To the Editor:—

There is a significant risk of losing a proven difficult airway during nasal to orotracheal tube exchange. 1Various methods are described to achieve such conversions, 1–5but they are associated with technical disadvantages intrinsic to the method, lack of an optimal aid, procedural complications, and the stage at which the need for conversion arises. 3,6 

We successfully converted an oral endotracheal tube (ETT) to a nasal ETT in an 11-yr-old girl presenting for reconstruction of a postmandibulectomy defect secondary to osteogenic carcinoma. Airway assessment revealed agnathia, bucked incisors, a large tongue occupying the oral cavity, postradiotherapy contracture and scarring of the anterior neck, and a posttracheostomy scar. Neck mobility was adequate, and the nares were patent. The lateral view radiograph of the head and neck showed a large tongue base, an anteriorly placed larynx, and a noncompressed air column.

In view of the aforementioned findings, a flexible fiberoptic bronchoscope (FFB)–guided nasotracheal intubation was planned under sedation. Premedication included 150 mg ranitidine orally and intramuscular glycopyrrolate 1 h prior to the procedure. Informed consent was obtained from the parents after explaining the procedure. The child was moved to the operating room, and routine monitoring was applied. The nasopharynx was anesthetized with 10% lidocaine spray. Propofol, 1 mg/kg, was administered, and the FFB (FB-10X; Pentax, Tokyo, Japan) was introduced via  the right naris and advanced further while the child breathed 100% oxygen via  a nasal cannula placed in the left naris. The fiberscope repeatedly met the large tongue base, obstructing the view. Oral fibroscopy also failed to negotiate the base of the tongue on multiple attempts. By this time, the child had desaturated to an oxygen saturation of 90%. Flexible fiberoptic bronchoscopy was abandoned. Direct laryngoscopy (Miller blade #2) showed a Cormack and Lehane 7grade III cords view. A 5.5-mm uncuffed ETT was blindly placed into the trachea with the help of a stylet. One hundred percent oxygen was given, and saturation improved. As per the requirement of the procedure, oral to nasotracheal tube conversion was then performed. The FFB was advanced via  the right naris and retrieved orally. The proximal end of the existent oral ETT holding the connector was cut. The fiberscope was passed through the oral tube to just above the carina. The tube-FFB assembly was grasped with fingers inside the oral cavity, and the tip of the fiberscope was anteriorly flexed to prevent dislodgment. The fiberscope and the ETT were gradually withdrawn retrogradely through the nasal passage and out of the naris. The FFB was removed, bilateral air entry was reconfirmed, and the ETT was secured. The conversion took 80 s and was atraumatic and without any desaturation. Thereafter, anesthesia was maintained with 1–2% halothane and 66% nitrous oxide in oxygen.

The FFB may be a less than ideal device to gain airway control in certain difficult airway situations. 8Orally or nasally guided flexible fiberoptic bronchoscopy may fail to locate the glottis adequately in conditions in which the airway anatomy is distorted. 5,9,10Partial and complete airway obstruction add to the difficulty of fibroscopy, and certain maneuvers 11,12and intubation 13have proven effective in opening up the airway.

Our patient was a child with major airway abnormalities. This resulted in the following problems: (1) the maneuvers designed to aid oral and nasal flexible fiberoptic bronchoscopy were inapplicable, (2) we could not have kept the child awake before airway control, and (3) nasotracheal intubation was necessary. The former two presumably led to the failure of our FFB-aided intubation attempts. The last problem posed a significant challenge. We were able to convert the existing oral ETT to a nasotracheal tube with the help of the FFB, but the limitations of this method can be manifold, such as breakage of optical fibers, trauma, failure, and/or inadvertent extubation. An uncuffed polyvinyl chloride ETT is flexible enough to allow bending without transmitting tension to the FFB. The absence of jaw and tongue retraction led to minimal oral space in our patient, which significantly decreased the arc of negotiation of the FFB-ETT unit and consequently prevented damage to the optical fibers. Moreover, the possibility of accidental extubation was lessened, as the tube and the FFB were firmly grasped, the tip of the fiberscope was anteriorly flexed, and the pull of the FFB through nose was gentle. FFBs have been utilized previously to effect safer conversion of a nasal tube to an oral tube. 5,14Ours is probably the first case in which an oral to nasal ETT conversion was carried out with the help of a FFB. This case not only reiterates the few significant limitations of the FFB while gaining a difficult airway, but it also shows that deft handling of this delicate equipment may improve outcome.

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