Published ahead of print on May 3, 2007, doi:10.1164/rccm.200702-206OC
Am. J. Respir. Crit. Care Med., Volume 176, Number 3, August 2007, 300-305
A more recent version of this article appeared on August 1, 2007
Submitted on February 7, 2007
Accepted on May 1, 2007
Exercise-induced Arteriovenous Intra-Pulmonary Shunting in Canines
Michael K Stickland1*, Andrew T Lovering1, and Marlowe W Eldridge2
1 University of Wisconsin School of Medicine and Public Health, John Rankin Laboratory of Pulmonary Medicine, Madison, WI, USA,
2 University of Wisconsin School of Medicine and Public Health, John Rankin Laboratory of Pulmonary Medicine, Madison, WI, USA; University of Wisconsin School of Medicine and Public Health, Pediatrics and Biomedical Engineering, Madison, WI, USA
* To whom correspondence should be addressed. E-mail: michael.strickland{at}ualberta.ca.
Rationale: Previously we have shown, using contrast echocardiography, that intra-pulmonary arteriovenous pathways are inducible in healthy humans during exercise, however this technique does not allow for determination of arteriovenous vessel size or shunt magnitude. Objectives: The purpose of this study was to determine if large diameter (>25 µm) intra-pulmonary arteriovenous pathways are present in the dog, and whether exercise recruits these conduits. Methods: Through the right fore-limb, 10.8 million 25 µm stable isotope-labeled microspheres (BioPAL, Inc.TM) were injected either at rest (n=8) or during high-intensity exercise (6-8mph, 10-15% grade, n=6). Systemic arterial blood was continuously sampled during, and for three minutes after injection. Following euthanasia, tissue samples were obtained from the heart, liver, kidney and skeletal muscle. In addition, 25 and 50 µm microspheres were infused into four isolated dog lungs that were ventilated and perfused at constant perfusion pressures similar to exercise. Measurements and Main Results: Blood and tissue samples were commercially analyzed for the presence of microspheres (BioPAL, Inc.TM). No microspheres were detected in the arterial blood or tissue samples from resting dogs. In contrast, five of six exercising dogs showed evidence of exercise-induced intra-pulmonary arteriovenous shunting, as microspheres were detected in arterial blood and/or tissue. Furthermore, shunt magnitude was calculated to be 1.4±0.8% of cardiac output (n=3). Evidence of intra-pulmonary arteriovenous anastomoses 50µm was also found in three of four isolated lungs. Conclusions: Consistent with previous human findings, these data demonstrate that intra-pulmonary arteriovenous pathways are functional in the dog and are recruited with exercise.
Key words: intra-pulmonary arteriovenous anastomoses, shunt, pulmonary gas exchange, pulmonary circulation.
This article has been cited by other articles:

|
 |

|
 |
 
A. T. Lovering, M. W. Eldridge, and M. K. Stickland
Counterpoint: Exercise-induced intrapulmonary shunting is real
J Appl Physiol,
September 1, 2009;
107(3):
994 - 997.
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
Rebuttal from Hopkins, Olfert, and Wagner
J Appl Physiol,
September 1, 2009;
107(3):
997 - 998.
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
Rebuttal from Lovering, Eldridge, and Stickland
J Appl Physiol,
September 1, 2009;
107(3):
998 - 998.
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
R. L. Jones, A. W. Sheel, R. Naeije, J. M. B. Hughes, and M. L. Bates
Pathophysiological insight into shunted bubbles.
J Appl Physiol,
September 1, 2009;
107(3):
999 - 1000.
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
A. T. Lovering, M. W. Eldridge, and M. K. Stickland
Last Word on Point:Counterpoint: Exercise-induced intrapulmonary shunting is imaginary vs. real
J Appl Physiol,
September 1, 2009;
107(3):
1003 - 1003.
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
S. R. Hopkins, I. M. Olfert, and P. D. Wagner
Point:Counterpoint: Exercise-induced intrapulmonary shunting is imaginary vs. real
J Appl Physiol,
September 1, 2009;
107(3):
993 - 994.
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
A. T. Lovering, H. C. Haverkamp, L. M. Romer, J. S. Hokanson, and M. W. Eldridge
Transpulmonary passage of 99mTc macroaggregated albumin in healthy humans at rest and during maximal exercise
J Appl Physiol,
June 1, 2009;
106(6):
1986 - 1992.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
A. T. Lovering, M. K. Stickland, M. Amann, J. C. Murphy, M. J. O'Brien, J. S. Hokanson, and M. W. Eldridge
Hyperoxia prevents exercise-induced intrapulmonary arteriovenous shunt in healthy humans
J. Physiol.,
September 15, 2008;
586(18):
4559 - 4565.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
A. T. Lovering, L. M. Romer, H. C. Haverkamp, D. F. Pegelow, J. S. Hokanson, and M. W. Eldridge
Intrapulmonary shunting and pulmonary gas exchange during normoxic and hypoxic exercise in healthy humans
J Appl Physiol,
May 1, 2008;
104(5):
1418 - 1425.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
I. Vogiatzis, S. Zakynthinos, R. Boushel, D. Athanasopoulos, J. A. Guenette, H. Wagner, C. Roussos, and P. D. Wagner
The contribution of intrapulmonary shunts to the alveolar-to-arterial oxygen difference during exercise is very small
J. Physiol.,
May 1, 2008;
586(9):
2381 - 2391.
[Abstract]
[Full Text]
[PDF]
|
 |
|
Copyright © 2007 American Thoracic Society
|
|
|