Document Detail


Exercise-induced intrapulmonary arteriovenous shunting in healthy humans.
MedLine Citation:
PMID:  15107409     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
We hypothesized that increasing exercise intensity recruits dormant arteriovenous intrapulmonary shunts, which may contribute to the widened alveolar-arterial oxygen difference seen with exercise. Twenty-three healthy volunteers (13 men and 10 women, aged 23-48 yr) with normal lung function and a wide range of fitness (mean maximal oxygen uptake = 126% predicted; range = 78-200% predicted) were studied by agitated saline contrast echocardiography (4-chamber apical view). All 23 subjects had normal resting contrast echocardiograms without evidence of intracardiac or intrapulmonary shunting. However, with cycle ergometer exercise, 21 of 23 (91%) of the subjects showed a delayed (>3 cardiac cycles) appearance of contrast bubbles in the left heart. This pattern is consistent with passage of contrast bubbles through the pulmonary circulation. Because the contrast bubbles are known to be significantly larger than pulmonary capillaries, we propose that they are traveling through direct arteriovenous intrapulmonary shunts. In all cases, the intrapulmonary shunting developed at submaximal oxygen uptakes [%maximal oxygen uptake = 59 +/- 20 (SD)] and once evident persisted at all subsequent work rates. Within 3 min of exercise termination, the contrast echocardiograms with bubble injection showed no evidence of intrapulmonary shunting. These dynamic shunts will contribute significantly to the widened alveolar-arterial oxygen difference seen with exercise. They may also act as a protective parallel vascular network limiting the rise in regional pulmonary vascular pressure while preserving cardiac output during exercise.
Authors:
Marlowe W Eldridge; Jerome A Dempsey; Hans C Haverkamp; Andrew T Lovering; John S Hokanson
Related Documents :
18317379 - Sex differences in pulmonary function during exercise.
6705589 - Pulmonary arteriovenous fistula showing a fall in shunt fraction during exercise.
507509 - Hypoxemia during exercise in patients with chronic obstructive pulmonary disease.
20871839 - What limits cardiac performance during exercise in normal subjects and in healthy fonta...
6061739 - Physiologic studies of the pulmonary capillary bed after barium sulfate embolization.
17846299 - Nonlinear power loss during exercise in single-ventricle patients after the fontan: ins...
22507359 - Exercise for rotator cuff tendinopathy: a systematic review.
23075089 - Restrictive lung disease is an independent predictor of exercise intolerance in the adu...
3168979 - Exercise as a buffer of life stress: a prospective study of adolescent health.
Publication Detail:
Type:  Clinical Trial; Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.     Date:  2004-04-23
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  97     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  2004 Sep 
Date Detail:
Created Date:  2004-08-30     Completed Date:  2005-02-10     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:  797-805     Citation Subset:  IM    
Affiliation:
John Rankin Laboratory of Pulmonary Medicine, University of Wisconsin, Medical School, Madison, Wisconsin 53792-4108, USA. meldridge@wisc.edu
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Descriptor/Qualifier:
Adaptation, Physiological / physiology
Adolescent
Adult
Blood Flow Velocity
Echocardiography
Exercise Test
Female
Heart Ventricles / physiopathology*,  ultrasonography
Humans
Lung / blood supply*,  physiology*,  ultrasonography
Male
Middle Aged
Oxygen Consumption / physiology*
Physical Endurance / physiology*
Physical Exertion / physiology*
Pulmonary Artery / physiopathology,  ultrasonography
Pulmonary Circulation / physiology*
Pulmonary Gas Exchange / physiology
Pulmonary Veins / physiopathology,  ultrasonography
Respiratory Function Tests
Grant Support
ID/Acronym/Agency:
R01 HL-15469-33/HL/NHLBI NIH HHS; T32 HL-07654-16/HL/NHLBI NIH HHS

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


Previous Document:  Preclinical models of human peripheral arterial occlusive disease: implications for investigation of...
Next Document:  Body-weight-support treadmill training improves blood glucose regulation in persons with incomplete ...