Document Detail


Tissue Doppler of early mitral filling correlates with simulated volume loss in healthy subjects.
MedLine Citation:
PMID:  21175513     Owner:  NLM     Status:  In-Process    
Abstract/OtherAbstract:
OBJECTIVES: The accurate noninvasive assessment of preload in emergency department (ED) patients remains elusive. Point-of-care ultrasound (US) imaging, particularly evaluation of the inferior vena cava (IVC), has been shown to be qualitatively helpful. Doppler and tissue Doppler are now routinely available on ED US equipment, but few studies have looked at the correlation of dynamic changes in these parameters in a controlled model of hypovolemia. Our objective was to examine the correlation of Doppler parameters to simulated volume loss in healthy subjects using a lower-body negative pressure (LBNP) model and to compare these measurements to commonly used IVC measurements of preload.
METHODS: Twelve paid volunteers with no known cardiovascular disease between the ages of 23 and 31 years old (mean ± SD = 25.5 ± 2.5 years old) were recruited. Hypovolemia was simulated using graduated LBNP levels with measurements taken at 0, -30, and -60 mm Hg and lower pressures as tolerated. Vital signs were monitored in all patients. US measurements recorded at each negative pressure level included IVC maximum (IVC(max)) and minimum (IVC(min)) dimensions; early (E) and late (A) transmitral filling velocities using pulsed-wave spectral Doppler; and early (E') and late (A') tissue Doppler velocities at the septal ((sep)) and lateral ((lat)) mitral annulus, using pulsed-wave tissue Doppler.
RESULTS: Lower-body negative pressure correlated significantly and positively within subjects for all US parameters except for the A filling wave. E'(lat) and E'(sep) showed the strongest correlation with R² values of 0.749 (95% confidence interval [CI] = 0.577 to 0.854) and 0.738 (95% CI = 0.579 to 0.875) respectively, followed by A'(sep) 0.674 (95% CI = 0.416 to 0.845), IVC(max) 0.638 (95% CI = 0.425 to 0.806), A'(lat) 0.547 (95% CI = 0.280 to 0.802), IVC(min) 0.512 (95% CI = 0.192 to 0.777), and E 0.478 (95% CI = 0.187 to 0.762). Ratios correlated only moderately with LBNP level, including E/ E'(lat) R² of 0.430 (95% CI = 0.131 to 0.706), E/ E'(sep) 0.416 (95% CI = 0.183 to 0.686), and IVC collapsibility index (IVC(CI)) 0.201 (95% CI = 0.003 to 0.681). Vital signs, including heart rate and blood pressure, did not vary significantly with LBNP levels.
CONCLUSIONS: In this pilot study of healthy subjects, tissue Doppler assessment of early diastolic filling correlated most strongly with simulated hypovolemia.
Authors:
Christopher L Moore; Edward T Tham; Kathleen J Samuels; Robert L McNamara; Nicholas J Galante; Nina Stachenfeld; Kirk Shelley; James Dziura; David G Silverman
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Academic emergency medicine : official journal of the Society for Academic Emergency Medicine     Volume:  17     ISSN:  1553-2712     ISO Abbreviation:  Acad Emerg Med     Publication Date:  2010 Nov 
Date Detail:
Created Date:  2010-12-23     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9418450     Medline TA:  Acad Emerg Med     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1162-8     Citation Subset:  IM    
Copyright Information:
© 2010 by the Society for Academic Emergency Medicine.
Affiliation:
Department of Emergency Medicine, Yale University School of Medicine, New Haven, CT, USA. chris.moore@yale.edu
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