Yet another cause for difficult extubation of nasotracheal tube.

Sir

Nasotracheal intubation is the preferred technique in oral and maxillofacial surgery. Resistance to the removal of nasotracheal tubes has been reported due to physical impingement (mucosal oedema and clots), failure of deflating mechanism or surgical transfixation by stitches or Kirschner wire.[1234]

We encountered one such problem during extubation of a 6.0 mmID nasotracheal tube in a 25-year-old, 40 kg female patient who underwent anterior maxillary osteotomy for prognathism. The only significant intraoperative event was refixation of the tube once due to loosening of plaster. At the end of surgery, after thorough oral suctioning and throat pack removal, cuff of the tube was deflated and tracheal extubation attempted. The nasotracheal tube which was initially fixed at 24 cm could be pulled out up to 16 cm, beyond which resistance was encountered. Surgical transfixation of tube was ruled out. Intravenous fentanyl 50 μg was given and check laryngoscopy was done. The deflated cuff was seen between the vocal cords. Removal was attempted under vision but could not be done. However, the tube could easily be slid into the trachea without any resistance. Thus, mechanical obstruction distal to the nasopharynx was ruled out. Another gentle attempt to extubate was made, and this time we observed that as the tube was being pulled out, the pilot balloon with cuff-inflating channel was getting drawn into the nasal cavity. As the pilot bulb abutted against the nasal opening, resistance was encountered. Suspecting that the cuff-inflating channel could be winding around the posterior end of one of the turbinates, decision was made to cut the channel. Following this, the nasotracheal tube with a portion of inflating channel was removed, and the rest of the cuff-inflating channel with the pilot balloon could be removed separately without difficulty.

Tracheal tubes passed through the nasal cavity either take a lower pathway along the floor of the nose below the inferior turbinate or an upper pathway between the middle and the inferior turbinate.[56] Once the tube passes through one pathway, its migration to the other pathway is usually prevented by medial border of the inferior turbinate. The cuff-inflating channel can, however, migrate as it is smaller in diameter and is not attached to the endotracheal tube (ETT) along the entire length. This can happen if the attachment of the inflating channel to the ETT is extending beyond the posterior end of the turbinate. In a 6.0 mmID cuffed Portex tracheal tube, the cuff-inflating channel is 22 cm long and is attached to the tube at 15 cm [Figure 1a]. In the present case, the tracheal tube was fixed to skin at 24 cm mark which meant 9 cm of the cuff-inflating channel was present inside the nasal cavity free of the tracheal tube. A post-operative nasal endoscopy was done, and the distance between the vestibule and the posterior border of the inferior turbinate was measured to be 7 cm. Retrospectively, we analysed that if 9 cm of pilot tube was inside the nasal cavity, then 2 cm of the tube was free, behind the posterior border of the turbinate which could have looped around it during intraoperative head and neck movements by the surgeon [Figure 2a]. Figure 1a shows the point of attachment of cuff-inflating channels in 6.0 mmID Rusch, Portex and Rusch reinforced ETTs. The point of attachment is much more proximal in Portex when compared to Rusch tubes. In reinforced Rusch tubes, the cuff-inflating channel is attached along the full length of the tube. Smaller the diameter of the ETT, more proximal is the attachment of the cuff-inflating channel to the tracheal tube [Figure 1b]. Winding the cuff-inflating channel around the tracheal tube before nasal insertion can assure that the tracheal tube and cuff-inflating channel travel en masse and such a complication can easily be prevented [Figure 2b].

Figure 1

(a) The point of attachment of cuff-inflating channels in 6.0 mmID Rusch, Portex and Rusch reinforced endotracheal tubes. (b) In 6.0 mmID endotracheal tube, the attachment of cuff-inflating channel is more proximal than in 6.5 mmID tubes

Figure 2

(a) Diagrammatic representation of looping of cuff-inflating channel around the posterior border of the turbinate. (b) Winding the cuff-inflating channel around the tracheal tube ensures the movement occurs en masse

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