Most people are not fully awake during a transesophageal echocardiogram (TEE), but they are not completely unconscious either. The standard approach for a diagnostic TEE done in a cardiology lab is moderate sedation, a level where you can still breathe on your own and respond to verbal cues but are drowsy enough that you probably will not remember much of the procedure. When a TEE is performed during open-heart surgery, you are under general anesthesia and completely unaware. The distinction matters because it shapes what you feel, what you remember, and how quickly you recover.
What Moderate Sedation Actually Means
The word “sedation” covers a wide range, and the version used for most outpatient TEE exams sits in the middle of that range. Moderate sedation, sometimes called conscious sedation, means your consciousness is depressed enough that you tolerate the probe in your throat without distress, but you can still breathe independently and respond if someone speaks to you or taps your shoulder. You are not “awake” in the way you would be sitting in a waiting room, and you are not “asleep” the way you would be during major surgery.
When anesthesia providers are involved, they may deliver what is called monitored anesthesia care, which describes a specific anesthesia service rather than a fixed depth of sedation. In practice, monitored anesthesia care can range from light sedation to something close to general anesthesia, depending on the patient and the drugs used. General anesthesia, by contrast, means complete unresponsiveness to painful stimulation, with the possibility of impaired breathing and the need for airway protection.1PubMed Central. The Quality and Safety of Sedation and Monitoring in Adults Undergoing Non-Operative Transesophageal Echocardiography For a routine diagnostic TEE, general anesthesia is usually unnecessary and adds cost and recovery time.
Why You Need Sedation in the First Place
A TEE probe is roughly the diameter of a finger and gets passed through your mouth, down your esophagus, and positioned behind the heart. The esophagus sits right next to the heart’s back wall, so the ultrasound images are far sharper than what you get from a standard echocardiogram done on the chest. The trade-off is that swallowing a probe triggers a powerful gag reflex in most people, making sedation close to essential for comfort and image quality.
Before the probe goes in, your throat is typically sprayed or swabbed with a topical anesthetic, often lidocaine, to numb the back of your throat and reduce gagging. This local numbing helps, but on its own it is rarely enough for most adults to tolerate a full examination that can last 15 to 30 minutes. That is where intravenous sedation comes in.
The Medications Involved
The most common sedative for outpatient TEE is midazolam, a fast-acting benzodiazepine. In one monitoring study, roughly nine out of ten patients undergoing routine TEE received midazolam intravenously.2PubMed Central. Routine arterial oxygen saturation monitoring is not necessary during transesophageal echocardiography Arterial desaturation during transesophageal echocardiography Midazolam works quickly, wears off relatively fast, and has a useful side effect: it tends to cause retrograde amnesia, meaning you may not form lasting memories of the procedure even if you were somewhat responsive during it.
Other drug options exist. Dexmedetomidine, a sedative that works through a different pathway, has been studied head-to-head against combinations like ketofol (a blend of ketamine and propofol) for outpatient TEE sedation.3PubMed Central. Dexmedetomidine versus Ketofol Sedation for Outpatient Diagnostic Transesophageal Echocardiography: A Randomized Controlled Study Propofol is another popular choice, especially when deeper sedation is needed or when an anesthesia provider is present. Each drug has a slightly different profile in terms of how fast it kicks in, how deeply it sedates, and how quickly you bounce back.
Will You Remember Anything?
This is the question most people really want answered when they ask whether they will be “awake.” The honest answer is: probably not much. Midazolam in particular is well known for erasing the memory of procedures even in patients who were responsive during them. A study looking at cognitive function after TEE found that when patients were given midazolam followed by flumazenil (a reversal agent), their recall of items learned before sedation was not significantly different from patients who did not get the reversal. In other words, the amnesia from the sedation itself does most of the work; reversing the sedation afterward does not bring memories back.4PubMed Central. The role of flumazenil in outpatient transesophageal echocardiography
Some patients do retain fragmentary memories, brief impressions of gagging or feeling pressure in the throat, usually without significant distress. People who have had the procedure before sometimes describe it as “I remember starting to feel drowsy and then waking up in recovery.” Researchers have even tested hypnosis as an alternative to midazolam for TEE sedation and found that patients under hypnosis reported less anxiety and more alertness afterward, though this approach remains unusual in clinical practice.5PubMed Central. Hypnosis for sedation in transesophageal echocardiography: a comparison with midazolam
When You Really Are Completely Asleep
If your TEE is being done during cardiac surgery or another procedure that already requires general anesthesia, you will be fully unconscious and intubated. In that setting, the TEE is added to guide the surgeon in real time, and the anesthesia team manages both the surgery and the echocardiogram simultaneously. A large case series of over 7,200 cardiac surgical patients who had intraoperative TEE found a complication rate from the TEE itself of about 0.2 percent, with zero deaths attributable to the echocardiogram.6PubMed. The safety of intraoperative transesophageal echocardiography: a case series of 7200 cardiac surgical patients The fact that patients are already under general anesthesia makes the TEE component essentially invisible to them.
TEE under moderate sedation is also used to guide certain catheter-based procedures. In transcatheter aortic valve replacement, for instance, TEE guidance under moderate sedation has been associated with shorter procedure times and fewer additional imaging steps compared to transthoracic echocardiography, which has lower resolution when the patient is lying on an operating table.7PubMed Central. Comparison of transesophageal and transthoracic echocardiography under moderate sedation for guiding transcatheter aortic valve replacement In these scenarios, the sedation plan is tailored to the procedure’s length and complexity, and sometimes tips closer to deep sedation than what you would get for a straightforward diagnostic exam.
How Anxiety Affects the Experience
If you are anxious going in, you may need more sedation. A study that measured anxiety levels in patients referred for TEE found that people with moderate or high anxiety required a larger supplemental dose of midazolam compared to those with little or no anxiety. The more anxious group needed around 2 mg of additional midazolam on average, versus about 1.5 mg for the calmer group.8ABC Imagem Cardiovasc. The Impact of Anxiety on Patients Referred for Transesophageal Echocardiography Interestingly, the study found no significant link between anxiety levels and factors you might expect to matter, such as having received prior instructions about the exam or having undergone TEE before. Anxiety before a medical procedure tends to be its own beast, not easily tamed by experience alone.
If you know you tend to be anxious about medical procedures, it is worth mentioning this to your care team beforehand. They can adjust the sedation plan, sometimes starting with a small dose before the procedure begins so that you are already relaxed by the time the probe is ready.
What Happens During the Procedure
You will lie on your left side. An IV line delivers the sedation, and you will have monitoring equipment tracking your heart rate, blood pressure, and blood oxygen levels throughout. Once the sedation takes effect and your throat has been numbed, the sonographer or cardiologist passes the probe. You may be asked to swallow to help guide it down. From there, the probe is angled and rotated to capture images from various positions behind the heart.
During the exam, the team watches for drops in oxygen levels, changes in heart rate, or blood pressure swings. When anesthesia providers manage the sedation, rates of transient low blood pressure can be notable. In one large study, about one in five patients in the anesthesia-managed group experienced a temporary blood pressure drop, and roughly 8 percent had a brief episode of low oxygen.1PubMed Central. The Quality and Safety of Sedation and Monitoring in Adults Undergoing Non-Operative Transesophageal Echocardiography These episodes are typically mild, short-lived, and managed easily by the care team. Serious complications from the TEE itself are rare in adults.
Why TEE Is Ordered in the First Place
Understanding the reason for the test can ease some of the anxiety around it. TEE is ordered when standard chest-based echocardiography cannot provide clear enough images, or when specific structures need a closer look. One of the most common indications is checking for blood clots in the heart before cardioversion, the procedure that restores a normal heart rhythm in atrial fibrillation. In one review of TEE indications before cardioversion, about a quarter of exams were prompted by symptoms and another quarter by heart failure or hemodynamic instability.9PubMed. Indications for TEE before cardioversion for atrial fibrillation: implications for appropriateness criteria Other common reasons include evaluating heart valve disease, looking for infections on heart valves, assessing congenital heart defects, and guiding catheter-based procedures.
Recovery and Going Home
After the probe is removed, you will stay in a recovery area until the sedation wears off enough for you to be safely discharged. For most people, this takes 30 minutes to an hour. Your throat will likely feel sore or scratchy for the rest of the day, sometimes into the next morning. You should not eat or drink until the numbness from the throat spray has fully resolved, usually an hour or two, because the numbed throat raises the risk of accidentally inhaling food or liquid.
Because the sedation can continue to affect your coordination and judgment even after you feel alert, you will need someone to drive you home. Most facilities will not discharge you without a companion. You are also typically advised to avoid signing important documents, making major decisions, or operating machinery for the rest of the day. The memory-erasing effect of midazolam can be oddly selective: some patients feel completely normal in recovery but later have no memory of conversations they had there.
Pediatric TEE and Deeper Sedation
Children pose a different challenge. Young children and infants cannot cooperate with the instruction to swallow or hold still, and the smaller anatomy makes the procedure more delicate. In pediatric practice, deeper sedation or general anesthesia is the norm. A study comparing deep sedation (using drugs like ketamine, propofol, or a combination) with general anesthesia in children found that deep sedation led to shorter procedure times and faster recovery, averaging about 7 minutes to recovery versus 11 minutes with general anesthesia, without an increase in complications like low blood pressure, low oxygen, or airway spasms.10PubMed. Deep Sedation Versus General Anesthesia in Pediatric Transesophageal Echocardiography: A Retrospective Comparative Study
For very young children, typically under two years old, intubation during the procedure is common practice because the airway is so small that the probe can compress it. In one pediatric sedation study using propofol, children under two were routinely intubated, and about one in five non-intubated children experienced brief low oxygen episodes. Major complications were uncommon, occurring in roughly 4 percent of cases.11Cardiology in the Young. Safety and efficacy of sedation with propofol for transoesophageal echocardiography in children in an outpatient setting Children are also more vulnerable to tracheal complications from the TEE probe because their windpipe has a smaller internal diameter, which means there is less room for the probe to sit alongside the breathing tube without causing compression.12Frontiers in Cardiovascular Medicine. Transesophageal echocardiography related complications
Transnasal TEE and the Possibility of No Sedation
An emerging alternative is transnasal transesophageal echocardiography, where a much smaller probe enters through the nose instead of the mouth. This approach bypasses the gag reflex almost entirely, because the probe does not touch the back of the tongue or the pharynx in the same way. Early clinical experience suggests that transnasal TEE can sometimes be performed with little or no sedation, which would be a significant shift in how these exams are done. The potential benefits include expanded availability, since the exam could be done without an anesthesia team present, shorter recovery periods, and reduced risk of oropharyngeal injury.13Wiley Online Library (Echocardiography). The Emerging Role and Clinical Utility of Transnasal Transesophageal Echocardiography
Transnasal TEE is not yet widely available and the probes currently offer somewhat lower image resolution than conventional TEE probes. But the technology is improving, and for patients who have difficulty with oral intubation, whether due to anatomy, prior throat surgery, or severe gag reflexes, the nasal route provides a genuine alternative. If widespread adoption continues, it could eventually change the default answer to “are you awake during a TEE?” from “sort of” to “yes, and it was not that bad.”
Risks Specific to the Probe Itself
Setting aside the sedation, the physical act of passing a probe down the esophagus carries its own small set of risks. The most talked-about serious risk is esophageal perforation, which is exceedingly rare but life-threatening when it occurs. More common minor issues include sore throat, minor bleeding from abrasion, and transient hoarseness. In intubated patients during surgery, the probe can occasionally displace the breathing tube or compress the trachea, and there have been case reports of severe airway obstruction caused by the probe kinking the endotracheal tube.12Frontiers in Cardiovascular Medicine. Transesophageal echocardiography related complications Accidental tracheal intubation with the TEE probe, meaning the probe goes down the windpipe instead of the esophagus, has been reported at a rate of roughly 0.27 percent in ambulatory adults.
Another downstream risk that has gotten more attention in recent years is swallowing difficulty after the procedure, particularly after long cardiac surgeries. Research has shown that acquiring a large number of TEE images during surgery is an independent risk factor for aspiration problems in the days following the operation. This connection is thought to relate to minor vocal cord injury and airway swelling from prolonged probe manipulation. For a short outpatient diagnostic TEE, this risk is far lower, but it is another reason the sore throat you feel afterward should be taken as a signal to eat and drink carefully for the first few hours.