To the Editor:—
Placement of double-lumen endobronchial tubes (DLTs) may be difficult because of anatomic factors that predispose patients to difficult intubation and because of the large external diameter of DLTs. 1,2Moreover, rupture of the proximal endotracheal cuff of the DLT may occur during difficult intubation because the thin-walled cuff is located 8–11 cm from the tip of the DLT, where it can easily be torn on the maxillary teeth.
We describe the use of fiberoptic laryngoscopy with the WuScope (Pentax Precision Instruments, Orangeburg, NY) to facilitate placement of a DLT in two patients with abnormal airway anatomy.
A 33-yr-old man was involved in a motor vehicle accident that resulted in multiple injuries, including a descending thoracic aortic laceration just below the left subclavian artery. He was scheduled for repair of the aortic laceration. The patient’s trachea had been intubated with use of a standard tube, and no intubation difficulties were noted at that time. Cervical spine radiographs were normal, but, because of a depressed level of consciousness, there was still a chance of spine injury, and a rigid cervical collar was in place. Examination showed that the airway was otherwise normal.
The trachea and oropharynx were suctioned, and the endotracheal tube was removed after 10 min of preoxygenation. A 39-French, left DLT (Broncho-cath; Mallinckrodt Medical, St. Louis, MO) could not be inserted using conventional laryngoscopy because of poor glottic visualization. A 37-French, left DLT then was inserted using a Heine Corazzelli-London articulating laryngoscope (Heine USA Ltd., Dover, NH) and inline stabilization (grade II view with external laryngeal pressure and activation of the lever). The endotracheal cuff, however, was torn by the patient’s upper teeth. Another attempt, using a 35-French DLT, had a similar cuff rupture.
Fiberoptic laryngoscopy using the WuScope was performed with use of large, adult-sized blades. 3A 35-French, left DLT was inserted via the passage created by the main blade and bivalve element (fig. 1)
through the vocal cords and into the trachea (grade 1 view). Flexible fiberoptic bronchoscopy confirmed satisfactory tube position, and surgery was completed without complications.
A 37-yr-old woman presented with a 7-month history of dry cough. Radiographic examination showed a dilated noncommunicating bronchus, with mucoid impaction and a large feeding arterial vessel arising from the distal thoracic aorta at the lower diaphragm. She was scheduled for right lower lobectomy.
Airway examination showed a 35-mm mouth opening with temporal mandibular joint clicking, a normal thyromental distance, protruding maxillary incisors, and Mallampati II classification.
After induction of general anesthesia and neuromuscular blockade, a 37-French, left DLT could not be inserted using conventional laryngoscopy because of a grade III view. Insertion of a Univent tube (Fuji Systems Corp., Tokyo, Japan), size 7, using conventional laryngoscopy and an anteriorly directed stylet also was unsuccessful. A 35-French, left DLT was inserted with fiberoptic laryngoscopy using the adult-sized WuScope blades as described in patient 1. A grade I view of the glottis was obtained on the first attempt, and the DLT was inserted.
The WuScope is composed of a tubular, curved, bivalved rigid blade and a flexible fiberscope to facilitate oral intubation without the need for head extension. 4,5At least 20 mm of mouth opening is necessary to insert the rigid blades.
It has previously been shown that glottic exposure and tracheal intubation were relatively easy using the WuScope, even in patients with anatomic factors that would normally prevent a complete view of the vocal cords, such as cervical spine instability, hypoplastic mandible, and protruding maxillary incisors. 3
One advantage of the WuScope is that the two rigid blades combine to form a tubular exoskeleton, which not only provides a passage through which the DLT tube can be placed, but also protects the proximal endotracheal cuff from tearing as the DLT is moved through the glottic opening.
With the WuScope, it may be necessary to insert a DLT that is smaller than desired because of the tubular nature of the blade system. For example, we have found that, when using the large adult-sized blades, left 35- and 37-French DLTs slid through easily, whereas the left 39-Fr DLT was extremely tight. When using the adult-sized blades, only the 35-Fr DLT could easily be inserted.
Although other techniques for lung separation are available, the WuScope was used in these two patients because it was readily available, and considerable experience had already been achieved with this technique.
The WuScope permitted DLT intubation in two patients with difficult airway anatomy. Advantages of the WuScope include an oropharyngeal airway–shaped blade to allow a view of the laryngeal aperture without the need for head extension; a handle-to-blade angle of 110°, which allows easy placement into the mouth; a tubular blade structure, which protects the fiberscope from secretions, blood, and redundant soft tissue; a built-in passage through which the DLT can be inserted; and continuous viewing of the DLT as it moves into the trachea. Disadvantages of the WuScope include high cost (approximately $9,800), the need for smaller DLTs (e.g. , 35–37 French), and the need for learning to assemble and disassemble the blades and manipulate the scope.