KEY POINTS

1. One of the category I indications for TEE is evaluation of a hemodynamically unstable patient.
2. The speed of sound in the heart is assumed to be constant at 1540 m/sec.
3. The higher the transducer frequency, the better the image quality, but the more limited the depth of penetration.
4. Echocardiography relies on the time that it takes for the sound wave to travel between the probe and the imaged structure.
5. Doppler echocardiography is used to measure the velocity of blood in the cardiac chambers and across the valves.
6. The modified Bernoulli equation will transform the velocities into pressure units. ΔPressure = 4V² , where V = velocity in m/sec.
7. Continuous-wave Doppler measures high velocities but does not precisely identify the location of the velocities.
8. Pulsed-wave Doppler permits measurement of velocities at an exact location but is limited in its ability to measure high velocities.
9. Color Doppler codes for flows: Blue Away from the probe, Red Toward the probe (BART).
10. The abbreviated TEE examination will be adequate for the practice of basic TEE as defined by the 1996 SCA/ASA TEE guidelines.
11. The differential diagnosis of severe hypotension includes hypovolemia, ventricular failure, severe valvular regurgitation, cardiac tamponade, and low systemic vascular resistance.
12. TEE has been shown to be more sensitive than electrocardiography for the intraoperative detection of myocardial ischemia.