
Affiliation:
School of Medicine, Univ. of California, San Diego, 9500 Gilman Dr., La Jolla, CA 92093, USA.
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MeSH Terms
Descriptor/Qualifier:
Blood Flow Velocity / physiology*
Humans
Male
Oxygen Consumption / physiology*
Physical Endurance / physiology*
Physical Exertion / physiology*
Pulmonary Circulation / physiology*
Young Adult
Grant Support
ID/Acronym/Agency:
5-T35-HL-007491-26/HL/NHLBI NIH HHS; F32-HL-078128/HL/NHLBI NIH HHS; HL-080203/HL/NHLBI NIH HHS; HL-081171/HL/NHLBI NIH HHS; R01 HL080203/HL/NHLBI NIH HHS; R01 HL081171/HL/NHLBI NIH HHS; R01 HL081171-04/HL/NHLBI NIH HHS
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