To the Editor:—
Wire-reinforced endotracheal tubes (ETTs) are used in situations in which there is potential for kinking of the tube. 1Various complications have been described, one of which is permanent occlusion, which occurs when the tube is compressed between the teeth. 2,3We report a different but related type of complication.
A 4-yr-old girl was scheduled for tonsillectomy and adenoidectomy. General anesthesia was induced, and the trachea was intubated using a wire-reinforced 4-mm ID ETT (Bivona Inc., Gary, IN). A mouth gag with a grooved blade was positioned to protect the tube and permit surgical access. A clinically insignificant air leak was noted during the procedure. At the end of the surgery, the gag was removed, with no apparent change in the leak. As the patient emerged from anesthesia, the ETT was removed, but resistance was noted as a result of a partially closed jaw. However, only the proximal portion of the tube was retrieved, with a clean break noted, along with an unraveled reinforcing wire (fig. 1).
Signs of airway obstruction developed immediately, with stridor, retractions, and cyanosis. A laryngoscope was inserted, but the distal segment of the ETT could not be found in the oropharynx. Manual mask ventilation was started, with rapid improvement in oxygenation. Fluoroscopy showed that the distal ETT segment was just below the glottis. The level of the anesthetic was deepened, and the distal segment was extracted using endolaryngeal microsurgery forceps. There were no postoperative complications.
The cause of this event was not immediately evident. There was no evidence that the tube was compressed during surgery, and the minimal air leak makes it unlikely that the tube had been transected before removal was attempted. The most likely explanation was that the tube was lacerated soon after placement, perhaps between the mouth gag and the lower teeth. When traction was applied, the tube separated at the point of the initial cut.
To reproduce this event, we tested a new ETT of identical size and construction. A set of false teeth was placed on a firm surface, and the ETT was compressed between the lower teeth and the mouth gag. This did not result in persistent compression of the tube, but it did produce a laceration on the silicone coating of the tube. Manual traction applied to the lacerated tube resulted in relatively easy separation. The manufacturer of the ETT was informed of this event.
This report indicates that a wire-reinforced ETT can be cut during routine surgery. In such cases, separation of the tube at the point of the laceration can occur when force is used to remove the tube through partially closed teeth.