To the Editor:—
In the face of difficult intubation, it is sometimes useful to insert a small-diameter introducer through the laryngeal aperture in the trachea and then pass the endotracheal tube over it. 1–4We report a modification of this technique using the Univent bronchial-blocker tube (Fuji System, Tokyo, Japan) in a patient with unanticipated difficult intubation.
A 60-yr-old, 67-kg man with lung cancer was scheduled for right upper lobotomy. The patient had been in good health. After achieving the optimal head and neck position, anesthesia induction, and muscle relaxation, laryngoscopy was performed using a Macintosh No. 3 blade by an experienced anesthetist. Only the epiglottis was seen, despite application of external laryngeal pressure, and it was impossible to insert a 7.5-mm ID Univent tube into the trachea. The curvature of the distal end of the tube was changed using a stylet, but the second attempt at intubation also failed. After easy mask ventilation for a few minutes, the bronchial-blocker catheter was protruded maximally from the distal end of the main lumen of the Univent tube. At the third laryngoscopy, the bronchial-blocker catheter was gently advanced along the laryngeal surface of the epiglottis by blind probing. When a clicking sensation was felt with the curved tip, a 50-ml syringe was attached to the proximal end of a hollow lumen of the bronchial blocker. 5Withdrawal of the syringe plunger aspirated gas without resistance. This indicated that the bronchial blocker was in the trachea, and, therefore, the main body of the Univent tube was passed over it. The main lumen met with resistance under the epiglottis, but rotating its bevel 90° counterclockwise enabled easy advancement into the trachea. Successful intubation was confirmed by capnography during manual ventilation. The operation and the postoperative course were uneventful, except for a moderately severe sore throat, which improved gradually.
There are some useful features of the Univent tube as an aid to difficult intubation compared with common bougies. First, special equipment is not needed because the Univent tube is a combination of an endotracheal tube with a bronchial-blocker catheter that can act as an intubating introducer. Second, it is relatively easy to control the direction of the tip of the bronchial blocker by rotating the main lumen. 6Its direction is also changed by twirling the proximal end of the bronchial blocker in the fingers. 6Finally, the hollow bronchial blocker (2-mm ID) enables use of the esophageal detector device or of the self-inflating bulb for confirmation of the placement of the catheter tip in the trachea. 5,7Successful tracheal placement is also confirmed by feeling a clicking sensation as the catheter tip slides over the tracheal cartilages. In addition, the hollow catheter can be used as a channel for oxygen delivery or as a suction catheter.
We have experienced five cases of successful intubation using the Univent tube in which the laryngeal aperture was invisible during laryngoscopy. A possible problem with our technique is traumatic airway complication. Although the bronchial blocker is designed to pass safely into the trachea and bronchus, 6the bronchial-blocker catheter should be gently advanced. The fiberoptic bronchoscope–aided endotracheal intubation is the most reliable method in patients at risk for difficult intubation. However, the fiberoptic bronchoscope is not always readily available, and an intubation attempt may fail because of an inability to advance the endotracheal tube over the fiberoptic bronchoscope into the trachea. 8We believe that the Univent bronchial-blocker tube is a useful and simple aid to unanticipated difficult intubation.