perioperative echo

Adult Echo Calculator

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Body Surface Area

Body Surface Area

Body Surface Area can be calculated using a variety of formulas. The Du Bois formula is used here. BSA = 0.007184 × W to the power of 0.425 × H to the power of 0.725.

LV Dimensions

LV Dimensions

LV Dimensions are measured in systole and end-diastole in the PLAX view. Either M-Mode or 2D measurements can be made, but 2D is preferred. The measurement should be made 1cm distal to the tips of the mitral valve leaflets. Fractional Shortening (FS%) can be used to determine LV systolic function. A value >24% is considered indicative of normal LV systolic function. FS% < 14% indicates severe LV systolic failure.

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Stroke Volume & Cardiac Output

Stroke Volume & Cardiac Output

Stroke volume is calculated by multiplying the LVOT VTI and cross-sectional area of the LVOT. Normal stoke volume is between 47-99ml in women and 55-127ml in men. Cardiac output is obtained by multiplying stroke volume and heart rate.

Stroke Volume Index (SVI) relates SV to body surface area (BSA), thus relating heart performance to the size of the individual. The unit of measurement is millilitres per square metre (ml/m2). SVI = SV/BSA. ​Normal values for a resting healthy individual would be approximately 35-65mL/m2.

In general, a normal range for cardiac output at rest is between 4.0 - 8.0 L/min, with the average being 5 L/min. The normal value for the cardiac index should be between 2.5 - 4.0 L/min/m2.

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Aortic Valve

Aortic Valve Area: Continuity Equation

Aortic Valve Area: Continuity Equation

The aortic valve area can be calculated with the continuity equation. The continuity equation ids based on the conservation of mass principle. The volume (flow) of blood through the LVOT must be equal to the volume (flow) of blood through the aortic valve.

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Aortic Valve Index

Aortic Valve Index

The dimensionless index is obtained by dividing LVOT VTI by AV VTI. Peak or mean velocities can also be used. It is also known as the aortic valve index. The major source of error in calculation of AVA is measurement of left ventricular outflow tract (LVOT) diameter and area. The dimensionless index ignores LVOT size and instead considers the simple ratio of LVOT to aortic velocity.

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