Journal of Applied Physiology, Vol 68, Issue 1 94-104, Copyright © 1990 by American Physiological Society

ARTICLES

Gas exchange abnormalities after pneumonectomy in conditioned foxhounds

C. C. Hsia, J. I. Carlin, P. D. Wagner, S. S. Cassidy and R. L. Johnson Jr
Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas 75235.

Loss of a major portion of lung tissue has been associated with impaired exercise capacity, but the underlying mechanisms are not well defined. We studied the alterations in gas exchange during exercise before and after left pneumonectomy in three conditioned foxhounds. After pneumonectomy, minute ventilation and O2 consumption at comparable submaximal work loads were unchanged but arterial PCO2 at any work load was higher, implying that ventilatory response to CO2 was impaired. Arterial hypoxemia and an elevated alveolar-arterial O2 tension difference (AaDO2) developed during heavy exercise. Using the multiple inert gas elimination technique, we determined the distributions of ventilation-perfusion (VA/Q) ratios postpneumonectomy. Significant increase in VA/Q inequality developed during exercise while the foxhounds were breathing room air, accounting for an average of 42% of the total increase in AaDO2 while diffusion limitation accounted for 58%. While the animals were breathing hypoxic gas mixture, diffusion limitation accounted for an average of 88% of the total increase AaDO2. Cardiac output and O2 delivery were reduced at a given O2 consumption after pneumonectomy. After pneumonectomy, the animals reached O2 consumptions close to the maximum expected for normal dogs. Compensation for the impairment in O2 delivery post-pneumonectomy occurred mainly by an increase in hemoglobin concentration. Training probably played an important role in returning exercise capacity toward prepneumonectomy levels. We conclude that significant abnormalities in gas exchange develop during exercise after loss of 42% of lung tissue, but the animals demonstrate a remarkable ability to compensate for these changes.

This article has been cited by other articles:

				C. C. W. Hsia, D. M. Dane, A. S. Estrera, H. E. Wagner, P. D. Wagner, and R. L. Johnson Jr. Shifting sources of functional limitation following extensive (70%) lung resection J Appl Physiol, April 1, 2008; 104(4): 1069 - 1079. [Abstract] [Full Text] [PDF]

				Q. Zhang, O. W. Moe, J. A. Garcia, and C. C. W. Hsia Regulated expression of hypoxia-inducible factors during postnatal and postpneumonectomy lung growth Am J Physiol Lung Cell Mol Physiol, May 1, 2006; 290(5): L880 - L889. [Abstract] [Full Text] [PDF]

				C. C. W. Hsia Signals and mechanisms of compensatory lung growth J Appl Physiol, November 1, 2004; 97(5): 1992 - 1998. [Abstract] [Full Text] [PDF]

				Mechanisms and Limits of Induced Postnatal Lung Growth Am. J. Respir. Crit. Care Med., August 1, 2004; 170(3): 319 - 343. [Full Text] [PDF]

				C. C. W. Hsia, R. L. Johnson Jr, E. Y. Wu, A. S. Estrera, H. Wagner, and P. D. Wagner Reducing lung strain after pneumonectomy impairs oxygen diffusing capacity but not ventilation-perfusion matching J Appl Physiol, October 1, 2003; 95(4): 1370 - 1378. [Abstract] [Full Text] [PDF]

				C. C. W. Hsia Recruitment of Lung Diffusing Capacity: Update of Concept and Application Chest, November 1, 2002; 122(5): 1774 - 1783. [Abstract] [Full Text] [PDF]

				C. C. W. Hsia, E. Y. Wu, E. Wagner, and E. R. Weibel Preventing mediastinal shift after pneumonectomy impairs regenerative alveolar tissue growth Am J Physiol Lung Cell Mol Physiol, November 1, 2001; 281(5): L1279 - L1287. [Abstract] [Full Text] [PDF]

				C. C. W. Hsia, S.-I. Takeda, E. Y. Wu, R. W. Glenny, and R. L. Johnson Jr. Adaptation of respiratory muscle perfusion during exercise to chronically elevated ventilatory work J Appl Physiol, November 1, 2000; 89(5): 1725 - 1736. [Abstract] [Full Text] [PDF]

				C. C. W. Hsia, X. S. Zhou, D. J. Bellotto, and H. K. Hagler Regenerative growth of respiratory bronchioles in dogs Am J Physiol Lung Cell Mol Physiol, July 1, 2000; 279(1): L136 - L142. [Abstract] [Full Text] [PDF]

				J. A. Dempsey and P. D. Wagner Exercise-induced arterial hypoxemia J Appl Physiol, December 1, 1999; 87(6): 1997 - 2006. [Abstract] [Full Text] [PDF]

				S.-I. Takeda, M. Ramanathan, A. S. Estrera, and C. C. W. Hsia Postpneumonectomy alveolar growth does not normalize hemodynamic and mechanical function J Appl Physiol, August 1, 1999; 87(2): 491 - 497. [Abstract] [Full Text] [PDF]

				S.-I. Takeda, C. C. W. Hsia, E. Wagner, M. Ramanathan, A. S. Estrera, and E. R. Weibel Compensatory alveolar growth normalizes gas-exchange function in immature dogs after pneumonectomy J Appl Physiol, April 1, 1999; 86(4): 1301 - 1310. [Abstract] [Full Text] [PDF]

				O. M. HIJAZI, M. RAMANATHAN, A. S. ESTRERA, R. M. PESHOCK, and C. C. W. HSIA Fixed Maximal Stroke Index in Patients after Pneumonectomy Am. J. Respir. Crit. Care Med., May 1, 1997; 157(5): 1623 - 1629. [Abstract] [Full Text]