Mod1: Monitoring for Cardiac Surgery - TEE Flashcards by Olivier Mba

_{THE BASICS OF TRANSESOPHAGEAL ECHOCARDIOGRAPHY}

When was TEE first used and what were its limitations?

The first use of TEE was in 1975

Had a very limited range and very little ability to change the angle of the view

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_{THE BASICS OF TRANSESOPHAGEAL ECHOCARDIOGRAPH}

Which factors have contributed to the improvement of the quality and utility of today’s TEE’s and have expanded its use 100 fold?

Provision of multiple planes of view

Multiple frequency of probes

Color flow mapping

Pulse and continuous wave Doppler

Digital image processing

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THE BASICS OF TRANSESOPHAGEAL ECHOCARDIOGRAPH

In 2010, the ASA approved updates to guidelines which states that “the TEE should be used in which surgical procedures?

all open heart and thoracic or aortic surgical procedures and should be considered in CABG surgeries

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_{THE BASICS OF TRANSESOPHAGEAL ECHOCARDIOGRAPH}

In 2010, the ASA approved updates to guidelines which states that “the TEE should be used in all open heart and thoracic or aortic surgical procedures and should be considered in CABG surgeries for what purpose?

To confirm and refine the preop diagnosis

To detect new and unsuspected pathologies

To adjust the anesthetic and surgical plan accordingly

To assess the results of surgical intervention

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_{TEE COMMON INDICATIONS}

According to ASA TEE Guidelines, the TEE can be used by providers in which two ways?

Basic Perioperative TEE

Advanced Perioperative TEE

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_{TEE COMMON INDICATIONS}

What’s an advantage of the Basic Perioperative TEE over the PA catheter as a periop measure the determine a pt’s instability?

Previously, the PA catheter was used to determine why pt a may be hempdynamically unstable

Now the provider is able to used the TEE to determine the primary source of the pt’s instability

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_{TEE COMMON INDICATIONS}

What’s the major added benefit of the Advanced Perioperative TEE over the Basic Perioperative TEE?

The anesthesiologist performing the TEE can make therapeutic and surgical recommendations based upon their TEE interpretation

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_{TEE COMMON INDICATIONS}

What’s required from the provider to used the Advanced Perioperative TEE?

Requires Training and certification at all levels of perioperative echocardiography reading

It also may require additional credentialing at the practicing institution

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_{TEE COMMON INDICATIONS}

The TEE can guide the evaluation and treatment of which heart valve abnormalities?

Assessment of valvular function both intra and postop

Evaluation of valvular repairs and prosthetic valve surgery

Assessment of the aorta for arteriosclerosis, calcification and dissections

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_{TEE COMMON INDICATIONS}

When is it important to Assessment of the aorta for arteriosclerosis, calcification and dissections via TEE?

Before the aorta is clamped, and

Prior to coming off bypass

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_{TEE COMMON INDICATIONS}

What are other common indications for TEE?

Assessment of Global LVF and regional wall motion abnormalities (RWMA)

Detection of cardiac defects, masses, and vegetation

To see optimal de-airing after open heart surgery

For quick evaluation of severe hypotension intra and postop by ruling out conditions like cardiac tamponade, poor LV volume status, RWMA, malfunction of prosthetic valves, or aortic dissection

Inadequate or impossible transthoracic echocardiography

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_{TEE IN NON-CARDIAC SURGERY}

T/F: Although TEE is a fast and relatively non-invasive technique, its routine use for NON-cardiac surgery is yet to be established

True

Studies showing the routine use, though, of TEE in non-cardiac surgeries as a benefit are limited in number and equivocal in outcome

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_{TEE IN NON-CARDIAC SURGERY}

T/F: Many studies have revealed that TEE is more sensitive than EKG for EARLY detection of ischemia

True

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_{TEE IN NON-CARDIAC SURGERY}

When is TEE indicated in non cardiac surgery?

In situations where it is used to explain life threatening circulatory instability that persist despite corrective therapy

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_{PROPERTIES OF ULTRASOUND}

How does the TEE ultrsound probe work?

Ultrasound machines generate vibrations that vibrate surrounding tissue (muscle, blood, fat, or bone)

During the vibration, particles within the tissue compress, then spread apart, also known as compression and rarefaction

This sequence of compression and rarefaction is described using sine waves and characterized by:

Wavelength - Frequency - Amplitude - Propagation velocity

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_{PROPERTIES OF ULTRASOUND}

It is the distance b/t two peaks of the sine wave

It’s measured in millimeters

What is Wavelength?

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_{PROPERTIES OF ULTRASOUND}

Is the number of cycles that occur in one second

1 cycle/second = 1 hertz (Hz)

What is Frequency?

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_{PROPERTIES OF ULTRASOUND}

Ultrasound frenquency travel much higher than what is audible with the human ear. Which frequency can the human ear typically hear?

Between 2000 to 5000 Hz

Some experience show that we can hear up to 20,000Hz

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_{PROPERTIES OF ULTRASOUND}

Which US frequency do TEE uses?

Frequencies above 20,000Hz

TEE uses frequencies of 2.5-7.5 million cycles per seconds (MHz)

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PROPERTIES OF ULTRASOUND

What does amplitude measure?

Amplitude measures of tissue compression or “loudness” of tissue

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PROPERTIES OF ULTRASOUND

What is Propagation velocity?

The speed of an ultrasound wave traveling through tissue

Depends on the tissue

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PROPERTIES OF ULTRASOUND

What’s the ultrasound Propagation velocity in blood?

1540 meters per second (m/s)

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_{BASICS OF TEE}

How does the TEE probe generate US waves?

Echo probe has piezoelectrode in it that can convert electrical activity delivered to it into ultrasound wave

A piezoelectrode in the probe converts electrical energy delivered to the probe into ultrasound waves

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_{BASICS OF TEE}

Echocardiography uses ultrasound waves with frequencies of:

Study These Flashcards

2.5 to 7.5 million cycles per seconds (MHz)

_{BASICS OF TEE} What's the relationship between US frequency, depth of penetration, and resolution?

The slower the frequency, the greater the depth of penetration but produces poor resolution The faster the frequency, the greater the resolution, but penetration becomes poor

_{BASICS OF TEE} Why are frequencies greater than 7.5 MHz are not used?

d/t poor penetration

_{BASICS OF TEE} Why are frequencies less than 2.5 produce wavelengths not used?

too long for resolution of small objects

_{BASICS OF TEE} With TEE and cardiac procedures, which TEE technique do providers use to examine the function of the heart?

**Doppler Technique** Assesses blood flow through heart chambers and valves Assess LV function, chamber size, wall size and motion Valve patency Abnormal flow, structures, plaque, air, or vegetation

_{BASICS OF TEE} What equation does the Doppler effect used the determine pressure gradient between areas of different velocity?

**Bernoulli equation** Except for in the fetal heart, the volume of blood flowing through the heart must always be the same as the volume of blood that passes through the aortic valve *When the pathway through which blood flows becomes too narrow, the blood velocity must increase to pass the volume* Providers can read this velocity as it moves pass the ech probe using the Bernoulli equation The doppler principle creates a visual picture of the heart blood flow by assessing the color codes of the velocities in the heart

_{BASICS OF TEE} Based on the doppler effect, what's the color difference between blood flow directed towards the probe and blood flow going away from the probe? What is turbulent flow?

Blood *flow that is directed **towards** the probe* is **red** Blood *flow going **away*** from the probe is **blue** The higher the velocity of the flow, the lighter the color **hues**, and this is called *turbulent flow*

_{BASICS OF TEE} What's the first mode that echocardiograms were able to reproduce?

M-Mode Still used today One dimensional, or Ice pick view Single, narrow line of sight

_{BASICS OF TEE} What are applications of the M-mode?

Used today to view rapidly moving structures, such as valve leaflets Used to measure heart chambers, size of heart, and thickness of heart walls

_{BASICS OF TEE} What's a major drawback of the M-mode?

Only reveals a small portion of the heart at one time, which makes orientation and interpretation of special relationships difficult

_{BASICS OF TEE} Which mode was created to redirect the ultrasound beam over areas of interest, with the advantage that it could recognize anatomical and pathological landmarks

**2-D Echo** Sweeps US beam across a plane Provides views of structures and motion

_{BASICS OF TEE} T/F: Images from 2-D Echo are displayed in real time and can be recorded

**True** This allows the provider to view the structures at work, while also being able to record and view them later

_{BASICS OF TEE} What are the 3 types of 2-D Echo?

Pulsed Wave doppler Continuous Wave Color Doppler

_{BASICS OF TEE} Which type of 2-D Echo measures velocity and direction of blood flow using single transducer

**Pulsed Wave doppler** The operator can define a small area anywhere in the 2-D area which will display in real time blood flow velocity (left image) The beam must hit the target and travel back to the probe for interpretation

_{BASICS OF TEE} Which type of 2-D Echo uses two transducers?

**Continuous Wave Doppler** One transducer emits the ultrasound wave continuosly The other transducer receives the ultrasound wave continuously _{(Right image)} The ultrasound wave continiously move back and forth

_{BASICS OF TEE} Why is it that the provider cannot precisely define the location of the moving target using the Continuous Wave Doppler 2-D Echo?

Since the Continuous Wave Doppler 2-D Echo has two transducers (One that emits the ultrasound wave continuosly, while the other receives the ultrasound wave continuously) high veolcity can be read, but unfortunately ***depth from the transducer cannot be read***

BASICS OF TEE Which type of 2-D Echo is an enhanced form of continuous wave Doppler that displays real time blood flow in the heart over the 2-D image

**Color Doppler 2-D Echo** Displays real time blood flow in the heart over the 2-D image, and this is how direction of flow is determined

_{BASICS OF TEE} What's the newest TEE technology? What are its advantages over the older technology?

**3-D Echo** is the newest technology An array of transducers are used to reconstruct the heart in 3-D image Allows for better visualization of heat structures (valves, regurgitant valvular lesions, cardiac chamber volumes, 3-D stress imaging)

_{BASICS OF TEE} According to the Transesophageal Echocardiography Practice Guidelines, what are the two levels of TEE practice?

Basic and advanced

_{BASICS OF TEE} According to the Transesophageal Echocardiography Practice Guidelines which level of training are providers required to acheive? What minimum number of superivised TEE are they required to perform and interpret?

Providers are required to attain at least an ***intermediate level*** of training in echocardiography and to perform and interpret at least **50** supervised TEE examinations

_{BASICS OF TEE} On which prior recommendations are Transesophageal Echocardiography Practice Guidelines based?

On the prior recommendations for TransThoracic Echocardiography and are directed at training for TEE in both operative and non-operative application

_{BASICS OF TEE} How many cross sections constitute a comprehensive TEE examination?

There are ***20 cross sections*** in a comprehensive TEE examination.

_{BASICS OF TEE} In the OR, why are providers not expected to perform a comprehensive TEE exam for each case?

**Time contraint**

_{BASICS OF TEE} In the OR, how many cross-sections are providers required to produce at a minimum from a TEE exam?

A _minimum_ of ***8 different cross sections*** of the total 20 cross sections; ***4** of which* should both be in **2-D** and **colo**r doppler to assess valvular funtcion

_{COMPREHENSIVE EXAMINATION} Describe a comprehensive TEE examination

_{THIS IS A DEPICTION OF THE COMPREHENSIVE EXAMINATION.} _{FOR A FULL BREAKDOWN OF EACH INDIVIDUAL VIEW, PLEASE VISIT THE WEBSITE TO BE REDIRECTED TO THE GUIDELINES FOR PERFORMING A COMPREHENSIVE TEE EXAMINATION} *http://www.asecho.org/wordpress/wp-content/uploads/2014/05/2013\_Performing-Comprehensive-TEE.pdf*

_{BASICS OF TEE} When used in open heart surgery, when is TEE usually placed

Once General Anesthesia is induced OGT placed to facilitate emptying of stomach

_{BASICS OF TEE} Why is a bite block placed in patient’s mouth prior to insertion of TEE probe?

To prevent damage to the piezoelectrodes in the probe

_{BASICS OF TEE} How is the tip of the TEE probe inserted into the esophagus?

Tip of the TEE probe is covered with ***surgical lubricant*** and passed **"blindly"** into the esophagus Jaw lift or laryngoscope blade if unable to pass probe "blindly" ***Elevate head*** of resistance

_{BASICS OF TEE} When the TEE probe is inserted, how is it manipulated so the aortic valve can be visualized?

Inserted to TEE probe to 30 cm at the upper incisors Rotate the transducer until the three cups of the valve are visualized

_{BASICS OF TEE} In what percentage of cases is the provider unable to insert TEE probe?

**2%**

_{COMPLICATIONS OF THE TEE} T/F: TEE is traumatic and unsafe

**False** TEE is very safe and atraumatic if placed correctly

_{COMPLICATIONS OF THE TEE} How can complications such as Esophageal tears or perforations and burns associated with TEE insertion be avoided?

The probe should be introduced with ***gentleness*** and ***care*** and if ANY **resistance** is encountered, the probe should be *withdrawn and re-lubed* and then *another attempt* can be made to place it

_{COMPLICATIONS OF THE TEE} Why should the TEE machine always be placed on stanby mode when not in use? How is this done?

To avoid burn in the esophagus This is done by pressing "freeze" on the monitor

_{CONTRAINDICATIONS FOR TEE} Absolute contraindications to TEE placement are:

Presence of an esophageal obstruction Esophageal perforation Prior esophagectomy Esophageal tumor Recent suture lines as in gastric bypass

_{CONTRAINDICATIONS FOR TEE} Relative contraindications for TEE include:

Hiatal Hernia Esophageal varices Esophagitis Unexplained swallowing difficulties Mediastinal radiation Esophageal diverticulum Unexplained swallowing difficulties

Mod1: Monitoring for Cardiac Surgery - TEE Flashcards

(58 cards)