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Updated: Jul 26, 2026

Noninvasive Determination of Vortex Formation Time Using Transesophageal Echocardiography During Cardiac Surgery
Published on: November 28, 2018
Hemodynamic-induced changes in aortic valve area: implications for Doppler cardiac output determinations
1Department of Anesthesiology, Yale University School of Medicine, New Haven, Connecticut, USA. gray.pamela_e@west-haven.VA.gov
Transesophageal echocardiography for cardiac output (CO) monitoring can be simplified. Hemodynamic changes cause aortic valve area (AVA) variations, leading to minor CO calculation errors, supporting a less complex protocol.
Area of Science:
- Cardiology
- Medical Imaging
- Hemodynamics
Background:
- Transesophageal echocardiography is used for cardiac output (CO) monitoring.
- A simplified method relies on initial aortic valve area (AVA) measurements.
- Hemodynamic fluctuations can alter AVA, potentially introducing errors.
Purpose of the Study:
- To quantify hemodynamic-induced changes in AVA.
- To assess the impact of AVA variations on CO calculations.
- To validate a simplified CO monitoring protocol.
Main Methods:
- Seventeen anesthetized patients received dobutamine infusion to increase aortic flow.
- Ascending aortic flow velocity (Vmax) and AVA were measured at baseline and peak dobutamine.
- Hemodynamic variables including blood pressure were recorded.
Main Results:
- Dobutamine increased CO by 3.0 L/min and Vmax by 54.5%.
- Systolic blood pressure rose by 50.6%.
- AVA increased by 4.3% (P < 0.001), and the simplified CO method underestimated CO by 0.32 L/min.
Conclusions:
- Hemodynamic changes significantly alter AVA during dobutamine infusion.
- The simplified CO method using a single AVA measurement introduces clinically acceptable error.
- This supports a simplified CO protocol with reduced procedural complexity.
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