The Echo Doesn't Lie by Murphy
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Transcript of The Echo Doesn't Lie by Murphy
T H E E C H O D O E S N ’ T L I E
D E I R D R E M U R P H Y A L F R E D I C U
E C H O D O E S N ’ T L I E B U T I T C A N B E N D T H E T R U T H A L I T T L E
E C H O I S B A S E D O N A N U M B E R O F A S S U M P T I O N S
E C H O I S B A S E D O N A N U M B E R O F A S S U M P T I O N S
Sound travels at same speed though all tissues (It doesn’t)
Echoes are generated from centre of the beam
!
Z O E T R O P E T Y T H E TA S M A N I A N T I G E R
Important in utilising the technology that we understand the limitations so that we can use it to its full potential
C O M M O N H A E M O D Y N A M I C I N F O R M A T I O N
and the pitfalls in their measurement..
C A R D I A C O U T P U T
fundamental measure in critically ill patient
LVOT method
Assumes the LVOT is a cylinder
We can measure the VTI of blood flow in the LVOT by placing a pulse wave doppler gate in LVOT
This gives us the LVOT VTI
M A T H S …
Volume =CSA X height (distance)
!
Stroke volume= π r2 X VTI
!
Cardiac output= SV x heart rate
any measurement error will be
squared !
CSA= π r2
Major pitfalls
!
Flow acceleration at valve- measure 1 cm back
Ensure line up with cursor- inaccurate if >10°
U S E V I E W W I T H T H E B E S T D O P P L E R L I N E U P - D I F F E R E N T F O R D I F F E R E N T PA T I E N T S
5 chamber view
3 chamber view
H O W D O Y O U K N O W Y O U ’ V E G O T A G O O D D O P P L E R T R A C E
PW Doppler spectral outline
Trace not “filled in”- in moving front of blood flow
Not jagged feathery ends
Measurement of VTI or stroke distance
Average 3 in sinus rhythm Average 5 if arrhythmia
T H E LV O T I S E L L I P S O I D
! !
! !
A G R E E M E N T W I T H T H E R M O D I L U T I O N
Reasonable
Operator needs to be aware of the sources of error
!
Patient commenced on adrenaline after study
LVOT measured at 1.0 cm, VTI N
LVOT in adult 1.8-2.6
R V S P ( PA P R E S S U R E E S T I M A T I O N )
Based on Bernoulli equation
Pressure gradient =4V2
RVSP= PG + CVP
PA pressure = RVSP
W H A T A R E T H E R E Q U I R E M E N T S ?
Need to evaluate in a number of views to get the best line up with the colour jet
R S I D E D C A R D I A C O U T P U T
Useful to quantify shunts,
MCS RVOT inflow
velocites lower and vary with
respiration
PA Diastolic (PR jet) 8 mm (+ RAP) mmHg
PA pressure estimation from Pulmonary Acceleration time
W H A T A B O U T V O L U M E S TA T E A N D E C H O ?
E A R LY S T U D I E S L O O K E D A T LV E D A
Problems as doesn’t take into
account compliance
afterload states
S TA T I C E S T I M A T E S O F R A T R I A L P R E S S U R E A N D E C H O
IVC dimension (spontaneous breathing) and collapsibility
!
IVC = <2.1 and varies > 50% Estimated RAP =3
In between =8
IVC = > 2.1 and doesn’t vary Estimated RAP =15
L H E A R T P R E S S U R E SEcho assessment of left atrial pressure
!
Mitral valve E/e’
E/A > 2 PAOP >18
!
E/e’ > 15 PAOP > 18
S O M U C H F O R S TA T I C PA R A M E T E R S . .
F U N C T I O N A L H A E M O D Y N A M I C S
Describing the effects of cardiorespiratory interactions in positive pressure ventilation
IVC distensibility index
Change in IVC with positive pressure
!
> 18% significant !
Sensitivity 90% Specificity 100%
– Cut off of 18%
–Max IVC D-min IVC D/ Mean IVC D Max IVC diameter-min IVC diameter/ mean IVC diameterFeissel et al ICM 2004
SVC collapsibility
V useful as intrathoracic
TOE
>36% significantMax-Min/Max
value
Viellard-Baron et al ICM 2004
P U L S E P R E S S U R E VA R I A B I L I T Y / S T R O K E V O L U M E VA R I A B I L I T Y
Can assess with echo
Need to be v entilated
Sinus rhythm
PA S S I V E L E G R A I S E
Volume responsiveness and echo using passive leg raise
Change in VTI (SV) of 12% predicts fluid responsiveness
Lamia et al ICM 2007. Monnet at al CCM 2006
VTI =19 VTI =27
45%
Mandeville. Can Transthoracic Echo be Used to Predict Fluid
Responsiveness in Critically Ill? Crit Care Research and Practice 2012
3 HEART BEATS
INSPIRATION
POST INSPIRATORY DROP IN LV OUTPUT ONLY IF VOLUME RESPONSIVE
B E N E F I T O F U S I N G E C H O
assess for false positives
W O U L D Y O U G I V E F L U I D T O E I T H E R O F T H E S E PA T I E N T S ?
A V O L U M E R E S P O N S I V E N E S S S T U D Y W I L L T E L L Y O U B O T H
Increase intrathoracic pressure
Increase RV after load
Decreased RV stroke volume
Decrease LV stroke volume
V E N T R I C U L A R S Y S T O L I C F U N C T I O N
E C H O A S S E S S M E N T O F LV F U N C T I O N
F R A C T I O N A L S H O R T E N I N G
!
many assumptions
inaccurate if wall motion abnormality
any errors in measurement will be cubed for EF measurement
B I P L A N E S I M P S O N ’ S
1. Trace ED area A4C 1. Trace ES area A4C
B I P L A N E S I M P S O N ’ S
3. Trace ED area A2C 4. Trace ES area A2C
E Y E B A L L M E T H O D
3 D E C H O
Impressive pictures and more accurate quantification
R I G H T V E N T R I C L E
R V S Y S T O L I C F U N C T I O N
TAPSE >1.6cm
(Tricuspid Annular Plane Systolic Excursion)
R V S Y S T O L I C F U N C T I O N
S’ > 10 cm/S N
S O W H Y U S E E C H O A S A H A E M O D Y N A M I C T O O L ? ?
Tells you what the problem is currently (not just the haemodynamic effects of the problem)
!
What’s causing it
!
If what you are doing about it helps
C A S E S T U D Y
72 yo man post CAGs X 2 and AVR
“Good” LV intra-operative
Hypotensive
MAP 65 PAC: CO 3.6/ C.I 1.8
PA pressures 56/30
CVP 18
Management?
Inotropes and vasopressor: Milrinone 10 mcg/min, adrenaline 7 mcg/min, Noradenaline 17 mcg/min
D I F F E R E N T I A L
? Tamponade
? Graft ischaemia
Dx LV outflow tract obstruction (with
SAM)
Rx: Avoid hypovolaemia
Avoid inotropy Maintain afterload
D Y N A M I C LV O T O
Seen after cardiac surgery classically AVR
Seen in non-cardiac surgery patients also esp elderly females with hx HTN and DM
Haemodynamic situation worsened by inotropes and can contribute to downward spiral
S U M M A R Y
Echo plays key role in assessment of haemodynamics
Helps identify false positives in terms of volume responsiveness
Adds a subtlety to the haemodynamic assessment
Is user dependant and like any tool is more powerful when used optimally