Document Detail

Wave intensity analysis of right ventricular and pulmonary vascular contributions to higher pulmonary than aortic blood pressure in fetal lambs.
MedLine Citation:
PMID:  20562335     Owner:  NLM     Status:  MEDLINE    
Although fetal pulmonary trunk (PT) blood pressure may exceed aortic trunk (AoT) pressure, the specific mechanism(s) underlying this pressure difference remain undefined. To evaluate the potential role of ventricular and vascular factors in the generation of a fetal PT-AoT pressure difference, nine anesthetized late-gestation fetal sheep were instrumented with PT and AoT micromanometer catheters to measure high-fidelity pressure and transit-time flow probes to obtain blood velocity. The PT-AoT instantaneous pressure difference (IPD(PT-AoT)) was calculated from PT and AoT pressure profiles. PT and AoT wave intensity (WI) was derived from the product of the appropriate pressure and velocity rates of change. While diastolic pressures were near identical, systolic PT pressure exceeded AoT pressure (P < 0.001), with a maximal IPD(PT-AoT) of 6.5 +/- 2.5 mmHg. The comparison of IPD(PT-AoT) with wave-related PT and AoT pressure changes indicated that 1) a greater pressure-generating effect of the PT forward-running compression wave arising from impulsive right ventricular contraction in early and midsystole accounted for 2.3 +/- 2.3 mmHg (35%) of the maximal IPD(PT-AoT) and 2) a larger pressure-generating effect of a large midsystolic backward-running compression wave transmitted into the PT from the pulmonary vasculature contributed 4.0 +/- 1.5 mmHg ( approximately 60%) of the maximal IPD(PT-AoT). These results indicate that the higher PT than AoT blood pressure observed in fetal lambs is a systolic phenomenon principally related to the combination of a relatively higher level of right ventricular pump function manifest in early and midsystole and a pressure-increasing energy wave arising from the fetal pulmonary vasculature in midsystole.
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:  2010-06-18
Journal Detail:
Title:  American journal of physiology. Heart and circulatory physiology     Volume:  299     ISSN:  1522-1539     ISO Abbreviation:  Am. J. Physiol. Heart Circ. Physiol.     Publication Date:  2010 Sep 
Date Detail:
Created Date:  2010-08-31     Completed Date:  2010-09-22     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100901228     Medline TA:  Am J Physiol Heart Circ Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  H890-7     Citation Subset:  IM    
Heart Research Group, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia.
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MeSH Terms
Analysis of Variance
Aorta / physiology*
Blood Flow Velocity / physiology
Blood Pressure / physiology*
Fetus / physiology*
Pulmonary Artery / physiology
Pulmonary Circulation / physiology*
Ventricular Function, Right / physiology*

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

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