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