What is an Endobronchial Ultrasound?

What to expect when undergoing this procedure

An endobronchial ultrasound (EBUS) is a medical procedure that can be performed during a bronchoscopy to help diagnose or determine the stage of lung cancer. EBUS involves the insertion of a flexible scope through the mouth and into the larger airways of the lungs (called the bronchi) to image tissues using high-frequency sound waves.

EBUS is considered safe and minimally invasive, neither exposing you to ionizing radiation nor surgery. Typically performed on an outpatient basis, eBUS may cause throat pain or bleeding and, in rare instances, infection or a collapsed lung.

EBUS can also help diagnose certain inflammatory lung diseases that cannot be confirmed with standard imaging tests.

Purpose of the Procedure

If you have been diagnosed with lung cancer (or initial tests are strongly suggestive of lung cancer), endobronchial ultrasonography may be ordered alongside traditional bronchoscopy.

Unlike bronchoscopy, which directly visualizes airways through a viewing scope, EBUS can help doctors see beyond the airway tissues using refracted sound waves.

EBUS can be used to determine the extent of tumor invasion in the central airways, such as might occur with squamous cell carcinomas (which typically start in the airways) and metastatic lung adenocarcinomas (which can spread from the outer edges of the lungs and invade the central lung).

The two primary indications for EBUS are:

  • Staging of Lung Cancer: Staging is used to determine the severity of lung cancer so that the appropriate treatment is delivered. EBUS allows doctors to obtain tissue from within the lung or mediastinal lymph nodes in the chest using a technique called transbronchial needle aspiration (TBNA). The biopsied cells can then be sent to the lab for analysis and help determine how early or advanced the cancer may be.
  • Evaluation of Abnormal Lesions: If an abnormal lesion is found on a chest X-ray or CT scan, EBUS with TBNA can be used to obtain a sample of the affected tissues. Doing so can help confirm if swollen lymph nodes are caused by cancer or an inflammatory lung disease like sarcoidosis. It can also be used to sample lymph nodes in people suspected of having pulmonary lymphoma, a form of blood cancer.

EBUS is usually not the first tool a doctor will turn to diagnose lung cancer. It is typically ordered when the initial imaging tests and lab tests are strongly suggestive of lung cancer. EBUS is particularly useful in accessing a mass or nodule situated near a major airway rather than having to through the chest wall.

EBUS is most commonly used to stage non-small cell lung cancers (NSCLC) but is being increasingly used to stage small cell lung cancers (SCLC), a less common form of the disease.

Limitations

As effective a tool as EBUS is, there is only a limited amount of lung tissue that it can visualize. While it is good at visualizing the upper and front portions of the mediastinum (the membrane between the two lungs), it may not be able to visualize cancer that may have spread (metastasized) to other parts of the mediastinum.

EBUS is also sometimes used to diagnose lung infections, although its efficacy can vary. With tuberculosis, EBUS can access hard-to-reach lymph nodes and establish whether the bacterial strain is resistant to available antibiotics. Even so, with a sensitivity of roughly 77% in people with tuberculosis, EBUS is prone to false-negative results in three of every 10 procedures.

Similar Tests

Prior to the introduction of endobronchial ultrasonography, the accurate staging of lung cancer required invasive procedures that accessed the lungs via the thorax (chest). These include such procedures as:

  • Mediastinoscopy, in which a scope is inserted through an incision at the top of the sternum (breastbone)
  • Thoracoscopy, in which small incisions are made between the ribs of the chest to access the lungs using narrow, specialized tools and a viewing scope
  • Thoracotomy, an open surgery in which a portion of a rib or ribs are removed to access the lungs

Endobronchial ultrasonography can provide doctors with the information needed without the risks associated with surgery.

A 2015 study in the Journal of Thoracic Oncology concluded that EBUS with TBNA was superior to mediastinoscopy in the staging of non-small cell lung cancer and should be regarded as the first-line procedure for such purposes.

Risks and Contraindications

The risks and contraindications for endobronchial ultrasonography are similar to those of bronchoscopy. Some are mild and transient, resolving without treatment, while others require medical intervention.

The most common risks of EBUS include:

  • Laryngospasm (spasms of the vocal cords characterized by cough, difficulty swallowing, and sore throat)
  • Bronchospasm (spasms of the airways characterized by shortness of breath, cough, and wheezing)
  • Hypoxemia (low blood oxygen)
  • Infection (often related to bleeding at the biopsy site or accidental injury to the airways)
  • Cardiac complications (ranging from irregular heartbeat to heart attack, typically in those with a pre-existing heart condition)
  • Pneumothorax (also known as a collapsed lung, considered a medical emergency)

Because anesthesia is required, people may also experience nausea, vomiting, muscle pain, blood pressure changes, and bradycardia (slowed heart rate).

Due to these potential risks, EBUS In contraindicated in people with the following health conditions:

Before the Procedure

Like bronchoscopy, endobronchial ultrasonography is generally considered safe with a relatively low risk of complications. Knowing what to expect can help you prepare.

Timing

Even though the EBUS procedure takes only around 20 to 30 minutes to perform, it can take up to four hours to prepare for the procedure and recover from the anesthesia. It is best to book off the entire day and likely another to rest and recuperate.

Location

EBUS is performed in an operating room or special procedure suite of a hospital. The room is equipped with an electrocardiogram (ECG) machine to monitor your heart rate and a ventilator to deliver supplemental oxygen if needed.

What to Wear

As you will be asked to change into a hospital gown, dress comfortably in clothes that can be easily removed and put back on. It is best to leave any jewelry or valuables at home. Also, be prepared to remove any dentures, hearing aids, contact lenses, or eyeglasses before the procedure. You will be given a secure place to store these along with your clothing and other belongings.

Food and Drink

In most cases, you will be asked to stop eating at midnight the day before the procedure. Most EBUS procedures are scheduled in the morning so that you don't get excessively hungry. If the procedure is scheduled later in the day, the doctor may advise you to stop eating six hours beforehand.

You can drink water only (no tea, coffee, or other liquids) for up to two hours before the procedure. For the final two hours, you should not eat or drink anything.

Your doctor will also advise you about which drugs you need to stop prior to EBUS. Some medications can interfere with coagulation (blood clotting), leading to excessive bleeding and poor wound healing. Others may cause the excessive and harmful build-up of lactic acid in the blood.

Among some of the drugs of concern are:

Some of these medications may need to be stopped a week in advance, while others need only be discontinued on the day of the procedure. Advise your doctor about any and all drugs you take to avoid potential harm.

Cost and Health Insurance

EBUS costs slightly more than a standard bronchoscopy and can range in price from $2,500 to $5,000 or more depending on where you live and which facility you choose.

Prior authorization is required from your medical insurer before EBUS can be covered. To estimate your out-of-pocket expense, check the copay or coinsurance provisions in your policy before or after the deductible.

To reduce costs, ensure that the pulmonologist, anesthesiologist, and facility are all in-network providers with your health insurer. Out-of-network providers almost invariably cost more and, in some cases, may not even be covered by your insurance plan.

What to Bring

Be sure to bring your insurance card, an official form of identification (such as your driver's license), and an approved form of payment if copay/coinsurance fees are required upfront. Because there may be waiting time, think about bringing something to read or occupy yourself with.

Other Considerations

Because anesthesia is involved, you will need to bring someone with you to drive you home. Some facilities will not allow you to leave unless you have organized transport, ideally with a friend or family member who can escort you inside your house and stay with you overnight.

During the Procedure

Endobronchial ultrasonography is performed by a pulmonologist along with an anesthesiologist and surgical nurse.

Pre-Test

When you arrive at the hospital, you will need to fill out forms after presenting your insurance card and ID. This may include a medical history sheet outlining any conditions you have, surgeries you've undergone, medications you take, and adverse reactions you've experienced. There will also a consent form confirming that you understand the purpose and risks of the procedure.

After registration, you will be led to a dressing room to change into a hospital gown. A nurse will then escort you to an office or procedure room to measure your weight, height, blood pressure, pulse, and temperature.

The anesthesiologist will likely visit you in advance to double-check about any allergies you have or adverse reactions you've experienced with anesthesia. The doctor should also advise about the type of anesthesia is being used and what to expect afterward.

Shortly before the procedure, the nurse will insert an intravenous (IV) line into a vein in your arm through which anesthesia and other medications can be delivered. You will also have adhesive probes attached to your chest to monitor your heartbeat on the ECG machine. A pulse oximeter will be placed on your finger to monitor your blood oxygen levels.

Throughout the Test

Once you are prepared and transferred to a procedure table, an oxygen cannula (tube) may be placed under your nose to ensure your blood oxygen levels remain normal. Your nose and mouth may also be sprayed with a topical numbing spray, usually made of 1% to 2% lidocaine, to help reduce coughing or gagging.

EBUS is usually performed under procedural anesthesia, meaning that you will experience a "twilight sleep" but not sleeps as deeply as you would be with a general anesthetic. The procedure can be performed with a general anesthetic if needed. Once asleep, the pulmonologist will place a guard into your mouth to keep it open and protect your teeth.

Before the EBUS procedure begins, the doctor will first perform a regular bronchoscopy to visually examine the airways. The device will then be removed and replaced with an EBUS bronchoscope.

The EBUS bronchoscope consists of a flexible tube capped with a spherical ultrasound transducer that can deliver real-time images to a video monitor. The transbronchial aspiration needle can be extended and retracted from an opening in the neck of the scope to obtain tissue samples.

Unlike a regular bronchoscope, the EBUS bronchoscope can differentiate between normal and cancerous tissues by the visual patterns seen on the video monitor. Normal tissue tend to have a "snowstorm" appearance, unlike malignant tumors that tend to be dense.

If an abnormal mass, lesion, or lymph node is found, the doctor can obtain a tissue sample with the transbronchial aspiration needle, the sample of which is suctioned out of the needle for collection.

Once the procedure is complete, the EBUS bronchoscope will be gently removed. Anesthesia will be stopped, and you will be moved to the recovery room to monitor your condition until you wake up.

After the Procedure

Most people tolerate EBUS well and are able to leave the hospital on the same day. Even so, it is not uncommon to experience nausea and feel unsteady due to the anesthesia. Sore throat, hoarseness, and coughing are also common (although they tend to mild and resolve in a day or so). You may also have pinkish or reddish phlegm if a biopsy was performed, but this is normal and usually of little concern.

After returning home, it is best to relax and take it easy for a day or so. You should not drive or operate heavy machinery for at least 24 hours following the procedure.

If you experience any unusual, persistent, or worsening symptoms—including fever, chills, coughing up blood, or trouble breathing—call your doctor immediately as these may be signs of an infection.

If you experience rapid or irregular heart, chest tightness and pain, pain in the jaw or arm, lightheadedness, and shortness of breath after undergoing EBUS, call 911. These could be signs of a heart attack.

Interpreting Results

Following the EBUS procedure, your doctor will schedule an appointment to discuss your results. If a biopsy was performed, the results are usually returned within two to five days.

If the EBUS was used to stage lung cancer, the doctor will discuss the results of the transbronchial biopsy with you. The information may include:

  • The cancer type (such as lung adenocarcinoma, squamous cell carcinoma, large cell carcinoma)
  • The histological findings (cellular characteristics seen under the microscope that can determine how aggressive or invasive a tumor may be)
  • The molecular test results (a report of the genetic profile of your cancer, which can determine if you are a candidate for certain therapies)

These pieces of information can be used to stage and grade the disease and ensure the appropriate treatment.

If used for diagnostic purposes, the EBUS results would detail what, if any, abnormalities were found in the histology.

Generally speaking, if a visible lesion is situated within the airways, there is between an 85% and 90% chance that it is cancer. The risk is lower if the lesion is situated beneath mucosal tissues and may be explained by other conditions like sarcoidosis.

A Word From Verywell

The staging of cancer can be frustrating and stressful since it can take time and is not always straightforward. Endobronchial ultrasonography offers advantages as it can return results quickly and with minimal downtime or complications.

If you know you have lung cancer, the information provided by EBUS can be invaluable in selecting the right treatments for your specific tumor. If EBUS is used for diagnostic purposes, it can obtain tissues for evaluation without the need for more invasive surgeries.

If unsure about any part of an EBUS procedure, do not hesitate to ask why it has been ordered and what the aims of the test are.

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