Essentials of Transesophageal Echocardiogram.pptx

Essentials of Transesophageal Echocardiogram Vicente Gonzalez, DNP, CRNA Department of Nurse Anesthesiology Florida International University Objectives Understand how the TEE probe functions and obtains an image Image interpretation Probe positioning for image...

Essentials of Transesophageal Echocardiogram Vicente Gonzalez, DNP, CRNA Department of Nurse Anesthesiology Florida International University Objectives Understand how the TEE probe functions and obtains an image Image interpretation Probe positioning for image acquisition Most common views used in anesthesia Clinical significance of findings Terminology Like all procedures, understanding the terminology is extremely important to understand what you are viewing on the monitor and reading in a report. UE- upper esophageal view 20-25 cm ME- mid esophageal view 30-40 cm TG- trans-gastric view 40-45 cm Deep TG- deep trans-gastric 45-50 cm Terminology Short axis- (SAX) this is the view from the standpoint of the structure being viewed, not the ultrasound plane It refers to a cross-section view of the structure Long axis (LAX) this is the view of the structure along its long axis As you can see this is a Mid Esophageal This is the same aortic valve view of the aortic valve in a short axis at the same level as the SAX view. Note the semicircular indicator at but we now see the valve and the top right indicating about a 30-40 aorta in their long axis view. degree rotation of the omniplane Note the semicircular transducer indicator at the top right, indicating about 120 degrees rotation of the omniplane transducer TEE Probe The TEE probe is very similar to a gastroscope Inserted in a similar fashion Components Control housing Cable Transducer controls Flexible shaft Tip Transducer lens Probe Manipulation The tip can be moved in different planes to obtain images Basic movement Advance- withdraw- movement into or out of the esophagus Rotation- axial rotation right or left Antiflex- Retroflex- flexing the tip anteriorly or posteriorly Flex- flexing the tip right or left (a) Advance, withdraw: Pushing or pulling the tip of the TEE probe; (b) turn to right, turn to left (also referred as clockwise and anticlockwise): rotating the anterior aspect of the TEE probe to the right or left of the patient; (c) anteflex, retroflex: anteflex is flexing the tip of the TEE probe anteriorly by turning the large control wheel clockwise. Retroflex is flexing the tip of the TEE probe posteriorly by turning the large wheel anticlockwise; (d) Flex to right, Flex to left: flexing the tip of the TEE probe with the small control wheel to the patient’s right or left. The probe flexion to the right and left may not be necessary and should be avoided to minimize trauma to the esophagus Lens TEE transducer lens is known as a multiplane or omni plane It allows imaging in different axis by rotation of the lens This changes the view and will provide a SAX or LAX depending on the structure of interest Lens adjustment The planes on the lens can be thought of as a beam on the face of a clock The following images will illustrate this Keep in mind that the images are displayed differently on the screen (more on that later) The images show a clock face on the left to simulate the plane of the beam On the right you will see what it looks like on the monitor Monitor Image The image acquired by the transducer is not oriented in the same way that it is obtained By convention the image is flipped top to bottom, it is then rotated left to right Closest structures to the transducer are at the top What the transducer sees if no After image manipulation image manipulation is done Challenges to Imaging Body planes are at right angles to each other The heart is not aligned in any particular plane, but it lies in multiple planes Adjustments to the transducer must be made to acquire images and evaluate structures Other Challenges Heart is a 3D structure that we are trying to image on a 2D screen That means that there are anterior, posterior, left and right structures that need to be evaluated by changing the transducer orientation and position within the esophagus and the stomach Anatomical Features Aorta and pulmonary arteries are at right angles to each other Pulmonary veins are parallel to the base of the heart Superior and inferior vena cava are at right angles to the base of the heart Left main stem bronchus is anterior the aortic arch Therefore, it is not possible to assess the ascending portion of the aorta There are individual variations in the position of the esophagus in relation to the heart Image Acquisition Probe is advanced into the esophagus in a systematic fashion At different depths different structures will be seen All structures should be evaluated in different planes The table that follows indicates what anatomical structures are seen, depth and angle TEE Cardiac Evaluation Cardiac Evaluation Standard TEE is comprised of over 20 different views Useful when performing a complete exam to evaluate the entire cardiac muscle This is not practical in a dynamic evaluation or in cases of shock More useful is a left ventricle evaluation and a hemodynamic evaluation LV evaluation Need to obtain ME views and TG views LV function evaluation consists of Systolic function Diastolic function Combined evaluation Challenges LV is not in a convenient anatomical plane Axis of the heart varies from person to person Must evaluate in different positions to obtain an accurate function assessment Evaluation consists of evaluating Anterior and posterior surfaces Left and right margins LV function measurement LV is divided into thirds from base to apex. There are 17 segments for TEE evaluation 6 segments at the base near the mitral valve 6 at the mid-papillary muscle level 4 at the apex I at the apical cap Ventricle is not uniformly shaped. Therefore the size of the chamber varies according to the level examined LV function measurement TG mid papillary SAX at 0 degrees Common starting point of exam Preferred views TG mid papillary SAX ME views The TG SAX mid papillary view evaluates blood from all the major coronaries (LAD, RCA and Cx) LV function measurement Qualitative evaluation EF Quantitative CO Contractility Volume LV function measurement These measurements are time consuming and require multiple views Instead fractional shortening is used Percentage of change in left ventricular dimension with contraction Normal is 25-45% Simple to do One dimension May not represent the whole LV LV function measurement It is calculated by measuring diameters Left ventricular end diastolic diameter (LVED) Left ventricular end systolic diameter (LVES) Divide the difference by LVED and multiply by 100 to obtain percent change LV function measurement EF can be calculated much the same way Use volume instead LV function measurement Another quick and simple is to calculate fractional area change Similar to fractional shortening but using area instead Since it is a 2D measurement they may not reflect ventricular function Mitral regurgitation may confound these values LV function measurement Cardiac output can also be determined using doppler volume flow The diameter of the LVOT is measured Velocity time integral (done by the machine) calculates stroke distance Multiplying the 2 results measures stroke volume Q= volume flow, V=velocity, CSA=cross sectional area This is a table showing volume status as a function of LVED area Valve evaluation Aortic valve TEE can be used to evaluate valve anatomy, function and hemodynamics. The evaluation of the aortic valve comprises the LVOT, cusps, sinuses of Valsalva, and proximal ascending aorta Views to evaluate the aorta ME aortic valve SAX ME aortic valve LAX Deep TG LAX TG LAX Aortic valve views ME SAX 40 to 60 degree Prob in neutral position Evaluate: Number of leaflets Mobility of leaflets Commisural fusion Regurgitation (use doppler) Aortic valve ME LAX Angle 110- 140 degrees Probe neutral Evaluate: Aortic root Regurgitation by color flow Evaluate the ascending aorta for: Aneurysms Abnormal root Dissection Partial obstruction of LVOT Aortic valve deep TG and TG Angle 0-120 degrees Probe position- anteflex Evaluate: Grading regurgitation by color flow Transvalvular gradient to evaluate AS Measuring volume time integral (VTI) for calculation of aortic valve area and CO Mitral valve TEE used to evaluate Leaflets Chordae Mitral annulus Papillary muscles Mitral valve ME four chamber (you can also see the tricuspid in this view) ME two chamber view ME long axis (similar point as the AV long axis) TG view Mitral valve Evaluation of the motion of the leaflets Thickening Abnormal motion (too much or too little) Papillary muscle evaluation (TG view) Chordae