Exercise-induced Intrapulmonary Shunting Research Articles

Not hearing is believing: novel insight into cardiopulmonary function using agitated contrast and ultrasound

the advancement of science depends heavily on the development and successful application of new techniques. Progress in ultrasound technology has allowed researchers in physiology to examine many important parameters noninvasively, including cerebral blood flow velocity, pulmonary artery systolic

Comments on Point:Counterpoint: Exercise-induced intrapulmonary shunting is imaginary vs. real

Comments on Point:Counterpoint: Exercise-induced intrapulmonary shunting is imaginary vs. real

Last Word on Point:Counterpoint: Exercise-induced intrapulmonary shunting is imaginary vs. real

to the editor: We completely agree with the letter writers ([3][1]) that it is important to apply quantitative techniques for the measurement of intrapulmonary shunt before drawing conclusions. Both MIGET and the 100% oxygen technique are quantitative and have consistently shown insignificant

Rebuttal from Hopkins, Olfert, and Wagner

Rebuttal from Hopkins, Olfert, and Wagner

Counterpoint: Exercise-induced intrapulmonary shunting is real

The conventional pulmonary circulatory route begins with the pulmonary artery that travels in parallel with the airway, dividing with the airway, until finally reaching the capillary bed within the acinus ([4][1]; [Fig. 1 A ][2]). The capillary bed consists of vessels 7 to 10 μm in diameter, never

Last Word on Point:Counterpoint: Exercise-induced intrapulmonary shunting is imaginary vs. real

to the editor: We thank our colleagues from UCSD for this enjoyable discourse as well as the additional commentaries from colleagues around the world. In reviewing the Point:Counterpoint ([3][1], [5][2]) and the commentaries submitted (see Ref. [4][3]), it appears that there is general agreement

Point:Counterpoint: Exercise-induced intrapulmonary shunting is imaginary vs. real

Pulmonary gas exchange efficiency deteriorates with exercise in both humans and other species, increasing the alveolar-arterial PO2 difference (AaDO2) ([2][1]). The potential contributors to this are ventilation-perfusion inequality, alveolar-capillary diffusion limitation, and shunt ([20][2]).

Intrapulmonary shunting and pulmonary gas exchange during normoxic and hypoxic exercise in healthy humans

Exercise-induced intrapulmonary arteriovenous shunting, as detected by saline contrast echocardiography, has been demonstrated in healthy humans. We have previously suggested that increases in both pulmonary pressures and blood flow associated with exercise are responsible for opening these intrapulmonary arteriovenous pathways. In the present study, we hypothesized that, although cardiac output and pulmonary pressures would be higher in hypoxia, the potent pulmonary vasoconstrictor effect of hypoxia would actually attenuate exercise-induced intrapulmonary shunting. Using saline contrast echocardiography, we examined nine healthy men during incremental (65 W + 30 W/2 min) cycle exercise to exhaustion in normoxia and hypoxia (fraction of inspired O(2) = 0.12). Contrast injections were made into a peripheral vein at rest and during exercise and recovery (3-5 min postexercise) with pulmonary gas exchange measured simultaneously. At rest, no subject demonstrated intrapulmonary shunting in normoxia [arterial Po(2) (Pa(O(2))) = 98 +/- 10 Torr], whereas in hypoxia (Pa(O(2)) = 47 +/- 5 Torr), intrapulmonary shunting developed in 3/9 subjects. During exercise, approximately 90% (8/9) of the subjects shunted during normoxia, whereas all subjects shunted during hypoxia. Four of the nine subjects shunted at a lower workload in hypoxia. Furthermore, all subjects continued to shunt at 3 min, and five subjects shunted at 5 min postexercise in hypoxia. Hypoxia has acute effects by inducing intrapulmonary arteriovenous shunt pathways at rest and during exercise and has long-term effects by maintaining patency of these vessels during recovery. Whether oxygen tension specifically regulates these novel pathways or opens them indirectly via effects on the conventional pulmonary vasculature remains unclear.

Exercise-induced intrapulmonary shunting of venous gas emboli does not occur after open-sea diving

Paradoxical arterializations of venous gas emboli can lead to neurological damage after diving with compressed air. Recently, significant exercise-induced intrapulmonary anatomical shunts have been reported in healthy humans that result in widening of alveolar-to-arterial oxygen gradient. The aim of this study was to examine whether intrapulmonary shunts can be found following strenuous exercise after diving and, if so, whether exercise should be avoided during that period. Eleven healthy, military male divers performed an open-sea dive to 30 m breathing air, remaining at pressure for 30 min. During the bottom phase of the dive, subjects performed mild exercise at approximately 30% of their maximal oxygen uptake. The ascent rate was 9 m/min. Each diver performed graded upright cycle ergometry up to 80% of the maximal oxygen uptake 40 min after the dive. Monitoring of venous gas emboli was performed in both the right and left heart with an ultrasonic scanner every 20 min for 60 min after reaching the surface pressure during supine rest and following two coughs. The diving profile used in this study produced significant amounts of venous bubbles. No evidence of intrapulmonary shunting was found in any subject during either supine resting posture or any exercise grade. Also, short strenuous exercise after the dive did not result in delayed-onset decompression sickness in any subject, but studies with a greater number of participants are needed to confirm whether divers should be allowed to exercise after diving.

Inert gas elimination characteristics of the normal and abnormal lung

ARTICLESInert gas elimination characteristics of the normal and abnormal lungM. P. Hlastala, and H. T. RobertsonM. P. Hlastala, and H. T. RobertsonPublished Online:01 Feb 1978https://doi.org/10.1152/jappl.1978.44.2.258MoreSectionsPDF (2 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformation Cited ByMeasurement of the distribution of ventilation-perfusion ratios in the human lung with proton MRI: comparison with the multiple inert-gas elimination techniqueRui Carlos Sá*, A. Cortney Henderson*, Tatum Simonson, Tatsuya J. Arai, Harrieth Wagner, Rebecca J. Theilmann, Peter D. Wagner, G. Kim Prisk, and Susan R. Hopkins18 July 2017 | Journal of Applied Physiology, Vol. 123, No. 1Multiple inert gas elimination technique by micropore membrane inlet mass spectrometry—a comparison with reference gas chromatographyMoritz Kretzschmar, Thomas Schilling, Andreas Vogt, Hans Ulrich Rothen, João Batista Borges, Thomas Hachenberg, Anders Larsson, James E. Baumgardner, and Göran Hedenstierna15 October 2013 | Journal of Applied Physiology, Vol. 115, No. 8Hypoxic Pulmonary VasoconstrictionJ. T. Sylvester, Larissa A. Shimoda, Philip I. Aaronson, and Jeremy P. T. Ward1 January 2012 | Physiological Reviews, Vol. 92, No. 1Point:Counterpoint: Exercise-induced intrapulmonary shunting is imaginary vs. realSusan R. Hopkins, I. Mark Olfert, and Peter D. Wagner1 September 2009 | Journal of Applied Physiology, Vol. 107, No. 3Pulmonary PhysiologyCO2 relaxes parenchyma in the liquid-filled rat lungMichael J. Emery, Randy L. Eveland, Seong S. Kim, Jacob Hildebrandt, and Erik R. Swenson1 August 2007 | Journal of Applied Physiology, Vol. 103, No. 2Therapeutic Hypercapnia and Ventilation-Perfusion Matching in Acute Lung InjuryChest, Vol. 130, No. 1Carbon dioxide added late in inspiration reduces ventilation-perfusion heterogeneity without causing respiratory acidosisThomas V. Brogan, H. Thomas Robertson, Wayne J. E. Lamm, Jennifer E. Souders, and Erik R. Swenson1 May 2004 | Journal of Applied Physiology, Vol. 96, No. 5Modeling kinetics of infused 13NN-saline in acute lung injuryK. O'Neill, J. G. Venegas, T. Richter, R. S. Harris, J. D. H. Layfield, G. Musch, T. Winkler, and M. F. Vidal Melo1 December 2003 | Journal of Applied Physiology, Vol. 95, No. 6Pulmonary Dead Space and SurvivalNew England Journal of Medicine, Vol. 347, No. 11Correlation between ventilation and perfusion determinesV˙a/Q˙ heterogeneity in endotoxemiaAnthony J. Gerbino, Steven McKinney, and Robb W. Glenny1 June 2000 | Journal of Applied Physiology, Vol. 88, No. 6Imaging obstructed ventilation with NMR using inert fluorinated gasesDean O. Kuethe, Arvind Caprihan, H. Michael Gach, Irving J. Lowe, and Eiichi Fukushima1 June 2000 | Journal of Applied Physiology, Vol. 88, No. 6Measurement of cardiac output during exercise by open-circuit acetylene uptakeRebecca C. Barker, Susan R. Hopkins, Nancy Kellogg, I. Mark Olfert, Tom D. Brutsaert, Timothy P. Gavin, Pauline L. Entin, Anthony J. Rice, and Peter D. Wagner1 October 1999 | Journal of Applied Physiology, Vol. 87, No. 4Pulmonary embolization causes hypoxemia by redistributing regional blood flow without changing ventilationWilliam A. Altemeier, H. Thomas Robertson, Steve McKinney, and Robb W. Glenny1 December 1998 | Journal of Applied Physiology, Vol. 85, No. 6Pulmonary gas-exchange analysis by using simultaneous deposition of aerosolized and injected microspheresWilliam A. Altemeier, H. Thomas Robertson, and Robb W. Glenny1 December 1998 | Journal of Applied Physiology, Vol. 85, No. 6Pulmonary Blood Flow Redistribution with Low Levels of Positive End-expiratory PressureAnesthesiology, Vol. 88, No. 5Shunt and ventilation-perfusion distribution during partial liquid ventilation in healthy pigletsElisabeth A. Mates, Jacob Hildebrandt, J. Craig Jackson, Peter Tarczy-Hornoch, and Michael P. Hlastala1 March 1997 | Journal of Applied Physiology, Vol. 82, No. 3Gas Exchange during Gas and Liquid Ventilation1 November 1996 | Journal of Intensive Care Medicine, Vol. 11, No. 6Gas exchange and regional redistribution of pulmonary blood flow during resuscitation of acute pulmonary bead embolizationPulmonary Pharmacology, Vol. 5, No. 4Dynamics of soluble gas exchange in the airways: II. Effects of breathing conditionsRespiration Physiology, Vol. 83, No. 3The matching of ventilation and perfusion in the lung of the Tegu lizard, Tupinambis nigropunctatusRespiration Physiology, Vol. 60, No. 3Interaction of series and parallel dead space in the lungRespiration Physiology, Vol. 54, No. 1Resolution of the multiple inert gas method for estimating V̇a/Q̇ maldistributionRespiration Physiology, Vol. 49, No. 3Interpretation of inert gas retention and excretion in the presence of stratified inhomogeneityRespiration Physiology, Vol. 46, No. 3Inert gas elimination from lungs with stratified inhomogeneity: TheoryRespiration Physiology, Vol. 44, No. 3Gas exchange abnormalities produced by venous gas emboliRespiration Physiology, Vol. 36, No. 1 More from this issue > Volume 44Issue 2February 1978Pages 258-266 Copyright & PermissionsCopyright © 1978 the American Physiological Societyhttps://doi.org/10.1152/jappl.1978.44.2.258PubMed204617History Published online 1 February 1978 Published in print 1 February 1978 Metrics

Measurements of capillary dimensions and blood volume in rapidly frozen lungs.

Measurements of capillary dimensions and blood volume in rapidly frozen lungs.