How to get a Regurgitant Fraction by Continuity Equation in Pulmonary Regurgitation.
Measure the Diameter of the RVOT. The diameter can be of the RVOT should be obtained from the midesophageal RVIO view, in mid systole, and under the zoom mode. The view of the RVOT should not be an obtuse angle view. The pulmonary valve leaflets should be clearly seen. The zoom mode will decrease the error present in the calculation. Since the RVOT diameter changes throughout systole, the mid systole measurement should be obtained.
Obtain a VTI of the RVOT. The VTI of the RVOT is obtained from a PWD of the RVOT. The CWD of the LVOT should be obtained. The CWD beam should not be off more than 15Âº from parallel to the RVOT flow. After tracing the flow on the echocardiographic machine, a VTI of the CWD tracing will be calculated.
Obtain a Tricuspid Valve Diameter. The area of the tricuspid valve can be calculated from this measurement. This enter some inaccuracy into the equation since the mitral valve is not a circle (it is oval). Therefore, the aortic valve could be used instead. This measurement is to be used to generate a value that represents normal forward flow in the cardiac cycle. The valve included in the measurements should not have significant regurgitation.
Obtain a Tricuspid Valve VTI. Using the PWD mode, trace the envelope of the entire (E wave and A wave) flow profile of the tricuspid valve.