What is Endobronchial Ultrasound Scan and biopsy?

Overview

Endobronchial Ultrasound Scan (EBUS) is a procedure that combines the benefits of bronchoscopy and ultrasound scan. It is an effective procedure to diagnose certain lung conditions. When the same bronchoscope is endowed with tools at its tip, a biopsy of lung tissue can be performed in the same session. Such a biopsy is more accurate and useful. In this article, we will learn why EBUS is done, how it is done, and risks from the procedure.

Introduction

In earlier articles, we have examined bronchoscopy and how various procedures can be performed during a bronchoscopy session. In addition to using the procedure for diagnosis (when combined with biopsy), bronchoscopy can be used to perform some interventions, that help treat certain lung conditions.

Now, there are various methods that help the doctor guide the bronchoscope to the desired spot in the lungs, in order to collect relevant samples of tissue for examination under a microscope. This includes X-ray and CT scan before the bronchoscopy, and then a bronchoscope that is fitted with a camera and light at its end.

Another technique involves the use of ultrasound. Ultrasound waves emitted by a transponder fitted to the end of the scope are bounced off by lung tissue or lymph nodes in the vicinity. The echo waves are harvested and a map or image of the concerned tissue is created on a computer monitor kept in the OT.

This way, the doctor has a precise idea of where to move the bronchoscope inside the lungs. Once anchored in the desired position, a biopsy of the lung tissue can be done, using various tools such as blades, brushes, syringes or fine needles (called trans-bronchial needle aspiration or TBNA which is the most common method) or even a lavage (washing) can be done. Given the higher accuracy of ultrasound-based imaging, the doctors can collect the most relevant sample of tissue for examining under the microscope. This is the primary advantage of EBUS.

Further, EBUS is a minimally-invasive procedure and carries lesser risk than procedures such as mediastinoscopy which was used earlier. Mediastinoscopy involves making incisions in the chest wall and inserting similar scopes into the lung(s).

What are the Benefits of EBUS?

• EBUS produces clear images of the lung surface, surface of the airways, insides of the lungs, blood vessels in the lungs and lymph nodes in the vicinity, all in real-time.
• Accurate images mean the doctors can easily view hard-to-reach areas and then access tiny lymph-nodes to collect samples for biopsy, using thin aspiration needles. This is more effective than traditional mediastinoscopy. For example, Mediastinoscopy offers limited access to perihilar lymph nodes.
• Compared to mediastinoscopy, EBUS is also faster. So, more and more patients can be examined. Samples collected can be examined immediately on the spot and based on the findings, additional samples can be collected, or some intervention performed then and there.
• EBUS is generally performed under moderate sedation and rarely under general anesthesia. This means, patients can be discharged the same day once their vitals are stable.

Why is EBUS done?

• To diagnose lung infections such as tuberculosis
• To diagnose sarcoidosis
• To detect lymphoma
• Biopsy: to perform transbronchial needle aspiration (TBNA) to collect samples of tissue or fluid from the lungs and lymph nodes in the vicinity, without incisional surgery or techniques like mediastinoscopy.
• To check at what stage is the cancer in and help in management of lung cancer

Preparing for EBUS

The patient must stop taking all medications, especially blood-thinning medicines such as warfarin, clopidogrel and aspirin, a few days before the procedure. His/her medical history and physical examination are done to check for overall health and suitability for this procedure.

Four hours before the procedure, the person must not eat or drink anything. He/she must leave all aids like contact lenses, bridges, glasses and dentures, at home. Upon discharge, the person must be accompanied by a friend or family member. While most EBUS procedures involve a flexible bronchoscope, some cases may involve a rigid scope. The latter will require general anesthesia while sedation is enough for flexible scope. However, if the patient so desires (to minimize discomfort), general anesthesia is given.

Just before the procedure, the patient must lie on a bed with arms at the sides, after which he/she will be wheeled into the bronchoscopy suite. Sedatives are injected into the arm and numbing medication is sprayed down the throat. All these minimize pain and discomfort.

During the procedure

A special bronchoscope is used for the procedure. An ultrasound-transponder is attached to its end. Tubes or channels within the scope carry a thin needle required for aspiration or sucking up the required sample. A computer screen in the OT maps the echoes of sound waves into an image. The scope is gently guided through the mouth, throat, trachea (wind-pipe) and into the lungs. The imagery on the screen guides the doctor’s action or movement of the scope.

Once the desired spot is reached, the doctors use the thin needle to draw sample tissue. The sample is quickly evaluated under the microscope, on the spot (called Rapid On-site evaluation or ROSE). Based on the findings, the doctors may take more samples, or they may perform some intervention as required.

After the procedure

The patient is wheeled out of the bronchoscopy suite and into the ward, and vitals like BP, oxygen, heart-rate and pulse monitored continuously. The nose and mouth feel numb for a few hours in which time, the patient cannot consume anything. Once the numbness goes away, he/she is given soft foods such a soups or porridges, and beverages. The nose and throat may pain for a few days. The doctor will prescribe pain-killers for relief. In case of sedation only, the person can be discharged the same day once his/her vitals stabilize. In case of general anesthesia, he/she will stay in the hospital for a day.

Risks from EBUS

• No to Minimal risks if done under the right expertise.

 

Kauvery Hospital is globally known for its multidisciplinary services at all its Centers of Excellence, and for its comprehensive, Avant-Grade technology, especially in diagnostics and remedial care in heart diseases, transplantation, vascular and neurosciences medicine. Located in the heart of Trichy (Tennur, Royal Road and Alexandria Road (Cantonment), Chennai, Hosur, Salem and Bengaluru, the hospital also renders adult and pediatric trauma care.

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