Function Equations
Continuity Equation
PISA
100
What is the CSA Equation?
Given a diameter of 2.0 cm, what would the CSA be?
CSA= 0.785 x Diameter2
CSA= 0.785 x 22
CSA= 3.14 cm2
100
What is the Continuity Equation used to measure?
What are the measurements needed to perform this equation on the Mitral Valve?
Valve Area
LVOT diam, LVOT VTI, MV VTI
100
What do you use PISA to find? (in general, and specifically)
It calculates the effective regurgitant orifice area (EROA) and regurgitant volume by measuring the radius
It is used to measure the Severity of a Regurgitaion
200
What is the Equation for Stroke Volume?
What measurements would you need to perform in order to get the Stroke Volume?
SV= VTI x CSA
You would need to get the LVOT diameter, and trace the AV CW in order to get the VTI.
200
What is the Continuity Equation?
CSAsten= (CSAproxx VTIprox)/VTIsten
V1= VTIProx
V2= VTISten
200
What is done to the nyquist limit when measuring PISA during a TEE?
During a TTE?
TEE- baseline up to ~30
TTE- baseline down to ~30
300
What is Cardiac output measuring?
What is the unit used for this measurement?
What is the Equation for Cardiac Output?CO measures the amount of blood pumped out of the ventricle per minute
CO unit is L/min (or ml/sec)
CO= SVxHR
300
To Measure AVA with the continuity equation, what measurements would you need to acquire?
What would the equation look like?
LVOT diam, AV VTI, LVOT VTI
AVA= (CSAlvot x VTIlvot)/VTIAV
300
What measurements do you need to perform PISA of MV on Echo
Color of MV with Nyquist limit turned down around 30, measuring the Pisa Radius (r)
Trace the MR CW jet (VTI)
400
What is the Cardiac Output Index (CI)?
What is the equation for this?
The Cardiac output normalized with the patient's BSA.
CI= (SVxHR)/BSA
400
What is the equation for Dimensionless Index?
How Is the Dimensionless Index a better measurement than Continuity Equation?
DI= Peak Vellvot/Peak VelAV
It doesn't use the LVOT Diam, therefore there are fewer chances for overestimation (because the LVOT Diam is 2 in the continuity equation.
400
What is the EROA Equation?
((2pir^2)Va)/(Vp)
Va= aliasing velocity
Vp= peak regurgitant volume
500
you are evaluating a patient in the ICU. these are some of the numbers you have measured.
HR= 80 bpm
LVOT diam- 2.0 cm
LVOT VTI- 15 cm
Mitral VTI- 12 cm
BP 130/70
Using the above information what is this patient's CO?
A. 3.0 L/min B. 3.3 L/min
C. 3.8 L/min D. 4.0 L/min
E. 4.5 L/min
CSA= 0.785x22= 3.14
SV= 15x3.14 = 47.1
CO= 47.1x 80 =3,768 ml/sec
CO= 3.768 L/Min
500
What is the MV Continuity Equation?
What measurements are needed to solve the Continuity equation for the Mitral valve?
MVA = CSALVOT x VTIlvot/VTImv
LVOT Diam, LVOT VTI, MV VTI
500
What is the equation for simplified EROA (estimated regurgitant Orifice Area)?
What is assumed with this simplified version?
EROA= R2/2
assumes
Nyquist at 40
MR Vel = 500