الفهرس 
Basic principles of echocardiographyOnly 14 pages are availabe for public view
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Abstract
TEE technology has rapidly evolved with the advancements provided by flexibe endoscopic probes and phased array transducers ultrasound technology.
The additional information available from pulsed wave, continuous wave, and colour Doppler data has led to the rapid acceptance of TEE by the medical, surgical and anesthetic communities. TEE is a diagnostic examination with an ultrasound device passed to the oesophagus to create a clear image of the cardiac muscle and other parts of the heart.
TEE probes are variable, but share several common features, there are adult and pediatric sizes, it can be introduced in Awake patient with local anesthetic and sedation or in anesthetized patients.
The tips of all TEE transducers can be flexed to some degree both antroposteriorly and laterally to accommodate the different angles that may be required to visualize various parts of the heart and great vessels. A refrence is usually displayed on the screen indicating longitudinal (L) or transverse (T) plane.
In transverse plane (0) the probe is moved up and down in the oesophagus in order to obtain the standard imaging planes. While imaging in the longitudinal plane, the operator rotates the probe clockwise and counterclockwise along its long axis.
Preinsertion check should be done before use to exclude the contraindicatins and to check the probe and to preset the monitor.
TEE is a special tool and not a standard intraoperative technique. It provides a unique information that no other diagnostic procedure can provide. TEE permits ongoing assessment of CVS function and immediate treatment of abnormalities related to surgical intervention, anesthesia effects and changing patient conditions.
American College of Cardiology / American Heart Association/ American Society of Echocardiography (ACC, AHA, ASE) have provided guidelines for clinical use of TEE, These Guidelines are important as they present a scientific evidence for use of TEE.
However, The clinical indications of TEE, continues to be defined as the major indications for TEE were for cardiac sources of embolism, endocarditis, prosthetic heart valve dysfunction, native valvualr disease, aortic dissection or aneurysm, intracardiac tumor, mass or thrombus ,and congenital heart disease.
In the operating room, TEE becomes a monitor of the cardiovascular system rather than an intermittently diagnostic tool.
In this setting it is valuable in assessment of the global and regional left ventricular function, right ventricular function, and assessment of the hemodynamics of the circulation. Its also valuable in verifying the proper placement of atrial or ventricular septal patch and the adequacy of defect closure and as a guide in other port access techniques.
In CABG, cardiac valvular surgery and congenital heart surgery, it may identify unexpected and or residual defects that need to be repaired before the patient leaves the operating room. Similarly in patients with severe, persistent hypotention or cardiac failure after surgery, TEE has a vital role because it usually reveals the true etiology of the complication and the need for potentially life saving changes in therapy and management.
In conditions that need urgent assessment of unstable patients e.g with suspected aortic injury or aortic dissection, or high risk patients undergoing emergency noncardiac surgery, it has a role because it is sensitive, specific, and faster than alternative techniques in the intensive care unit. TEE may be helpful for evaluating the etiology of hypotention .and also in patients submitted to mechanical ventilation, where it permits a daily evaluation of the adverse impact of the respiratory support.
There are benefits and risks for the use of TEE, benefits are derived from the information that it provides which may not be as readily obtained by any other technique. The risks of TEE are those related to mechanical trauma from the probe as well as those of an incorrect TEE interpretation by the echocardiographer.