Assessment of
perioperative
hemodynamics
S.Zahra Ojaghi Haghighi .MD,
FACC
Hemodynamic Data Obtainable with 2-D
Doppler Echocardiography
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Volumetric measurement
Pressure gradients
Valve area
Intracardiac and pulmonary
artery pressures
Ventricular dp/dt
Assessment for Accurate Doppler
Stroke Volume Calculations
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Blood flow is laminar with a spatially flat flow
velocity profile.
Measurements of the velocity-time integral
and cross-sectional area(i.e,diameter) are
made at the same anatomic location.
The velocity-time integral measurement
represents the average velocity-time
integral(several measurements shouId be
averaged for a patients in normal sinus
rhythm,whereas 8 to 10 should be averaged
for a patient in atrial fibrillation.
The velocity- time integral is measured with
doppler beam parallel to blood flow
Calculation of Cardiac Output
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Usually measured at LVOT or aortic valve in
the absence of AI.
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Correlate well with thermodilution.
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Doppler TEE has been used for continuous
measurement of CO
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CO=SV*HR
SV=CSA*VTI
CSA=0.785*D(LVOT)*D(LVOT)
Method
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LVOT(probe in the stomach,turned leftward,in the
flexed position):
1-Parallel pulse Doppler of LVOT
2-Diameter obtained from either
the stomach or the midesophageal 120degree view
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RVOT by pulse wave
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Pulmonary artery by pulse wave
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Aortic valve by continuous wave(cross-setional area of
the aortic valve during mid systole)
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Mitral valve(CSA=0.785*D1*D2)
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LVOT Stroke Volume
Calculation
Pulse wave SV in LVOT proximal to the
AV(approximately 1cm)
Determination of the LVOT VTI:
Transgastric long axis view or
deep transgastric long axis view
Diameter of LVOT:
midesophageal long-axis view of aortic
valve(approximately 1 cm)
SV=CSA*LVOT VTI
Practical consideration
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For intraoperative TEE ,LVOT is the
most reproducible.
Accuracy is improved by assessing
multiple Doppler flow profiles,typically
3-5 for a regular rhythm and 10 for an
irregular rhythm.
Pulmonary –Systemic Flow
Ratio(QP/QS)
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Indicates:
Magnitude of a shunt(ASD,VSD,
PDA)
Timing of surgery
Method
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Systemic SV(at LVOT or AV)
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Pulmonic SV(at PA or RVOT)
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Qp/Qs=(PA SV * HR) / (LVOT SV * HR)
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QP/Qs=PA SV / LVOT SV
Doppler Measurement of
Regurgitant Volume and Fraction
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Volumetric Method
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Proximal Convergence Method
Assessment of Mitral Regurgitation
by Volumetric Method
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RVmv=SV mvi – SV lvot
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RVmv(%)=(RVmv/SVmvi)*100%
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Perform infrequently during TEE
due to time and possible error in
SVmvi
Assessment of Mitral Regurgitation by
Proximal Convergence Method(PISA)
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PISA flow=MR flow
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2* 3.14 * r2 * PISA velocity=EROA * MRv
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6.28 * r2 * Aliasing velocity=EROA * MRv
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EROA=PISA flow rate/Regurgitant velocity
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EROA=(6.28 * r2 *Aliasing velocity)/MRv
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RV=EROA * VTI(reg jet)= (6.28 * r2 *Aliasing velocity *
VTIreg jet)/MRv
Method
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Color flow imaging of PISA from
MR
PISA radius
Aliasing velocity
Continuous Dopplerof MR jet to
measure peak velocity and VTI of
MR
Simplified proximal
convergence method
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Based on the assumption:
MR velocity =5 m/s
Aliasing velocity is set at 40 cm/s
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EROA=r2/2
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Doppler Measurments of
Pressure Gradients
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Bernoulli euation:
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dP= 4(V2-V1)2
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dP=4(V2)2
Doppler Determination of
Valve Area
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Continuity equation:
SV1=SV2
CSA1 * VTI1=CSA2 * VTI2
CSA2=CSA1 * (VTI1/VTI2)
Doppler Determination of
Valve Area
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Flow Convergence Method:
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CSA=PISA flow/peak velocity
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CSA= (6.28 * r2 * Aliasing velocity/VMS)
Pressure Half-time
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Defined as the time required for the
peak pressure gradient to decline by
50%
MVA(cm2)=220/PHT
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PHT(msec)=0.29 * DT(msec)
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AI severity and acute AI(<250msec)
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Intracardiac Pressure
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RVSP=4(VTR)2+RAP
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RVSP=SBP - 4(Vvsd)2
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MPAP=4(Vearly PI)2 + RAP
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PADP=4(V late PI)2 +RAP
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LAP=SBP – 4(VMR)2
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LVEDP=DBP – 4(Vend AI)2
PVR
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PVR=TRV / VTI RVOT* 10 + 0.16
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TRV/VTI
RVOT
<0.2 = low PVR
LVEDP
PVa duration>MVA duration
PVa >35CM/S
Mean LAP=35-0.39 * (systolic fraction)
DTof MV
Systolic fraction of PV
E/Em >15 ,E/Vp>2.6
LAP=(1.24 * E/Em) +1.9
PAWP
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PAWP=5.27 * (E/Vp) + 4.6
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PAWP=1000 / (2 * IVRT)+Vp
Estimation of RAP
Doppler Measurement of
dp/dt
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Calculated from time interval between
1m/s and 3m/s on MR Doppler
velocity using simplified Bernoulli
equation to calculate the LA-LV
pressure gradients.
LVdp/dt=32mmHg/dt
LV dp/dt
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Normal >=1200mmHg/sec
Reduced LV
dysfunction<1000mmHg/sec
Positioning of Intravascular
Devices
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Intra-aortic Balloon Pump
LV assist device
RV assist Device(to avoid
impingement on the tricuspid
valve
LV Vent(to drain excess
ventricular volume on bypass.
Assessment of preload(LV
volume)
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Doppler estimation of LA pressure
1-SBP-MRgradient=LA pressure
2- systolic fraction in PVinflow
3-TDI(1.24*E/E1)+1.9
2-D measurement ofLV cross-sectional
area