performing transesophageal ultrasound using the six landmarks approach and tissue sampling

Integrating Transesophageal Ultrasound with an Echoendobronchoscope

Endoscopic ultrasound is a key procedure in the diagnosis and staging of lung cancer and allows safe sampling from mediastinal or hilar lymph nodes1,2. Endoscopic ultrasound comprises endobronchial (EBUS) and transesophageal ultrasound (EUS), are considered complementary procedures2.
Interventional pulmonologists are trained with the EBUS endoscope but are rarely familiar with the larger EUS endoscope (Figure 1), which requires special training to handle correctly3. EBUS and EUS are often performed by different departments and on separate sessions/days4. However, trained pulmonologists experienced with EBUS techniques can insert the smaller EBUS endoscope into the esophagus and perform safe examination and biopsy sampling from mediastinal lymph nodes and other lesions adjacent to the esophagus and stomach - a technique termed as EUS-B5. This leads to extension of pulmonologists&#39; ability to safely and conclusively sample lesions in many different anatomical sites such as lung6, pleura7, pericardial effusion8, mediastinal lymph nodes1,5, left liver lobe and retroperitoneal lymph nodes9, pancreas10 and the left adrenal gland11,12 (Figure 2).
The EUS-B procedure is a pulmonologist friendly version of the gastroenterologists&#180; EUS using an endoscope that the pulmonologist already masters. The EUS procedure is performed with a gastroendoscope which is both larger and heavier than the EBUS endoscope, has a different handle (with wheels, see Figure 1) and is unlike EBUS performed with the patient in left lateral decubitus. Learning EUS as a pulmonologist is challenging and requires a lot of training and supervision2.
EUS-B and EUS are so far very similar regarding diagnostic yield when performed in the field of pulmonology5,13,14,15. EUS-B is patient friendly since the endoscope is significantly thinner than that of EUS, and therefore less unpleasant for the pharynx and esophagus. Unlike EBUS, EUS-B does not cause direct airway irritation and is therefore safe to use in patients with suspected cancer resulting in severe respiratory impairment due to mediastinal tumor masses16.
The combination of EBUS and EUS-B is preferred over either test alone in any patient suspected of lung cancer, but EUS-B should especially be considered in patients with suspicious lesions out of reach by EBUS, but within range by transesophageal ultrasound (Figure 2). Adding EUS-B to EBUS in lung cancer work-up expands the interventional pulmonologists&#180; ability to perform diagnostic work-up during a single session using the same endoscope by one proceduralist, which is more convenient for the patient, saving both time and costs.
The complication risk of EUS-B is extremely low and is to our knowledge only limited to infectious complications17,18. EUS-B training should be easy and a natural continuation of EBUS, and the following protocol will describe how to perform EUS-B in mild sedation in an out-patient clinical setting.

Author Spotlight: Advancing Biopsy Techniques with Transesophageal Ultrasound

Using the Endoscope for Endobronchial Ultrasound in the Esophagus

Our scope is to identify new ways to perform biopsies from otherwise difficult to access areas in the most patient-friendly way. Thus, conclusive biopsies with few adverse events, low patients discomfort, and low costs. EUS-B is a safe technique in the hands of respiratory physicians.Despite that biopsies are taken not from the lungs or airways, but from the esophagus or stomach, it allows for more complete investigation of patients with possible lung cancer or other cancer. We have contributed significantly to the field by exploring utility and safety of EUS-B, including identification of new targets that can be reached and sampled. The aspect of patient safety is of utmost importance, and EUS-B has no serious complications.EUS-B is an emerging technique, and there's still no simulators or phantoms that allows for safe learning of the technique. This protocol provides a clear and stepwise instruction to support beginners and mentors to improve the learning curve.

Performing Transesophageal Ultrasound Using the Six Landmarks Approach and Tissue Sampling

To begin, position the patient in a supine and apply monitoring equipment. Continuously monitor 3-lead telemetry, oxygen saturation, pulse, and intermittent blood pressure. While standing behind the patient's head, hold the handle of the echo endobronchoscope with the left hand, thumb in the lever, and distal end in the right hand.Apply local anesthetic gel on the tip of the endoscope, then orally or through the nostril, introduce the endoscope into the oropharynx of the anesthetized patient. Advance the endoscope into the laryngopharynx while the epiglottis in front of the scope. Visualize the vocal cords using the bronchoscopic view.Next, turn the scope left or right to direct it lateral to the adenoids. Ask the patient to swallow and slowly bend the endoscope posteriorly, introducing it into the esophagus following the patient's swallowing movement. If required, spray two milliliters of topical lidocaine in the oropharynx.To identify six endoscopic ultrasound landmarks, shift to the ultrasonic image and introduce the endoscope into the stomach. At landmark one, turn the endoscope slightly counterclockwise to visualize the left liver lobe. At landmark two, turn the scope clockwise to visualize the abdominal aorta with the celiac trunk in superior mesenteric artery.Turn the scope further clockwise at landmark three to visualize the left adrenal gland. At landmark four, retract the endoscope to the mediastinum to locate the mediastinal lymph station 7. Next, retract the endoscope a few centimeters and observe the reflections from the trachea.Now turn the endoscope counterclockwise and at landmark five find mediastinal lymph node station 4L between the aortic arch and the left pulmonary artery. At landmark six, turn the endoscope clockwise and pass the trachea to find the azygos vein and mediastinal lymph node station 4R. Insert the sheath in the endoscope and adjust the length such that the tip is one millimeter outside the endoscope.Then lock the sheath in place. Move the FNA needle with the stylet forward and retract the stylet a few millimeters to sharpen the needle. Under realtime ultrasonographic guidance, hit the target lesions.Then retract the stylet and apply suction to the needle. Move the needle back and forth. Remove the suction and lock the needle in the upper position before removing the equipment from the endoscope.The transesophageal ultrasound tissue sampling technique shows that diagnostic hit rates vary according to location with slightly higher diagnostic success rates of intrathoracic lesions.

performing-transesophageal-ultrasound-using-six-landmarks-approach

Research

JoVE Journal

Medicine

EUS-B is a procedure using the echoendobronchoscope in the esophagus and stomach. The procedure is a minimally invasive, safe, and feasible approach that pulmonologists can use to visualize and biopsy structures adjacent to the esophagus and stomach. EUS-B gives access to many structures of which some may also be reached by EBUS (mediastinal lymph nodes, lung or pleural tumors, pericardial fluid) while others cannot be reached such as retroperitoneal lymph nodes, ascites, and lesions in the liver, pancreas or left adrenal gland. The procedure is a pulmonologist- and patient- friendly version of the gastroenterologists' EUS using the thin EBUS endoscope that the pulmonologist already masters. Thus EUS-B training should be easy and a natural continuation of EBUS. With the patient under conscious sedation and in the supine position, the echoendoscope is introduced either through the nostril or mouth into the oropharynx. Then the patient is encouraged to swallow while the endoscope is slowly bent posteriorly and introduced into the esophagus and stomach. Using the ultrasonic image, the operator identifies the six landmarks by EUS-B and EUS: the left liver lobe, abdominal aorta (with the celiac trunk and superior mesenteric artery), left adrenal gland, and mediastinal lymph node stations 7, 4L, and 4R. Biopsies can be taken from suspected lesions under real-time ultrasonographic guidance- fine needle aspiration (EUS-B-FNA) using a technique similar to that used with EBUS-TBNA. The biopsy order is M1b-M1a-N3-N2-N1-T (M = metastasis, N = lymph node, T = tumor) to avoid iatrogenic upstaging. Pre- and post-procedural observation is similar to that of bronchoscopy. EUS-B is safe and feasible in the hands of experienced interventional pulmonologists and provides a significant expansion of the diagnostic possibilities in providing safe, fast, and thorough diagnosis and staging of lung cancer.

Transesophageal ultrasound (EUS-B) is a safe and feasible procedure using the echoendobronchoscope (EBUS) in esophagus and stomach. After identifying six anatomical landmarks, additional structures can be identified and biopsied, sparing subsequent diagnostic sessions. Thus, EUS-B is an ideal continuation of bronchoscopy and EBUS in diagnosing lung cancer and other diseases.

EUS-B is a procedure using the echoendobronchoscope in the esophagus and stomach. The procedure is a minimally invasive, safe, and feasible approach that ...