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85 Cards in this Set
- Front
- Back
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define hemodynamics
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the study of the low of blood and theorces concerned therin
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what is blood made up of?
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-plasma
-blood components(red and white cells) |
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Flow profile
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Flat flow profile=plug flow=low flow in the same direction
Variable flow profile=different velocity and same direction(laminar( |
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Define the doppler effect
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change in freqeuncy of sound caused by a change in motion of source or observer
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The angle btw the ultrasoun beam and blood flow should not be greater than how many degrees? why?
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20 degrees because of underestimation of blood flow
-at 60 degrees, blood flow is underestimated by half. |
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what is the doppler eqation?
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2FVcos/C
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What is the bernouli eqation? what does it represtent?
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4Vsquared
-convective acceleration -change in cross sectional flow area |
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Fast forier
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mathematical procses that anylyzes doppler signal
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WHat is modal frequency?
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greatest doppler ampitude(brightest)
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T/F color flow does not have the same properties as PW?
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false-color flow has all the same properties as PW
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define pusled wave
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1 crystal
-transmits and recieves -governed by niquist limit |
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define continuous wave
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-utilized transducer that receives U/S waves constantly
-2 crystals -1 continuously transmitting -1 continuously receiving |
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what is the advantage of PW?
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able to localize flow
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list the disadvantage of pusled wave
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-PRF depends on depth
-aliasing |
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what is the formula for niquist limit?
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# of pulses/sec
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what are the advantages of continuous wave?
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-no niquist limit
-high velocities w/out aliasing |
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hat are the disadvantages of continusous wave?
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-cannot determine depth
-range ambiguitiy |
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define pusle repitition frequency
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-# of U/S pulses emitted by the transducer/sec
-not frequency related; related to depth |
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define aliasing
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-caused by flow velocity above the niqust limit
-appears above and below the baseline |
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what are color flow controls?
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-color gain
-sector length -depth gain contraol -color maps -varience -smoothing and ensamble |
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what are some indications for doppler?
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-valvular heart disease
-intracardiac wall defects -shunts prosthetic cardiac valves -pathological changes in suply and drainage vessels -filling disturbances of cardiac cavities -diastolic and systolic function |
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T/F Doppler can quantify or define the severity of regurge and stenosis?
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true
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explain doppler of the mitral valve
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-PW of MV-best view is apical 4
-sample at MV tips -Normal flows=0.6-1.3 -low pitch sound -biphasic pattern(m-shape) -postivie shift(above the baseline) |
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explain doppler of the tricuspid valve
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-PW done in more than 1 view
-Doppler views=short axis, RVIV, and apical 4 -lowest flow because of large dimention -flow may increase with respiration -bisphaic flow -normal flow=0.5-0.8 -postive shift above the baseline |
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explain doppler of the aortc valve-
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-PW-best view-apical 5, apical long, suptrasternal, right PX
-highest flow due to smallest area -normal flows=1-2m/s -negative shift below the baseline |
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explain doppler of the pulmonary valve
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-PW of PV-best view is short axis, RVOT
-same flow as AO, but with lower pressures -normal flows=0.6-0.9 -negative shift below the baseline |
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doppler of the pulmonary veins
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best view is apical 4
4 components-early systols, late systole, diastole, flow reversal |
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doppler of hepatic veins
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best view is subcostal
-4 components=systole, systolic flow reversal, diastole, diastolic flow reversal |
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toward the transducer is above the baseline, and away is below
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true
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what are some technical tips for dopler?
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-wide dynamic grayscale
-avoid overgain -filters -adjust scale according to velocities -use a sweep speed of 100 -average measurements |
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define ASD
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atrial septal defect: abnormal flow from Lt to Rt(shunt)
-flow is lower(.25-1m/s) -mest recorded in PSSA or subcostal |
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define VSD
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venstricular septal defect:
-high velocity(because of big difference btw LT and Rt ventricle) -PSLA-best view -rare in adults -get a waveform that's high in systole, and low in diastole. |
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what is the bernouli equation?
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4Vsquared
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what do the variables P and V represent in the bernouli equation?
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P=pressure gradient
V=instantaneous peak velocity |
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what is spectral analysis?
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to asses true blood flow conditions, the signal received must be broken down into individual components by means of spectral analysis. This is charted as amplitude vs. frequency
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how fast does FFT anylize doppler signals?
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25,600 times per second
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what are the 3 components of the bernouli equation?
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1. convection acceleration-when there is a change in the cross sectional flow area
2. flow acceleration-change of flow rate with time 3. viscous friction-caused by friction among blood cells |
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What are volumentric measurements of doppler?
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-stroke volume and cardiac output
-regurgitant volume and fraction -pulmonary-systemic flow ratio |
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what are some intracardiac pressures?
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-pulmonary artery pressres
-left atrial pressures -LV end diastolic pressures |
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what does TVI stand for? how is it measured?
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stroke distance
-measured by tracing PW doppler profile at LVOT(apical 5) |
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what is normal cardiac output?
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4-8l/min
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what is the normal RVOT diamter?
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2.5 cm
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what is the normal RVOT TVI?
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10-13 cm
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what is the normal LVOT diamter?
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1.8-2.2 cm
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what is the normal LVOT TVI?
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18-22cm
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what is the continuity equation based on?
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conservation of flow
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pressure half tie
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time interval for the peak pressure gradient to decrease by half
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what is the continuity eqation? what is the formala for it?
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-flow through a non-stenotic region should equal flow through a stenosis
-(stroke volume)1=(stroke volume)2 -A1 |
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what is pressure half time used for?
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-to estimate the stenotic native mitral valve area(MV=220/PHT)
-to asses the severity of aortic regurge(if it is less than 250, there is sever AO regurge). This is due to rapid increasein LV diastolic pressure and dicrease in aortic pressure. |
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why can the velocity of regurgitant jets be used to determine intracardiac pressures?
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becasue the velocity of regurgitant jets is directly related to the pressure drop across a valve and thereform can ve used to determine intracardica pressures
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What does right ventricular systolic pressure equal?
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systolic pulmonay artery pressure(in the absence of an RVOT obstruction)
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what does pulmonay regurge velocity represent?
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pressure differeces btw PA and RV during diastole
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what is used to estimate pulmonary artery pressure?
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peak pulmonary regurg
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what is acceleration time?
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the time interval btw the beginning of flow and peak velocity.
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where is the sample volume when measuring the acceleration time?
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sample volume is at the pulmonary valve annulus.
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when the pulmonary artery preassures are increased, what happens to the acceration time?
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becomes shorter
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what is normal acceleration time
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less than 120 ms
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what is the pressure gradient btw the LA and LV in systole(normal heart)
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worksheet for solution
answer: 110mmHG |
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-The peak velocity of the aortic valve is 1.5m/s what is the pressure gradient?
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see worksheet
answer: 9mmhg |
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the pressure gradient of the aortic valve is 16mmhg, what is the peak velocity?
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see worksheet
answer: V=2m/s |
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LVOT=2cm
TVI=15 cm HR=65b/min what is the troke volume what is thecardiac outpit? |
SV=47.1ml
cardiac output=3.1l/min |
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LVOT diameter=2cm
VTI(lvot=10cm VTI=50 cm what is the aortic valve area of this patient? PHT=220msec what is the mitral valve area of this patient? |
AVA=0.6cm2
MVA=1cm2 |
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peak tricuspid regurge=4m/s
right atrial pressure=20mmhg what is the pulmonary artery pressure of this patient? |
84mmhg
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what are the 3 ways to get pulmonary artery pressure?
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1. TR=RVSP=PAP
2. PR=end diastole 3. acceleration time |
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What are the 3 measurements for continuity?
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2D diameter of LVOT
PW doppler LVOT CW Ao valve |
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what does CSA stand for?
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cross sectional area`
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explain VTI
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the distance in centimeters that blood travels with each stroke
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what is the formula for stroke volume?
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CSAxTVI=.785d2xTVI
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what is the formula for cardiac output?
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SVxHR
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what is the formula for cardiac index?
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CO/BSA
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what is the acceleration time of severe pulmonary hypertention?
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<60msec
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what is the formula for LVOT area?
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D2x.785
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What is the continuity equation?
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(A1)(TVI1)=(A2)(TVI2)
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how do you figure out mitral valve area?
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220/PHT
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What is PAEDP formula?
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4(PR)2+RAP
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are flow velocities higher with stenosis or insuficiency>
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insuficency
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what is the best way to detect pulmonary hypertention?
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tricuspid regurge-tricuspid jet may be used to estimate right ventricular systolic pressure based on the bernoili eqation.
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why is pulmonay reguge always seen in a normal person?
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because pressures aren't as high, so valve doesn't close as tight. (the a-dip is associated with this)
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explain valvular stenosis?
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valve is diseased and leaflets become thickened and progressively lose their mobility
-valve is narrowed which obstructs flow -stenosis becomes more severe with a decrease in valve orifice and this causes an increase in the pressure gradient |
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what is normal AO valve area?
What is the area with sever AO stenosis? |
normal AV area=3cm2
severe stenosis=.7cm2 |
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what aortic velocities indicate stenosis?
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mild stenosis=1-3m/s
moderate=3-4m/sec severe=greater than or equal to 4m/s |
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what is the pressure gradient of mild and severe AO stenosis?
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mild=<30mmhg
severe>50mmhg |
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what happens to the E-F slopw, and pressure half time with mitral stenosis
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decreased E-F slope which results in an increase ni pressure half time
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what is the normal pressure half time for the mitral valve? what is it in mild and severe stenosis?
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30-60msec
mild stenosis=90-150msec severe=22msec |
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what is the normal MVA, and the MVA in mild and severe stenosis
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normal=4-6cm2
mild=1.5-2.5cm2 severe=<1cm2 |
