Overview of Intraoperative Echocardiography

Transesophageal echocardiography, or TEE, is a type of ultrasound that was first introduced in the 1970s. It lets doctors see images of the heart by using a small device that goes down into the esophagus, which is the tube that connects your mouth to your stomach. This is possible because the esophagus is very close to the heart, so it provides a clear view. It wasn’t until the 1980s, though, with the introduction of new tools and techniques, that it became widely used.

Today, TEE is used in many different medical settings including during heart surgery, in the intensive care unit, in outpatient clinics, and as part of procedures to diagnose or treat heart conditions. It’s especially useful during heart surgeries because it doesn’t interfere with the sterile surgical area. Recent advances have also made it possible for doctors to see the heart in 3D using TEE, which is extremely useful for more complicated procedures like replacing a heart valve.

In 1999, a set of guidelines was introduced by the Society of Cardiovascular Anesthesiologists and the American Society of Echocardiography. This was to standardize how TEE was used during surgery to make sure it was done consistently and the information was stored properly. These guidelines were updated in 2013 and now include more standard views as well as 3D imaging. There are also guidelines for using TEE outside of heart surgery, recognizing its broader use in diagnosing and monitoring heart conditions.

Doctors who use TEE usually become certified by the National Board of Echocardiography. They have to pass a test and meet other requirements, including personally doing a certain number of TEE exams.

Anatomy and Physiology of Intraoperative Echocardiography

The transesophageal echocardiography (TEE for short) is a medical procedure that uses an ultrasound device, called a probe, to take pictures of your heart. The probe is gently put into your mouth and then down into your esophagus, which is the tube that connects your mouth to your stomach. Because the esophagus is so close to the heart, the TEE can make detailed images of your heart, its chambers, and valves. It can also take images of your lungs, liver, major blood vessels around heart, and stomach. However, one thing to note is that TEE is not perfect; it can’t show the parts of the heart that are behind the large airway branching off your windpipe.

The 2013 Basic Perioperative Transesophageal Echocardiography Examination guidelines suggested 11 specific views, or angles, for the probe to be positioned in for a basic TEE. Some of these are from the middle of the esophagus and others are from the stomach. Each of these views allows the doctor to see different parts of the heart and its surrounding structures.

Likewise, a more comprehensive version of this guideline suggested 28 different views to allow an even closer look at the heart’s structures. This could be useful for complex cases where an especially thorough examination would be beneficial.

There’s also a special TEE using 3D technology that can provide a more detailed image of your heart. This kind of TEE has its specific guidelines on how to use it during surgery.

Why do People Need Intraoperative Echocardiography

When the heart’s function needs to be evaluated, there are a few different tools or tests doctors can use. One method, called Transesophageal echocardiography or TEE for short, provides an especially detailed view of the heart. However, because it’s a bit more invasive than other tests, it should only be used when really needed.

The TEE is particularly useful in different scenarios:

  • If a patient is suspected of having an urgent problem with their aorta (the main blood vessel that carries blood from your heart to your body), such as a tear (dissection) or break (transection).
  • When a person has artificial heart valves, and these need to be thoroughly checked.
  • If an infection around a heart valve (paravalvular abscess) is suspected.
  • When the TEE can provide critical information that will inform whether and how patient care should be changed, particularly when other imaging methods aren’t giving a clear picture.
  • For all types of heart valve and aorta surgeries, and during surgery to bypass blocked coronary arteries (known as CABG).
  • During certain procedures that involve threading devices into the heart via a catheter (a thin, flexible tube), like TAVR (a way to replace a damaged heart valve), implanting a device in a small pouch in the heart (left atrial appendage), or closing a hole in the wall between the two upper chambers of the heart (atrial septal defect).

TEE can also be valuable when a patient is having surgery unrelated to their heart, but their heart disease might cause complications during the procedure. Similarly, if someone has severe, unexplained problems with their circulation that isn’t improving with treatment, this test might offer an explanation. If a blood clot in the lung or air bubbles in the bloodstream are suspected, particularly following brain surgery, the TEE can confirm this. The presence of fluid around the heart (pericardial effusion) and congenital heart defects (problems with the heart’s structure that are present at birth) can also be evaluated with a TEE during surgery.

When a Person Should Avoid Intraoperative Echocardiography

Transesophageal echocardiography (TEE), which is a method doctors use to see your heart and its blood vessels through your esophagus, is generally safe. However, there can be varying opinions on when it should not be used. Most healthcare providers agree that certain conditions make it unsafe:

Absolute reasons not to perform a TEE

  • Perforated viscous – a tear in the wall of an organ.
  • Esophageal problems such as narrowness (stricture), injury (trauma), growths (tumors), hardening of tissue due to an autoimmune disease (scleroderma), a rip in the lining caused by vomiting (Mallory-Weiss tear), or an out-pocketing of the esophagus wall (diverticulum).
  • Active bleeding in the upper part of your digestive tract.
  • Recent surgery on the upper part of your digestive tract.
  • History of full or partial removal of the esophagus.
  • A hole (fistula) connecting your windpipe and esophagus that hasn’t been fixed.
  • Poor airway control.
  • Severe trouble with breathing.
  • Patients who are not cooperative or not sedated.

Reasons that might make a TEE risky (Relative)

  • Disease in the joint connecting the first two vertebrae at the top of your spine.
  • Severe arthritis in your neck.
  • Prior radiation treatment to your chest.
  • Having a hernia at the top part of your stomach that causes symptoms.
  • Recent bleeding in the upper part of your digestive tract.
  • Presence of inflammation or ulcers in your esophagus or stomach.
  • An enlargement in your blood vessels in your chest and abdomen.
  • Barrett’s esophagus, which is a condition where the cells lining your esophagus change.
  • A history of difficulty swallowing.
  • Having a bleeding disorder or low platelet count.
  • A history of surgery on your esophagus or stomach.
  • A history of esophageal cancer or enlarged blood vessels in the esophagus.
  • A condition where a blood vessel wraps around your windpipe.
  • Mouth or throat disease.

According to guidelines, a TEE can still be used in patients with mouth, esophageal, or stomach conditions if it’s more beneficial than risky and the necessary precautions are taken. This could include shortening the exam, avoiding unnecessary movements of the probe, having the most experienced doctor perform the test, getting advice from a gastroenterology specialist, and considering other imaging options.

Equipment used for Intraoperative Echocardiography

To get a useful TEE (or Transesophageal Echocardiography) image, it’s crucial to understand the principles of ultrasound and know how to use the echocardiography machine. This knowledge helps in avoiding misleading images and preventing wrong diagnoses. The required equipment for this procedure includes an echocardiography machine, a special sensor (or transducer), and a way to save and store the finished exams.

The TEE probe, which we can adjust from zero to one-hundred eighty degrees, has a connector that we can attach to the ultrasound machine. It also has 2 dials that help control the probe’s movement. At the end of this probe, there’s an ultrasonic transducer, which has ceramic lead zirconate titanate and an array of piezoelectric crystals. These crystals can both emit and receive ultrasound waves.

Depending on the specific exam, the probe and transducer can be either 2-dimensional or 3-dimensional, and they may have significantly more crystals. When doing an examination, the probe position is sensitive to the esophagus or stomach. It generates sound waves that bounce back (or reflect) from certain heart structures. We then convert these sound waves to electric pulses to create an image of the heart or other structures.

The TEE probe’s one end can be connected to the echocardiography machine. Its handle has two control wheels and buttons for rotating the sensor’s elements. These controls adjust the movement of the probe. The handle also has a lock that lets the user keep the probe in a specific configuration that is set using these controls. In addition to these movements, we can insert or remove the probe and rotate it left or right. Pediatric TEE probes are like gastroscope (a special instrument doctors use to look at the upper digestive tract), but smaller, more flexible, and with higher frequency.

The controls of the echocardiography machine offer various options to adjust the probe, capture, and display the image. Some options include system gain setting (which controls the brightness of the image), image depth and width, color Doppler (which shows the blood flow), pulse wave Doppler (which measures the speed of the blood flow), and image freeze (which allows the captured image to be stored for later review).

Who is needed to perform Intraoperative Echocardiography?

A transesophageal echocardiography (TEE) is a procedure where a special type of ultrasound is used to create detailed images of your heart. Although the procedure is usually safe, it’s slightly invasive and does carry some rare but serious risks. Because of this, it should only be done by doctors who are specially trained. Updated guidelines recommend what training is needed for doctors to use this kind of ultrasound, especially during surgery. Many heart doctors (cardiologists) already know how to do a similar procedure that is less invasive before they learn how to do a TEE. This is not always true for anesthesiologists (doctors who give medicine to help you sleep or prevent pain), who tend to use TEEs more frequently during surgeries.

The main guidelines for intraoperative (during surgery) echocardiography (another term for ultrasound tests) come from the American Society of Anesthesiologists (ASA), the Society for Cardiovascular Anesthesiologists (SCA), and the American Society of Echocardiography (ASE). These organisations oversee training, qualification tests, and ongoing professional development to ensure doctors using these procedures maintain high levels of skill and proficiency.

To prove their competence in this procedure, doctors must complete a training program and pass specific exams. The National Board of Echocardiography (NBE), established in 1998, provides these key examinations and certifications to ensure doctors can demonstrate competence in different areas:

  • The ASCeXAM is for doctors who are proficient in all aspects of ultrasound tests of the heart – this certification is most commonly pursued by heart specialists.
  • The Advanced PTEeXAM is designed for physicians with expertise in the advanced use of TEE during surgery – this certification is often sought after by cardiovascular anesthesiologists. The aim of this exam is to demonstrate full diagnostic and surgical decision-making skills in TEE use during surgery.
  • The Basic PTEeXAM covers the basics of using TEE during surgery. This certification is aimed at anesthesiologists and is not specifically designed for those who specialize in cardiovascular anesthesia. This certification is about using TEE as a monitoring tool during surgeries.

To get these certifications, not only do doctors need to pass these exams, but they also must meet several other requirements. These include performing a set number of these ultrasound tests, completing a certified training program, keeping up with continuing education requirements, and achieving board certification in their specialty.

Preparing for Intraoperative Echocardiography

Before any medical procedure, doctors need to have a detailed understanding of a patient’s health history and current physical condition. This helps them understand if there’s any reason the procedure might not be safe or effective for the patient. Part of this process involves evaluating if the patient is a good candidate for ‘moderate sedation’. This is a level of sedation where you’re relaxed and may not recall the procedure later, but you can still respond to conversation or stimulation.

The doctor will pay special attention to any factors that might increase a patient’s risk when taking sedative or pain-relief medications. For example, they’ll be looking out for conditions affecting the heart and lungs, kidneys or liver, as these can affect how your body processes the drugs. They’ll also want to know about any allergies or past issues with anesthetics. Even if you snore or have sleep apnea (a condition where you stop breathing briefly in your sleep), that’s important information for the doctor to have, because it might affect your breathing during sedation.

How is Intraoperative Echocardiography performed

During this procedure, after the necessary checks, a probe (kind of like a thin tube) is inserted into your mouth while you are in a moderate sleep-like state. It’s important that your heart rate, blood pressure, and other vital signs are continually watched over during the procedure. The probe is inserted and moved around to take different pictures of your heart. This might sound very technical, but it’s just a way for doctors to get a thorough look at your heart from different angles.

To explain the movements of the probe, let’s imagine that the starting point is the probe looking at the heart from the front, while you’re laying on your back.

When the tip of the probe that’s inside you turns clockwise, it’s called “turning to the right”, and when it turns in the opposite direction, it’s “turning to the left”. If the probe is pushed deeper into the esophagus or stomach, it’s called “advancing the transducer” and when it’s pulled back, it’s “withdrawing the probe“.

Now, the probe has two control wheels. The main wheel is used to bend the tip of the probe forward (called “anteflexing”) or backward (called “retroflexing”). The smaller wheel bends the tip of the probe to your right or left, which is simply called “flexing to the right” or “flexing to the left”.

The probe also has a feature, called a “transducer,” with which the angle can be changed from flat (zero degrees) towards a half circle (180 degrees). This action is referred to as “rotating or multiplane forward”, and when it moves in the opposite direction towards flat again, it’s known as “rotating or multiplane back”.

Possible Complications of Intraoperative Echocardiography

Transesophageal echocardiography (TEE), a type of imaging test that helps doctors to see the inside of your heart, is generally considered safe. However, there is still a small risk of complications that can vary from minor to potentially serious. These issues can occur due to the insertion and operation of the TEE probe during the test, especially when it’s used in surgery. The percentage of people who experience complications due to TEE is quite low, with most studies showing that it’s between 0.2% and 1.4%.

During a surgical procedure, TEE may present slightly different risks compared to when it’s performed outside of surgery or an “ambulatory setting”. This is because during surgery, patients are typically under general anesthesia and the muscles that help with swallowing are blocked, meaning the patients can’t swallow and may not be able to control the positioning of the TEE probe. Moreover, in the operation theatre, the TEE device might remain inserted for a longer time, especially during heart surgeries.

Despite these potential difficulties, the rate of complications linked to TEE seems to be almost the same whether it takes place in surgery or outside of surgery. It is important to note that some complications related to TEE might not show up until a day after the procedure. This might have caused health experts to underestimate the overall risks of TEE-related complications in the past.

Possible injuries related to TEE include:

– Cut on the lip
– Loose or broken tooth
– Tongue sore
– Cut in the mouth or throat
– Difficulty swallowing
– Painful swallowing
– Swelling in the throat
– Loss of voice or voice changes
– Stomach inflammation
– Stomach ulcers
– Inflammation in the food pipe
– Tear in the food pipe
– Tear at the junction of the stomach and food pipe
– Abnormal heart rhythms
– Pressure on the organs or structures in the chest
– Accidental removal of the breathing tube during surgery.

What Else Should I Know About Intraoperative Echocardiography?

Over recent years, there has been a noteworthy rise in the use of transesophageal echocardiography (or TEE, an ultrasound test that takes pictures of your heart). It’s not only used in heart surgeries but also as a monitoring tool or emergency aid for high-risk patients during non-heart surgeries. More doctors are learning to use TEE, and the equipment is more readily available, leading to its increased use.

How does TEE benefit patients during surgery? It can help doctors manage patients’ blood flow and breathing and reveal any changes that might need to be made to the surgery. Doctors have found TEE helpful in detecting previously unidentified conditions such as low blood volume, irregular heart wall movements, and failures of the right side of the heart. With this information, doctors can better decide how much blood, medicine to constrict or dilate blood vessels, or medicine to increase heart contractions a patient needs.

Specialists also use TEE to check the quality of heart valve repair or replacement surgeries. Suppose the ultrasound results show that the surgery wasn’t up to the mark. In that case, the patient might have to undergo heart-lung machine treatment again for surgical revision or even a switch from valve repair to valve replacement.

Sometimes, after being on a heart-lung machine, TEE can reveal an issue with heart wall movement. This might indicate trapped air that needs to be released from a by-pass graft, or a more serious problem that requires further surgical revision of the graft. If the patient’s blood oxygen levels are slightly low, it could be due to a patent foramen ovale (a hole in the heart that didn’t close after birth). Doctors can manage this by properly adjusting the resistance of the blood vessels in your body.

Several unrecognized issues can result in changes to the surgical plan- like a large patent foramen ovale, a hole in the walls of the heart, or clot in the left side of the heart’s auricle. Sometimes, severe blood circulation instability may be due to clots detected in the right side of the heart or the lung artery. Occasionally, if TEE shows signs of right-side heart failure indicating blockages in the lungs, it can prompt further studies to confirm lung clots. Patients might then need clot-dissolving therapy or even surgical removal of the clot.

TEE is undoubtedly a valuable tool for non-heart surgeries too, especially when persistent life-threatening disturbances in the blood flow need explaining. Not only this, but TEE is often used in surgeries where the patient has severe heart-related co-conditions that may lead to substantial blood circulation, lung, or neurological instability during the procedure.

We will see more frequent use of echocardiography with more focus on ultrasound education during medical training and easier access to ultrasound equipment. So, expect its use to continue to grow in the future.

Frequently asked questions

1. What is the purpose of the intraoperative echocardiography during my surgery? 2. Are there any specific risks or complications associated with the procedure? 3. How will the intraoperative echocardiography results be used to guide my treatment or surgical decisions? 4. Are there any alternative imaging or diagnostic tests that could be used instead of intraoperative echocardiography? 5. How experienced is the doctor who will be performing the intraoperative echocardiography?

Intraoperative echocardiography, specifically transesophageal echocardiography (TEE), is a medical procedure that uses an ultrasound device to take detailed images of the heart, its chambers, and valves. It can also capture images of the lungs, liver, major blood vessels around the heart, and stomach. TEE can be beneficial in complex cases where a thorough examination is needed, and there is also a special TEE that uses 3D technology for even more detailed images. However, it is important to note that TEE cannot show the parts of the heart that are behind the large airway branching off the windpipe.

You may need Intraoperative Echocardiography if you are undergoing surgery and there is a need to monitor your heart and its blood vessels in real-time during the procedure. This imaging technique can provide valuable information about the structure and function of your heart, as well as detect any abnormalities or complications that may arise during surgery. Intraoperative Echocardiography can help guide the surgical team in making informed decisions and ensuring the safety and success of the procedure.

You should not get Intraoperative Echocardiography if you have conditions such as perforated viscous, esophageal problems, active bleeding in the upper part of your digestive tract, recent surgery on the upper part of your digestive tract, history of full or partial removal of the esophagus, a hole connecting your windpipe and esophagus that hasn't been fixed, poor airway control, severe trouble with breathing, or if you are not cooperative or not sedated. Additionally, there are relative reasons that might make Intraoperative Echocardiography risky, such as disease in the joint connecting the first two vertebrae at the top of your spine, severe arthritis in your neck, prior radiation treatment to your chest, presence of inflammation or ulcers in your esophagus or stomach, and a history of difficulty swallowing.

To prepare for Intraoperative Echocardiography, the patient should provide their doctor with a detailed health history and current physical condition. The doctor will evaluate if the patient is a good candidate for moderate sedation and will assess any factors that might increase the patient's risk during the procedure. It is important for the patient's vital signs, such as heart rate and blood pressure, to be continuously monitored during the procedure.

The complications of Intraoperative Echocardiography include cut on the lip, loose or broken tooth, tongue sore, cut in the mouth or throat, difficulty swallowing, painful swallowing, swelling in the throat, loss of voice or voice changes, stomach inflammation, stomach ulcers, inflammation in the food pipe, tear in the food pipe, tear at the junction of the stomach and food pipe, abnormal heart rhythms, pressure on the organs or structures in the chest, and accidental removal of the breathing tube during surgery.

Symptoms that require Intraoperative Echocardiography include urgent problems with the aorta, artificial heart valves that need thorough checking, suspected infections around a heart valve, critical information needed for patient care, heart valve and aorta surgeries, procedures involving catheter threading into the heart, heart disease that might cause complications during surgery, severe unexplained circulation problems, suspected blood clots or air bubbles in the bloodstream, fluid around the heart, and congenital heart defects.

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