A bougie, formally known as the Tracheal Tube Introducer, is a device used in emergency medicine to secure a patient’s airway during tracheal intubation. This flexible, semi-rigid guide assists the clinician in safely placing a breathing tube into the windpipe. The introducer is designed to increase the success rate of this intervention by providing a reliable pathway into the trachea, especially when direct visualization of the vocal cords is difficult.
Design and Purpose of the Tracheal Tube Introducer
The bougie is a long, slender device, typically measuring 60 to 80 centimeters in length with a narrow external diameter of 4 to 5 millimeters (15 French) for adult models. It is constructed from flexible plastic, such as low-density polyethylene, allowing it to be firm enough for guidance yet pliable enough to conform to the airway’s curvature.
A defining feature is the angled tip, known as the Coudé tip, which is bent at about a 30 to 40-degree angle. This forward-aimed tip allows the clinician to guide the device beneath the epiglottis and into the tracheal opening, even when the view is poor. The bougie acts as a guidewire inserted into the trachea first. Once placement is confirmed, the larger endotracheal tube (ETT) is “railroaded,” or slid, over the bougie into the windpipe.
This railroading technique prevents the ETT from getting caught on anatomical structures, a common difficulty when placing the tube without a guide. Since the bougie is much smaller than the ETT, it is easier to maneuver into the correct location under limited visibility. The device significantly aids in achieving successful intubation.
When the Bougie is Essential
The bougie is designed as a rescue device for a “difficult airway.” This scenario occurs when the clinician cannot get a clear view of the vocal cords during laryngoscopy. Clinicians use the Cormack-Lehane classification system to grade the view of the glottis; a Grade 2 or 3 view indicates a partial or absent view of the vocal cords.
The bougie is often used when a patient has anatomical challenges, such as a receding jaw, a short neck, or limited neck mobility. It is also employed during manual in-line stabilization (MILS) in trauma scenarios, which restricts the airway view. The use of the bougie significantly increases the first-pass success rate of intubation, particularly in patients with difficult airway characteristics.
In Cormack-Lehane Grade 3 cases, where only the epiglottis is visible, the bougie improves the chances of successful placement compared to using a tube and stylet alone. Facilitating a higher first-attempt success helps reduce the risk of hypoxia and complications associated with prolonged or multiple intubation attempts.
Understanding Tactile Feedback and Insertion Technique
The practical application of the bougie relies on the clinician’s ability to interpret subtle physical sensations known as tactile feedback. The bougie is inserted under direct or video-assisted laryngoscopy, often with the clinician only seeing the tip disappear past the epiglottis. Once the tip enters the trachea, the clinician feels two distinct sensations that confirm correct placement.
The first sensation is “tracheal clicks,” which are rhythmic vibrations felt as the Coudé tip slides over the rings of cartilage forming the trachea. This confirms the bougie is in the windpipe and not the smooth-walled esophagus. The second sign is the “hold-up sign,” which occurs when the bougie is advanced further and its tip lodges against the walls of the lower airways, typically a mainstem bronchus.
This resistance reliably confirms tracheal cannulation, as the bougie would pass much deeper into the esophagus without resistance. Once placement is confirmed, the bougie is stabilized, and the endotracheal tube is threaded over it, using the bougie as a guide. If the ETT snags on the arytenoid cartilage during advancement, a slight counter-clockwise rotation of the tube helps the bevel clear the obstruction and slide smoothly into the airway.