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In vitro validation of a right ventricular thermodilution ejection fraction system
R Mukherjee1, F G Spinale, A F von Recum
1Division of Cardiothoracic Surgery, Medical University of South Carolina, Charleston 29425.
Annals of Biomedical Engineering
|January 1, 1991
Summary
Thermodilution (TD) methods offer a simplified way to measure right ventricular ejection fraction (RVEF). This study found TD accurately predicts RVEF in vitro, independent of heart rate, suggesting clinical utility.
Area of Science:
- Cardiovascular physiology
- Medical device technology
Background:
- Right ventricular ejection fraction (RVEF) assesses RV pump function but clinical measurement requires complex imaging.
- Thermodilution (TD) methods using rapid response thermistors are proposed as a simpler alternative for RVEF measurement.
Purpose of the Study:
- To validate thermodilution-derived ejection fraction (EFTD) against known ejection fractions (EF) in an in vitro system.
- To assess the influence of stroke rate on TD measurements of EF.
Main Methods:
- An in vitro system was used to compare EFTD with known EF values ranging from 17-78%.
- Stroke rates were varied independently from 50-100 strokes/min.
- EFTD was calculated by fitting the downslope of the TD curve to a monoexponential function.
Main Results:
- A significant correlation was found between EFTD and actual EF (r = 0.96, p < 0.001).
- Bias analysis indicated measurements were within a 95% confidence interval of +/- 12%.
- Multivariate analysis showed stroke rate did not significantly affect TD measurements (r = 0.03, p > 0.7).
Conclusions:
- Thermodilution accurately predicts ejection fraction in an in vitro setting.
- TD measurements of EF appear independent of stroke rate.
- TD methods may offer a simple, reliable approach for serial RVEF assessment in clinical practice.