Week 12 Handout TEE

Question 1

What is Transesophageal Echocardiography (TEE)?

Answer 1

TEE is a semi-invasive ultrasound-based tool, inaudible to human ear, used to obtain high-resolution cardiac images.

Question 2

What is the primary use of TEE?

Answer 2

It helps assess heart structure and function in real time, especially during surgery.

Question 3

What ultrasound frequencies does TEE use?

Answer 3

Uses ultrasound frequencies >20,000 Hz; TEE range is typically 3.5–7.5 MHz.

Question 4

How do piezoelectric crystals function in TEE?

Answer 4

Piezoelectric crystals in the probe emit and receive sound waves.

Question 5

What is the effect of shorter, high-frequency pulses in TEE?

Answer 5

Shorter, high-frequency pulses result in clearer images (better resolution).

Question 6

How are echoes from tissues processed in TEE?

Answer 6

Echoes from tissues are converted into electrical signals and displayed as images.

Question 7

What are the primary ultrasound imaging modes in TEE?

Answer 7

M-Mode, 2D Imaging, and 3D Imaging.

Question 8

What is M-Mode used for?

Answer 8

High temporal resolution, 1D image for motion assessment, narrow ultrasound beams.

Question 9

What is 2D Imaging used for?

Answer 9

Triangular images, lower frame rate, good for spatial orientation.

Question 10

What is 3D Imaging used for?

Answer 10

Provides volumetric visualization; helps in valve surgery planning.

Question 11

What is the purpose of Doppler ultrasound in TEE?

Answer 11

Doppler detects RBC movement to evaluate blood flow velocity and direction.

Question 12

What does Color-flow Doppler indicate?

Answer 12

Red = toward the probe, Blue = away.

Question 13

What does aliasing indicate in Doppler ultrasound?

Answer 13

Aliasing indicates turbulent or abnormal flow.

Question 14

What are the standard probe manipulation terms in TEE?

Answer 14

Right/Left Turn, Anteflexion/Retroflexion, Lateral Flexion, Rotating Forward/Back.

Question 15

What key parameters are assessed with TEE?

Answer 15

Stroke Volume (SV), Cardiac Output (CO), Ejection Fraction (EF), Preload.

Question 16

What is the normal myocardial tissue velocity?

Answer 16

Normal myocardial tissue velocity = 8–15 cm/s.

Question 17

How is intracavitary pressure estimated in TEE?

Answer 17

Estimates intracavitary pressure using Bernoulli equation.

Question 18

What is assessed via the continuity equation in TEE?

Answer 18

Valve function is assessed via continuity equation.

Question 19

What are Wall Motion Abnormalities (SWMAs)?

Answer 19

Hypokinesia, Akinesia, Dyskinesia.

Question 20

What is hypokinesia?

Answer 20

Reduced contraction, wall thickening is decreased.

Question 21

What is akinesia?

Answer 21

No wall motion (seen in MI).

Question 22

What is dyskinesia?

Answer 22

Paradoxical motion (outward during systole, seen in MI & ventricular aneurysm).

Question 23

What is the best view for assessing wall motion abnormalities?

Answer 23

Best view: Short-axis at midpapillary level.

Question 24

What are common TEE views?

Answer 24

ME 4-Chamber, TG Mid-SAX, ME Bicaval, ME LAX.

Question 25

What is the ME 4-Chamber view used for?

Answer 25

Most comprehensive & easiest to image.

Question 26

What is the TG Mid-SAX view used for?

Answer 26

Best for assessing all the walls of the left ventricle simultaneously and ventricular volume status.

Question 27

What is the ME Bicaval view used for?

Answer 27

SVC/IVC cannula placement; foramen ovale assessment with bubble study.

Question 28

What is the ME LAX view used for?

Answer 28

Frequently used when separating from CPB to assess for air before discontinuation of the aortic root vent.

Question 29

What are the advantages of TEE perioperatively?

Answer 29

Diagnose source of hemodynamic instability, estimate hemodynamic parameters, diagnose structural diseases of the heart, guiding surgical interventions.

Question 30

What are the indications for TEE?

Answer 30

Cardiac surgeries, non-cardiac surgeries, most sensitive intraop monitor for myocardial ischemia.

Question 31

What is the CRNA role in TEE?

Answer 31

Secure airway & anesthesia, decompress stomach, monitor airway, assist with probe adjustments.

Question 32

What are contraindications for TEE?

Answer 32

Esophageal disorders: perforation, tumors, strictures, recent surgery, diverticula, traumatic interruption.

Question 33

What are the complications of TEE?

Answer 33

Esophageal perforation, GI bleeding, airway trauma, oral injury, misinterpretation.

Question 34

What should be considered in medication selection for TEE?

Answer 34

Choose agents based on cardiac function and comorbidities.

Question 35

What are the effects of inhalation agents in TEE?

Answer 35

Dose-dependent myocardial depressant, vasodilation, & hypotension but has myocardial protection & blunt sympathetic responses.

Question 36

What is the preferred agent for poor LV function?

Answer 36

Etomidate is preferred over propofol due to minimal myocardial depression.

Question 37

What is the role of opioids in TEE?

Answer 37

Stable hemodynamics, no direct cardiac depression.

Question 38

What is the effect of midazolam in TEE?

Answer 38

Useful premed, but may cause hypotension with opioids.

Question 39

What is the safety of muscle relaxants in TEE?

Answer 39

Most nondepolarizing agents are safe with minimal cardiac effects.

Question 40

What is the primary purpose of a Transesophageal Echocardiography (TEE)? A) To measure lung function B) To monitor brain activity during surgery C) To create detailed images of the heart and assist in cardiac monitoring D) To assess kidney function

Answer 40

Answer: C) To create detailed images of the heart and assist in cardiac monitoring Rationale: TEE is a semi-invasive diagnostic tool for monitoring numerous cardiac parameters to guide medical, surgical, and nursing care. Identification of systolic wall motion abnormalities (SWMA) and vascular aneurysms, calculation of ejection fraction and ventricular preload, and measurement of blood flow within heart chambers and across valves are a few ultrasound imaging utilities that are applied during TEE.

Question 41

Which frequency range is typically used for TEE probes? A) 1-2 MHz B) 3.5-7.5 MHz C) 10-15 MHz D) 20-25 MHz

Answer 41

Answer: B) 3.5-7.5 MHz Rationale: The frequency of the piezoelectric crystals in TEE probes ranges from 3.5 to 7.5 MHZ. The TEE probes operate within this frequency range to balance image clarity and tissue penetration. Higher frequencies provide clearer images but have lower penetration.

Question 42

What can the Bernoulli Equation be used to estimate during a transesophageal echocardiogram? A) It calculates stroke volume B) It assesses heart rhythm abnormalities C) It measures oxygen saturation D) It estimates pressure differences across narrowed heart valves

Answer 42

Answer: D) It estimates pressure differences across narrowed heart valves Rationale: The Doppler effect in echocardiography helps measure the direction and speed of blood flow in the heart. Blood flow follows the conservation of mass—the same amount of blood must pass through different heart structures (e.g., left ventricular outflow tract and aortic valve). If a narrowing occurs (e.g., aortic stenosis), blood must flow faster to maintain volume. Increased velocity is detected by the Doppler probe. The Bernoulli equation (ΔP = 4 × V²) estimates pressure differences across narrowed areas.

Question 43

What is a contraindication for performing a TEE? A) Perforated viscus or esophageal pathology B) Hypertension C) Previous cardiac surgery D) History of asthma

Answer 43

Answer: A) Perforated viscus or esophageal pathology Rationale: Among the most feared complications of TEE are esophageal or gastric perforation. For skilled practitioners, this complication is extremely rare. Patients with extensive esophageal and gastric diseases are at highest risk of perforation. TEE is contraindicated in patients with esophageal abnormalities like strictures, perforations, or recent gastric surgeries due to the risk of complications.

Question 44

Which ultrasound technique used during a TEE incorporates the concept of frequency shift? A) M-mode B) 2D imaging C) Doppler D) 3D imaging

Answer 44

Answer: C) Doppler Rationale: The Doppler exam incorporates the concept of frequency shift. The concept involves viewing red blood cells (RBCs) as moving reflectors of ultrasound. As ultrasound reflects off the moving RBCs, echoes are produced and then recorded by the TEE transducer. With the flow of RBCs toward the TEE probe, the distance between the sound source and its reception changes. This technique allows different colors to be assigned to RBCs moving in different directions and allows for easy visualization of retrograde flow of blood across incompetent heart valves.

Question 45

At what depth is the TEE probe placed for the midesophageal imaging plane? A) 25cm B) 30-35cm C) 40-45cm D) 50cm

Answer 45

Answer: B) 30-35cm Rational: There are four general areas where the transducer may be positioned within the esophagus and stomach that have associated imaging planes: upper esophageal (UE), midesophageal (ME), transgastric (TG), and deep transgastric (DTG) (Fig. 26.12). The probe depth is determined on an individual basis, but UE structures usually come into view at about 25 cm and ME structures at 30 to 35 cm. TG images require anteflexion of the probe and advancing to 40 cm or more.