TEE 101: What you need to know to know what you needIan Hewer, MA, MSN, CRNAAssistant Director Nurse Anesthesia ProgramWestern Carolina University

Things we will not do today• Learn how to do a perfect TEE exam

• Be ready to pass the Cardiology Boards

More things we are not going to talk about• M-mode• Original echo exam mode• 1 dimensional view that shows structures directly traversed by

beam, plotted against time

• 3-D TEE• Newer technology• Beyond scope of today• Good for mitral valve visualization

Objectives• Outline the function of the TEE

• Outline the major views used for some common problems

• Describe non- CV surgery situations when a TEE might be useful

• Try to think like a 3D computer*

*may not be achievable

Some problems to be aware of• The TEE probe is rigid, & can cause damage

• “Minor”• Dental injury• Soft tissue injury in mouth

• Serious• Esophageal perforation

• Who places the probe?

Poor candidates for TEE• Esophageal narrowing, varices, or other upper GI bleeding

• Previous esophageal or stomach surgery• Esophagectomy, esophageal perforation, obstruction or bleeding

= absolute contraindication

• Full stomach

• Pts with good cardiac function & no valve issues for “monitoring”• Exception- monitoring for air emboli

Some basics• TEE is a form of ultrasound

• Ultrasound uses the reflective properties of different mediums to create a picture• Reflective structures are white; non-reflective are black• What if the structure you want to see is behind something

reflective..?• Contact is critical; air is your enemy!

More basics• (Until recently) images are always 2D= a slice of reality..

• That means orientation is critical..

• ..but picturing orientation is one of the most difficult parts

The slice of cake- more• The U/S beam cuts a slice through the heart• We see a wedge shaped view

• To see a different part of the heart, we have 2 options• Move the probe• Change the angle of the slice

Basic movements• Probe• Advance/withdraw• Flexion• Side-to-side movement• Rotation• Crystal- which way is the beam angled?*

*here’s where the 3D brain comes in handy..

Basic controls

• Gain

• Depth/ focus

• Doppler• Box position & size• (scale)

Gain• More power is good, right?

• WRONG!

• Can adjust gain by depth (more advanced)

Depth/focus• Used to keep focus on area of interest

• Adjustment of focal range usually not as important

• Shhh…kind of intuitive

Doppler analysis (color)• For analysis of valve function, we need to look at flow

• Standard echo is black & white/grayscale, shows MOVEMENT but not FLOW

• Complex computing allows this to be transformed into a color picture

Doppler physics reminder• Remember the police siren..? (easier for the English)

• Doppler effect refers to the compression of waves as an emitter moves towards a receiver, or stretching as it moves away

• Makes pitch change..or in this case, image change

Doppler basic controls• Gain- “just right”

• Color box• Size• Position

• Nyquist limit/scale

Nyquist limit?!• A problem for color flow Doppler

• Determined by the U/S frequency

• Basically, if the speed of blood flow exceeds the Nyquist limit, there will appear to be color flow reversal• Simply put, it will look worse than it should!

• Adjusting the scale can limit/eliminate this problem- can also exaggerate the problem too

Pulsed/continuous wave• Sometimes we want to calculate the velocity of flow- typically

across a valve

• Again, complex math

• Pulsed wave looks at a specific area on the vector • Good for areas of varying velocity where we are interested in one

part & other areas may cause misleading signals, e.g. mitral regurg

• Continuous wave measures all along the vector• Good for high velocity waves e.g. aortic stenosis

3D echo• Latest technology

• Not available on all machines

• Nice for mitral valve repair in particular

• Requires yet another layer of skill

Standard views• 20 standard views

• 4 basic positions from which to obtain these views• Mid esophageal• Transgastric• Deep transgastric• (Upper esophageal)

20 Standard TEE views

Abbreviated views (Miller)

• ME aortic valve SAX• ME aortic valve LAX (with color)• ME bicaval• ME RV evaluation• ME 4 chamber• ME 2 chamber (LV)• TG SAX• Desc aorta SAX

Basic things to look for• Ventricular dysfunction• Poor contractility or filling

• Valvular dysfunction• Masses• Pericardial effusions• Aortic dissection

Step 0• Empty stomach?

• Bite block?

• Equipment ready?

Step 1: ME views• Advance probe to about 28-32 cm

• Et voila!

• Adjust “depth” appropriately to fit size of heart

• Most people will focus exam on area of interest rather than same order every time

ME views• At 0 degrees, maybe slight retroflex, 4 chamber view

• A very gross idea of function, certain abnormalities

• Depth about 14 cm, but adjust in order to see

• In the ME view, we can see a lot of “stuff”

Mitral valve• Valve has 2 leaflets, anterior & posterior, that are split into

scallops

• Our concern is stenotic/calcified or leaky (or both)

• We can view the MV from various angles, but best to start from the 4 chamber view

• While looking at the MV, we can also assess the LV in detail

MV: more• Imaging the MV is complex, & beyond the scope of today

• We will LOOK at 0 deg, 90 deg (2 chamber), 135 deg (LAX)

• In each view, we are looking for problems with the valve, AND ventricular dysfunction

• If leaky, size of the jet is important (sigh) BUT eccentric vs central also critical

LV function in the ME view• 0 deg• 4 chamber view- we can see the lateral & septal walls of the LV, as

well as the free wall of the RV

• 90 deg• 2 chamber (LA & LV) view- we can see the basal/apical segments

of the anterior & inferior LV

• 135 deg• LAX view of the LA/LV, anteroseptal/inferior wall LV

• Note: the TG view is frequently used for LV assessment

Academic CRNAs disregard..

• We often don’t assess the LV in a systematic, rigorous fashion

• Does it matter?

Mitral stenosis/regurgitation• Easy to see a calcified valve

• Determining the degree of stenosis requires calculating a gradient

• Easy to see a regurgitant valve; quantifying not so easy

• Look for “weird” structures!!• Flail or prolapsed leaflet

Systolic Anterior Motion• Can be fatal

• Not always easy to see

• But be suspicious in a patient with HOCM

ME aortic views

• Aortic valve is EASY to see, is usually examined in 2 views

• From ME 4 chamber view:• Pull back slightly• AV in middle of screen (use depth)• Multiplane to about 30 deg • Gives AoV SAX view

More ME aortic views• After the SAX view, multiplane to about 110 deg to see the

LAX view

• This is a great spot to see a regurgitant jet with color flow

• Also good for aortic dissection (Type I)

• And for ascending thoracic aortic aneurysm

ME bicaval view• From this same spot, a slight right turn of the probe will lead

to the bicaval view, usually with multiplane at approx 110 deg

• Shows the right atrium with superior & inferior vena cava

• Can also rotate probe to see the left atrium

• Can see effusions or masses that might restrict inflow here

• Also coronary sinus if having problems with retrograde catheter

Right side of the heart• Crystal back to 0 deg, find the 4 chamber view again

• Pull back a little & multiplane past the AV to 60 deg

• RV & RVOT with pulmonic valve will come into view

• Can also look at the tricuspid & pulmonic valve with color flow

And finally..• Crystal back to 0 deg

• Advance ~ 5 cm

• Anteroflex probe

• If you see the “fisheye” mitral valve view, advance a little further until you see the papillary muscles at 12 & 3 o’clock• Great view for assessment of ventricular function

Short transgastric..more• If you rotate the crystal to 90 deg, you will now have a long

axis view of the left (or right) ventricle

Descending aortic view• From mid esophageal 4 chamber view, rotating the probe to

the left will reveal a great view of the descending aorta

• Pulling up the probe leads to the aortic arch

• Can see thoracic (type III) dissections here

• X-plane- nice way to see 2 cuts at 90 deg to each other on split screen simultaneously

A bad day at the office• TEE is useful because it can give a quick answer

• Consider using it for assessment of hemodynamic collapse with unknown or uncertain etiology

Questions?