To the Editor:—
Several surgical procedures require single-lung ventilation. Because a double-lumen tube (DLT) allows for independent ventilation therapy (e.g. , continuous positive airway pressure), suctioning, and bronchoscopy of each lung, the DLT is the accepted standard for the treatment of patients undergoing thoracic surgery.1A difficult intubation in this subset of patients is particularly challenging because tube insertion is impeded by the special shape of the DLT and the two separate cuffs, which can be damaged by the patient’s teeth and during repeated insertion maneuvers using intubation tools with sharp surfaces.
Recently, in two patients scheduled to undergo a minimally invasive direct coronary artery bypass procedure requiring DLT insertion, direct laryngoscopy failed. Because at our institution the Bonfils intubation fiberscope (Karl Storz GmbH, Tuttlingen, Germany), a rigid fiberscope with a curved tip, is routinely used for managing unexpected as well as anticipated difficult airways,2,3we decided to use the device to aid in DLT placement. The Bonfils intubation fiberscope has a length of approximately 40 cm and an OD of 5 mm. According to the manufacturer, tracheal tubes with an ID of 5.5 mm or greater and a length of 39 cm or less may be used. The length of the DLTs (including tube connector) used in our cases is approximately 42 cm, and the largest ID of the bronchial lumen is approximately 5.1 mm (37 French) and 5.3 mm (39 French), respectively. Usually, the tube is too long for insertion of a Bonfils intubation fiberscope. After shortening both the tracheal and the bronchial connectors to a complete length of 38.5 cm and after ensuring adequate lubrication of the scope with silicone spray, however, the tube’s bronchial lumen was mounted on the scope easily (fig. 1). Shortening of the proximal connectors did not prevent connecting them to the endotracheal tube adapter and subsequently to the right angle adapter attached to the breathing circuit.
Using the Bonfils intubation fiberscope, the patient’s mouth is opened, and the scope inserted from the right side of the mouth along the molars after the patient’s head is adjusted in a neutral position. With the insertion of the device, the anesthesiologist performs a jaw-thrust maneuver with his or her left hand to enhance the retropharyngeal space. After this, guided by the right hand, the Bonfils intubation fiberscope is advanced in the glottic aperture. The tube is then released from the scope with the left hand (or by an assistant) and inserted into the trachea under direct visualization. Sometimes, performing simultaneous laryngoscopy with a conventional Macintosh blade by a second anesthesiologist may be helpful to lift up a large tongue impeding advancement of the fiberscope. Finally, the correct position of the tube must be verified with a fiberoptic bronchoscope, because the rigid Bonfils intubation fiberscope should not be advanced in the trachea.
In the two cases denoted, the Bonfils intubation fiberscope was an effective tool for placing a DLT. The time to intubation was clinically acceptable, and no damage occurred with respect to the patient’s teeth or soft tissues. Importantly, the cuffs were intact after placement despite a very desolate set of teeth in one patient. The right-sided insertion approach of the scope along the molars may be advantageous in such cases, because touching the front teeth is avoided, and molars are not as sharp-edged as the anterior and canine teeth.
Few intubation tools are suitable for DLT placement. The fiberoptic bronchoscope, which has evolved as an accepted standard for management of the difficult airway,4may not be suitable for oral DLT insertion. The limited ID of the bronchial lumen of the DLT only allows use of a relatively small fiberoptic bronchoscope, and elastic oropharyngeal soft tissues, especially a large tongue, may prevent successful passage through the mouth. In conclusion, the Bonfils intubation fiberscope may be used with DLTs of 37 French or greater after appropriate tube shortening in patients with a difficult airway anatomy.
* University Hospital Schleswig-Holstein, Campus Kiel, Germany. bein@anaesthesie.uni-kiel.de
