Document Detail

Ductus arteriosus wave intensity analysis in fetal lambs: midsystolic ductal flow augmentation is due to antegrade pulmonary arterial wave transmission.
MedLine Citation:
PMID:  19692659     Owner:  NLM     Status:  MEDLINE    
In midsystole, fetal pulmonary trunk (PT) and arterial (PA) blood flows characteristically fall, despite pulmonary blood pressure increasing, while ductus arteriosus (DA) flow continues to rise to a delayed peak. Wave intensity (WI) analysis indicates that midsystolic fetal PT and PA flow reductions are related to a very large midsystolic PA backward-running compression wave (BCW(ms)), which originates in the pulmonary microvasculature and is partially transmitted into the PT. This study tested the hypothesis that midsystolic augmentation of DA blood flow was related to transmission of the PA BCW(ms) into the DA. DA, PT, and PA WI analysis was performed in eight anesthetized late-gestation fetal sheep instrumented with DA, PT, and left PA micromanometer catheters to measure pressure (P) and transit-time flow probes to obtain blood velocity (U). In a subgroup (n = 5), the main PA was briefly occluded to abolish wave transmission from the lungs. WI was calculated as the product of P and U rates of change. PA and PT WI profiles both contained a prominent BCW(ms), approximately 5-fold larger in the PA (P < 0.005), which increased P but decreased U. By contrast, the DA WI profile demonstrated a large midsystolic forward-running compression wave (FCW(ms)), which increased DA P and U, and occurred 5 ms after PA BCW(ms). Furthermore, both DA FCW(ms) and PT BCW(ms) were abolished by main PA occlusion. These results suggest that the fetal PA BCW(ms) undergoes retrograde transmission into the PT as a BCW(ms), but antegrade transmission into the DA as a FCW(ms) that augments midsystolic DA flow.
Joseph J Smolich; Jonathan P Mynard; Daniel J Penny
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2009-08-19
Journal Detail:
Title:  American journal of physiology. Regulatory, integrative and comparative physiology     Volume:  297     ISSN:  1522-1490     ISO Abbreviation:  Am. J. Physiol. Regul. Integr. Comp. Physiol.     Publication Date:  2009 Oct 
Date Detail:
Created Date:  2009-09-28     Completed Date:  2009-10-13     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100901230     Medline TA:  Am J Physiol Regul Integr Comp Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  R1171-9     Citation Subset:  IM    
Department of Paediatrics, Heart Research Group, Murdoch Children's Research Institute, University of Melbourne, Melbourne, Australia.
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MeSH Terms
Blood Flow Velocity
Blood Pressure
Carbon Dioxide / blood
Coronary Circulation*
Ductus Arteriosus / physiology*,  ultrasonography
Echocardiography, Doppler
Fetal Blood / metabolism
Gestational Age
Hydrogen-Ion Concentration
Oxygen / blood
Pulmonary Artery / embryology,  physiology*,  ultrasonography
Pulmonary Circulation*
Regional Blood Flow
Reg. No./Substance:
124-38-9/Carbon Dioxide; 7782-44-7/Oxygen

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

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