Assessment of perioperative hemodynamics
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Transcript Assessment of perioperative hemodynamics
Assessment of
perioperative
hemodynamics
S.Zahra Ojaghi Haghighi .MD,
FACC
Hemodynamic Data Obtainable with 2-D
Doppler Echocardiography
Volumetric measurement
Pressure gradients
Valve area
Intracardiac and pulmonary
artery pressures
Ventricular dp/dt
Assessment for Accurate Doppler
Stroke Volume Calculations
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
Usually measured at LVOT or aortic valve in
the absence of AI.
Correlate well with thermodilution.
Doppler TEE has been used for continuous
measurement of CO
CO=SV*HR
SV=CSA*VTI
CSA=0.785*D(LVOT)*D(LVOT)
Method
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
RVOT by pulse wave
Pulmonary artery by pulse wave
Aortic valve by continuous wave(cross-setional area of
the aortic valve during mid systole)
Mitral valve(CSA=0.785*D1*D2)
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
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)
Indicates:
Magnitude of a shunt(ASD,VSD,
PDA)
Timing of surgery
Method
Systemic SV(at LVOT or AV)
Pulmonic SV(at PA or RVOT)
Qp/Qs=(PA SV * HR) / (LVOT SV * HR)
QP/Qs=PA SV / LVOT SV
Doppler Measurement of
Regurgitant Volume and Fraction
Volumetric Method
Proximal Convergence Method
Assessment of Mitral Regurgitation
by Volumetric Method
RVmv=SV mvi – SV lvot
RVmv(%)=(RVmv/SVmvi)*100%
Perform infrequently during TEE
due to time and possible error in
SVmvi
Assessment of Mitral Regurgitation by
Proximal Convergence Method(PISA)
PISA flow=MR flow
2* 3.14 * r2 * PISA velocity=EROA * MRv
6.28 * r2 * Aliasing velocity=EROA * MRv
EROA=PISA flow rate/Regurgitant velocity
EROA=(6.28 * r2 *Aliasing velocity)/MRv
RV=EROA * VTI(reg jet)= (6.28 * r2 *Aliasing velocity *
VTIreg jet)/MRv
Method
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
Based on the assumption:
MR velocity =5 m/s
Aliasing velocity is set at 40 cm/s
EROA=r2/2
Doppler Measurments of
Pressure Gradients
Bernoulli euation:
dP= 4(V2-V1)2
dP=4(V2)2
Doppler Determination of
Valve Area
Continuity equation:
SV1=SV2
CSA1 * VTI1=CSA2 * VTI2
CSA2=CSA1 * (VTI1/VTI2)
Doppler Determination of
Valve Area
Flow Convergence Method:
CSA=PISA flow/peak velocity
CSA= (6.28 * r2 * Aliasing velocity/VMS)
Pressure Half-time
Defined as the time required for the
peak pressure gradient to decline by
50%
MVA(cm2)=220/PHT
PHT(msec)=0.29 * DT(msec)
AI severity and acute AI(<250msec)
Intracardiac Pressure
RVSP=4(VTR)2+RAP
RVSP=SBP - 4(Vvsd)2
MPAP=4(Vearly PI)2 + RAP
PADP=4(V late PI)2 +RAP
LAP=SBP – 4(VMR)2
LVEDP=DBP – 4(Vend AI)2
PVR
PVR=TRV / VTI RVOT* 10 + 0.16
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
PAWP=5.27 * (E/Vp) + 4.6
PAWP=1000 / (2 * IVRT)+Vp
Estimation of RAP
Doppler Measurement of
dp/dt
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
Normal >=1200mmHg/sec
Reduced LV
dysfunction<1000mmHg/sec
Positioning of Intravascular
Devices
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)
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