Week 5 - Anesthetic Application of TEE

Question 1

What five questions should you always try to answer with a TEE?

Answer 1

1) Is there an obvious pericardial effusion?
2) Is RV dilated and the septum pushed toward the left?
3) Is the LV functioning well?
4) Is there an obvious hypovolemia?
5) Is there an obvious valvular problem?

Question 2

What are the indications for when TEE should be used in critical care?

Answer 2

When diagnostic info that is expected to alter management cannot be obtained by transthoracic echo or other modalities in a timely manner

Question 3

What are the indications for TEE in noncardiac surgery?

Answer 3

• May be used when the nature of the planned surgery or the pt’s known or suspected cardiovascular pathology might result in severe hemodynamic, pulmonary, or neurologic compromise
• If equipment and expertise are available, TEE should be used when unexplained life-threatening circulatory instability persists despite corrective therapy
• anytime anesthesia help is called to the room

Question 4

What are the absolute and relative contraindications of TEE?

Answer 4

Absolute:

• Esophageal stricture or mass
• Esophageal laceration/perforation
• Esophageal diverticulum
• Unstable C-spine

Relative:

• Esophageal varices
• Large Diaphragmatic hernia (makes image worse decreasing benefit of TEE)
• Mediastinal irradiation (makes image worse decreasing benefit of TEE)

Question 5

When might a TEE be beneficial intraop?

Answer 5

• If pt has cardiac arrest
• Pts who are unstable or sick and going through a big surgery
• Pt is at risk for intraop MI or hemodynamic instability

Question 6

What are the limitations of intraop TEE?

Answer 6

• Observer
• Inability to pass the probe (<2%)
• Transgastric views not always optimal
• Large hiatal hernia
• Visualization of pulmonic valve can be difficult

Question 7

What frequency does TEE use?

Answer 7

2-7 MHz

Question 8

How does frequency of ultrasound affect resolution and penetration?

Answer 8

HIGHER frequencies provide better RESOLUTION

LOWER frequencies provide better PENETRATION

Question 9

Define reverberations in ultrasound

Answer 9

When the waves hit a strong reflector and causes artifact

Question 10

What are A-mode and B-mode of an ultrasound?

Answer 10

A-mode = amplitude mode
B-mode = brightness mode

-Distance (time-lapse) plotted against intensity

• strong signal = hyperechoic (whiter)
• weak signal = hypoechoic (blacker)

Question 11

What is M-mode of an ultrasound?

Answer 11

M-mode = Motion mode

-repeated B-mode over time