Hypoxia-induced intrapulmonary arteriovenous shunting at rest in healthy humans
- 1 October 2010
- journal article
- research article
- Published by American Physiological Society in Journal of Applied Physiology
- Vol. 109 (4), 1072-1079
- https://doi.org/10.1152/japplphysiol.00150.2010
Abstract
Intrapulmonary arteriovenous (IPAV) shunting has been shown to occur at rest in some subjects breathing a hypoxic gas mixture [fraction of inspired oxygen (FiO2) = 0.12] for brief periods of time. In the present study we set out to determine if IPAV shunting could be induced at rest in all subjects exposed to hypoxia for 30 min. Twelve subjects (6 women) breathed four levels of hypoxia (FiO2 = 0.16, 0.14, 0.12, and 0.10) for 30 min each in either an ascending or descending order with a 15-min normoxic break between bouts. Saline contrast echocardiography was used to detect IPAV shunt and a shunt score (0–5) was assigned based on contrast in the left ventricle with a shunt score ≥ 2 considered significant. Pulmonary artery systolic pressure (PASP) was determined using Doppler ultrasound. The total number of subjects demonstrating shunt scores ≥ 2 for FiO2 = 0.16, 0.14, 0.12, and 0.10 was 1/12, 7/12, 9/12, and 12/12, respectively. Shunt scores were variable between subjects but significantly greater than normoxia for FiO2 = 0.12 and 0.10. Shunt scores correlated with peripheral measurements of arterial oxygen saturation (SpO2) ( r w = −0.67) and PASP ( r w = 0.44), despite an increased shunt score but no increase in PASP while breathing an FiO2 = 0.12. It is unknown how hypoxia induces the opening of IPAV shunts, but these vessels may be controlled via similar mechanisms as systemic vessels that vasodilate in response to hypoxia. Despite intersubject variability our results indicate significant IPAV shunting occurs at rest in all subjects breathing an FiO2 = 0.10 for 30 min.Keywords
This publication has 43 references indexed in Scilit:
- Exercise-induced intrapulmonary arteriovenous shunting in healthy humansJournal of Applied Physiology, 2004
- Echocardiographic and invasive measurements of pulmonary artery pressure correlate closely at high altitude.American Journal of Physiology-Heart and Circulatory Physiology, 2000
- Time course of the human pulmonary vascular response to 8 hours of isocapnic hypoxia.American Journal of Physiology-Heart and Circulatory Physiology, 1997
- Hypoxia-induced activation of KATP channels limits energy depletion in the guinea pig heartAmerican Journal of Physiology-Heart and Circulatory Physiology, 1995
- Two-dimensional contrast echocardiography in the detection and follow-up of congenital pulmonary arteriovenous malformationsThe American Journal of Cardiology, 1991
- Hypoxic Dilation of Coronary Arteries Is Mediated by ATP-Sensitive Potassium ChannelsScience, 1990
- Continuous wave doppler determination of right ventricular pressure: A simultaneous Doppler-catheterization study in 127 patientsJournal of the American College of Cardiology, 1985
- Quantitative assessment of pulmonary hypertension in patients with tricuspid regurgitation using continuous wave doppler ultrasoundJournal of the American College of Cardiology, 1985
- Guinea pig ductus arteriosus. I. Cellular and metabolic basis for oxygen sensitivityAmerican Journal of Physiology-Legacy Content, 1971
- The Pulmonary Circulation1The Journal of Physiology, 1894